TAN 11- FIRE PROTECTION MEASURES IN SCOTTISH HISTORIC BUILDINGS

Page 1


l

Preparation and use of Lime Mortars (revised 1995)

No.2

Conservation of Plastenvork (1994)

No3

Performance Standards for Timber Sash and Case Windows (1994)

No.4

Thatch & Thatching Techniques; A gr& to cotvmEnnngScorrisI~ tlmtching troditions (1996)

No5

The Hebridean Blackhouse: A glide to nmterinls, covrmt[ctionand tmintemnce (1996)

No.6

Earth Structuresand Construction in Scotland: A g[& to tlze Recojilition nnri Cot~ervatiot~ ofEnrt11TrcI11~01ogy in SconisI~BltiMings (1996)

No.7

Access to the Built Heritage: Advice on rlzeprovisioiz of mcessforpeople wit11disabilities to Izistoricsites opml to rite phlic (19961

No.8

Historic Scotland Guide to International Conservation Charters (1997)

No.9

Stonedeaningof Granite Buildings (1997)

No.10

Biological Growths on Sandstone Buildings: Connoland Treczhl~ent(1997)

No.11

Fire Protection Measures in Scottish Historic Buildings (1997)

Available from: Historic Scotland Technical Conservation,Research and Education Division Scottish Conservation Bureau Longmore House Salisbury Place EDINBURGH EH9 1SH Telephone 0131 668 8668 Fax Ol31668 8669


ADVICEON MEASURES REQUIRED T O MINIMISE THE LIKELIHOOD OF FIRE STARTING AND T O ALLEVIATE THE DESTRUCTIVE CONSEQUENCES OF FIRE IN HISTORIC BUILDINGS

by Allwinkle, Bell, Franklin, Hibbard, McQue, Marchant, Marshall, Newsom, Todd and Wren Printed by The House on behalf of Historic Scotland Published by Historic Scotland EDINBURGH 1997 @Crown Copyright ISBN 1 900168 41 3 Commissioned by

TECHNICAL CONSERVATION, RESEARCH AND EDUCATION DIVISION

.


Cover P i c t u l ~Dunbar . Parish Church, January 1987


Authors This document has been researched and written by the following team under an agreement between Historic Scotland and the University of Edinburgh. Professor Sam Allwinkle, Napier University, Edinburgh Dr Dorothy Bell, Department of Architecture, Edinburgh College of Art Peter Franklin, Consultant, Dunfermline Geoff Hibbard, Edinburgh Fire Consultants Jerry McQue, George Berry and Partners, Quantity Surveyors, Edinburgh Dr Eric Marchant, Edinburgh Fire Consultants Alan Marshall, Gray, Marshall & Associates, Architects, Edinburgh Stephen Newsom, Simpson & Brown, Architects, Edinburgh Colin Todd, C S Todd Associates, Surrey James Wren, Wren and Bell, Structural Engineers, Edinburgh

Editors Eric Marchant, Alan Marshall, Stephen Newsom

Acknowledgements :Discussion Forum Invaluable help and advice was given at stages throughout the project by members of a specially convened discussion forum who have reviewed, given guidance and in many cases contributed to the document. Mr Ingval Maxwell, Director, TCRE, Historic Scotland Mr Richard Emerson, Principal Inspector of Historic Buildings, Historic Scotland Mr Robin Kent, Senior Conservation Architect, TCRE, Historic Scotland Mr John Knight, Regional Architect, Properties in Care, Historic Scotland Mr Gregor Stark, Regional Architect, Properties in Care, Historic Scotland Mr A N Morrison, HM Chief Inspector of Fire Services, The Scottish Office Mr H C Hunter, I-IM Inspector of Fire Services, The Scottish Office Mr C G N Stewart, Senior Assistant Inspector of Fire Services, The Scottish Office Mr G D Goodall, Assistant Inspector of Fire Services, The Scottish Office Mr J A Carter, Principal Architect, Scottish Office, Construction and Building Control Group Mr Gerald Guy, Scottish Office Development Department Mr Stewart Kidd, Director, Fire Protection Association Mr W Jackson, Buildings Manager, National Library of Scotland Mr W N Sharp, National Trust for Scotland Mr Alistair Macintyre, Strathclyde Fire Brigade Mr H Adie, Strathclyde Fire Brigade Dr Robert Docherty, Director of Fire Safety, Strathclyde Fire Brigade Mr Desmond Hodges, Former Director, The Architectural Heritage Society of Scotland Mr Sean O'Reilly, Director, The Architectural Heritage Society of Scotland MS Susan Brown, The Architectural Heritage Society of Scotland MS Valerie Ferris, Fire Protection AssociationLoss Prevention Council Mr Charles Robertson, Institution of Fire Engineers


Acknowledgements The authors would also like to thank the following individuals for access to properties and the use of their material and illustrations within the Technical Advice Note: Case studies and other properties visited: Mrs Helen Bullick Sir Charles Ferguson, Bt. George Heriot's Trust Mr & Mrs J M Hunt Douglas Laird Major David Murray National Library of Scotland Scottish Historic Buildings Trust Scottish Record Office Material, photgraphs and illustrations: Robert Blair Press & Journal, (Aberdeen Journals Ltd) Edinburgh New Town Conservation Committee Stewart Guthrie, Edinburgh and George Heriot's Trust Historic Scotland National Portrait Gallery Scottish Record Office G B Geotechnics, Cambridge Authors

Cover, Plates 4,6, 14, 17 and 31 Plate 1 Figures 4 , 5 and 6 Plates 19.20 and 21 Plate 22 Plate 23 Plates 3, l 1 and 12 Plate 12 Remaining plates and figures.

The authors would also like to thank the many individuals and organisations, too numerous to mention, who have helped in many ways with access to properties and the provision of material and illustrations for the research stages of the project.


PREFACE

With one important Scottish historic building currently being lost each month to the effects of fire, it can readily be seen that this is one of the single greatest threats to the fabric and contents of historic buildings in the country. Each year brings a steady toll of buildings destroyed or badly damaged. Authentic fabric lost to fire is irreplaceable; no matter how good subsequent restoration may be, the original has been lost forever. It follows that the conservation and protection of our historic buildings must involve giving them the best possible protection from fire. This is not to ignore the safety of occupants, which remains of paramount importance, rather to ensure that fire protection measures look beyond the immediate requirements of life safety to encompass the protection of the building fabric and contents as well. Much can be done by good management to prevent fires from occurring in the first place. Beyond this, the installation of fire detection and protection systems may be required. There are many devices available, from simple smoke detectors to carefully engineered detection, alarm and suppression systems. However, in some instances, such technology demands a level of intervention in the fabric that is unacceptable in conservation terms. Measures taken to protect the fabric must not damage what they set out to protect. A balance needs to be established. This document is concerned, firstly, with setting out measures to identify and eliminate risk from fire by effective management and, secondly, with reviewing appropriate technologies, whilst examining the effect of their introduction into historic buildings. Fire protection measures may range from simple common sense to, in the most developed form, a fire engineering approach which seeks to bring a rational, analytical process to bear. At every level of its consideration a great deal of care is required in order to achieve a balanced outcome which makes the best use of available resources and is consistent with accepted conservation principles. This Technical Advice note is the eleventh in an occasional series of notes on practical and technical issues which can arise in safeguarding the nation's heritage. It intends to give guidance on the principles involved in the effective protection of historic buildings from the effects of fire. It is not intended as a prescriptive document nor as definitive specifications for provisions on site. Although primarily aimed at offering advice and information of use to Historic Scotland staff, it is intended to be of value to others who have to consider fire risk and protection measures for historic buildings. Throughout the compilation of this publication Historic Scotland has been indebted to the support it has received from all the members of the Discussion Forum

Ingval Maxwell Director Technical Conservation, Research and Education Division Historic Scotland, Edinburgh

September 1997


Technical Advice Note 11 FIRE PROTECTION MEASURES IN SCOTTISH HISTORIC BUILDINGS Contents

Page

Preamble Chapter 1

Fire Protection and Conservation

1

Part I Chapter 2 3 4 5

The Scope of the Technical Advice Note The Vulnerability of Historic Buildings to Fire How Fires Develop Fire Safety Management and Fire Precautions

5 9 15 21

Compartmentation Doors and Door Closers The Performance of Historic Building Materials in Fire Fire Detection Alarm, Escape, Lighting and Signs Fire Suppression Smoke and its Control Fire Engineering and Historic Buildings Footnote

29 39 45 53 59 63 69 73 79

Part I1 Chapter 6 7 8 9 10 ll 12 13 14

Appendices Appendix I

I1 I11 IV V V1 V11 V111

Case Studies - Moy House, Forres, Moray - Kilkerran House, Maybole, Ayrshire - Logie House, Fife - Dunbar Parish Church, East Lothian - Torsonce House, Stow, Roxburghshire Glossary of Terms Legislation Risk Assessment Methodology Planning for Damage Control Insurance Organisations Bibliography

81 83 85 87 89 91 95 99 105 109 113 117


PREAMBLE CHAPTER 1

FIRE PROTECTION AND CONSERVATION

1.1

Listed Buildings

1.1.1 Today, the importance of maintaining the quality of our surroundings is probably more to the forefront of public consciousness than it has ever been before. In particular, the work that previous generations have left to us is recognised as one of the more valuable parts of the environment, of enormous benefit to society, and buildings that were once neglected are now appreciated and enjoyed. The best of these appear on the statutory "list". 1.1.2 By definition, all "listed" buildings have a special value to society. Scheduled monuments and "A" listed buildings - whether castle or croft are of national or international importance, either architectural or historic, or fine, little-altered examples of some particular period, style or building type. "B" listed buildings are of regional or more than local importance, or represent major examples of some period, style or building type which may have been somewhat altered. "C" listed are of local importance. All,to whatever degree, have this importance not because of their financial value or usefulness, but because of what they are in themselves. Their age, their history and their appearance, the quality of materials and craftsmanship, all combine to make the fabric itself irreplaceable, a non-renewable resource. No-one, however skilled, can repeat the work of another age and no copy, however costly, can compensate for the loss of a genuine part of our heritage. 1.1.3 Because of the special value that "listed" buildings have, not just to their current owner but to society at large, they not only need as much protection as we can give them - especially from the risk of fire, but the protective work itself needs to be carried out in an exceptionally careful way. It is this extra degree of care that makes the "conservation" approach to good standard practice different from the norm. 1.1.4 In most of their work, architects and fire consultants will try to achieve a balance between the simplest, most effective means of minimising the risks of fire and the effect of these means on the building's usefulness, its earning capacity and its basic financial value as real estate - the factors of most concern to its owner. It hardly needs stating that all decisions will automatically be made with these factors in mind, for it is obvious that no client would readily approve work that, for example, significantly decreased their property's usefulness if a less intrusive solution could be found. Normally, the designer looks not just for the safest, most direct method but


Chapter 1 for the safest, most direct method within these practical constraints and within the client's budget.

1.2

Conservation Approach

1.2.1 In a "listed building", exactly the same criteria have to be met as in normal practice but only in a way that causes minimal or no damage to whatever gives the building its special quality. Because the building's value to society rests just as much on the history it embodies as on its more immediately practical advantages (and in buildings of national or international importance this may far outweigh any other consideration), the standard framework for decision-making needs adjusting; rather than accommodating fire prevention and protection methods to the building's usefulness or economic value, the design takes the preservation of the existing fabric and aesthetic as its primary constraint. This "conservation" approach could almost be described as a brief within a brief; exactly the same aim - the protection of life and property - achieved by exactly the same method but with different constraints for decision-making. In effect, the normal design process is given an unaccustomed focus by the overlying need to conserve and protect the interests of posterity. 1.2.2 With new priorities, some solutions, impractical in other circumstances, now might be not only practical but preferable. Since usefulness, for example, may not be the primary criterion as it is with most buildings, it may be possible to restrict use (or even withdraw an area from use in the most extreme case) if that is the only way to avoid a conflict between potential risk to life and the retention of irreplaceable materials (as is done with fragile documents or paintings). The reverse is also true; what would be an obvious, practical solution in normal circumstances may be too noticeable or cause too much damage to the fabric to be acceptable, and other means will have to be found. In each case, the problem needs to be considered from first principles with the criterion of "value" in mind, and lateral thinking comes into its own. 1.2.3 Perhaps the greatest mental hurdle in accepting the "conservation" approach is the emphasis placed on saving what may seem an ordinary or even worthless part of the fabric. It is easy to appreciate the quality of an intricately moulded seventeenth-century plaster ceiling or an Adam fireplace, but the value of a lime-washed wall, a joist, or the particular thickness of a window astragal is far less obvious. Their importance lies not in their instant visual appeal or even, necessarily, their age, but in their contribution to the value of the whole - a perhaps small but very important part of the building's authenticity as a piece of architecture. Firstly, architecture is much more than an attractive scene-set, it has depth, strength and age, and every original detail, texture, proportion and space is essential to and inextricable from the quality and integrity of the design. Secondly, these less noticeable parts also have a value in themselves. Just as archaeologists now learn as much if not more from the "debris" of longgone civilisations as from any buried treasure, so the less "attractive" parts


Fire Protection and Conservation of buildings have much to tell our own and future generations. The value of the architectural past comes not only from the painting, gilding and carving on show in the state rooms of the rich and powerful but from the unobtrusive signs of everyday labour, for example, the cutting and jointing of timber, the pointing of stone, and the very careful positioning of vents and openings.

1.3

Minimal Intervention

1.3.1 Minimal intervention has become one of the basic components of good conservation - the less original material is lost, the less potential there is for damage to the building's cultural significance. Past experience shows that decisions made on the basis of one generation's taste and knowledge are usually bitterly regretted by its successors. In all, the conservation approach is simple: only change that is absolutely essential for the building's own good is acceptable; any change should be designed to have the least possible effect on the fabric's structure and appearance; if possible, it should be reversible; it should be discernible to close inspection; and, above all, it should only be carried out after all other options have been exhausted. Much of what is appropriate to good "conservation" practice is just as useful to good normal practice and many of the lessons to be learnt in the course of meeting the design challenge of protecting "listed" buildings will be eventually of great advantage to the whole of the building industry.


PART 1 CHAPTER 2

THE SCOPE OF THE TECHNICAL ADVICE NOTE 2.1

Introduction

2.1.1 "Fire is the single greatest threat to the fabric and contents of any building. In the case of an historic building, the loss of authentic fabric in a fire is irretrievable. Much can and should be done to minimise the likelihood of fire starting by the early elimination of major risks and the management of those risks which cannot be eliminated, and to alleviate the destructive consequences of fire" (Draft British Standards Institute (BSI) Guide to the Principles of Building Conservation). 2.1.2 The preamble sets out a conservation viewpoint. To give a building and its contents the best level of protection from fire may require a level of intervention in the fabric which is unacceptable in conservation terms. At the same time, the loss of the building from fire is unacceptable and therein lies a central dilemma for those who have to make recommendations or decisions regarding fire safety. The best form of protection is to prevent fire happening in the first place, therefore every effort should be made in terms of training, management and the removal of risk. Many practical common-sense fire precaution measures can be implemented at no significant cost. Beyond that, systems of detection, alarm and suppression require to be considered for each building individually, taking into account the special risks presented and the particular qualities of its construction and contents. 2.1.3 Any proposed alterations to a listed building, however apparently minor, may affect its character as a building of special. architectural or historic interest. Under section l(4) of the Planning (Listed Buildings and Conservation Areas) (Scotland) Act 1997 it will be a requirement to obtain listed building consent for objects or structures which are to be fixed to a listed building.

2.2

Life Safety

2.2.1 The primary consideration of much legislation and all those who are concerned with fire safety is the preservation of life. The authors and Historic Scotland wish to make it quite clear that this remains of first importance. It is beyond the scope of this Technical Advice Note to deal with this aspect of fire safety, and references to life safety within the document are generally confined to commentary or advice on how the physical requirements of this subject impinge upon the fabric of historic buildings.


Chapter 2

2.2.2 It is because of the concentration of legislation on life safety that it is necessary to provide additional advice and guidance on the preservation of the fabric and contents of historic buildings. All too often building owners derive a sense of security from an expensively installed fire detection and alarm system only to find that the property itself is not adequately protected. 2.3

Management

2.3.1 Effective fire precaution measures start with good housekeeping, proper training and the management of the many and varied considerations from risk assessment to the choice of systems or to disaster planning. Part I of the Technical Advice Note attempts to look at the particular features of historic buildings which may make them more vulnerable to fire, the process of fire itself and the need to exercise the proper management of fire protection. A Fire Risk Assessment should be carried out at the earliest opportunity prior to any fire protection measures being implemented. 2.4

Technical Aspects

2.4.1 Part I1 of the Technical Advice Note sets out various technical aspects of fire protection. Many of these topics have generated considerable research and documentation which it is impossible to cover in detail, therefore the main purpose of each section is to give a broad view of the available technology and methodology. Because the range of these technical applications is so large, it is important to understand that not only does this give a great degree of choice, but also that in many cases different components of fire protection planning can be balanced against each other to allow the best choices to be made for the particular building being considered. Each building must be assessed individually.

2.4.2 The single general conclusion of the Technical Advice Note is to suggest that the application of Fire Engineering principles enables a rational approach to the balancing of the different components. This may range from a very simple level to a highly complex study, and can be carried out by an individual or by a group possessing a variety of skills. The more complex the task the more informed and widely skilled will be the study group that is required to achieve the correct balance between fire engineering and conservation needs. 2.5

Post-Fire Recovery

2.5.1 It is outwith the scope of this document to deal with post-fire recovery. Fire action plans, which aim to limit damage in the event of fire, are, however, an essential consideration for all buildings. Further information may be found by reference to Appendix V. It is essential to


The Scope of the Technical Advice Note ensure a plan is in force to enable all those involved in the aftermath of a fire to take immediate steps which will include the following: appraise the stability of the remaining structure, and carry out emergency propping, make provision for drying out the structure and contents following saturation by water from fire fighting, protect or salvage all items of value, including building materials, protect the building from further damage by weather, attack by dry rot, vandalism or neglect, make records of remaining and fire damaged material. 2.6

Case Studies

2.6.1 Throughout the Technical Advice Note reference is made to a number of specific examples of historic buildings where recent fires had occurred and which were visited by the authors. These have been included as case studies in Appendix I. These examples allow parts of the document to be illustrated with real and practically based experience. The authors are grateful to those owners who kindly gave permission for details of the fires to be recorded.

2.7

Limitation

With each historic building, there will come a point when the application of greater degrees of fire protection technology will require unacceptable intervention. Risk may remain. Judgement is required, together with expert advice. However, those looking after historic buildings on a day to day basis must be able to understand the processes and the choices available and it is hoped that this Technical Advice Note will go some way towards that end. 2.7.1


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FRIDAY AUGUST I8 1995

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10 flee blaze as Moy mansion is ravaged Irreplacable loss as historic Moray home is left 'ready to fold' Plate 1 : Extract from the front page of the Press and Journal, 18lhAugust 1995.

>moKe sull

'rom MOY nouse, near t o m s . aner rzre tore tnrougn me DullOlng nna iert a mall or o

by L l s a Gra

A HISTORIC Moray mansion house which was destroyed in an overnight blare wa.. described as an irreplaceable piece o f history yesterday. The 10 residents o l Moy House. near Foms. narrowly escaped after being alerted by neighboun as the fire took hold early I n the morning. The A-listed. 18th century house. designed by architect John Adam. has been kli standing like a house of cards. ready to fold in on itself at any time, a fire officer said yesterday. Alexander Murray. son of Moy House owner Major David M u r n y (76). had to leap from a window to safety after being beaten hack by flames at his bedroom door. M r Murray (32) said the actions of his neighbours. Peter and Brenda Vidler. had saved h16 life

"If I hadn't heard MIX Vidler blaring her car horn I would have still been asleep and pmbably died." he said. "I can't thank them enough for saving my life. I was absolutely horrified to open my door and see this wall of flames. l was beaten back h y the heat and realised l had to get out and quick. "The window was the only option". Hic young daughter. Emrna. who also escaped from the house. saw all the presents she had received for her seventh birthday. hours before. go up in flamef. T h e blaze started in a disused workshop in a wing o f the 32- room listed mansion. It quickly tore through the roofspace of the main structure. destroying the building. More than 70 firefighters from throughout the district fought for four houa to bring the blaze under control having to take water from a srrratn

half-a-mile away to douse the flames. Tey were still damp~ng down the huilding last night and lrymg to ensure the shell o f the house was safe. Grampian Fi Brigade area divibional officer Andy Coueslant said: "All the inside stmcture has been destroyed. There are no supports left at all. "It is really just a hnxed shell which could fold in on itself at any minute. We are also very cconcemd about the towering chimney stacks which could topple." He also praised M r and Mrc Vidler who after hearing the smoke a l m s in Moy house had sprung into action and ensured no lives were lost. M r Vidler said he had been spurred on by complete panic. "At first I thought the alarm noise was coming from our car. But when we looked out the window we could see the house was alight." he said.

non. motograpn: ateve a a n

"Brenda jum I the car and sounded the horn to wake folk up and l lan around shouting at the windows." Robbie Robertson, chief planning assistant with Moray District Council, visited the site yesterday and explained the historical importance at Moy House. "The main p m of the building was designed by architect John Adam, which is why the building received its category A listing in 1989." he said. "The bricklayer was Colin Williamsan - the man who went on to help build the White House. the US presidential home i n Washington. "Some o f the side wings date back to the 1600's. There's no doubt it was o f great historical importance to this area. "As things look at the moment lwould say there is little chanceof a rebuild. This has been a crag. loss o f an imeplaceable piece of history."

Major Murray bou the house m 1945 with money from his war pension . His two sons. Alexander and William. were born there. Pan of the house was subdivided into flats where four male tenants lived. Maj Murray said he was numb from the shock o f seeing all his worldly possessions go up in flames. "Everything we own has just gone up in smoke before my eyes. Even the clothes I'm wearing have had to be loaned to me. "Idon't h o w what is gohg to happen now. We have lost everything even my hearing aid is somewhere in the wreckage. "Ithink the records on the house were inside too."


CHAPTER 3

THE VULNERABILITY OF HISTORIC BUILDINGS TO FIRE

3.1

Introduction

3.1.1 The periodic reporting of another fire leading to the damage or loss of an historic building is an unwelcome reminder of the vulnerability of such buildings (see Plate 1). During the course of preparation of this Technical Advice Note, a number of fires occurred reinforcing this view and underlining the fact that what is lost is irreplaceable. 3.1.2 Research into these fires and other previous examples has shown that once started, fires often spread quickly, becoming out of control and causing severe damage. Constructional features of the buildings studied have contributed to the spread of fire, often in unexpected ways, leading to the view that historic buildings can be particularly vulnerable to fire.

3.2

Building Types

3.2.1 Historic buildings include almost every building type, from crofts to palaces, warehouses to libraries, lighthouses to railway stations, chapels to cathedrals. They can be quite ancient, or may date from this century or anywhere between; the range is enormous with immense differences in scale, complexity and construction. It follows that their vulnerability to fire also varies considerably and a central theme of this Technical Advice Note is that each building is unique and may be vulnerable in its own distinct manner requiring individual assessment and, if necessary, precautionary measures. Plate 2: Some historic buildings may be particularly vulnerable because of their size and layout - with extensive interlinked spaces, combustible linings and furnishings and few effective fire barriers. Hopetoun House, West Lothian, 1723, (William Adam) illustrates the scale and complexity of a large country house (RCAHMS).


Chapter 3

3.2.2 The use and occupancy of historic buildings may also produce special circumstances. Large numbers of visitors, coupled with historic furnishings and decoration present one type of risk while the very remoteness and lack of occupancy of some buildings creates another, because of the time taken to raise the alarm and for the fire brigade to arrive at the building. The vulnerability of an historic school or church is very different during the periods of intense use compared with the, often, longer periods when the building may be empty and unvisited. 3.2.3 Construction techniques employed in historic buildings, can also create particular areas of risk. To some extent fire resistance is helped by the limitations of historic materials, which often dictated small spans and a tendency to cellularity in the form of thick stone walls at frequent intervals. However, the widespread use of timber floor construction, plaster finished on timber laths, and the frequent building-in of timber elements works against this. The presence of openings, flues and other voids also decreases fire resistance and may create paths for fire to spread. The need for individual appraisal of the building under consideration is paramount in thls respect. Stone vaulting, heather thatch or exposed early 20th century steel may each present obviously different circumstances and types of risk, but in most cases careful research is required to understand the construction and the connection of voids in often quite complex buildings. Plate 3: Large open volumes exist in many historic churches and public buildings, often roofed over with complex timber construction to create vaulted ceilings or domes. Roof voids may be large and can interlink with few or only partial fire divisions. General Register House, Edinburgh, 1774-90 (Robert Adam) The original drawing demonstrates substantial masonry vaulting in the wall and floor construction and a complex timber roof and dome.

3.3

Elements of Construction Walls

3.3. I Thick stone walls may give a sense of security, but in many buildings their integrity in fire is weakened by numerous flues and other


The Vulnerability of Historic Buildings to Fire voids. &er time "fe~lthm"forming the sub-division k m w n flues m y have k o m e damaged, mrtar may have loosened, m h o k ~ may have bmn created for services. Tagether with the common method of strapping d lining external walls to a t a t e a cantbumus air gap hehind, an$ the vorids khind windaw shutters or w a d door frames set into nwanry walls, these space:e may link throughout a building in u m a p w M way&.

3.3.2 ndlsonry comtru~tionmay be vuhrabk in several di&rent ways. For example, the tall ashlar W& of a gothic church or a &dy w u r M gmchecked Georgian stone st&cme, while n ~int themIves manbustible, m y fjeiactwt and fail during the oppXic~ti(rnof i n t e e b a t , or more dr~ti-cally when cooled quickly by water Eram fire b s . Plate 4: Dunbar Parish Church, East Lothian, The devastating fire that occurred in 1987 destroyed the interior and the roof. The stonework was badlq damaged - spalling and loss of thickness affected the columns and arches and large areas of tracery were destroyed.

Roofs 3.3.3 Roofs in historic buildings, frequently constructed of timber structural elements and timber sarking are not only vulnerable because of the combustibility of these materials. They must also be assessed in terms of the presence of rubbish and other combustible material which may have accumulated within roof voids over time. The size of the roof void itself is another consideration. A number of roof fires in churches, for example, have spread quickly through large voids, leading to total loss.

Floors

3.3.4 Floor construction in historic buildings presents a special area of vulnerability. A small number of buildings may have stone or brick vaulted floors with excellent fire resistance, but the most common constructions rely on timber joists or a system of heavy timber beams with lighter intermediate joists. Early forms of construction may then have only the floor boarding itself over the joists (sometimes with the underside painted)


Chapter 3 giving little fire resistance. Later buildings with ash deafening and plaster ceilings (on timber laths) will perform better, particularly if the plaster is sufficiently thick and sound, but may be vulnerable to fire spread through the ceiling voids or gaps at the perimeter. The fires at Moy and Kilkerran demonstrated the ease with which fire spread through such voids. Timbers are usually built into walls and it is not uncommon for timbers to be built into masonry containing flues or into walls under hearths. Plate 5 : Kilkcrran House, Ayrshire. A fire started with a spark from an open fire. After smouldering for some time. fire developed in the floor coverings. furniture and flooring in the middle of the room. It spread horizontally through the void between the floor and ceiling below, reaching the perimeter of the room, and then vertically through the spaces behind the lath and plaster and window panelling.

3.4

Changes in Construction over time

3.4.1 Many historic buildings have grown and been adapted over several generations and the re-use of some buildings for new purposes has greatly changed their vulnerability. Sometimes this is beneficial in fire risk terms, for example, the decline in use of open fires. In other cases the careless introduction of new services, or use of inappropriate materials or details may increase risk, both through the creation of routes for fire spread and an increase in possible sources of ignition, for example the increased use of electrical appliances.


The Vulnerability of Historic Buildings to Fire 3.5

Materials

3.5.1 Masonry and timber are mentioned above in the context of constructional systems, but they also require special consideration as significant materials. Fire damage to masonry, particularly to fine carving or tracery, is usually irreversible, while for timber detailing it is catastrophic. Although a number of treatments exist to improve the fire resistance of timber elements, these may produce major, often unacceptable changes in appearance and chemical composition. Where the surfaces are of historic importance, for example decoratively painted timber ceilings, these treatments are unlikely to be appropriate. 3.5.2 Traditional plaster, while theoretically giving a good level of fire resistance, is usually reliant on its backing and when on timber laths its condition will vary enormously. A good bond cannot be guaranteed. Performance in fire may be unpredictable and at a certain stage in a fire (as at Kilkerran House) complete failure may occur. 3.5.3 Surface treatments and decoration in historic buildings require careful consideration. They are extremely vulnerable to damage from fire and smoke and also from the fire suppression media, such as water or foam. They also serve as a "fuel source". The combustibility of materials such as wallpapers and fabrics may be obvious, but the accumulation of years of paint can also create risk by feeding fires and giving off thick smoke and toxic fumes.

3.6

Aged Construction

3.6.1 The age and condition of historic construction may present particular concerns in addition to those set out above. Some examples include: drying and shrinkage of timber. For example, split panels, warped or poorly fitting joinery will seriously reduce the fire performance of a door. water penetration may weaken mortar, rot timber fixings (such as dooks to wall linings) or lead to loss of bonding between plaster and laths, all of which affect fire performance. 3.6.2 Frequently it is the very age and character of such elements that enhances the value of the building, and careful assessment is required to balance the need to protect and conserve the original construction against the desire to protect from loss or damage by fire. 3.7

Causes of Fire

3.7.1 Historic buildings may be particularly vulnerable to fire in numerous ways, however the following represent some of the more common causes:


Chapter 3 electrical faults are the most common source of fire and are considered to be a major fire hazard. In many buildings the wiring itself may be of considerable age and where insulated with vulcanised India rubber (VIR) deterioration over time leads to the hardening and cracking of the rubber. Alterations over a period of years, or circuits becoming overloaded by the connection of too many appliances can lead to installations becoming unsafe. Faulty appliances can be a source of fire. Electrical appliances require regular checking and maintenance. building or maintenance work - several major fires have been caused by the careless application of heat. Leadwork to roofs, plumbing and paint stripping present particular risks. Hot work should be avoided or strictly controlled and monitored.

-

vandalism and malicious damage wilful fire raising has claimed many buildings, both in cities and at remote locations. open fires, stoves, grates and hearths are a serious risk. Many fires have started with a spark from a fire or because of a cracked hearth. defective flues - chimney fires are common and fire can spread to other parts of the building due to cracked or faulty flues or where timber joists project into the flueway. Bird's nests in flues have also resulted in fires. accidents include everything from carelessly dropped cigarette ends and matches to cooking fires or the careless use of portable heaters. lightning strikes have started a number of fires. miscellaneous - a number of known fires have occurred for reasons including: candles or spotlights close to flammable material, rodents gnawing through cables, and mirrors or glass focusing sunlight onto flammable material. Plate 6: Dunbar Parish, Church, East Lothian. However fires are started, the effects of unchecked fire growth are catastrophic. Even the prompt arrival of the fire brigade may be too late to save much of the fabric. The interior was totally destroyed in the fire of 1987.


CHAPTER 4

HOW FIRES DEVELOP

4.1

How Fires Start

4.1.1 In an historic building, as in any other, the three essential ingredients necessary for a fire to start are (i) a source of ignition (ii) presence of a fuel and (iii) a supply of air. A careful survey of the potential for fire to occur is essential to an assessment of the likely fire and smoke spread. (See Appendix IV for guidance on assessing risks). 4.2

Sources of Ignition

4.2.1 A source of ignition must generate sufficient heat to degrade a solid material or raise the temperature of a combustible gas to its ignition temperature. The degradation of solid combustible materials leads to the generation of combustible, volatile gases which can be ignited. The range of potential sources of ignition is very wide (as described in 3.6 above). All are associated with some form of heat applied to a combustible material. Some materials, alone or in combination (such as polishes) are prone to self heating in some environments and could cause "spontaneous combustion".

4.3

Fuels

4.3.1 Materials which may be ignited first need special attention. These may include stored materials such as paint, firewood or petrol. Curtains, loose covers, carpets and upholstery within rooms could be directly attacked by an ignition source. Generally, elements of the construction of a building will be affected by fire after the loose contents have been ignited. The exception being when ignition occurs within the construction of a building, such as when an electrical fault occurs behind timber framed or lined walls or floors. Waste materials, such as wood shavings, or litter within roof spaces or cavities represent another type of fuel which can be readily ignited. The storage of combustible waste is a common hazard. Corrugated cardboard boxes, if allowed to accumulate, are a particular danger. In considering the risk of fire, it is often possible to take simple steps to ensure these fuels are removed.

4.3.2 The ease with which a combustible material will ignite depends on the surface area which is available to the source of ignition and the potential for volatile combustible gases to be driven from the material by the application of heat. The burning characteristics of a fuel will depend on the material. The major source of fuel in historic buildings is wood and the rate at which it burns will depend on its size, moisture content and density. Certain types of paint will melt, ignite and burn quite readily.


Chapter 4

4.4

Air

4.4.1 Fires need an ample supply of air for the continued propagation of burning. Without air the fire may self-extinguish, especially where the transfer of heat is a slow process (eg wool carpets). The duration of burning depends on the amount of air available, so a smouldering fire could continue to burn for several days. If an excess of air is available (once windows in a room have broken for example) then fuel will burn vigorously, producing high temperatures. The duration of such a fire will be short but the severity of damage caused will be much greater. Plate 7: At Kilkerran House, Ayrshire, a serious fire gutted one wing of the house. It is thought to have started by a spark from an open fire setting fire to the carpet, furniture and floor boards. Fire then spread through the void between the floor and the ceiling below. This is a view from the room below the seat of the fire. Because this void connected with others within the building there was also a plentihl supply of air (see 4.4)

4.5

The Products of Combustion

4.5.1 The first product of combustion is heat. Heat transfers by convection, radiation and conduction. The ease with which heat can be transmitted to combustible and non-combustible elements within a space containing a fire will influence the rate at which fire will spread within and beyond that space.

4.5.2 Depending on the amount of air available the amount of smoke produced will vary. A freely burning material is more likely to produce gases of a higher temperature. Predicting smoke yield is made more difficult as fires alter in characteristics throughout their duration. Smoke contains irritants and toxic gases, such as carbon monoxide, and some materials yield gases which could be lethal in even small amounts. The acidic nature of such smoke will also effect the ease with which it can be cleaned from smoke-affected building fabric or contents, or the extent of damage to these surfaces.


How Fires Develop Plate 8: Logie House, Dunfermline, the stair well following reinstatement. Although the fire was contained within one room, the nature of the smoke, including that from a foam filled sofa, caused extensive damage throughout the house. Plasterwork and other finishes required extensive cleaning and redecoration at considerable cost.

4.5.3 The presence of flame indicates a volume of particles at high temperatures. Flames vary widely in temperature (500-1000째C). A small flame is a simple phenomena, but if the flame fills the space enclosing the fire then a complex and destructive condition exists in which the contents and fabric of the space will readily ignite when touched by the flame.

4.6

The Development of Fire

4.6.1 The development of a fire from its ignition to its greatest intensity is a complex topic requiring detailed explanations which are beyond the scope of this document. The following aspects should be considered when appraising the likely risk of fires occurring. 4.6.2 The location of the source of ignition and early fire development may affect the eventual spread of fire. In historic buildings, existing test data on flame characteristics may be inappropriate, due to the effects of age and of historic surface treatments. Some surfaces, such as layers of paint, waxes and polishes, have low resistances and will promote rapid fire spread. 4.6.3 As a fire continues to grow, a stage may be reached when all of the combustible surfaces in a room are producing volatile gases at the same time. If these gases ignite then the whole volume of a room can be filled with flame. This condition is termed "flashover", and it is at this stage when the fire is likely to find the gaps and holes through which it may spread into other spaces.


Chapter 4

Fig. 1: Diagram of the stages of fire development and the Effects of Uninterrupted Fire Development.

E

STAGE EVENTS

IGNITION of an item, smoke and toxic gases.

i Item burns, hot

Fire burns at full intensity. Temperatures>1000"C.

! gaseslsmoke

j accumulate.

: Temperature

j

decreases.

: Another item ignites, : dense smoke and hot : gases. I Fire grows to

i FLASHOVER. Smoke, : flames and high j temperatures. EFFECTS ON PEOPLE

Atmosphere polluted.

,! a

Atmosphere unpleasant

!

Intolerable

! Atmosphere lethal.

i

t t

Lethal EFFECTS ON FABRIC

None.

i Fabrics smoke tainted. :

Finishes destroyed,

j Contents, fabric and

Gaps in construction

! Surface heating.

: finishes smoke j blackened.

: Paint bubbles.

! structural timber burns.

j

! attacked and exploited.

i

: Structure stands if : fire resisted. j :

i

Structural timbers weaken and fail on limit of fire ; I resistance. Supported : j masonry collapses. j

:


How Fires Develop 4.7

Fire Spread between Rooms

4.7.1 Once any of the products of combustion touch the surfaces of a room, there is a danger that fire will spread out of the space. The flow of warm air, hot gases, smoke and flame through any weakness or opening in the boundaries of the space will spread the fire to further sources of fuel. The intervention of adjacent spaces formed of non-combustible materials will delay the spread of flame but not the spread of gases and smoke. Plate 9: Kilkerran House. The fire spread between rooms, often through gaps or voids in the construction, such as the cavities within the timber stud walls. Smoke and fire damage spread well beyond the immediate destruction at the seat of the fire.

Chapter 6 deals in more detail with the possible routes for fire spread, in general these include the following:-

4.7.2

open doors. closed but ill-fitting or slender doors. thin walls, for example at fireplaces or chimney flues. degraded walls, due to the presence of openings formed in them. ventilation or heating service routes. discontinuity of structural separation in the original construction, for example hidden pathways behind wall strapping and voids in floors and ceilings.


Chapter 4 discontinuity of structural separation due to later alterations in original construction, for example where chases have been made for services, or structural alterations.

4.8

Fully Developed Fire and the Aftermath

4.8.1 If the constructional boundary to a space on fire has few holes then little air can be drawn into it. When all the available air has been consumed by the fire, then burning will cease but the burning material will not cool. The re-introduction of air at this stage is potentially very dangerous as it would allow a very fast fire to develop. .4.8.2 Once the fire has burnt itself out, cooling will slowly occur. At this stage the stability of many historic building structures may be placed at risk due to the strains set up in the cooling materials (for example, stonework or cast iron may fracture). It has also been known for fires to re-start after smouldering, sometimes days afterwards. A thorough post-fire check is essential. Plate 10: At Moy House, the fire reduced the house almost to a shell. The central staircase shows the extent of damage. Towards the top right of the picture the remains of the stone pen-checked stair treads can be seen protruding from the wall. These may have fractured and collapsed due to the heat, water from fire fighting hoses causing rapid cooling, falling debris or perhaps a combination of all these.


CHAPTER 5

FIRE SAFETY MANAGEMENT AND FIRE PRECAUTIONS

5.1

Introduction

5.1.1 Fire safety management can be considered as the planning, organisation, control, monitoring and review of measures taken to safeguard the occupants, the structure and the contents of a building from the effects of fire. 5.1.2 Many historic buildings are subject to regular inspection by the fire authorities and the application of quite stringent fire precautions which may lull owners into believing they have adequate measures in place. Most legislation is concerned with life safety and often the precautions required will not extend to measures designed to protect the fabric or contents. Other historic buildings are in domestic use and may not have any form of fire precautions at all. The examples given throughout this document show the vulnerability of these buildings and the consequences of fire. 5.1.3 Nevertheless measures introduced to safeguard lives, such as compartmentation or division, will often be of some incidental benefit in protecting the structure. Fire detection and alarm systems are primarily concerned with giving early warning to ensure the rapid evacuation of buildings but modern, addressable systems are also capable of identifying the location of the fire as an aid to fire fighting. 5.1.4 Those responsible for historic buildings and the professionals involved in survey, repair, maintenance and other work should look beyond life safety and actively consider the safety of the.fabric and contents, by carrying out risk assessments, and making fire plans for the building. Recommendations in the draft British Standard Guide to the Principles of Building Conservation include precautions against fire as a fundamental part of a systematic approach to preventative conservation.

5.2 The need for a systematic approach to preventative conservation 5.2.1 Systematic care, based on good maintenance and housekeeping, both saves money and is fundamental to good conservation. Maintenance and housekeeping routines should be planned with a view to the prevention of deterioration, to the early identification of defects and to the avoidance of consequential damage. For significant buildings in institutional ownership or care, such a routine should be based on a conservation manual, a log book and a regular cycle of professional inspections leading, where necessary, to repairs. In simple form, a systematic approach to conservation and care is applicable to all buildings, however modest. The


Chapter 5 provision and updating of precautions against fire and other disasters aimed at prevention and damage limitation, and of appropriate insurance cover, should form part of this routine.

5.3

-

Developing a Strategy Understanding the Process of Fire

5.3.1 In Chapter 4, the ignition, growth and development of a fire were explained and shown in diagrammatic form. Intervention at different stages will hopefully prevent or limit this destructive course of events. The best intervention in the process is, of course, before the fire starts in the first place by effective fire prevention and management. A fire precaution strategy should be developed based on a methodical approach to assessing risks and implementing fire precaution measures. At every stage of the process there are several elements, or 'components' which can be balanced against each other to provide the best combination of training, prevention, detection, alarm and suppression for the particular building. The diagram opposite examines the relationship of these components to the development of a fire. 5.3.2 The strategy can range from the application of common sense to, at its most developed, a fire engineering approach. Expert advice is advisable in most situations. 5.4

Developing a Fire Safety Policy

5.4.1 Several organisations responsible for significant numbers of historic buildings have developed fire safety policies or recommend strategies which have shared aims and often common means of achieving these. They include:English Heritage - Model Fire Safety Manual 1996

Fire Protection Association - Heritage Under Fire 1995 Appendix I1 of the Council of Europe Recommendations on the Protection of Architectural Heritage against Natural Disasters

Department of National Heritage

-

Fire Protection Measures for the

Royal Palaces 1993. (Bailey Report) 5.4.2 In addition to the above the National Trust for Scotland have, for their own use, developed detailed emergency procedures which take into account many factors including the, often remote, location of their properties. The BSI Guide to the Principles of Building Conservation, currently in draft form (see 5.1.4), also contains summary recommendations on fire protection measures. 5.4.3 The essentials of the measures proposed in, and generally common to, all these organisations are set out under the headings on the following pages.


Fire Safety Management and Fire Precautions Fig. 2: Activities in the Duration of a Fire.


Chapter 5 5.5

Fire Safety Policy

5.5.1 Those responsible for historic premises should have a written Fire Safety Policy. Whether put into effect through committees or by individuals, there should be management mechanisms to ensure that the policy is properly implemented and regularly monitored. The fire safety policy should have regard to the normal activities at the location and also any special or occasional events. 5.5.2 Each property should have appointed a Fire Safety Manager with responsibility for implementing the fire safety policy. This is not necessarily a full time position dealing with fire safety but could be, for example, one person at a senior level having personal responsibility for fire safety matters. In some cases, particularly larger properties, Fire Safety Managers should be assisted by trained full time Fire Officers.

5.6

Fire Safety Manual

5.6.1 Each property should have a Fire Safety Manual setting out its strategy and detailing its plans in case of fire (see National Trust for Scotland, "Emergency Procedures", and English Heritage, "Model Fire Safety Manual"). A Log Book should also be maintained recording all fire related activities and events, such as drills, training, inspections, equipment maintenance and tests, incidents and other relevant matters.

5.7

Fire Risk Assessment

5.7.1 A Fire Risk Assessment should be carried out for each property. This may require a professional survey. The assessment should be in detail and include recommendations for improvements consistent with the historic fabric of the building. It is useful to consider the fire process, as set out in 5.3 (above), as a framework for carrying out a risk assessment. Hazards are posed by heat, smoke, direct burning, water and collapse. At risk, to a greater or lesser extent, are the occupants, the building fabric, the contents and the business operation. These should all be considered in the process of risk assessment. 5.7.2 Fire risk assessments will take into account the normal activities carried out in the property and periods when the building is unoccupied, which may present special problems when considering detection and emergency procedures, or security and arson risk. Special or occasional events may need their own arrangements, particularly where there are large numbers of visitors present who may be unfamiliar with the building. 5.7.3 Fire risk assessment can range from common sense appraisal in simple situations to quite complex analysis involving quantitative as well as qualitative factors. In the latter case specialist expertise from a fire consultant, fire engineer or person with specialist knowledge may be necessary. At whatever level of application, clear fire safety objectives are


Fire Safety Management and Fire Precautions essential. The varied nature of historic buildings means that each risk assessment will have to be developed for the individual building. A basic methodology which can be adapted to suit the particular circumstances is described in Appendix IV. 5.7.4 Much recent safety legislation requires employers to carry out a risk assessment. This type of statutory risk assessment deals primarily with risks to the health and safety of people at work. The type of fire risk assessment advocated in this document will go far beyond this in considering the risk to the fabric, contents and value of the building. The various types of risk will not necessarily be CO-located, ie one part of a building may pose a high risk to life whilst having a relatively low heritage value, and vice versa. A level of fire precautions well above the statutory minimum will often be necessary. 5.8

Building Contracts and Maintenance Work

5.8.1 Building contracts and maintenance work are of special concern and clear fire safety requirements should be included in all contracts. In addition to the obvious use of blow lamps, Hot Working includes hot air paint removal, welding, metal cutting or grinding and the like. Wherever possible hot work should not be permitted in historic buildings. Alternative materials, fixing or jointing methods or prefabrication off-site should be actively considered. When unavoidable the work should be carefully controlled and monitored by using a system of Hot Work Permits coupled with periodic inspections during the work, and over a defined period after work has ceased, to ensure incipient fires have not developed. Fire extinguishers must be available adjacent to the work. Smoking by workmen and the use of open fires for disposal of rubbish or any other purpose should also be prohibited. End of day inspections must be carried out. These procedures should be applied stringently. Before commencing operations contractors should be required to demonstrate their procedures and levels of training necessary to achieve a safe method of working. Small firms or sole tradesmen may require special training and their level of insurance should be carefully checked. 5.8.2 Many types of work are now covered by the Construction (Design & Management) Regulations 1994, which require risk assessments and safety procedures (not just for fire but all elements of the work). However minor works, certain internal ecclesiastical work and many types of work to domestic property are excluded from these regulations, yet still pose a risk to many buildings. The Loss Prevention Council and the Building Employer's Confederation/National Contractor's Group have produced a Joint Code on the Protection from Fire of Construction Sites and Buildings Undergoing Renovation. The Code is in its 3rd edition with a 4th revised edition due in the autumn of 1997. The Construction (Health, Safety and Welfare) Regulations l996 also apply; Sections 18 to 21 deal with fire safety matters.


Chapter 5 5.9

Fire Detection and Alarm System

5.9.1 The installation of a modern and reliable fire detection and alarm system is generally seen as a high priority. There are now a number of systems which can be installed in historic buildings with varying degrees of impact on the fabric and visual intrusion (see Chapter 9). It is essential that systems are then well maintained and regularly tested. The advantages gained by a sophisticated fire detection system will be wasted if proper arrangements are not made for immediate and effective action in the event of fire alarm actuation. This is even more important if the building is left unoccupied. The type of system required for life safety purposes will not necessarily provide adequate performance for property protection. 5.10

Life Safety

5.10.1 A principal purpose of the detection and alarm system is to provide for life safety through quick and effective evacuation. The full range of likely occupants must be taken into account. Residents and staff may benefit from regular fire drills, but the reaction of visitors, including overseas visitors unfamiliar with our language and procedures, disabled people including those with mobility, visual or aural impairment, children and elderly people will require careful assessment. Buildings or parts of buildings where people sleep also present particular risks. Historic buildings often require special consideration as the physical arrangement of the building may limit the choice of escape provisions which will either restrict the accessibility of the building or may require a greater level of staff training and management procedures. 5.11

Fire Fighting

5.11.1 To protect property the detection and alarm system must also initiate fire fighting and suppression measures. "First Aid" fire fighting by trained staff using portable extinguishers or hose reels may be effective in preventing a small fire developing into something more serious. Close liaison is also required with the local fire service, in terms of the property itself and also to ensure that there is proper and ready access, free from obstruction. It is essential to ascertain the availability of an adequate water supply and for trained staff and the fire service to be familiar with emergency access, services shut-down procedures and salvage and damage control strategies. Properties in locations remote from the Fire brigade may require special emergency procedures relying in the first instance on trained volunteers. 5.12

Automatic Fire Suppression

5.12.1 Automatic suppression systems provide major benefits in terms of rapid localised response, and the released suppression medium is likely to cause less damage than water from fire fighting hose streams. Such limited


Fire Safety Management and Fire Precautions damage should also be balanced against the likely total destruction of material by fire should this develop unchecked.

5.13

Containment & Compartmentation

5.13.1 Part of the fire risk assessment will address the existing compartmentation of the building into volumes separated by walls and floors with fire resisting properties and the ability to minimise fire and smoke spread by improving the compartmentation, without causing damage to the fabric of the building. (see Chapter 6).

5.14

Fire Procedures and Staff Training

5.14.1 Systematic and effective training programmes for staff are an essential part of fire safety management. Such training should include:-

minimising fire hazards by regular inspection and general observation, procedures on discovery of a fire, or on the activation of the fire alarm, evacuation procedures for staff, residents and visitors, including disabled people. In some buildings, special provision may be required for people with visual, aural or physical disabilities, salvage and damage control procedures (see 5.15 below), "first aid" fire fighting. 5.14.2 Staff training must be organised and practical demonstrations and drills should be carried out at regular intervals. This is especially important where there is a regular turnover of staff or volunteers. Records of training and drills must be kept. In some cases, depending on the use of the building, this is already a legal requirement and pending legislation (see Appendix 111) will increase the number of organisations affected and the need for accurate recording. Training should include provision for special or one-off events and for construction and maintenance work. In some cases, training should be extended to teams of local volunteers (or off duty staff) to provide immediate help or salvage parties, particularly in remote or isolated locations. The National Trust for Scotland, for example, set out a "tree" of contact telephone numbers to ensure a quick response and provide alternative contacts to cover absences. 5.14.3 Regular inspections may be required where the building contains residential apartments. Escape routes must be kept clear and available at all times.

5.15

Salvage and Damage Control

5.15.1 Many buildings have valuable contents and the deployment of trained salvaged teams working to a pre-determined plan can assist in reducing the overall loss. This is set out in more detail in Appendix V.


Chapter 5

5.15.2 It is essential that the fire alarm panel is readily accessible and shows clearly the location of the fire. In many cases plans of the building displayed beside the panel, with reference to the fire detection zones and locations, will be of great assistance to the Fire Brigade.

5.16

Reinstatement and Insurance

5.16.1 Reinstatement or "post fire recovery" is beyond the scope of this Technical Advice Note, however the Management Plan should address the need to ensure that those working on the building are adequately insured and that the building and its contents are also adequately insured. Insurers may require a certain amount of work to be carried out before providing cover. Incentives to carry out work may be available through reduced premiums. Insurance in relation to historic buildings and their contents is a specialised field requiring expert advice (see Appendix VI). 5.17

Records

5.17.1 Records should be made of the property and its contents, including measured drawings, photographs and inventories. They should be stored off site.

5.18

Building Services and Maintenance

5.18.1 Building services require regular inspection and maintenance. Electrical faults are a common source of fires and installations should be tested and upgraded according to a formal programme. 5.18.2 Heating systems and in particular boilers and flues, are potentially hazardous. Special provision will be required where stoves or open fires exist, including the installation of spark guards. The regular checking, maintenance and cleaning of hearths, chimneys and fluei should be carried out, particularly where wood is used as the main fuel. Wood should be properly stored and dry before use. 5.18.3 Lightning conductors are another potential risk if damaged, and these should be serviced and maintained on a regular basis. Installation should be in accordance with the appropriate British Standard (BS 6651). 5.18.4 Care is required when considering replacing or upgrading services. Listed building consent is likely to be required. It is important to employ services engineers with experience of, and sympathy with, historic buildings.

5.19

Review of Fire Precautions

5.19.1 An essential part of the Fire Safety Policy is the formalisation of monitoring, or auditing, of the procedures, tests and inspections. The National Trust for Scotland for example, set out specific timetables for such reviews. By their nature, many historic buildings will, even after improvements to fire precaution measures, continue to present risks and this increases the need for effective management procedures.


PART I1 CHAPTER 6

COMPARTMENTATION

6.1

The Purpose of Compartmentation

6.1.1 Compartmentation, or the sub-division of a building into smaller volumes by fire resistant walls, floors and other divisions is a major part of passive fire protection and serves several purposes; the limitation of damage from fire and smoke, the limitation of the size of the potential fire so that it can be controlled more readily by the fire fighters, the creation of spaces protected from the immediate effects of fire outwith the affected volume is a major benefit, not only to life safety but is a significant factor in minimising the damage or loss of historic fabric and contents. aiding access for fire fighting, the reduction of the likelihood of structural failure during a fire. 6.1.2 The concept of compartmentation is simple, but in practice historic buildings present many daculties by the nature of their construction and in terms of passive fire protection. Other factors must be considered in parallel, for example the presence of combustible materials within the volumes, the activities taking place, the overall geometry of the building, ease of escape, its accessibility for fire fighting purposes and the fire resistant properties of the building fabric.

6.2

Size and Scope of Compartments

6.2.1 Present day requirements are set out in the various technical standards, particularly the Building Standards (Scotland) Regulations, and depend on the activity being carried out in the building. Generally, the building regulations are not applied afresh to historic buildings until a change of use or physical alterations are under consideration, but a knowledge of the requirements may be a starting point for an assessment and will be essential if, as is quite common, relaxations from the regulations are sought, in order to minimise change to the fabric. 6.2.2 Assessment will involve analysing the construction of the building to look for its strengths and weaknesses. Many historic buildings are built of cellular masonry construction, with quite small volumes, although frequently fire resistance is compromised by voids, openings and the presence of combustible materials. The case studies demonstrate this. At


Chapter 6 Moy House, fire spread throughout the building and led to the complete loss of the interior. At Kilkerran House, an effective barrier between the wing containing the fire and the main building restricted the extent of damage to the wing itself.

6.2.3 The use of spaces will also be a major consideration. For example, at General Register House, Edinburgh, unique, irreplaceable records are stored in small individual rooms, each of which is a fire compartment. In an intensively occupied building such as a school, life safety and the protection of escape routes may be the first consideration.

6.3

Completeness of Compartments

6.3.1 For compartmentation to be effective, the boundaries (normally walls and floors) must exhibit both completeness and fire resistance. In many buildings the completeness of the original construction has been lost due to later alterations, poorly installed services or careless repair and much can be done to improve the fire performance of the construction while restoring or conserving these original elements. Unfortunately, it is also common for the original construction to contain openings or other weaknesses. It may be possible to deal with these in a non-intrusive way but there may be a point at which steps to improve compartmentation may conflict with conserving the integrity of the original construction. This situation may require a balance of other measures (management, detection, suppression etc) and the adoption of a fire engineering approach. Fig. 3: George Heriot's School, Edinburgh, 1628. Plan of the third floor showing classrooms in the corner towers and roof spaces above the south, east and west wings. Efforts to complete the natural compartmentation of the building were concentrated on the thick masonry walls of the corner towers and the crosswalls within the wings. Fire doors were fitted at key locations. (marked * on plan)


Compartmentation

6.3.2 Part of the assessment of a given building is to establish the boundaries of each compartment, whether required by regulation or as a common sense approach to fire precaution measures. In some cases, subcompartments will be required or may occur naturally. In each situation it is these compartment boundaries that should be closely examined for fire resistant qualities, as the other walls and floors that may exist within the compartment are not, in principle, the first concern. 6.4

Survey & Assessment

6.4.1 Fundamental to the risk assessment and appraisal of each building is the need to understand its geometry and construction in three dimensions. Important steps in this process involve:Appraisal from original and subsequent plans, records and archive material, including, for example, Dean of Guild or Building Control records and similar sources to give an understanding of the changes and development of the building. Early records may lack detail, and a knowledge of the construction methods employed at different periods (and in different areas) can prove to be extremely valuable.

Dimensional surveys and the preparation of plans and sections accurately locating walls, floors, hearths, doorways, windows, staircases etc. are essential. Discontinuity of construction may indicate weaknesses of construction and potential fire paths. Assessment of the construction to include appraising the extent of masonry walls, likelihood of built-in timbers, presence of voids, flues and other openings. Plate 1 1: General Register House, Edinburgh. Written records referred to Robert Adam consulting with James Watt in respect of the arrangements for heating and ventilating the building. Flues were stated as "spiralling within the dome", however the archive drawings and radar survey showed that these were within the floor of the central area of the dome and not within the walls.


Chapter 6 6.4.2 Historic buildings have often changed and developed over many years and can exhibit different types and qualities of construction. Even very thorough surveys will not identlfy all the potential weaknesses and fire paths within the building. Some careful physical exploration may be necessary, however every effort should be made to do this without causing damage. Some currently available non-destructive survey techniques include:radar surveys, which are particularly good at identlfylng flues and other voids within walls and floors, television surveys using remotely controlled mobile cameras can be extremely useful in showing the condition of flues, shafts and ducts, borescope investigation which can yield information on cavities and voids. Plate 12: Radar surveys at General Register House, Edinburgh, helped to identify the routes of the flues and the internal condition of the walls including identifying the presence of voids in the wall construction. Survey and drawing by G B Geotechnics, Cambridge.

6.4:3 Tests could include air pressure tests, which can reveal the integrity of volumes and smoke tests of chimneys, flues and ducts. 6.4:4 The measure of fire resistance is the outcome of a standard test procedure. Therefore establishing the fire resistance of historic construction can be difficult in practice, particularly in terms of satisfying local authorities. The National Fire Protection Association (USA) have published a guide containing extensive tables of the fire resistant properties of many types of construction. These may be acceptable to local authorities if the description in the document matches the construction of the building element and the published test results are to recognised standards. Alternatively, some fire engineers are able to assess the existing construction and assign a fire resistance. Fire testing of equivalent or sample elements is a further possibility, particularly where works are being carried out and samples can be obtained.


Compartmentation

6.5

Constructional Systems and Compartmentation Vaults

6.5.1 Vaulted masonry construction can give excellent fire performance and occurs in several forms, such as medieval or ecclesiastical vaulting, industrial brick vaulting, or, as in General Register House, Edinburgh, as an early example of "fireproof' construction. The construction can usually be readily seen, but careful assessment is required as the presence of cracks, fissures, built-in timbers, size of spans, proportion of openings, later intrusions and breaches of the vaulting (eg for services) will all affect fire performance. The type of material and its resistance to thermal effects and thermal shock are also a consideration. Careful repair and reinstatement of the integrity of the masonry will enhance fire resistance. Walls 6.5.2 Masonry walls of stone and brick can also give excellent fire performance, although this can be severely compromised by the presence of built-in timbers, degraded masonry, loose or missing pointing and the presence of voids and other openings. Some of these defects can be remedied as part of normal repair work, but several are inherent features of traditional construction, for example timber safe lintels and the building-in of structural timber beams and joists. Fig. 4 : Diagram showing a part plan of an external wall in a 19IhC property with a number of flues and other voids. Only a relatively thin stone separates the flue from the timber framing of the cupboard. Illustration taken from 'The Care and Conservation of Georgian Houses - a maintenance manual for Edinburgh New Town".

6.5.3 Plaster applied directly to masonry can, depending on its condition, add up to 30 minutes fire resistance, but can also conceal built-in timbers and other weaknesses. A further common feature is the poor fit of door frames into masonry walls, leaving gaps between frame and wall or lintel. In assessing the fire performance of doors (see Chapter 7) this junction of frame to surround should be considered. Unobtrusive improvement may be possible by filling with fire resisting or intumescent material hidden by the existing facings.


l

Chapter 6

6.5.4 The common construction of walls lined with lath and plaster, (or timber panelling) on timber straps fixed to the masonry with timber dooks, leaving a narrow cavity, presents one of the most vulnerable elements in terms of fire resistance. The cavities often link with those present in floors and can run throughout a building, giving an easy fire path with both fuel (timber) and air present (as at Moy and Kilkerran). The fire resistance of floor constructions will often be compromised by the presence of such cavities at the perimeter, yet filling or sealing the space can be unacceptably disruptive and may interfere with the natural ventilation necessary to maintain the timber elements in good condition. The application of intumescent strips at the floor edge, concealed behind skirtings may address these problems, but installation is disruptive and as yet, there is little practical experience of this application.

6.5.5 Care is also required in assessing other types of internal wall. Timber stud walls, with lath and plaster each side may have reasonable fire resistance from room to room but the void between the studs can provide a fire path with little resistance at the foot or head. Stud infilled with brick is also a common internal construction and can go undetected, appearing solid at first examination, but containing continuous timbers. Plate 13 : At Kilkerran House fire spread through the floor void and up the centre of a stud partition located over the room where the fire started. Fire damage is also visible around the window (panelling having been removed after the fire).


Compartmentation

Floors 6.5.6 Earlier forms of floor construction may comprise timber joists or beams with directly applied floor boarding. Some have painted decoration applied directly to the underside. These floors effectively offer no fire resistance and fire strategies may have to rely on methods such as improved management, detection or suppression, as the commonly available techniques for improving fire resistance (such as applied intumescent coatings or sheeting with fire resistant material) will destroy the historical integrity of the element. 6.5.7 A common form of floor construction comprises timber joists andfor beams with directly applied floor boarding, ash deafening on timber boards inserted between the joists and a lath and plaster ceiling applied either directly to the joists or frequently suspended below the ceiling on timber framing. Much of the fire resistance (from below) depends on the plaster, however the strength of the key (to the laths) may be uncertain and the age and condition of the plaster can affect its fire performance. Floors can be vulnerable, not only from below but also above, where sparks from fires or embers falling through cracked hearths can lead to ignition followed by the rapid spread of fire within the floor cavity which all too often links with the voids behind the wall strapping.

Fig. 5: Diagram showing a typical floor construction in an or 191hC property. Illustration taken from "The Care and conservation of Georgian Houses - a maintenance manual for Edinburgh New Town". hangers below and


I

Chapter 6 6.5.8 There are a number of recognised methods of improving the fire resistance of floors, each of which should be carefully considered in relation to the particular circumstances which prevail, including any potential change in environmental conditions:consolidate any deficiencies in the original construction, introduce mineral fibre quilt supported between or below the joists, insert intumescent sheet material over or under existing surfaces, insert intumescent material at the perimeter of the floor to close the link with the wall cavities in the event of fire, apply intumescent coatings to ceilings, apply additional layers of fire resistant boards to ceilings. 6.5.9 It may be more practical in certain cases to consider concentrating on reinstating the integrity of the walls, perhaps increasing the number of fire divisions in plan to compensate for the weaknesses in the floors, coupled with increasing other fire precaution measures such as detection or suppression.

Roofs, Domes & Spires 6.5.10 Fire attack from external sources such as sparks, fire from neighbouring buildings and lightning strikes requires consideration, particularly when thatch or shingle finishes are present, however, the complete destruction of roofs from fire originating within the building is, unfortunately, a more common occurrence. 6.5.1 1 Often, the masonry walls of otherwise quite cellular buildings do not continue into the roof space or, if they do, they are incomplete containing openings to allow access for maintenance. Flues passing through the roof space may also pose a threat if in poor condition. In many cases the compartmentation of the roof spaces can be completed by judicious building-up or the fitting of fire doors. 6.5.12 Large volume roofs, for example of churches or public buildings, are also vulnerable due to the ease with which fire can spread unhindered. It may be possible to consider their sub-division. Tall structures such as bell towers or spires can present special risks and are frequently poorly separated from other roof spaces. Domes, often double skinned may contain large quantities of timber construction with little fire resistance from below and little internal division. 6.5.13 Fire strategies should address the need to compartment roof spaces. At the same time all other hazards should be eliminated by cleaning out and removing combustible debris, removing or protecting electrical services and rectifying constructional deficiencies. The introduction of detection andlor automatic suppression systems should be considered. These may be less


Compartmentation disruptive to install within roof spaces than in other finished parts of the building. Plate 14 : Dunbar Parish Church, East Lothian

The whole roof ablaze January 1987

Service Routes, Ducts & Shafts 6.5.14 Flues are of particular concern due to their frequent poor condition and the presence of hot gases and sparks. Other ducts or shafts may be part of the original construction - waste shafts, natural ventilation stacks, bell pulley routes, dumb waiters and so on. These can represent serious fire spread hazards and care is required in dealing with them. A number of products exist for improving fire resistance including intumescent "pillows" which can be packed into voids but are quite "reversible".

6.5.15 Many historic buildings have suffered from the careless installation of services, often over several generations. Apart from the risks emanating from the condition of the services themselves, all too frequently routes have been driven through walls and floors destroying their effectiveness as fire barriers. Within floors the notching of joists, loss of deafening and the puncturing of finishes, often seriously reduces fire resistance. These routes and the materials comprising the services or service ducts create paths for fire to spread along. Ductwork, particularly when associated with catering, can be particularly hazardous becoming lined with grease deposits over time. PVC sheathed insulated wiring and plastic pipework also pose risks. Older electrical systems insulated with vulcanised India rubber are a potential source of ignition through the cracking of the insulation and consequent exposure of the live conductors.


Chapter 6

6.5.16 Much can be done to complete the effective natural compartmentation of a building by attending to these issues. Where it is not possible to remove services, attention is required to build up openings, firestop holes, restore deafening and other finishes and where necessary fit fire dampers to ducts or fire collars to pipework. Plate 15 : Moy House, Moray. The day after the fire the floor is still smouldering. In the corner behind, the remains of a vertical duct can be made out and directly below (at the bottom of the picture) a ventilation grille can be seen. The inside of the duct is heavily charred, suggesting that fire travelled or spread by this route.


CHAPTER 7

DOORS AND DOOR CLOSERS

7.1

Introduction

7.1.1 As doors may be the only combustible element in a wall which is otherwise resistant to fire, they can represent a fundamental weakness to the containment of fire itself or the effects of smoke. Doors which contain glazing or fabric panels or which have gaps in their construction may allow fire to spread between otherwise separate compartments. An open door will present no barrier to the spread of fire and smoke. However, experience has shown that many doors in historic buildings can provide useful resistance to the passage of frre and smoke. Plate 16: At Kilkerran House the fire was contained within one wing. This was mainly because the doors leading into the wing were shut at the time of the fire. In addition the arrangement of double doors helped prevent smoke spread. The photograph shows the panelled space between the two doors. The inner door was badly charred but helped contain the spread of the fire. (the fire was on the other side of the door)

7.1.2 Over the last few years, a better understanding of the performance of doors in fires has been developed, through observation and testing of specific forms of construction. This has lead to more confident prediction of a door's resistance to fire, and allowed any proposed requirements to be carefully judged in relation to its historic value and those of the spaces it serves within each property. Information is available from a number of sources as listed in Appendices V11 and VIII. 7.1.3 Some doors may not be capable of improvement due to their method of construction or because their intrinsic value makes alteration unacceptable. In such situations other ways of providing fire precautions may be possible, allowing the retention of the doors. Doors which may not appear to meet any recognised standard of fire resistance can still offer a degree of protection which might be considered acceptable in the particular circumstances.


Chapter 7 7.2

Performance of Doors in Fire

7.2.1 A fire door must perform as a fire resisting entity including the door, the frame and its ironmongery as installed in the building. These elements should be considered together when assessing the fire performance of doors in historic .buildings, and in some cases a number of unobtrusive improvements may be more effective than simply concentrating on the door leaf and closer. 7.2.2 In considering how well a particular existing door will perform in fire, the following aspects should be considered: thickness and size of door, condition of materials (eg split panels), method of construction (joints etc), types of material (timber species - softwood or hardwood), size of any gaps between door and enclosing opening or frame, presence of glass panels, any gaps between the door frame and surrounding structure, presence of any fabric linings or panels, type of ironmongery

- method of latching - method of closing - large parts of door cut to introduce locks

any existing "improvements" in fire resistance (eg intumescent materials, self closers). 7.2.3 The requirement for a door to resist fire or the passage of smoke depends upon its location. It may be the weak link in an otherwise impenetrable wall; it may enclose a room containing a high fire risk, or may protect an escape route or valuable interior setting. Special attention must therefore be given in considering whether improvements should be made to safeguard life and property. e~ written in the light of recent fires in Royal 7.2.4 The ~ a i l Report, Palaces, made recommendations to suggest special attention should be given towards developing visually unobtrusive self-closing mechanisms for use with doors in historic buildings. This was seen as a positive approach to the control of spread of fire and in particular in minimising the effects of smoke.

7.3

Methods of Improving Fire Resistance of Doors

7.3.1 Before considering the range of options available, it will be necessary to decide on the appropriate level of intervention. There may be some important doors which would be best removed to storage and replaced with another rather than attempt to alter them. In other cases,


Doors and Door Closers where appearance is less important, the simple expedient of facing one or both sides with non-combustible boards, which can be futed and later removed with minimum damage, may be satisfactory. 7.3.2 If it is decided that improving the performance of a door's fire resistance through alteration will create benefits for the building and its occupants, the primary aim should be to carry out any alterations with minimum physical effect on the fabric, and with little or no visual alteration. A number of available publications listed in Appendix V111 give general guidance on methods of alteration, and the anticipated benefit related to the recognised standards for "fire rating". 7.3.3 From the list of aspects in 7.2, apart from those concerning glazed or fabric panels, where improving fire resistance directly has not been found possible, the two areas of potential improvement are (a) increasing the fire resistance of the constructional parts of the door or (b) by sealing gaps through which fire or smoke could penetrate.

7.4

Increasing Fire Resistance

7.4.1 Timber doors in which all constructional parts are of thick or multilayered timber will resist fire longer than those with thin components. Typically, the thinner panels of a door, cracks in panels or ill fitting frames are the most vulnerable elements. Before considering making any alterations to a door care should be taken to respect any particular qualities such as its construction, detail and surface finishes; the loss of integrity of which would be unacceptable. 7.4.2 The following alterations to panels give recognised improvements in fire resistance (in ascending fire resisting value): bed panel (into rails) in intumescent paste, as above, and coat each side of panel in intumescent coating or apply intumescent paper, saw cut through panel to split in half, introduce intumescent sheet sandwiched between each half, and bed panel into rails in intumescent paste, as above, and coat each side of panel in intumescent varnish or apply intumescent paper. 7.4.3 All of the above methods require the doors to be dismantled and reassembled, and were techniques developed during recent consideration of upgrading doors in the Palace of Westminster. They were designed to advance options for upgrading beyond the simple (and reversible) but obvious method of applying new fue-resisting board material onto the face of door panels. 7.4.4 Special consideration should be given prior to the use of intumescent coatings. Each product manufacturer will have advice on


Chapter 7 preparation of surfaces to be coated. This may involve removing existing paint or other surface finishes, which may not be acceptable. In addition, certain spirit-based intumescent coatings may adversely effect existing materials. Thorough trials should be carried out in advance of any proposed work. 7.4.5 Where a need for improvement is identified, applying intumescent surface treatments can assist a door to achieve a nominal 20 minutes fire resistance. If a higher standard of performance is required then intumescent strips may have to be fitted to the door edges or frames.

7.5

Sealing Gaps in Doors

7.5.1 Sealing cracks in door panels and stiles or rails can be achieved by the methods specified above (7.4.2). Badly fitting doors can be given improved fire resistance by grooving the edge of the door leaf (or frame) to insert pre-formed intumescent strips which will expand to close such gaps when attacked by fire; this method will not restrict the passage of smoke at ambient temperatures. 7.5.2 The overall thickness of the wood in a door must be suficient to allow a suitable and fully tested proprietary intumescent strip to be fitted. 7.5.3 Where the door protects an escape route similar intumescent material which expands at lower temperatures may be installed to prevent smoke from escaping into adjacent rooms or corridors. Cold smoke seals, in the form of brushes or flexible blades which prevent smoke leakage through gaps between doors and door frames, can be fitted in a relatively unobtrusive manner.

7.6

Available types of Door Closers

7.6.1 Following on from the Bailey Report, enquiries were made by the authors of this Technical Advice Note to a large number of ironmongery manufacturers, to establish whether the recommendations on visually acceptable door closers were being developed. From the returns made, it does not seem that the industry has recognised this market. Most manufacturers appear to concentrate on the "new door" market, and few available devices meet the criteria which careful conservation work on historic buildings demands. 7.6.2 There are five main groups of self-closing mechanisms currently available. These are listed below: Face fixed overhead closers with lever arms - These may be fixed on the door or the frame, and on either the opening or closing side of the door. It is generally recommended that they are fmed at the head of the door. They operate principally through hydraulic or rack-and-pinion mechanisms and are manufactured in different sizes, each capable of closing doors up to a defined weight. They are adjustable to vary the force exerted and incorporate a 'checking action' to avoid impacting


Doors and Door Closers violently on the frame. These closers are designed for new building work, but some varieties of closer may be suitable for installation in historic buildings. Fixing the closer is a simple operation, involving minimal screw holes in timbers. However, potential damage may occur to existing adjacent surfaces if the scope of movement of the several parts is not fully understood.

Concealed overhead closers - They are similar in operation to facefixed, but the barrel of the mechanism is hidden from view by forming a recess in the door or frame. The lever arm remains visible. There are minimum dimensions of door rail members into which this type of closer can be fitted. It may not be acceptable to consider cutting the door for this closer. Care must also be taken to avoid reducing the fire-resistance of the door by cutting it. Floor springs - These operate by means of an arm or shoe which is fitted to the bottom of the door at its hinge point. A hydraulic or springoperated closer is contained in a casing which is sunk into and fmed to the solid structure of the floor. Jamb closers - The mechanism consists of springs and a hydraulic unit contained within the cut out butt end of the hinge stile of a door (or corresponding part of door frame). Loss of material in cutting the door will affect its fire resistance. Chains connect the unit to a fixed plate. This type of closer is closest to achieving a visually unobtrusive installation and may cause least damage to the fabric. There are limitations on the weight of door which can be satisfactorily closed and experience has shown there may be difficulties where differing air pressures exist on either side of a door. Other closers - Tail sprung and flap closers are available but these are suitable only for the lightest type of door. They comprise a metal cylinder containing a coiled spring and the whole assembly is face fmed to the door frame. A tail rod or flap bears onto the surface of the door and forces it closed under direct pressure. Rising butt hinges, which rely on the weight of a door to close it, will not generally be an acceptable choice. 7.6.3

Hold open or Free Swing Devices

Hold open devices - Although these devices are not closers they are used extensively in locations where normal usage of the doorway is heavy and a closed door would be a nuisance; and where doors are neGded for compartmentation but it is preferred for the door to remain open. They are usually operated by electro-mechanical devices. In the event of a fire being detected by an alarm system, the electric power to the magnet is shut down allowing the door to be closed by self-closers fitted to the door. These devices are preferable to the familiar image of a self-closing door wedged or propped open, which must not be allowed. Care is needed in locating the device as in some situations the action of the device working against the closing spring can warp the door making it ineffective as a fire door (in addition to damaging the door).


Chapter 7 Ideally the hold open device and closing mechanism should be installed at the same height on a door. Free-swing closer - These are useful where the occupants include elderly or disabled people. They allow a door to be used normally, ie without being automatically closed each time and capable of being left partially open, until the fire detection system triggers the closing mechanism after which it behaves as a self-closing door. 7.6.4 A number of these devices require cable connection to the detectionlalarm system and some also require an electrical supply, usually a spur outlet, close to the closer. The disruption caused by installing these devices must be carefully considered against the benefits offered. 7.6.5 A battery powered hold open device actuated by the audible fire alarm signal has been developed, which has the advantages of not requiring any wiring.

7.7

Latches

7.7.1 If the self-closing device does not have the required degree of fire resistance latches may be necessary to maintain the door in a closed position when subjected to fire. Door fastenings on escape routes need to be available without the use of a key. Conflicts between security and escape from fire can usually be resolved by careful selection of ironmongery.

7.8

Testing and complying with Local Authority Requirements

7.8.1 Test certificates or compliance with published standards of construction are frequently required by local authorities. In many cases an independent assessment by a recognised fire safety consultant, taken in the context of other fire precaution measures, may lead to more sympathetic solutions which will also be acceptable to the local authority. (BS 476 : Part l, describes testing for guaranteed performance).


CHAPTER 8

THE PERFORMANCE OF HISTORIC BUILDING MATERIALS IN FIRE

8.1

Introduction

8.1.1 Whilst it is essential to understand the way in which different materials have been combined in "constructional systems" in a building, it is also useful to have knowledge of the behaviour of materials in general terms when subjected to attack by fire. It may be necessary to consider how the effects of age, physical treatments and other degradations on the material could alter their behaviour in fire. In considering any materials, the options available for directly improving their behaviour in fire using other protective coatings and devices, which may alter the physical appearance or original form, must be understood.

8.2

Testing

8.2.1 Information on the likely performance of some materials or forms of construction can be obtained from published test data. There is at present no co-ordinated data on Scottish building materials. Useful information can be found in the following: Timber Research and Development Association (TRADA) publications, (note: the Fire Division of TRADA now operates under the name "Chiltern, International Fire" - see Appendix VII) National Fire Protection Association (NFPA) data, (note: this Association is based in the USA), English Heritage publications, manufacturer's literature relating to the application of fire protective treatments. 8.2.2 In newly constructed buildings, "standard" combinations of materials can be tested without restrictions. This is not the case in historic buildings where each component is unique and has value. All other options should be considered before subjecting historic fabric to destructive tests. 8.2.3 The authors commend the setting up of a national co-ordinating body for test data on historic building fabric performance in fire. Follow-up effort will be required before this can be achieved, meanwhile the submission of relevant past and future test information to Historic Scotland, (TCRE), is to be encouraged. 8.3

Masonry

8.3.1 Stone and brick are non-combustible and when built in mass form, combined with appropriate mortar binding, can have great resistance to the

45


Chapter 8 passage of smoke, heat and flame. In addition to the construction of external walls, internal dividing walls, and floors using vaulted construction, masonry is used to enclose fireplaces and form hearths on otherwise combustible constructions. The condition of the stonework and pointing, in such circumstances, is critical to its fire performance. Fig. 6 : Typical wall and floor construction at a fireplace in 181h and 191h Century properties. Note the timber beam shown dotted. In some buildings this can occur directly under the hearth. Illustration taken from 'The Care and Conservation of Georgian Houses - a maintenance manual for Edinburgh New Town)

I

::I

U1 Stone ttnlel over tiwplace openmg, onen wlh relievlw arm above Marble chimneyplece

..

Urns monar and rubble packing Metal angle

Cast Imn

regislw grate

8.3.2 In fires of very high temperature it is possible for water particles contained within masonry to expand and cause a sudden fracturing of stones. Rapid cooling by water from fire hoses can also lead to fracturing. Plate 17 : At Dunbar Parish Church the intensity of the fire and possibly drenching and rapid cooling from water from fire hoses lead to a significant reduction in the thickness of the stone columns. Stone can delaminate in an "onion skin" way as a result of the stresses caused by heating and rapid cooling. The arches were also seriously weakened.


The Performance of Historic Building Materials in Fire 8.4

Timber

8.4.1 As combustible material, timber can contribute rapidly to a fire within a building. It does, however, also have a degree of fire resistance which increases with the thickness of the component under attack. Hence, while thin timbers such as shutter and door panels, lining boards and other trims will readily bum, large timber stud frames, and structural elements such as beams, columns and roof members will burn at a slower rate and may perform their function for longer and even beyond the duration of the fire. This resistance may also be affected by the species, moisture content and growth characteristics of the timber, as well as by its subsequent treatment and applied finish. Attack by woodworm or wet rot and dry rot fungi can weaken its structural strength and hence its ability to resist fire. Care must also be taken to assess whether hidden timbers have undergone repairs or been notched to enable service pipes or cables to be inserted into the building. The presence of shakes, splits or shrinkage cracks will also adversely affect the behaviour of the timber in fire. Timber may have been treated with spirit-based insecticides or anti-fungal treatments or with polishes, waxes and painted finishes, which would increase the potential for fire development. (see 8.9) 8.5

Steel, Wrought and Cast Iron

8.5.1 One reason for the development of metal as a structural element was specifically as a response to the performance of timber structures in fire. Whilst these metals can be considered effectively as non-combustible, and therefore offering a degree of fire resistance, they also have characteristics which are themselves potential risks in a fire. Metal structures will commonly be embedded within other constructional materials; brick, stone and timber. All metals have a crystalline structure and will expand when exposed to heat. In a fire this expansion can disrupt the end supports of steel and wrought iron beams and dislodge elements supported on iron columns. Beyond the natural period of fire resistance of the metal structural element complete failure can be expected. 8.5.2 The location and nature of any metal elements should be identified by inspection and measurement wherever possible, so that potential risks can be assessed.

8.5.3 Steel and wrought iron will fail by elongation of the material under constant loading and temperature. Cast iron is a brittle material, due to the arrangement of its crystalline structure, and failure is most likely to be a fracture across the material, which will occur suddenly and without warning.

8.5.4 Conventional methods of fire protecting metal structures involved encasing them in mortar, concrete sprayed material or fireproof board, and filling hollow sections with concrete. Modern methods include coating with intumescent material, which can provide up to 2 hours fire resistance (see 8.12).


Chapter 8 8.5.5 The application of water during a fire can cause sudden cracking and collapse of structural cast iron; this may determine the type of suppression system to be used. Equally some cast iron elements can withstand the effects of fire, depending upon the type of fire to which the structure is exposed, and it may be possible for these to be re-used in repair or reconstruction. Assessment will be based on observation of the components, combined with consideration of future risk.

8.6

Mortars, Plasters and Renders

8.6.1 Whether applied direct onto solid masonry, or onto a framework providing a ventilated air gap against an outside wall, or an internal timber partition, traditional lime or gypsum plasters are inherently resistant to fire. However, where the plaster's "key" onto its substrate is damaged due to decay or another physical cause, its ability to withstand fire will be significantly reduced. Sudden collapse of a plaster ceiling can occur in fire as a result of the already weakened state of the "key" with the timber laths. 8.6.2 There are no recognised methods currently available for directly protecting valuable ornamental plasterwork from fire.

8.7

Thatch

8.7.1 Thatch is obviously combustible and is vulnerable to fire from defective chimneys and flues which allow hot gases to escape. In the event of a defective flue heat will build up deep within the thickness of the material, the insulating properties of which cause temperatures to rise to a level at which combustion will occur. Chimney fires, particularly where wood is used as a fuel, and wind-blown sparks from fires outwith the property, can also cause fires in thatch roofs. Fig. 7: Diagram showing potential heat build-up in thatch adjacent to a chimney stack. Where possible, chimneys should be lined with noncombustible insulation so that the temperature of the outer surface does not exceed 160'~.

Thatch thickness

P-

-------


The Performance of Historic Building Materials in Fire 8.7.2 Improvement of thatched properties, introducing draught proofing and double glazing, together with higher temperature heating appliances, are likely to increase the risk of fires occurring as flue temperatures will be increased with little corresponding cooling. 8.7.3 Once started thatch fires are very difficult to extinguish as fires can burn unseen within its depth and smouldering materials cannot be reached. Wire netting, commonly found enclosing thatch, renders access dSicult. As a thatched roof is designed to resist water, normal methods of fire fighting can be ineffective. 8.7.4 Due the difficulty of extinguishment, the aim must be to prevent fires occurring at all. Consideration should be given to lining and regularly maintaining flues. Although fire retardant chemical treatment may be applied which will provide some protection to thatch, their usefulness is likely to be minimal and may cause earlier degradation of the material. (The health of thatch depends on free ventilation). Traditional treatments which involved the use of a clay dressing are also worth considering. 8.8

Glass

8.8.1 Glazed openings are a potential weakness in the passive control of fire in otherwise sealed compartment walls, and there may therefore be great pressure to create improved fire resistance to these openings. Every effort should be made to retain historic glass and replacement should be seen as an option of last resort. Any glass removed should be handled carefully and stored for repairs or re-use. 8.8.2 The range of options which could be considered include improvements to the way glass is held into its frame, provision of secondary glass and frames and replacement of existing glass with thicker or fire resistant glass. 8.8.3 Fire resistant glass is now available in several forms, including "wired" glass, modified toughened or laminated glasses, and insulated glass, to comply with BS 476 pt. 22. Most glasses in these categories rely for success on combination with an appropriate frame and futing system, and therefore their consideration for use in historic buildings must be carefully judged. Specialist advice may be required. 8.9

Paint and Other Surface ~reatments

8.9.1 Whilst some polishes and varnishes may be themselves liable to ignition, it is the heavy build-up of layers of paint which some historic surfaces have received that renders them potentially vulnerable to fire, and also potentially dangerous to people escaping from a fire. 8.9.2 An assessment of fire risk might necessitate an exploration of paint build-up, which could be aided by paint scrapes for analysis. Such analysis may be required in any case to determine the nature of original treatments


Chapter 8 and colour schemes. Laboratory analysis may be required to establish the chemical composition of the layers of paint and the degree of fire hazard.

Plate 18 : Paint peeling and charred as the result of a fire test. Thick layers of paint can peel, ignite and produce dense smoke and falling globules of burning material.

-

8.9.3 There may be circumstances where painting schedules should be restricted to prevent further coats being added to surfaces. This would allow a balance to be made between the increasing risk from thick paint layers and loss of information of historic paints and decorative room treatments. Where paint removal from surfaces in historic buildings is being considered, such work may require listed building consent and detailed investigation and analysis of the paint and methods to be employed prior to work starting. Traditional methods of washing and cleaning down existing paintwork, rather than repainting, may be more appropriate in certain circumstances.

8.9.4 Care must be taken in the method of removal of paint. Tools such as blow lamps or hot air guns are themselves hazardous and a fire risk, and physical abrasion can cause damage. The use of chemical poultices or hot steam strippers may be successful, provided their use is carefully controlled, and only after thorough test samples are carried out. 8.10

Insulation from fire

8.10.1 Materials which are combustible or otherwise vulnerable to fire may be 'passively' protected by providing insulation to delay the rise in temperature. Examples of these in historic buildings could include: Ash, sand or lime pugging in floors, Thick plasters or renders over timber structures, Concrete filling of cast iron columns, Over-sized timber beams which char without loss of effective structural strength.


The Performance of Historic Building Materials in Fire 8.10.2 Modern intumescent products function by expanding to give additional insulation to vulnerable thin components.

8.11

Flame Retardants

8.11.1 Depending on their material or finish, the surfaces of walls and ceilings may contribute to the spread of fire within buildings. In many cases proposed alterations to surface treatments are now controlled by legislation to ensure that the spread of flame from an ignited part to adjacent surfaces is restricted. 8.1 1.2 The main areas of concern in historic buildings will be from timber panelling, surfaces of all kinds which have many layers of paint, and large fabrics such as wall hangings and curtains, particularly in rooms visited by the public. Many such fabrics may themselves be of historic value. Once other fie precautions have been implemented it may be that some form of retardant to the spread of flame on such surfaces will require to be considered. 8.1 1.3 Spraying or dipping of modern fabrics can be carried out to retard flame spread. It may be necessary to apply the treatment on a regular basis to ensure proper protection. It is unlikely that this would be appropriate for historic fabric and such treatment should not be undertaken without specialist advice and consultation with Historic Scotland. 8.1 1.4 For timber and painted surfaces thin film intumescent paints might be applied provided the original finish had no particular historic merit. When subjected to heat these paints will expand to produce a layer of rigid closed-cell foam which inhibits the spread of flame. The material will also provide some insulation to the base material from the high fire temperatures. Each surface to be treated should be investigated to determine the nature of previous coatings, and these may have to be removed before effective protection can be obtained. The proper preparation of the surfaces is fundamental to the success of the application. 8.11.5 Because of the potential loss of historic fabric through removal of previous coatings, and as the new treatment is not easily reversed, the application of flame spread retardants should be considered the last resort in all but exceptional circumstances.

8.12

Intumescents

8.12.1 A range of products is available on the market which have been chemically formulated to react to the presence of heat from flames or hot smoke. The active ingredients of these products are commonly sodium silicate, ammonium phosphate or intercalated graphite. The reaction of the active ingredient with heat, causes it to expand, thus providing a protective insulating shield to the material or construction to which it has been applied. A further benefit of such expansion when heat is applied is to cause gaps in construction (which are necessary in a normal condition or may have


Chapter 8 occurred as an ageing process) to be sealed under fire conditions, thus preventing the spread of fire and smoke through the gaps. 8.12.2 The products which are available include paint and other applied coatings, sheet material, encapsulated strips, reinforced rolls, pre-formed collars and emulsion based mastics. Each has been designed to suit a specific application and can be formulated to give a range of expansions of varying volumes and exerted pressures. Intumescent paint may be used to increase fire resistance of timber and structural metalwork, whilst providing a decorative finish.

Intumescent coatings are by definition thicker than paints, and therefore, have less satisfactory visual appearance, but can offer substantially greater fire protection. Elements of structure which will be subsequently encased with another finishing material could receive intumescent coatings. Intumescent sheets - can vary in thickness from the equivalent of a thin card, up to several millimetres and they can be secured to the surface of a material using glue, nails or screws. Depending on the method of fixing, there may be advantages over painted treatments as they can be later removed without adversely affecting the material to which they were applied. Intumescent rolls and collars - larger masses or rolls of intumescent material can be reinforced and contained in "pillows" or rigid PVC or steel collars to provide a good seal around service ducts, pipes or wires when they pass through otherwise fire resistant walls or floors. High pressure and volume expansion would be specified to completely close off a pipe passing through a floor to prevent fire or smoke penetrating between compartments. Intumescent pastes and mastics - are used in combinations with any of the other intumescent products to ensure edge conditions are not vulnerable to fire. They are also used for repair of physical damage to intumescent coatings and can combine as a bedding material for fire resistant glass to achieve periods of fire resistance for glazing into window frames. 8.12.3 There is no available research into the effect of intumescent material on its host substrate. Nor is any information available on the long term effects on its host material or on the continuing stability and efficacy of the intumescent. Most applications are irreversible, and in the event of a fire after intumescing,. it is not clear how many of the products could be satisfactorily removed. Intumescents can not be overcoated with other decorative materials. Care must also be taken to protect their integrity when cleaning or through accidental damage. The materials do, however, have great potential in enabling otherwise inadequate construction to provide some degree of fire resistance and used judiciously may satisy many of the special criteria. which dealing with fire precautions in historic building demand.


CHAPTER 9

FIRE DETECTION

9.1

Introduction

9.1.1 The earlier a fire can be detected the greater the benefit in reducing the risks to both life and property. Even small fires can cause widespread, irreversible damage, for example, through the effects of smoke. 9.1.2 People can be the most sensitive detectors of fire but may be remote from the location at the time of ignition. Automatic detection systems operate from a more limited range of environmental stimuli than people and operate by sensing changes in physical or chemical phenomena which alter the environment containing the fire. The selection of an appropriate fire detection system is based on an assessment of which of these changes are likely to result from the ignition and growth of a fire in a particular room or building. 9.1.3 The choice of a system will also depend on the value of the building fabric and contents at risk. Any loss of historic fabric is unacceptable, but in practice it is not possible, either practically or economically, to apply the highest level of protection in all situations and value judgements have to be made. Practical consideration will also play a part in deciding how quickly a fire detection system should operate. For example, works of art or priceless documents may require the greatest level of sensitivity of detection equipment. A range of detector responses from seconds to many minutes is available. 9.1.4 Owners of historic buildings, in seeking advice on fire precautions, may have first contact with firms marketing specific products. Many f m s have first class products but may not offer a balanced view covering what has now become a large and complicated field. Independent professional advice may well be necessary. 9.1.5 The installation of fire detection and alarm systems should be carried out in accordance with British Standard. BS 5839 : "Fire detection and alarm systems for buildings". Part 1 of this series, Code of Practice for system design, installation and servicing (1988) and its related Guide give information about the selection and location of sensors and describe the relationships between spaces in buildings, their contents and the most suitable types of system. BS 5839 : Part 6 applies to fire detection in dwellings and could be applicable to historic houses. 9.1.6 The design of a system to suit an historic building may have to use the available guidance in a flexible way to achieve adequate detection coverage while taking account of the physical nature of the particular

53


Chapter 9 building. Listed building consent may be required due to the nature of the work. The need for this should be established at the earliest opportunity.

9.2

Detectable Phenomena

9.2.1 A fire may release any or all of the following: electromagnetic radiation (such as infra-red or ultra-violet emissions), heat, fine liquid particles known as 'aerosols', solid particles of carbon (smoke), a number of different gases, sounds. 9.2.2 The amount of each phenomenon, and the elapsed time after ignition that it occurs, will vary in each instance. These variables may affect the decision on which equipment to use as a sensor to detect the fire. It is possible to obtain equipment which combines detection of more than one phenomenon in a single sensor.

9.3

Types of Fire Sensor

9.3.1 Flame detectors - Sensors are available to detect the ultra-violet or infra-red wavelengths of radiation emanating from a flame. These are very sensitive with response times being much less than one second. The detector is only able to detect flames in its field of vision which is a direct and unobstructed straight path between the sensor and the flame, but it is possible to obtain sensors which can scan across a space. In general, it is likely that a flame will be sensed well before any smoke would have risen to the ceiling of a room. The detection system can discriminate between "wanted" and "unwanted" flames (for example, candles). This type of sensor could be valuable in parts of buildings where combustible objects of very high value are kept or displayed. 9.3.2 Projected Beam detectors - These sensors use light or infra-red beams. The beam is projected to a receiver that may be located from a few to 100 metres distant from the emitter. When the properties of the projected beam are altered by rising smoke andlor hot gases the energy level at the receiver will change, causing a warning signal to be transmitted. It is important for this type of system to have an unbroken "line-of-sight" between the emitter and the receiver. It is possible to allow the beam to pass through glass, but in this case the active length of the beam would be reduced. Beam detectors are most valuable in large spaces which are likely to remain undisturbed for long periods of time, although it is possible for the beam to be broken, momentarily, without triggering a false alarm. Care should be exercised in the selection of beam detectors as the coverage


Fire Detection claimed for the various systems only relate to specific situations of building geometry.

9.3.3 Point smoke detectors - "Point detectors" are detectors which are in a fixed location. Smoke is commonly detected by either ionisation or photoelectric (optical) detectors. Each type is sensitive to solid or liquid particles of a particular size. Ionisation types are most sensitive to small "invisible" particles generated by fast burning cellulosic, woody materials, whilst optical sensors are sensitive to large particles. 9.3.4 Aspirating smoke detectors - The principle involved is of a small fan at a central location which draws air through a number of plastic tubes to an analyser which measures the optical density of the air. Smaller branch tubes with open ends are led to where sensing points are required, the number and location being designed to suit the spaces at risk. With careful planning all of the system can be hidden from view except for an unobtrusive 4 - IOrnm diameter hole or a small length of plastic pipe. The system can be very sensitive but may be adjusted to suit the circumstances. Plate 19: George Heriot's School, Edinburgh. Council Chamber ( 1690) An aspirating smoke detection system has been installed with sensing points in the Council Chamber, refectory, chapel and other rooms. One of the sensing points is located in the small, square coffered section of plasterwork nearest the door.

The installation was carried out from above with no disruption in the principal spaces.

Plate 20 (left) :The main sensing box is located in a hall cupboard directly above the Council Chamber. Plate 2 1 (right) : detail of the sensing point - a small plastic tube just protruding from the ceiling in the corner of the coffer.


Chapter 9 9.3.5 Point heat detectors - There are two types of system which rely on sensing heat. A fvted temperature detector is calibrated to detect a rise in temperature of a fvted amount above the ambient temperature of the room. A rate of rise detector reacts to the speed with which temperature in a room increases as well as to the actual temperature in the environment. The operation of a' point heat detector will generally be slower than a smoke or gas detector, but may be less likely to produce false alarms in areas where smoke or steam are commonly produced, such as kitchens or laundries. 9.3.6 Fusible links - These are mechanical links with relatively low, predetermined melting points which operate when subjected to heat, to close off mechanical parts such as shutters or dampers in a ventilation duct. Their slow response may not prevent heat, smoke or flame from passing through the shutter and where they have been previously installed it may be necessary to check their operation and review their purpose. 9.3.7 Line detectors - These are defined in BS 5839 : Part 1. Examples include continuous conductors with insulation designed to melt at a predetermined temperature or where the electrical resistance is changed with increasing temperature. These effects cause a signal to be received by the detection system. It is natural to expect the effect to occur near to the source of ignition and it is therefore possible to determine the location of the fire. This type of sensor can be added to cable trays which have been used where extensive rewiring of the electrical systems has been carried out. Care must be taken in zoning these systems. 9.3.8 Multi-sensor detectors - Several companies are developing multisensor detectors. The detector housing will include temperature sensors (therrnistors), optical or ionisation smoke sensors. With this combination of sensors the quickest and most reliable detection should be achieved. 9.3.9 Manual Call Points - although not strictly detectors, manual call points are an essential part of most installations. Occupants of the building may detect fire, or incipient fire, at an early stage and strategically placed call points can operate the alarm system. These are most commonly "break glass" call points located on exit routes. 9.3.10Sprinkler systems also act in a fire detection capacity as the sprinkler heads are operated by rising temperature.

9.4

The Location of Sensors

9.4.1 The recommended spacing and locations of sensors as set down in BS 5839 has .been built up from laboratory experiments and field experience. For buildings of conventional geometry following the Code is a useful first step in the design of a system. In tall rooms special problems occur, especially when the spaces are heated, as there is a strong possibility of a layer of warm air building up at ceiling level making it difficult for the early plume of smoke rising from a small fire to reach the sensor. In this situation duplicate beam detectors could be placed at a lower height.


Fire Detection 9.4.2 In large spaces containing large windows, the cool surface of the glass will cause down draughts to develop. It may be an advantage to locate additional detectors at the bottom of such windows. 9.4.3 Many historic buildings will have complex layouts or distinctively proportioned rooms which, in addition to any aesthetic constraints, can complicate the design of the detection system. Expert advice will be required. 9.5

Signal Transmission within the Building

9.5.1 The principal techniques for signal transmission are by wire and by radio. 9.5.2 The majority of fire detection systems have their components linked by wire. The most common type of wire is mineral insulated copper covered cable (MICC). In these cables the conductor runs in an electrical insulation medium which has a high temperature resistance. The outer copper tube can be sheathed in plastic for durability or aesthetic reasons but this may not be necessary for many applications. Discrete installation can be restricted by the limits to which the cable can be bent. 9.5.3 Advances in control and indicating equipment have made it possible for a single wire run to be linked directly to as many as 200 sensors. This "addressable" type of system has a central controller that polls each device in turn using the unique electronic address of each sensor. The devices can be monitored very quickly; 200 sensors can be monitored in a few seconds 9.5.4 Until recently, the fire resistance of MICC wires was necessary to maintain the link between the sensor and the indicating equipment until the alarm signal was given. Now sensors can be addressed from either direction in a wiring loop. If part of the loop is damaged then each detector can be addressed from one direction or another and the location of the break defined.

9.6

Radio Signalling

9.6.1 The principal alternative to wires linking the sensors and the control system is radio. The use of radio technology to transmit signals from fire sensors to control and indicating equipment has developed over the last decade. Several commercial companies have made radio technology available. The detector heads incorporate batteries to power the detector and transmitter allowing installation without the difficulty of routing wiring through the building, which may be a great advantage in some buildings. Such systems rely on batteries in each sensor which will require changing at intervals and must therefore be reasonably accessible. The battery pack increases the bulk of the detector. This could be reduced if the power pack and the fire sensors could be separated. This would enable a smaller head to be fitted within the space in the building with the remainder housed in a suitable adjacent floor or wall void, provided that reasonable access is available for maintaining the equipment and changing batteries.


Chapter 9 9.6.2 Care must be taken in considering the suitability of this system to ensure that the signal can penetrate the building fabric. Recent research has indicted that the construction and geometry of some historic buildings can lead to them being unsuitable for this type of installation. 9.6.3 The possibility of electro-magnetic interference should be established and guarded against. For example, a building may be in area with a high level of radio activity, which can lead to interference and false alarms.

9.7

Appearance and Acceptability

9.7.1 Great care is needed in the selection, from the large range of systems and products available, of the most appropriate installation for a given building. In some buildings different types of detection may be required in different locations. 9.7.2 The installation of cabling for wired systems can be quite disruptive. Surface wiring can be visually intrusive, although in some buildings routes can be chosen to hide or minimise the effect. It may be acceptable to consider surface wiring as being reversible. The installation of concealed wiring, while hidden on completion, may result in significant damage to plasterwork and joinery finishes and cause hidden damage through, for example, the notching of joists. It may be a more appropriate installation in very dilapidated buildings undergoing repair or as part of the general upgrading of other electrical services. 9.7.3 Radio detectors can overcome some of the problems of cabling described above, particularly where it is important to avoid disrupting decorative finishes. Developments in miniaturisation are continuing and newer detectors are reducing in size. 9.7.4 Aspirating detectors can offer the least visual intrusion with tiny sensor points which are capable of being easily concealed. However, the system relies on these small tubes leading to larger (eg 25mm) plastic tubes connected to a quite large sensing and analysing box. This can lead to a disruptive installation procedure, although in many cases there may be existing spaces suitable to house the installation. 9.7.5 Systems must be designed with care to provide detection in all the volumes at risk, including attics, roof voids and other spaces, to ensure complete cover. 9.7.6 It is now quite common to install hybrid systems incorporating several types of detector. Combining radio signalling for detectors in visually sensitive areas with hard-wired links elsewhere is also possible. The use of microprocessor driven "addressable" systems can give a great deal of flexibility to allow the design of a detection systeril to be tailored specifically to suit an individual building.


CHAPTER 10

ALARM, ESCAPE, LIGHTING & SIGNS

10.1

Alarm and Communication

10.1.1 The successful installation of a fire detection system into a building can only be judged on its ability to communicate the presence of a fire. The objectives of a detection and alarm system are to enable the following: the early and orderly evacuation of the building, the alerting of the emergency services, including fire fighting personnel, the activation of fire suppression systems, if installed (see Chapter 1l), the activation of smoke control systems at the early stages of a fire (see Chapter 12), the release of magnetic door hold-open equipment and dampers, the shutting down of key mechanical and electrical systems. 10.1.2 The physical implications of alarm, evacuation and fire fighting requirements are far reaching in all buildings. The Building Standards (Scotland) Regulations, British Standards and other legislation can be quite detailed and they contain many specific and sometimes quite onerous requirements which may be difficult to achieve in historic buildings. Much of this is concerned with life safety, for example the design of escape routes or of protected zones. The nature and amount of written material involved are beyond the scope of this Technical Advice Note, therefore this chapter is intended to draw attention to the key areas where the physical installations impinge on the fabric and appearance of historic buildings. 10.2

Fire Warning System

10.2.1 The automatic detection system or activation of a manual call point will initiate the alarm signal. In some buildings the system can be quite sophisticated to allow phased evacuation of the building or evacuation from an area at risk to another protected part of the building. 10.2.2 Careful consideration should be given to fire alarm audibility as it may be difficult to achieve the minimum levels specified in the British Standard, particularly where people may be asleep in the building. Special consideration will also have to be given to buildings occupied or visited by people with disabilities, including profoundly deaf, blind or partially sighted people. Types of alarm include: Audible - bells, sirens, electronic sounders. In some complex buildings there may be a need for voice warning and guidance as to escape routes (by pre-recorded messages),


Chapter 10 Visual - usually in the form of stroboscopic lights or beacons with rotating mirrors. The colour of the light within the context of the space is important and the periodicity of the light requires careful attention as it may, in some people, induce nausea or fits, Tactile - ripple pillows or mats, vibrating arm bands or other similar devices. The design of warning systems for people with disabilities is a specialised field and is beyond the scope of this Technical Advice Note. 10.2.3 The best detection system will be of little use unless alarm, evacuation and fire fighting procedures are established. A fire alarm panel on an "addressable" detection system can provide information on the precise location of the fire. Detection and alarm systems can be linked directly by a dedicated telephone link to a central control point which automatically alerts the fire services. A more economical, but less reliable method using auto-dial equipment can also communicate this message.

10.3

Evacuation Procedures and Fire Fighting

10.3.1 Chapter 5 set out the need for formalised management procedures and training to ensure the most effective action in the event of a fire. These procedures will be different for each building and are outwith the scope of this Technical Advice Note. 10.3.2 Small fires may be fought by trained staff or occupants using portable extinguishers. Early warning and knowledge of the location of the fire will increase the chance of success. The effective deployment of the fire brigade will depend on their prompt arrival at the scene, and early detection and alarm are essential, particularly where the building is unoccupied or in a remote location.

10.4

The Design and Installation of Fire Alarm Systems

10.4.1 The Code of Practice (BS 5839 : Series) provides guidance on the installation of all types of detection and alarm systems ranging from the single smoke alarm to complete sophisticated warning systems. The British Fire Protection Systems Association has produced a code of practice on voice alarm systems. This is likely to become BS 5839 : Part 8. 10.4.2 Domestic smoke alarms to BS 5446 may be installed in smaller domestic properties, but owners should be aware that these may be limited in effect. It should be ensured that all such detectors are interlinked and that the system is powered from the mains electricity supply with battery back up. Such systems do not send signals beyond the building. Therefore, a continuous human presence is advised - and a-telephone to summon the emergency services and other assistance.


Alarm, Escape, Lighting and Signs 10.4.3 As with detection systems, the installation of alarm systems may have significant impact on the fabric of historic buildings and great care is needed in selecting and locating devices. Sounders are not required to be red and can be chosen or painted to be less intrusive (provided functioning is not impaired). Audibility tests may help in choosing less obtrusive installations - for example, two sounders located in passageways outside either end of a "principal room" may give adequate sound levels, as opposed to one sounder within the room. 10.4.4 The installation of wiring can be disruptive to finishes and needs careful consideration. Radio signalling between the detectors and the alarm systems (including the sounders) over short and long distances, can be designed and installed. The principal advantage in historic buildings is the avoidance of disruption to the fabric. 10.4.5 Many unwanted fire signals are the result of the actions of employees or contractors who may not be aware that an automatic fire detection system is in operation. The problem of false or unwanted alarms must be addressed in the fire management procedures (see Chapter 5). 10.5

Escape Routes and Signs

10.5.1 All routes leading from rooms within buildings must be clearly defined so as to allow occupants to escape once the alarm has been raised in a fire. The visual information which must be received by someone during evacuation of the building must be clear and readily understood. Some escape routes may be complex, with geometries which confuse, causing the effort required to escape to increase, and proper lighting and clear signs are therefore essential. 10.5.2 The need for signs to assist evacuation from a building is covered by a number of regulations. (See Appendix 111). Signs need not carry complex messages, they may be simple pictorial indicators which are now widely understood in most countries. Legislation requires certain signs to be illuminated so that they are visible in the event of a power failure in the building. Some exit signs may require to be self-illuminated, others may be indirectly lit from adjacent emergency light fittings. Some recent developments have produced electro or photo luminescent signs, fluorescent signs and light emitting diodes or miniature incandescent lamps, all of which can reduce the impact of standard lights and signs in a building.

10.6

Lighting

10.6.1 Lighting is required to enable people to make their way out of the building safely and quickly; it is also needed to provide illumination of safety signs and equipment. Emergency lighting is designed to operate or remain lit after the failure of normal lighting power supplies and is often necessary to satisfy Building Regulations and other legislation. There is a wide range of standard products available for this purpose. Many of the


Chapter 10 standard products are unfortunately not aesthetically appropriate for use in historic buildings. Alternatives which avoid the need for standard emergency luminaires could include the use of some existing light fittings adapted for use in emergencies. This can be achieved by connection to a power supply which is available when ordinary power supplies fail. The use of photoluminescent surfaces which emit sufficient illumination to satisfy the standards may be considered. The level of lighting required in conventional emergency light systems at the end of the required performance period (which may be from 1-3 hours) need be no more than 0.2 lux for defined escape routes, the equivalent of bright moonlight. An average of 1 lux is required for undefined escape routes (BS 5266). These compare with 200 lux which is accepted as the level needed to comfortably read a book.

10.7

Selection

10.7.1 The fire risk assessment of a building and the requirements of applicable regulations will dictate the nature and scope of the installations necessary to give the desired level of protection to the property. The selection and assessment of the components from the wide range available is a complex task, however it is possible to minimise the intrusion of detection, alarm, signage and lighting systems by careful design and a knowledge of what is available commercially. In certain spaces the quality of the historic fabric may require fittings to be specially designed or adapted to meet legal requirements while also being suited to the surroundings. Clearly, specialised knowledge is required and it is important that fire safety advisers work closely with other consultants responsible for the conservation of the building to ensure the greatest level of sympathetic integration of these elements into the building.


CHAPTER l 1

FIRE SUPPRESSION

11.1

Introduction

1 1.1.1 The control of a growing fire in any building is a major factor in limiting fire loss. Generally, the size of the fire at the time of control being first exercised can be related to the eventual extent of the loss. This section deals with the control of fire through the introduction of systems designed to inhibit fire growth. Inhibitors include fire suppressants and fire extinguishants. The materials may be gaseous, liquid or solid and can be introduced into the burning zone either locally or generally. 1 1.1.2 Local application could be the use of hand-operated or portable fire extinguishers, or could be the application of piped extinguishant where this takes place in only that part of the volume containing the risk. Hand operated extinguishers should be provided in all buildings, especially those which are open to the public. The effectiveness of an extinguisher is dependant upon its operational characteristics, including the extinguishant, and the training of the people who are expected to be able to use it. 1 1.1.3 Because of the possible dangers to untrained operators of fire hose

reels, where users may remain longer in the location of a growing fire than is safe, their provision should be carefully considered. This is particularly relevant where large or complex buildings are concerned, or where no trained staff will be on hand. The difficulty of installing hose reels into historic buildings without causing damage may in any case make this option impractical. 11.l .4 Sprinkler systems have a proven track record of effectiveness. However to give an even degree of protection to a building, a network of piping is required; and in many cases the degree of disruption to the fabric may be unacceptable. Where building are badly dilapidated, where major repair or other new work is proposed, the installation of pipework may be more easily accommodated as part of the general work to the building. 11.1.5 In addition to the pipework itself, consideration has to be given to other components of the system. A reliable water supply is required and in some cases large tanks may have to be accommodated. (At Duff House, Banff, these were buried under a lawn). Pumps may be necessary and the whole installation will require regular maintenance. Accidental discharge must be avoided and this may require protective cages, for example, in roof spaces. Frost protection involving trace heating and adequate insulation to vulnerable pipework must be used. As with fires extinguished using water hoses, the drainage of water after a fire and the means of drying out the fabric requires consideration.

63


Chapter 11

11.1.6 The value of the material at risk must also be considered. For example, at the National Library of Scotland, Edinburgh, and at Duff House, Banff, the contents required a special degree of protection over and above considerations for the building fabric.

11.2

Water systems

11.2.1 The most common liquid used as an extinguishant is water, either in the form of a spray or mist. In addition to the need for distribution and controls, these rely on an available water supply, independent of the domestic system. This frequently requires a large water storage capacity to be located close at hand.

Traditional water systems 11.2.2 The hand held water-filled extinguisher may be the first line of fire fighting and can be effective, particularly if users have had some basic training. They should not generally be used in fires where electricity or liquids are involved.

11.2.3 Hoses distributing pumped water may be used by fire brigades, sometimes utilising dry or wet risers. These are fured pipework systems within a building. Dry risers allow the fire brigade to pump water through the system while wet risers are charged with water at pressure ready for use. Both systems obviate the need for the fire brigade to deploy long lengths of hose. Large amounts of water can be supplied quickly to the fire area. The amount of water supplied may ultimately have a detrimental effect on the fabric of adjacent areas but may be an acceptable method of suppression in many cases.

Sprinkler systems 11.2.4 Sprinkler systems have been in use for more than 100 years and represent a well tried system of fire suppression. The operational characteristics of sprinklers vary widely according to the application for which they are designed. The essential components of a sprinkler system are the water supply, a pipe network, sprinkler heads, and an activating device. Pumps are also generally needed. The release of water is activated by preset temperature sensing devices. The time periods of the system response can vary with the amount of heat generated by the combustible materials and other properties of the constructional systems in the building, and the systems can thus be designed by appropriate sensor location to be very quick or delayed by several minutes after ignition. 11.2.5 Different sprinkler heads (identified by colour) respond at different temperatures and can be selected to suit the circumstances. Many fires are controlled by the release of water from only 1 or 2 heads. Modem control systems can introduce increasing degrees of control, for example sprinkler


Fire Suppression heads which will shut off when the temperature drops. Quick response sprinkler heads or activation by other sensing devices such as optical detectors as discussed in chapter 9, have become available. Similarly, Early Suppression Fast Response systems have become used widely in commercial properties and in places of public assembly. These systems often have extra large orifice sprinkler heads which create very large drops from which sufficient water is available to penetrate the hottest part of the fire. 11.2.6 There are two principal patterns of water delivery from the sprinkler heads. The most common is the umbrella-shaped overhead spray, the alternative is the sidewall sprinkler which produces a horizontal throw of water for a distance up to about 6 metres. Both types of head were recently installed in Duff House. Sprinkler heads can be recessed into wall or ceiling surfaces to give a flush finish, but care is required during subsequent redecoration to avoid impairing their performance. 11.2.7 Well designed sprinkler systems with efficient controls can be extremely effective in preventing fire growth. Water damage can be minimised and there is a strong argument that limited water damage is preferable to the total loss of material by fire. 11.2.8 A recent example is the design and installation of a sprinkler system in the National Library of Scotland. The main installation is in the book stacks. Here the stainless steel pipework is positioned with accuracy (within 10 mm of the design location). A secondary benefit in this case is that warm water is circulated in the pipes to provide background heating.

Water mist systems 11.2.9 Water mist is a distribution of very small water particles. The advantages of such systems are that very small quantities of water are needed, the speed of extinguishment is very rapid, the medium is readily available, it is environmentally benign and there are no toxic products. 11.2.10Water mist applications have been developed for cabins and engine rooms in ships; electrical and electronic systems in cabinets; turbine enclosures; paint and chemical hoods and aircraft engines; food processing machinery; and for explosion protection. The Loss Prevention Council are investigating the value of water mist systems for application in low hazard spaces such as libraries as there may be the opportunity for water sprays to replace sprinkler systems. 11.2.1 lResearch work with water mist systems in Norway has shown that such systems can protect historic buildings in an effective manner. A system of water mist pipework has been developed for stave churches (which are vulnerable to fire as they are built from small sections of wood and are coated with tar). When a temperature of 170 degrees Celsius is sensed by the system, water mist is released in the affected part of the church. The


Chapter 11 system extends to the whole of the church floor in which "pop-up" mist delivery pipes are housed. The effectiveness of the spray to combat typical malicious fires has been proved in the test building. The amount of water used to extinguish a fire was very small - (260 litres to protect a 200 cu m. space in 40 seconds). In another test, only 22 litres of water were needed to extinguish a ground level malicious fire. The tests indicate the system to have major potential as a positive and fast method of fire control. However for small smouldering fires the effectiveness of water mist is still to be proven.

Water spray systems 11.2.12 In spray systems, the particle distribution is slightly different from that of mist. Larger particles are produced and there is a higher proportion of larger droplets. The special application is for spaces which contain electrical transformers. The possible application of water sprays to historic buildings is uncertain.

11.3

Dry powder Systems

11.3.1 Where the use of a clean extinguishing agent is not essential then dry powder systems will provide a very efficient means of rapid fire extinction. They are commonly used to protect areas of special risk such as cooker hoods, boiler rooms and main cable ducts. They are, however, ineffective where fires are likely to re-ignite, as would be the case with flammable liquids. The particles in the powders affect the active particles in the flame so that the reactions in the flame are stopped. The residues of some dry powders are likely to adversely affect polished wooden surfaces, marble and other fine finishes 11.3.2 Dry powder systems are not practical for total room discharge applications. They are commonly used only for local application.

11.4

Foam systems

11.4.1 Low expansion and high-expansion foams are available. Both types are mixtures of water and additives aspirated by the inclusion of air. Low expansion foam expands to approximately 10 times the volume of the liquid mixture, whilst high expansion foam can reach up to 1000 times its original volume. The action of both types is to exclude air from the burning zone, thus they can only be employed where no occupants are present. 11.4.2 Local applications, such as hand held devices to address small fires in basement boiler rooms, have been tried with mixed success. It may be possible to consider using high expansion foams on a wider scale in certain large volume spaces. 11.4.3 The compatibility of the surfaces in the space (including all contents) with the active chemicals in a foam mixture must be considered.


Fire Suppression

11.5

Gaseous systems

11.5.1 Gaseous systems are effective in terms of limiting fire growth but they need to be regarded as most useful in special, high risk circumstances. A major problem is that of the leakage of the building generally and of the space to be filled with extinguishant especially. Gaseous extinguishants are available in portable form (which can be large cylinders on trolleys), as well as in futed pipe networks. 11.5.2 The main advantage of gaseous systems is the availability of "clean" extinguishing agents which do not damage the remaining fabric. 11.5.3 The inflow of inert gases will result in a reduction in the level of oxygen in the atmosphere. This reduction can be tolerated for short periods only. However, breathing is affected (rapid breathing may be induced) and this must be carefully assessed in relation to those in the building. The timing of the release of extinguishant in relation to escape times for occupants is a major consideration. In all cases a control system will be required to phase the release of gas. 11.5.4 Storage areas for the gas bottles and a piped network to discharge nozzles are required. The volume of gas required and the pressure at which it is stored dictates the size and type of the storage vessels. In some cases these can be large and heavy. This may well present particular difficulties in installing these systems in historic buildings. 11.5.5 To date such systems have been developed for the protection of electrical and electronic hazards, telecommunications systems, electronic data systems, flammable liquids and flammable gases. There are currently no examples of historic buildings being effectively protected by gaseous systems. Research indicates that the largest practical space which can be so protected in an historic building may be an archive or muniment room. 11.5.6 Research has been progressing to find effective replacements for halon which has been removed from use through legislation against gases which are harmful to the environment. The choice is between inert gases and halocarbons. Several manufacturers have developed inert gas mixtures that perform by reducing the oxygen concentration in the protected space. The gases in this mixture are nitrogen, carbon dioxide and argon. Systems must be carefully designed to take account of the risk from the gases to occupants of protected areas, and the risk of corrosive by-products to fabric and contents. 11.5.7 Carbon dioxide has been used for many years as a gaseous fire controller. It can be introduced into the space containing the fire locally or by total flooding.


Chapter 11

11.6

Conclusion

11.6.1 In many cases it is possible to install systems to control fires in historic buildings. The selection of the most appropriate system or systems for a particular situation should be preceded by a careful survey of the risk to be protected. The principal criterion for choice could be the speed of action should a fire occur. This will depend on many aspects of the potential fire and the response characteristics of the systems. The building fabric and contents must be carefully assessed in terms of possible irreversible chemical damage caused by some fire suppression media. Equally a carefully designed suppression system may be able to control a fire with only a limited release of suppressant. In many instances this may be far more acceptable than the total loss of fabric or contents caused by fire. 11.6.2 The disruption to the building fabric caused by installing extensive pipework requires careful consideration and may be more acceptable when, for example, repairing a badly dilapidated building, than in buildings with undisturbed original fabric. 11.6.3 Regular maintenance and testing of the equipment is essential and this requires adequate access. Associated equipment will include pumps, frost protection measures which involves cabling, and fail-safe measures such as back up pumps and standby generators to cope with mains failure. Plate 22 : Duff House, Banff. The recently installed sprinkler system required on-site water storage which was concealed under the lawn adjacent to the building. The chamber also contains pumping equipment and back up facilities in case of mains power failure. All of these require a substantial amount of space. Regular maintenance and testing of the equipment is essential.


CHAPTER 12

SMOKE AND ITS CONTROL

12.1

The Hazards of Smoke

12.1.1 Smoke is made up of particles and gases produced by the burning fuel, diluted with the other gases present in air. 12.1.2 During combustion many toxic or irritant gases can form, such as carbon monoxide, hydrogen chloride, nitreous oxides and hydrogen cyanide. Mixtures of these may be more toxic than any of the individual gases. There are also safe visibility limits through gas and particles, beyond which escape will be dacult. The presence of smoke can delay or prevent evacuation and also hamper the positive actions of those fighting the fire. Statistics show that 60% of the victims of fire have succumbed to the effects of smoke and toxic gases. 12.1.3 Due to the pervading nature of the spread of smoke through a building if un-checked, the potential for loss of the building fabric and contents through smoke damage as a result of a fire is much greater than through that of fire or heat damage. It is therefore essential to understand the effects of smoke during a fire when considering fire risk. 12.1.4 Smoke control is one aspect of fire risk policy design which allows specialist fire consultants to calculate anticipated smoke flows and to design methods of its control or dispersal. There may be huge benefits to be derived from relatively simple smoke control measures in the protection of life and of property. 12.2

The Effects of Smoke on building fabric and contents

12.2.1 Smoke damage to the fabric and contents of a historic building may be long-lasting and often permanent. Apart from the most obvious surface deposits of soot and grime, the acidic nature of smoke may cause permanent degradation of many materials. The range of effects will depend on the distance of the smoke from the materials which are being burned. Plastered walls, stonework and wooden surfaces that are only briefly immersed in smoke can be washed clean; however, the penetrating effect of the "heavy" constituents of smoke may also have occurred, and this can result in more long term damage becoming apparent many months after immersion. In post-fire evaluation, the effects of smoke damage should not be underestimated. 12.2.2 In historic buildings valuable surface treatments such as wallpapers and paint and contents such as upholstery, floor coverings, wall hangings,


Chapter 12 paintings and muniments can be damaged. The cleaning techniques required in such cases will demand highly specialised skills.

12.3

Smoke Control Techniques

12.3.1 The principal concepts of smoke control are containment and release. These can be achieved by a combination of active and passive techniques. It is recommended that in anything other than the simplest buildings, specialist advice should be sought on application of smoke control techniques. 12.3.2 Smoke control systems are designed to contribute to life safety and damage limitation. During an assessment of risk of a historic building, the degree of vulnerability and value of the building and contents should be considered. The purposes of smoke control can be set out as follows: to enhance the standard of life safety to reduce the potential for damage to contents to reduce the potential for damage to fabric to assist fire fighting to enable effective post-fire purging of accumulated smoke

12.4

Smoke Control Methods

12.4.1 The main features of a space or spaces to be considered are volume, geometrical complexity and criticality. Volume is a simple measurement of the cubic content of the space. Geometrical complexity allows for uneven smoke spread in a space, for example, the presence of a balcony under which smoke may be contained within a larger space. Criticality is based on an assessment of values, including life safety and historic value of fabric and contents. In making recommendations which involve physical changes to the building, these must be carefully considered in relation to the likely benefits obtained in reducing the overall risk. The following techniques may be considered: 12.4.2 Containment by smoke filling - This is the simplest technique which essentially allows the room in which a fire starts to fill with smoke (usually from the ceiling downwards).

Fig. 8 : Containment by smoke filling.


Smoke and its Control A common example is the use of smoke doors to isolate corridors or stairwells. The technique allows sufficient time for occupants to escape, but sacrifices the fabric and any contents of the space to the full effects of smoke damage. It is desirable to have available some method of removing (purging) smoke during and after the fire. 12.4.3 Containment by construction - This technique is similar to 'smoke filling' but with a recognition that smoke should not be allowed to escape into adjacent spaces. There is a reliance on the completeness of the construction of walls and floors of the space. This will require careful assessment of these elements, including any potential weaknesses such as hatches, doors, windows and ventilation openings.

Fig. 9 : Containment by construction.

12.4.4 Active pressurisation - This is a positive technique of smoke control which involves the generation of differential air pressures between adjacent spaces. The creation of a higher pressure in the spaces to be protected or a lower pressure in spaces to be sacrificed will have the same effect. The principle is simple, but in practice is made complex by leakages which occur through the separating walls or floor. The installation of pressurisation fans into historic buildings would require careful consideration.

Fig. l0 : Active pressurisation.


Chapter 12 12.4.5 Natural release ventilation - The objective of this technique is to allow smoke to flow out of the top of the space which contains the fire. In order to achieve this the space must be immediately adjacent to the roof of the building and fresh air must be able to flow easily into the space either directly or by fan-assistance. Following a fire in the south transept of York Minster in 1986, the lead covered roof has been provided with hatches which will open when fusible metal links activate catches on reaching a predetermined temperature. Fig. 11 : Natural release ventilation.

12.4.6 Release cross-ventilation - this method utilises windows or other openings which serve to disperse smoke. As with 12.4.6 replacement air supply is necessary. This technique requires more complex calculations to allow for the effects of wind direction and strength.

Fig. 12 : Release cross-ventilation.

12.4.7 Fire suppression - One of the beneficial side-effects of fire suppression systems such as sprinkler installations is in the control of smoke yield.

12.5

Application

12.5.1 Careful collaboration between the fire consultant and other professionals is essential in order to minimise the disruption to the building fabric. For example roof hatches could be sized to fit between timber roof members and be located on less visible, inner roof slopes.


CHAPTER 13

FIRE ENGINEERING AND HISTORIC BUILDINGS

13.1

What is Fire Engineering?

13.1.1 Within the last 20 years Fire Engineering has developed into a recognised discipline with a professional organisation, several established courses and a growing body of expertise. In spite of this few people outside the discipline understand fully what is meant by "fire engineering" and a good, simple definition is elusive. However the objectives of fire engineering are more readily definable and can be seen as; ensuring the safety of the occupants of a building and others who may be affected by a fire,

preserving heritage by protecting property, contents and artefacts from fire, preventing or minimising environmental damage, minimising damage to the fabric and contents of a building should fire occur, prevention of fire spread to other buildings. 13.1.2 These, of course, are precisely the concerns of this Technical Advice Note. In the preceding chapters the methods of achieving these objectives can be seen to range from the common sense, or organisational approach to fire prevention to the use of often very technical devices to detect and combat fire. Fire engineering is the application of engineering (science based) methods to the processes of fire risk assessment and the application of fire precaution measures. Engineering methods encompass.. . research and investigation - identifying fire risks and threats; establishing the physical and environmental conditions, evaluation of data; assessing levels of application; predicting outcomes, testing and verification of results (this will include component selection and evaluation), application, appraisal in uselfeed-back. 13.2

The changing approach to setting standards

13.2.1 Regulations involving fire precautions have generally evolved to become functional requirements supported by detailed Technical Standards. When these regulations are applied inflexibly to historic buildings this can lead to difficulties either in terms of forcing alteration on the building or


Chapter 13 through the need to seek relaxations from the regulations. Recent trends in the UK (as elsewhere in Europe) have been away from prescriptive regulations towards performance based standards. 13.2.2 A fire engineering approach can achieve balance between the various elements of fire safety planning and particular conservation issues in order to achieve an optimum application for each building. Building owners and their advisers, faced with the application of the building regulations or other legislation can seek alternative or compensatory measures in order to work within the constrzints of the building. 13.3

Balancing Fire Engineering with Conservation Aims

13.3.1 Fire engineering technology is based on well defined components that can be considered in terms of effectiveness and practicability. fire safety management fire prevention fire detection and alarm means of escape control of fire growth control of fire spread structural stability smoke control fire fighting 13.3.2 Balanced against these are the particular demands which an historic building will place on the process: site location and accessibility form and layout of building age and value occupancy and use location and character of important spaces quality of finishes contents 13.3.3 The consideration of both sets of components will inevitably be complex and a combination of professional advisors may have to be involved.


Fire Engineering and Historic Buildings 13.4

Level of Fire Engineering Practice

13.4.1 In work affecting historic buildings the level of fire engineering practice which is required will depend on the use, complexity and historic value of the particular building and will involve each of the following being combined with a thorough understanding of the particular building, how it is constructed and the likely effect of practical fire engineering solutions: Judgement based on experience, published guides and real fire experience. Application of codified experience - Building Standards (Scotland) Regulations, British Standards, legislation and other codes such as those produced by certain sectors of industry, set against the constraints consequent on their adoption. Compensatory engineering - looking at alternative components or systems to balance performance against existing values. Lateral thinking is essential in dealing with historic buildings. Quantitative analysis - for example, the mathematical probability of fire occurring or the results of commissioning tests assessed against an understanding of the particular building. Computer modelling andor simulation based on the level of detailed survey and analysis required to understand the building. 13.4.2 To achieve an optimum approach to fire safety requires the application of engineering principles and expert judgement based on a knowledge of human behaviour and a scientific understanding of the phenomena of fire and its effects. The challenge is to achieve this within the constraints of historic buildings.

13.5

Fire Safety Engineering Methods

13.5.1 There are four principle stages in the process. The first is a qualitative assessment of the problems, to arrive at a brief, with design criteria which are specific to the building and the fire risks. This should include consideration of all the points listed at 13.3.1 and 13.3.2. 13.5.2 A quantitative analysis is then carried out which gives values in numerical terms to the design criteria and suggests available options with differing levels of benefit and differing levels of intervention within the historic structure and its details. 13.5.3 These result in recommendations being made which are assessed against the criteria to see if they are acceptable. 13.5.4 The analysis and recommendations are then presented to the decision making group.


Chapter 13

13.6

Application to Historic Buildings

13.6.1 The most common application of quantitative or numerical techniques is for the design of components of fire safety. For example, the design of systems such as warning systems, smoke control systems and fire suppression systems, or passive components such as compartmentation. For historic buildings the ability to test various components against each other or in combination is a significant benefit over less structured analysis. For example, where the need to avoid or minimise intervention may prevent effective compartmentation, greater weight may be placed on other components such as detection, suppression or smoke control systems. 13.6.2 Some components cannot be calculated but can be organised rationally to make a positive contribution to fire safety, for example, the training of staff in fire safety matters and the arrangements for fire emergency pre-planning. The benefits of some of this activity may become quantitative, for example, the effectiveness of fire extinguishers in controlling small fires can be as high as 98% but in untrained hands a much lower value can be expected.

Plate 23 : Duff House, Banff, William Adam, 1735-39. Restored in 1995 to form an art gallery with associated visitor and educational facilities. A fire safety consultant was appointed and a fire risk assessment was carried out. The principal recommendations were to improve the fire containment properties of the construction, install a fire detection system and a fire suppression system. The sprinkler system required the provision of water storage as there was insufficient mains supply. An underground storage and pumping chamber was built, concealed beneath the lawn to the right of the house (see Plate 22).

13.6.3 The level of fire engineering applied to historic buildings will vary according to the identified fire hazards and the importance attached to the building structure, finishes and contents. The components of fire safety each have a differing impact on the building in terms of intervention, and there are major advantages in using a fire engineering approach to balance


Fire Engineering and Historic Buildings and select the most appropriate applications. These advantages can be seen as : Each risk can be assessed individually. Precise safety objectives can be used as a basis for design. Life safety and property protection aspects can be considered simultaneously. Relative merits of design solutions can be compared. Safety capability can be re-assessed if the use of the building changes. Each building can be treated as an unique entity.

Plate 24 : Duff House, Interior. An aspirating smoke detector sensing point is concealed at the top of the chandelier chain and sprinkler heads are carefully set and disguised within the decorative plaster ceiling.

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CHAPTER 14

FOOTNOTE

14.1 The potential for loss from fire in an historic building is a significant risk, of which all associated with their care should be aware. Because of the special nature of historic buildings as cultural resources, it is inevitable that there will be risks that cannot be eliminated. There are many cornrnonsense precautions which can be taken at little significant cost, but there will be others where cost will be secondary to the need to protect in the most appropriate way. 14.2 Apart from physical intervention, the role of management and planning can reduce the burden of risk. The need to seek and obtain advice from the right source at the right time is fundamental to the process. 14.3 In the duration of this study it is inevitable that areas which may eventually be fruitful in unlocking new approaches to fire precautions in historic buildings have had to be left unaddressed. It is hoped that further papers will follow as a result of the research done to date. The constant reviewing of existing knowledge and of new techniques and technologies must lead to less intrusive and therefore less damaging solutions to the protection of historic buildings from fire.


APPENDIX I

CASE STUDY l Moy House, near Forres, Moray

Location Building type Date of fire

: : :

Moy House, near Forres, Moray 17 - 1gthcentury private house, 'A' listed. 18 August 1995

Plate 25 : The building shell after the fire. (see also Plate 1 for an account of the fire).

The house had been built in three main phases. In the early hours of Friday morning 18 August 1995 a fire began in one of the wings and spread quickly to other parts of the house. Although ten people were in the house at the time of the fire they escaped relatively unharmed. Much of the house was destroyed, leaving an incomplete masonry shell.

The Cause: Although the direct cause of the fire is unknown it was noted to have started in an unused two storey workshop. The Fire Spread: The initial route for the fire was in the cavities in the walls between the lath and plaster and the surface of the masonry wall. This cavity was vertically and horizontally continuous in most of the central section of the house. After the flames reached the roof space the fire spread on the inner surfaces of the roof very quickly. The greater part of the roof was burnt away, save for a few charred remains of rafters. Observations: 1. The wall cavities and other voids within the house allowed the fire to spread rapidly. 2. In various parts of the building heavy timber beams had fallen to lower levels and exhibited extensive and deep char patterns, most of the joists and all the floor boards had been burnt away.


Appendix I : Case Study, Moy House 3. The main staircase (approached from the principal door) had collapsed. The pattern of failure, with only one third of the stone cantilever steps remaining is typical of fire damage to a stone staircase.

4. The initial response from the local fire station was prompt but it became clear on their arrival that the fire was beyond the control of the two appliances. During the night a total of 10 appliances arrived with 70 fire fighters. 5. The water supply to the house was a domestic supply only and no better supply was found in the immediate vicinity of the house. A stream was located 400 metres away and a water relay was laid. The lack of proper water supply prevented the hoses from being completely effective. The main fire fighting effort continued for 13 hours.

6. Most of the external masonry walls were intact after the fire. Plate 26: The interior was reduced to a burnt out shell. Fire spread through various cavities and consumed the roof and most of the internal timber.


CASE STUDY 2 Kilkerran House, Maybole, Ayrshire

Location Building type Date of f i e

: Kilkerran House, Maybole, Ayrshire : Late 18th century house with later additions : 17 April 1994

Plate 27: The fire started in the room at first floor in the wing on the right with the curved end elevation.

A fire occurred in the first floor drawing room of this isolated four storey house in the early morning of 17 April 1994.

The Cause: An open wood-burning fire was in the fireplace, and sparks from burning green wood had been extinguished by the owner the previous evening. Examination found a cracked hearthstone sitting on the wooden floor construction, but careful investigation suggests this was not the cause. As the seat of the fire was situated about 1.5 metres from the open fireplace, it is reasonable to assume that the fire was caused by a burning spark from the open fire igniting the carpet.

The Fire Spread: It is believed that the fire smouldered for some considerable time, until the floor boards burnt through. Although there was a substantial amount of ash deafening below the floor boards, there was also free ventilation, due to a ceiling void below the floor, and the fact that the lath and plaster walls of the unused double-storey kitchen below had been stripped as part of a dry rot treatment, leaving air gaps all round the edge of the suspended ceiling. Although the fire also developed within the drawing room, its growth was limited by the fact that the air supply was restricted as both doors to the room were substantial, close fitting and shut at the time the fire developed. The main fire spread was within the wall and floor


Appendix I : Case Study, Kilkerran House structure of the building. It passed upwards behind the lath and plaster construction of the drawing room walls, into the floor1 ceiling construction above the drawing room, then up to the roof by means of the wooden stud/lath and plaster internal walls, and behind the wooden window shutter boxes on the external walls of the upper floor.

Observations: 1. There was no functional fire detection and alarm system. A system of smoke detectors passing signals over the mains electric wiring had been installed, but the control box had caught lire soon after installation. The firm concerned had ceased trading. Although this technology is used in baby alarms, to our knowledge, there are no fire detection and alarm systems marketed using this technology at the present time. There is no doubt that early detection and alarm would have reduced considerably the amount of damage caused by the fire. 2. An efficient spark guard should be provided and used when burning wood on open fires.

3. Open fires should not be burnt in fireplaces which have cracked hearth stones - they may well be sitting on wooden floorboards or joists. 4. The fire was effectively confined in the wing of the building by solid fire resisting walls (formerly the outer wall of the building), openings were fitted with substantial, well fitting doors which were shut. 5. Fire spread was principally within the wall and floor cavities.

6. The fire brigade had some difficulty in fighting the fire in the early stages due to lack of water. Water had to be pumped some considerable distance from the river. Plate 28 : The wall and ceilings of the room in which the fire started. To the left the ceiling plaster has been taken down by the fire fighters to enable the fire in the hidden voids to be extinguished. Fire spread to the rooms above through the voids in the external wall and floor, including one section where ash deafening had been removed previously.


CASE STUDY 3 Logie House, Fife

Location Building type Date of fire

Logie House, Dunfermline, Fife Early 1 9 ' ~century house in large grounds, occupied as family home : 6 January 1988 : :

Plate 29 : The fire started in the room on the right at first floor.

The fire started in the morning room after a 2 hour absence by the occupants. The room was destroyed but damage to the remainder of the house was limited to the effects of severe smoke and heat.

The Cause: The cause of the frre is said to have been an electrical fault in wiring within a skirting board adjacent to the fire place. The fireplace grate had also been used the previous day. The fire alarm was raised by an occupant of an adjacent wing after they were alerted by the sound of glass breaking in the morning room window. The Fire Spread: The fire spread to the contents of the room and appears to have travelled fairly rapidly into the cavities behind the lath and plaster linings. Although the flooring was affected, it retained its integrity. The lath and plaster ceiling with ash deafening also prevented fire spread to the rooms above. Observations: 1. The door of the room had been left open. This allowed smoke and hot gases to enter the central stair and thence to the rest of the first and the second storeys of the house.


CASE STUDY 4 Dunbar Parish Church, East Lothian Location Building type Date of fire

: : :

Dunbar, East Lothian Early 1 9 ' century ~ church, 'A' listed. January 1987

Plate 30 : The interior of the church was destroyed except for the tower.

The fire started within the roof space. Virtually all the timber work in the church was destroyed, although the upper levels of the tower were saved. Fire damage to the masonry within the Church was severe. The four walls and tower, of red sandstone, remained, and inside the Church two masonry arched colonnades remained standing, but in an unstable condition. The Cause: The fire was thought to have been caused by an electrical fault within the roof space.


Appendix I : c a s e s t u d y , Dunbar Parish Church

The Fire Spread: The fire spread throughout the roof, which was completely destroyed, and to the remaining internal timber. Long horizontal timbers were built into the inside face of the outer walls as nailing strips to take vertical strapping which in turn carried lath and plaster. These billgates were substantially burnt out of the wall. The upper part of the tower was saved, it is thought, by a heavy lath and plaster ceiling immediately above the vestibule. A valuable white marble or alabaster monument suffered badly under the intense heat and subsequently became the subject of extensive specialised restoration. The red sandstone of the great arch at the apse suffered deep spalling due to the intense heat and, possibly, the quenching effect of fire-fighting water. The circular sandstone columns of the colonnades also spalled severely, which, combined with the loss of (timber) restraint at the head, resulted in structural instability such that demolition was required. Observations: 1. The undivided nature of the roof space and voids within the construction allowed fire to spread rapidly throughout the Church. The substantial separation of the tower and presence of an effective barrier helped save that part of the building. 2. Apart from the catastrophic loss of the interior, the biggest problem related to the insurance settlement proposed by the loss adjusters. Since the whole of the Church together with the tower and belfry remained standing, and relatively stable for restoration, the proportion of the insured cost which this represented was achieved by the process often described as 'averaging'. In general terms this makes it almost impossible to achieve insurance cover for the total cost of restoration after a fire, since over-insurance would be frowned upon, and there will almost invariably be a large masonry shell remaining. Advice on insurance is given in Appendix VI.

3. Regular inspection, testing and maintenance of electrical installations, properly rated fuses or breakers for all electrical circuits and close attention to maintenance are essential to the prevention of this type of fire.


CASE STUDY 5 Torsonce House, Stow, Roxburghshire

Location Building type Date of fire

Torsonce House, Stow, Roxburghshire. Victorian house (1868) with Edwardian additions, set in grounds on steep wooded hillside. Unlisted. 22 January 1992

Plate 3 1 : The building shell after the fire.

The Cause: An electrical fault is thought to have caused the fire which quickly spread to destroy all the external upper floors and roof. The Fire Spread: A likely path of fire spread may have been the cavities of the brick walls, into which floor timbers were built. Observations: 1. After the fire, all the external walls still stood, albeit the upper parts of the 3 storey walls had been weakened. After assessment it was decided to rebuild the house with some modifications. '

2. A decision was taken to salvage and reuse as many original components as possible, and this meant a laborious and often difficult task of measuring, noting and photographing hundreds of elements. The most significant elements which were saved were the massive stone window units complete with moulded mullions, transoms and margins, together with their metal casement windows, which were "tied" together, complete with their bronze security bars and lifted in one piece from the ruins. The largest of these units measured 5 X 2 metres. 3. Further details of the fire, post fire salvage and the restoration process can be found in the SSCR Journal Vol. 7, No. 4, November 1996.


APPENDIX I1

GLOSSARY

addressable: a system where a central control system communicates with all of the sensors in a circuit individually and a unique response is gained from the sensor. criticality: an assessment of the relative importance of a fire safety measure, OR an assessment of the people and property at risk to decide on the level of vulnerability to attack by fire. fire breaks: the designed space between "packages" or blocks or stands of combustible material so that it is unlikely that fire will spread from one package to the next. fire consultant: a person who is knowledgeable about aspects of fire safety design and who is aware of the performance characteristics of the components of fire safety technology. fire engineering: the use of appropriate logic, science and technology to minimise the losses should a fire occur in a particular part of a building. (fire) management plan: see fire plan. fire plans: the management arrangements, which are set down in a document, for the operations needed when a fire occurs. fire precautions: a group of management techniques and physical parts of buildings that will reduce the loss impact of a fire in the building. fire prevention: the management of the building and its contents and its occupants with the objective of reducing the chance of ignition. fire protection: the function of those parts of a building which will retard the progress of a fire. fire rating: a performance expectation that relates directly to performance in the standard tests specified in legislative or insurance requirements for a specific type of building. fire resistance: the ability of a constructional or services component of a building to withstand a standard test fire for a specified length of time with respect to integrity (no leakage of fire across the thickness of the specimen), insulation (that the non-fire exposed side of the specimen stays cool), and stability (that the


Appendix I1 component under test retains sufficient strength for the specified period of time).

fire retarding: a treatment on the surface of a material that will increase the time needed for the material to respond to increasing temperatures. fire routine: the actions to be carried out by the people in a building should a fire occur. fire safe spaces: volumes in a building into which fire is most unlikely to penetrate (for example, staircases enclosed with fire resisting passive construction). fire safety manager: a person in an organisation who will make professional assessment of fire risk and who will arrange for the maintenance of systems and arrange the training of the people in a building. fire safety manual: a document that is unique to a building which has technical descriptions of the fire safety systems installed in the building and describes their performance, materials and maintenance requirements. fire safety policy: the principal objectives arising from of a consideration of fire losses at national, local or single building levels. fire strategies: the intellectual consideration(s) of the management and technical aspects of fire safety in order to minimise potential loss due to fire. fire technology: the physical components of systems and services that are dedicated to the minimisation of loss due to fire. flashover: the stage in the progress of a fire when all of the combustible surfaces are sufficiently hot to produce volatile gases which will ignite rapidly over the whole of the space containing the fire. fusible ;links: metal components of systems (such as the mechanism of a roller shutter) that will melt at a predetermined temperature to allow a safety component to operate. hot. work permit: a document issued by a responsible person to a competent person indicating that the task to be undertaken is a fire hazard but that the best practice will be exercised. inhibitors: chemicals that will interfere with the ordinary sequence of combustion by altering the rate of response of the material to increasing temperatures. They may impregnate the material or , be a surface treatment.


Glossary passive: a generic term applied to those parts of a building that have a defined fire safety function such as a wall, door or floor. post-fire evaluation: an examination of the site of a fire to assess the problems and possible costs of repair andtor restoration. protected zone: that volume in a building that is surrounded by fire resisting construction - usually refers to corridors and staircases. purging: the removal of smoke from a space in a building during and after fire control procedures. seat (of the fire): the location in the building where a fire was most likely to have started. smoke detectors: sensors that will detect the presence of smoke from fires by measuring the optical density of the atmosphere or the concentration of solid particles in the air. snatch list: the list of objects in value rank order that should be removed from a building should those objects be threatened by fire. spontaneous combustion: the stage reached in a materid when no chemical or physical change is needed before that material ignites. suppression: the process of reducing the burning rate of the materials that have been ignited. thermal shock: the sudden exposure of the surface of a material to a large increase in temperature. volatile: evaporates readily at ordinary temperatures.



APPENDIX I11

LEGISLATION

1

Introduction

The following comments are intended to give some guidance on the 1.1 more generally applicable legislation. The range and scope of legislation which may apply to historic buildings and relates to fire safety is wide and diverse and changes are frequent. Those concerned should ensure that expert advice is obtained in order to ensure compliance and to assess the impact of any proposed changes in use or to the physical environment. The descriptions which follow must not be regarded as definitive. 2

Building Control Legislation

The Building (Scotland) Acts 1959 and 1970 (as amended) are the 2.1 principal vehicles governing the construction, alteration, extension and change of use of buildings in Scotland and are based on securing the health and safety of persons who are likely to be in and around buildings, and of the public generally. The Acts also cover the cases of dangerous buildings and demolition, and give power to the Secretary of State for Scotland to make Building Standards and Procedure Regulations, and to grant relaxations and dispensations from their requirements in certain circumstances. A building warrant is required for all building work (including demolition work - following a fire) and for changes in the use to which buildings are put. Building warrants will be obtained from the appropriate local authority.

Note : The need for a building warrant must not be confused with the requirements for other approvals under planning and listed building legislation. 2.2 The Building Standards (Scotland) Regulations 1990-1996 together with their mandatory Technical Standards, apply to virtually all building work, (there are certain exceptions given in the regulations) and to changes in use of a building. When using these Regulations it is important to correctly identlfy the extent to which they apply to the case. A proposed change of use may well mean that all of the regulations have to be applied to the existing building. An alteration to a building, which will in itself have to meet the Regulations in full, may also lower the standard of some aspect of the existing building. The Building Acts recognise that difficulties can arise in such situations within many existing buildings, and the power was therefore given to the

95


Appendix I11 Secretary of State to relax the requirements. The overriding factors in giving such a relaxation being safety of people and reasonability in the specific case. In the case of historic buildings it is envisaged that authorities may take the recommendations of this Technical Advice Note into consideration when dealing with relaxation applications. The Building Standards regulations cover structural fire precautions 2.4 and means of escape from fire, which are determined, at the time of the application for building warrant, by the building control authority in consultation with the fire authority. Fire safety legislation covering buildings in use is described in section 3 below. The current editions of the following should also be considered: 2.5 Technical Standards for compliance with the Building Standards (Scotland) Regulations. Building (Procedure)(Scotland) Regulations. Building (Forms)(Scotland) Regulations. Building Standards Regulations.

(Relaxation

by

Local

Authorities)(Scotland)

Construction Products Regulations 199 1. BSI : British standard BS 6187 : Code of Practice for Demolition.

3

Fire Safety Legislation

Historic Buildings are put to a wide variety of uses and may come 3.1 within the scope of a range of legislation covering particular activities. Where new work or a change of use is proposed, compliance with the relevant Technical Standards under the Building Standards (Scotland) Regulations should ensure that the required standards are met in relation to means of escape from fire, structural fire resistance and some other matters. Existing buildings are unlikely to meet these standards in full and there will often be additional requirements for fire alarms, fire fighting equipment, fire safety signs and management procedures relating to fire safety. For this reason there is a need for additional legislation to ensure a satisfactory level of fire safety with regard to the use of the building. Legislation may apply both to the normal activities within the building and also to one off events such as concerts, displays or exhibitions. 3.2 The Fire Precautions Act 1971 is one of the few pieces of legislation which deals exclusively with fire safety. At the time of writing it is applicable primarily to hotels and boarding houses, factories, offices, shops and railway premises. Within premises of this type those of higher risk are dealt with by a system of fire certification whereas those deemed to be of lower risk are subject to general duties placed on the occupier or owner to provide a certain minimum standard of fire safety appropriate to the circumstances. The Act is enforced by fire authorities through the local fire


Legislation brigade or, in the case of premises owned or occupied by the Crown, through HM Inspectorate of Fire Services at the Scottish office. The Fire Precautions (Workplace) Regulations are currently in 3.3 preparation and will apply to most places of work which do not require a fire certificate. These will require employers to assess the risks to their staff in the event of fire and to introduce appropriate fire precautions and emergency procedures to deal with the risks identified. These regulations will also amend the existing Management of Health and Safety at Work Regulations 1992 to include general risks from fire.

3.4 Legislation covering other uses may involve various systems of licensing or registration which require some consideration of fire precautions, amongst other matters, before such a licence or registration is granted or renewed. Enforcing authorities will generally seek the views of the local fire authority with regard to fire safety matters before grant or renewal. 3.5 Whilst the advice given in this document should be taken into account sympathetically by fire authorities when applying and interpreting the relevant legislation, situations may occur where, in the interest of life safety, works are required which may be considered inappropriate in the context of the historic building. In such circumstances an alternative solution will need to be developed or, in extreme cases, the use of the building may need to be restricted, in order to safeguard the historic features of the building from such alterations. In these cases early and informed discussions with the appropriate enforcing authorities are strongly advised. 3.6 The following references are given for legislation which may be applicable. The list is not exhaustive and change is inevitable.

General Fire Precautions Fire Precautions Act 1971 Fire Precautions (Workplace) Regulations (in preparation) Management of Health and Safety at Work Regulations 1992 Health and Safety (Safety Signs and Signals) Regulations 1996

Licensing Civic Government (Scotland) Act 1982 Licensing (Scotland) Act 1976 Theatres Act 1968 Gaming Act 1968 Cinemas Act 1985


Appendix I11

Residential and Other Uses Nursing Homes Registration (Scotland) Act 1938 Social Work (Scotland) Act 1968 Housing (Scotland) Act 1987 Education (Scotland) Act 1980

4

Construction Safety Legislation

As a result of the high accident rate on construction sites, legislation 4.1 and guidance in this area has recently been strengthened. The resulting codes recognise the increased risk of fire arising during construction operations and the fact that fire protection measures required for the finished building may not yet be fully completed. Whilst the measures are aimed at reducing the risk to construction workers in the event of fire, many of these will also reduce the likelihood of a fire occurring and limit the damage which may subsequently be caused. The Construction (Design and Management) Regulations 1994 4.2 apply to projects above a certain size or duration and place duties on clients, their agents, planning supervisors, designers and contractors. The regulations require that a health and safety plan and a health and safety file are created and maintained throughout the life of a construction project from conception, design and planning through to the execution of works on site and subsequent maintenance and repair. A 'planning supervisor' and a 'principal contractor' must be appointed by the client and they assume overall responsibility for health and safety matters relating to the planning and execution phases of the project respectively. The Construction (Health, Safety and Welfare) Regulations 1996 4.3 apply to most construction projects. Regulations 18 to 21 make reference to the prevention of risks from fire, the provision of emergency escape routes, the preparation and implementation of evacuation procedures and the provision of fire fighting equipment, fire detection and fire warning systems. Further guidance may be found in the following publications:Loss Prevention Council : Joint Code for the Protection from Fire of Construction Sites and Buildings Undergoing Renovation

4.4

HSE : Managing Construction for Health and Safety HSE : Fire Safety in Construction Work (in preparation) HMSO : Standard Fire Precautions for Contractors Engaged on Crown Works (1995 edition)


APPENDIX IV

RISK ASSESSMENT METHODOLOGY

1

Objectives of a Fire Strategy

Chapters of this Technical Advice Note deal with current approaches 1.1 to detection, alarm, containment and suppression. Part of the risk assessment will be to compare the existing situation with the appropriate best practice set out in these chapters. Comparison with current building regulations and other technical standards can also be made, although the inability to comply with such standards may be a major factor in many listed buildings. 1.2 Conventional risk assessment techniques balance the likelihood of an "event" occurring against the seriousness of the consequences, usually in the form of a matrix. However, for historic buildings and their contents the consequences of fire are usually catastrophic and it is suggested that effort should be concentrated on the likelihood of an event occurring. 2

Risk Assessment

There is no set method for carrying out a risk assessment although 2.1 most will involve a small multi-disciplinary team working through the following process. Set Objectives: Clear fire safety objectives will establish the acceptable level of loss or damage and will consequently set the standard of protection that the proposed fire safety measures are intended to achieve.

Identify Hazards: A detailed survey of the building and its environs should be carried out identifying possible sources of ignition, assessing fire loadings and evaluating the potential for fire and smoke to spread. A checklist similar to the example reproduced below may be used as an aide memoire, but it should be stressed that the varied nature of historic buildings means that each risk assessment will have to be developed for the particular building. Evaluate the Risk: An estimate should be made of the degree of risk to the occupants, structure and contents in different parts of the building from the direct and indirect effects of a fire. The estimate should take account of existing fire barriers and other fire safety measures but should also consider the reliability of these measures and the consequences of their failure. This estimation may be simple and qualitative, eg high, medium or low risk, or it may in more complex cases involve quantitative risk analysis as part of a fire engineering study. Decide if the risk is Acceptable: A judgement must then be made as to whether the fire safety measures already in place have controlled the risk


Appendix IV to an adequate level. Life safety measures can be judged against the minimum legal standards and the general arrangements can be compared with any relevant technical standards and with examples of best practice recommended in this document or adopted elsewhere.

Prepare Action Plan: If additional measures are deemed necessary, identify possible solutions and consider these in relation to their effectiveness, cost and reliability as well as the associated level of intrusion, intervention and disruption to the historic fabric. The acceptability of the various solutions should be discussed with the relevant enforcing authorities, the insurers and local planning officers and Historic Scotland inspectors before implementation. In many cases listed building consent will be required for the proposals. Review: Finally, review the action plan to ensure that it presents an integrated and practical solution to the problems identified and that it is likely to meet the defined fire safety objectives. 3

Check List

Example check lists are shown on the following pages. Each historic 3.1 building is different and care is needed to ensure that the particular circumstances of the building being surveyed are taken into account.


Risk Assessment Methodology

FIRE SAFETY SURVEY AND EVALUATION CHECK LIST 1.0

The Building

1.1

Name of building

1.2

Full address with telephone numbers. Means of access to the building, including approaches to site or grounds

1.2

Surveyor: Name and address of the person(s) carrying out the survey

1.3

Date and Purpose of survey:

2.0

Historic Building Information

2.1

Description of the Building Type Including other buildings/structures within curtilage.

2.2

Detailed Description of Building Height of building or part Number of storeys Floor area External fabric Internal building fabric Fixtures and fittings Fabrics and furnishings Building use External environment

2.3

Record of significant past alterations

2.4

Record of previous fire inspections/installations.

3.0

Appraisal of External Environment Location Road access Pedestrian access Car parking arrangements Landscaping features Fire Brigade Access Fire hydrant location and details Water supply details Adjacent structures Boundaries


Appendix IV 4.0

Appraisal of Building Construction General appraisal of constructional system(s) Construction materials Walls Floors Windows, locations, size and type Doors Roof construction and finishes Wall finishes Wall fixtures and fittings Internal fabrics and furnishings

5.0

Appraisal of Building Interior

5.1

Spatial arrangements

•

General assessment of the layout of the building Relationship between floors Relationship between rooms and corridors Relationship between corridors and staircases EntranceIExit doors

5.2

Means of escape and access for fire fighting

a

a

General assessment of escape routes Travel distance and exit widths Escape to protected zones Protected zones and staircases Fire compartments Fire doors

6.3

Appraisal of Fire Protection and Life Safety measures

a

a a a

Fire breaks Compartmentation Flame retarding treatment Fire detection and alarm systems Fire suppression systems Smoke control system Fire fighting facilities including water supply Emergency lighting Provision of fire escape signs


Risk Assessment Methodology Fire Risk Evaluation Positive aspects External environment Building construction Building interior Existing fire protection and life safety measures Negative aspects (Hazards) Sources of ignition Presence of fuel (combustible contents) External environment Building construction Building interior Existing fire protection and life safety measures Overall assessment Potential for ignition Isolation of ignition risks Potential for smoke spread Potential for fire spread - continuity of available fuel Ease of escape from the building Access for fire fighters Provision (where required) for disabled people Degree of compartmentation Presence of automatic fire detection system Presence of automatic fire suppression systems Facilities for calling the emergency services Presence of portable fire extinguishers Presence of signs Training of people in the building Evacuation drills when building in use

Summary of Conclusions Recommendations Urgent Work Necessary Work Desirable Work


Appendix IV

OWNER'S OR RESIDENTS CHECK LIST 1.0

Grounds and Access Access routes kept clear for emergency vehicles Procedures agreed for fire brigade attendance Supply of fire fighting water available

2.0

Adjacent Structures Consider implications of adjacent building uses Include procedures for fire fighting in outbuildings

3.0

External Fabric Access to all elevations for evacuation and fire fighting External security arrangements and effect on the above

4.0

Interiors Roof spaces free of combustible materials Fire break walls intact and continuous through attic Flues swept and suitable for type of heating appliance Fires in grates properly controlled and protected Principal living rooms protected by adequately closed doors Smoke and heat detectors in high risk areas Fire detection systems maintained and tested Exit routes kept clear and properly marked

5.0

Management Adequate fire precautions taken during maintenance or alteration work 'Snatch list' for salvage of contents Evacuation procedures in place Adequate records of building and contents


APPENDIX V

PLANNING FOR DAMAGE CONTROL; FIRE ACTION PLANS

1

Preparing the Plan

The disruption caused by a fire and the time during which the 1.1 building is out of use can be minimised by proper pre-planning. In larger buildings a contingency planning committee should be set up.

1.2 The local Fire Prevention Oficer should be involved in the preparation of the Fire Action Plan or at least consulted on site to discuss its purpose. The whole building should be inspected and emphasis placed on the need to assist the fire brigade and at the same time safeguard the building and contents, the historic value of which may not immediately be obvious during an emergency. 2

Fire Brigade Access

Assess access for fire tenders. Refer to the Building Standards 2.1 (Scotland) Regulations; an access width of 3.2m and turning circle of 19.2m may be required. The route must be capable of supporting the weight of fire tenders; cattle grids, bridges, areas of grass and the like should be checked. Establish the best location for the tender(s). Check hose routes for length and freedom from obstruction. Establish the existence of adequate sources of water for fire2.2 fighting, such as hydrants, water courses and reservoirs. Identlfy the location of the existing water mains supply (if present). Where drawings showing the floor layout of the building exist they 2.3 should be made available to the fire brigade. A copy located at the fire alarm panel clearly marked to show the fire zones will aid fire fighting. The position of fire-fighting equipment within the building should be identified.

3

Life Safety

Life safety is, of course, of the highest priority and the Fire action 3.1 Plan should identify measures to safeguard staff, residents and visitors, including disabled people. Sleep risk is of particular concern and areas containing bedrooms, such as a custodian's flat, should be clearly identified. 4

Priorities for Salvage

A detailed inventory of contents should be prepared. It should 4.1 indicate the location of each item and establish a basic priority coding system, for example on a 1 - 5 basis, indicating the order for removal.


Appendix V

Areas need to be identified for the temporary storage of items 4.2 removed. The need for specialist removal or storage should be established and arranged in advance (for example, removing sodden documents to a cold store). Rooms of special value or large items that cannot be removed (or 4.3 are built into the structure) should also be given a priority code, both to direct fire-fighting effort and to allow an order of post-fire salvage work to be established. Plans may include arrangements for draining or diverting water from fire fighting and for protection and drying out. Photographs, drawings and other records of the building should be 4.4 made and should be kept off-site or in a fire-resisting cabinet. This may mean special photography or possibly photogrammetry. Off-site storage will reduce the risk of a total loss in case of disaster and will secure restoration plans. A photographic record of the building and its contents will prove invaluable in the event of a fire. Copies of these records should be made, covering specific areas in which teams are to work. 5

The Salvage Team

The number of people who will be available and can be summoned 5.1 quickly should be identified. These should be organised into teams assigned to specific areas of responsibility with back-up roles in other areas. The teams must be familiar with the building and the priority of the items for removal and salvage. If volunteers are not available then external resources, such as contractors, could be appointed to be available to carry out the work in the event of a fire. The scope of the tasks should be assessed in relation to the number of people likely to be present and the equipment that will be required. The teams should undertake practical training and be involved in 5.2 joint exercises with the fire brigade. There must be a clearly laid down procedure for immediately sounding the alarm and calling the fire brigade in the event of an incident and for calling out team members. This must be effective 24 hours a day. A readily accessible list of the telephone numbers and addresses of 5.3 all key personnel and services should be kept, including, Local authority departments, Building contractors, plumbers, joiners, electricians, heating engineers, Experts in the care and recovery of historic items (conservation experts), Smoke residue removal experts, Utilities emergency telephone numbers (gas, water, electricity),


Planning for Damage Control Insurers/loss adjusters, Plant hire contractors (for pumps, generators, heating equipment). The equipment and tools for the salvage operation should be 5.4 accessible at all times. It may be possible for a selection of salvage equipment to be kept on, or adjacent to the premises. These might include heavy waterproof sheets for roof protection, shovels, ladders, ropes, brooms, hard hats, gloves, emergency lighting equipment, heavy duty plastic sacks and plastic sheeting for protecting internal surfaces. 6

Implementing and Reviewing the Plan

Once a plan has been formulated all those involved in its execution 6.1 must receive both initial and regular familiarisation training. The plan should be regularly reviewed, at least annually, and if and when there are changes to the premises, contents or staff which will affect the implementation of the plan. Any changes required should be made as soon as possible and should also be notified to the fire brigade. The personnel of fire stations who will attend an incident should be 6.2 invited to make regular familiarisation visits. The fire fighting team must be familiar with the access, water supply, building layout and items or features of special importance. 7

After a Fire

Access to the site may be restricted by safety considerations or 7.1 while an investigation of the cause of the fire is proceeding. The structural integrity of the building or its remains must be established as a first priority by specialist advisers and any stabilising measures carried out before access is allowed for any other purposes. The debris should be searched for any valuable items. These should 7.2 be labelled and the position in which they were found recorded. In some situations it will be necessary to carry out a full survey of the fire damage before any disturbance is caused. A damaged roof should be covered with tarpaulins in order to minimise subsequent weather damage. Such temporary work should be designed by a competent professional to ensure adequate f ~ i n gand that structural stability is maintained.

7.3

7.4

Appropriate baniers, warning signs and other measures should be erected.

As far as possible residual water should be removed using appropriate 7.5 equipment. The building should be thoroughly dried out either naturally or by means of de-humidifiers, but special care must be taken to avoid the over-drying of some elements. Care must be taken to avoid a further fire.


Appendix V Specialist advice should be sought on the conservation of damaged 7.6 artefacts. Premises should be safeguarded against theft. Damaged windows 7.7 and doors should be secured in a way compatible with a need to ventilate the building. F i e fighting equipment should be checked, recharged and returned 7.8 to full working order. Detection and alarm systems should be reinstated.

Plate 32 : Duff House, Banff. The fire alarm panel at the main access point for fire fighting purposes. Note the plans of the property and the torches and gloves.


APPENDIX V1

INSURANCE

1

Responsibility to Insure

Owners or managers responsible for historic buildings are strongly 1.1 advised to insure their building to cover reinstatement liabilities as required by legislation which deals with listed buildings. This should mean provision for reinstatement after an all but total loss. In such a situation, the owner will be obliged to rebuild to the present design, quality and style, but also in accordance with current legislation. Any deviation is likely to require an application for Listed Building Consent. Fire is one of the group of "perils" which are classified by the 1.2 insurance industry as 'standard'. Insurance can be arranged under a range of terms involving more or less risk in relation to the premiums paid. Contents as well as the building fabric should be assessed and insured. 1.3 It is important to assess the correct value for reinstatement, including allowances for professional services, temporary site works, demolition and site clearance, and any other costs likely to be incurred due to the loss of use and re-building. The application of VAT should also be considered. In most instances, specialist advice from appropriately qualified professionals should be sought on the value of buildings and contents. 1.4 It is important to ensure that any change in circumstances concerning the insurance terms, due to alterations carried out, or increases in risk (eg - due to temporarily vacating a building) are notified to insurers.

1.5 The adoption of other risk management strategies which are recommended in the Technical Advice Note may also reduce the risk of loss of historic fabric and thus reduce the cost of insurance particularly by: using physical barriers to reduce fire spread reducing hazards through good management installing fire detection and alarm systems introducing a suppression system 2

Historic Scotland Guidlines

2.1 Historic Scotland recommend owners to seek advice from specialist insurance brokers or companies at the earliest opportunity when considering insurance matters. The following is an extract from a forthcoming revision to the Memorandum of Guidance on Listed Buildings and Conservation Areas.


Apendix V1

"MakingGood Fire Damage In choosing an appropriate level of insurance for a building most owners will simply consider safeguarding the market value of the building as a financial asset. They will probably give little thought to how they may be required to make good damage caused by a fire. In the case of listed buildings and, to a lesser extent, buildings within conservation areas, an owner's freedom of action following a fire is limited by the legislation which seeks to protect the architectural and historic interest of these buildings. If a listed building or building within a conservation area is partially destroyed, demolition of the remains will require consent. If the remains of a listed building are to be kept and the damaged area replaced in a way which does not replicate exactly what was there before the fire, consent will again be needed. In most cases of total loss, it is likely that the special interest of the building will be considered to have been irrevocably lost. Where this is so, the construction of a replica will probably serve little purpose and rebuilding in a different manner using different materials may be acceptable. However, if the building formed an integral part of a large architectural entity such as a square or terrace, the exact reinstatement of at least the exterior will almost certainly be required. Partial loss is much more common and potentially more problematic. The extent to which full restoration can reasonably be required is a matter of judgement, based on a full and careful assessment of what constituted the special architectural or historic interest of the building. It is difficult to identify the point at which a building becomes so damaged that full reinstatement is not worthwhile. Clearly the extent and type of the damage and the importance of the damaged part to the overall architectural quality of the whole must be considered in each case and it is consequently impossible to provide hard and fast rules. In some instances it may be considered essential to reinstate fully even though a substantial proportion of the histoic fabric has been lost. This may be the case, for example, where the damage affects a building of undoubted architectural quality or one which is symmetrical, and will almost inevitably be required where the damaged building forms part of a formal composition. If the interior is almost entirely lost but the shell remains substantially intact, repair of the external walls and reinstatement of the roof to their appearance before the fire may be required but rebuilding of the interior in a different manner permitted. However where fragments of the interior survive, replicating the lost elements may be encouraged in some cases and required in others. A great deal will depend upon the quality of the interior in whole or in part before the fire and the ability accurately to recreate it on the basis of surviving fragments of the built fabric, photographs and drawings. In general the reinstatement of interior space of acknowledged architectural merit will be sought where this is feasible. Certainly the destruction of


Insurance surviving, albeit incomplete, high quality decorative work to permit a refitting in a different style is most unlikely to be viewed favourably. Where it may be acceptable to rebuild a partially damaged building in a different manner, it is essential that replacement respects the character of the surviving building. Proposals which are inappropriate in terms of design and materials should not receive consent. The fact that the building owner may wish reinstatement or the Planning Authority require it should always be borne in mind. Immediately following the fire it is therefore important to sift carefully through the debris and set aside all items, no matter how small or damaged, which may assist reinstatement at a later date. In the case of buildings of outstanding architectural quality nothing should be removed until there has been a full archaeological survey of the interior and of the debris. After the fire the building will need protection from the weather. Temporary propping and stabilisation of the structure may also be required. Both should be arranged speedily to avoid the risk of further damage to the fabric. A photographic record of the damage should be made. At the earliest opportunity, the Planning Authority and the Historic Buildings Inspectorate Area Inspector should meet to discuss and agree future action and should thereafter promptly advise the building owner of what will be required."



APPENDIX V11

ORGANISATIONS

The Architectural Heritage Society of Scotland, The Glasite Meeting House, 33 Barony Street, Edinburgh EH3 6NX Tel 0131 557 0019; Fax 01315570049 Association of British Insurers, 51 Gresham Street, London EC2V 7HQ Tel017 1 600 3333; Fax 0171 696 8999. British Automatic Sprinkler Association, Carlyle House, 235 - 237, Vauxhall Bridge Road, London SW l V 1EJ Tel017 1 233 7022; Fax 017 1 828 0667. British Fire Protection Systems Association, 55 Eden street, Kingstonupon-Thames, Surrey KT1 1BW Tel0181 459 5855; Fax 0181 547 1564. British Standards Institution, 389 Chiswick High Road, London W4 4AL Tel0 181 996 9000; Fax 0 181 996 7400. Chartered Institution of Building Services Engineers, Scottish Region, c10 Steensen, Varming Mulcahy and Partners, The Matrix, 64 Newhaven Road, Edinburgh EH6 5QB Tel013 1 554 3666; Fax 013 1 555 1723. Chiltern International Fire Limited, Stocking Lane, Hughenden Valley, High Wycombe, Bucks. HP14 4ND Tel 01494 563 091; Fax 01494 565 487 (Note: Chiltern International Fire Limited is the fire division of TRADA, (Timber Research and Development Association) at the same address). Edinburgh New Town Conservation Committee, 13A Dundas Street, Edinburgh, EH3 6QG Tel0131 557 5222; Fax 0131 556 6355 Edinburgh Old Town Renewal Trust, 343 High Street , Edinburgh EH 1 IPS Tel0131 225 8818; Fax 0131 225 8636 English Heritage, 23 Savile Row, London WlX 1AB Tel0171 973 3000; FaxO171973 3001 Fire Extinguishing Trades Association, Neville House, 55 Eden street, Kingston-upon-Thames, Surrey KT1 IBW. Tel 1081 549 8839; Fax 0181 547 1564. Fire Protection Association, Melrose Avenue, Borehamwood, Herts WD6 2BJ Tel0181 207 2345; Fax 0181 236 9701.


Appendix V11 Building Research Establishment Ltd, Bucknall's Lane, Garston, Watford, Herts WD2 7JR Tel01923 69 4000; Fax 01923 66 4910. Fire Resistant Glass and Glazed Systems Association, 44-48 Borough High Street, London SE1 1XB Te10171 207 5858; Fax 0171 357 7458. Glass and Glazing Federation, Fire Resistant Glazing Group, 44 - 48, Borough High Street, London, SE1 1XB Tel 0171 403 7177; Fax 0171 357 7458. Guild of Architectural Ironmongers, 8 Stepney Green, London E l 3JU Tel0171 790 3431; Fax 0171 790 8517. Health and Safety Executive, Belford House, 59 Belford Road, Edinburgh EH4 3UE Te10131 247 2000; Fax 0131 247 2121. Historic Scotland, Longmore House, Salisbury Place, Edinburgh EH9 1SH Tell031 668 8600; Fax 0131 668 8788 Institute of Fire Safety, 21 Bilton Road, Rugby, Warwickshire. CV22 7AG Tel01788 553661; Fax 01788 550152. Institute of Public Loss Assessors Limited, 14 Red Lion Street, Chesham, Bucks HP5 1HB Tel01494 782 342; Fax 01494 774 928. Institution of Fire Engineers, 148 Upper New Walk, Leicester LE1 7QB Tel0116 255 3654; Fax 01 16 247 1231. Institution of Structural Engineers, Scottish Branch c/o D. J. Nicoll 4 Dixon Road, Helensburgh, Dumbartonshire G84 9DW. Tel01436 675 100. International Council on Monuments and Sites, 10 Barley Mow Passage, London W4 4PH Te10181 994 6477; Fax 018 1 747 8464. Intumescent Fire Seals Association, 20 Park street, Princes Risborough, Bucks. HP27 9AH Tel01844 275500; Fax 01844 274002. Loss Prevention Council, Melrose Avenue, Borehamwood, Herts. WD6 2BJ Te10 181 207 2345, Fax 0 181 207 6305 National Library of Scotland, George IV Bridge, Edinburgh EH1 1EW Te10131 226 4531; Fax 0131 220 6662. National Trust for Scotland, 5 Charlotte Square, Edinburgh EH2 4DU Te1013 1 226 5922, Fax 013 1 243 9501 Photoluminescent Safety Products Association, P 0 Box 93, Woking Surrey GU2 1 l FG.


Organisations Royal Commission on the Ancient and Historical Monuments of Scotland, John Sinclair House, 16 Bernard Terrace, Edinburgh EH8 9NX Tel0131 662 1456, Fax 0131 662 147711499 Royal Fine Art Commission for Scotland, Bakehouse Close, 146 Canongate, Edinburgh EH8 8DD Te10131 556 6699, Fax 0131 556 6633 Royal Incorporation of Architects in Scotland, 15 Rutland Square, Edinburgh EH1 2BE Tel 013 1 229 7545; Fax 013 1 228 2188. Royal Institution of Chartered Surveyors in Scotland, 9 Manor Place, Edinburgh EH3 7DN Te10131 225 7078; Fax 013 1 226 3599. Scottish Conservation Bureau, Historic Scotland, Longmore House, Salisbury Place, Edinburgh EH9 1SH Tel 013 1 668 8668, Fax 0131 668 8669.E-mail : ~cbrown.hs.scb@gtnet.gov.uk> Scottish Office, Victoria Quay, Edinburgh EH6 6QQ. Tel0131 556 8400; Fax01312447454 Scottish Society for Conservation and Restoration, The Glasite Meeting House, 33 Barony Street, Edinburgh EH3 6NX Tel 0131 557 0019; Fax 013 1 557 0049. Smoke Ventilation Association, Sterling House, 6 Furlong Road, Bourne End, Bucks. SL8 5DG Tel 01628 531 186; Fax 01628 810 423.E-mail infor@feta.co.uk Internet : http:llwww.feta.co.uW TRADA (Timber Research and Development Association) Technology Limited, Stocking Lane, Hughenden Valley, High Wycombe, Bucks. HP14 4ND Tel01494 563 091; Fax 01494 565 487 Thatching Advisory Services Ltd, Faircross Offices, Stratfield Saye, Reading, Bucks, RG7 2BT. Tel : 01256 880828 Fax: 01256 880866 UKIC (United Kingdom Institute for Conservation of Historic and Artistic Works), 6 Whitehorse Mews, Westminster Bridge Road, London SE1 7QD. Tel : 0171 620 3371 Fax : 0171 620 3761



APPENDIX V111

BIBLIOGRAPHY

Preamble

1

Fire Protection & Conservation

McCaig, I. (1991), "Fire and its aftermath - Protecting Historic 1.1 Buildings", Conservation Bulletin, Issue 13, pp. 1 to 4. British Standards Institution "Guide to the Principles of Building 1.2 Conservation" final draft, (July 1995) (private communication). 1.3 Building Conservation Directory, Special Report No 1, "The Conservation and Repair of Ecclesiastical Buildings", (Second edition 1995) Cathedral Communications Limited.

Part 1

2

The Scope of the Technical Advice Note

2.1 Department of National Heritage: Bailey, Sir Alan, D. Insall and P. Kilshaw, (1993), "Fire protection measures for the Royal Palaces", London, HMSO.

Marchant, E .W. (1985), "Analysis of Recovery from Fire Risk in 2.2 Industry and Commerce", The Geneva Papers, Vol 10, No. 37, October 1985, pp. 268- 292. Pearce, P. (1993), "Uppark - rising fi-om the ashes", Fire 2.3 Prevention, December 1993, No. 265, pp. 22 - 23.

3

The Vulnerability of Historic Buildings to Fire

Mien, M. (1996) "Fire Gutted", AHSS (Architectural Heritage 3.1 Society for Scotland), Magazine, No 3, Spring 1996, p 25. 3.2 Anon, (1993), " Fire Threat to Edinburgh Proved a Turning Point", Fire Prevention, No. 258, April, p. 28.

Editors (1993), Fire 93 "Heritage Under Fire", "From the Beano to 3.3 Mary Queen of Scots' last letter - protecting Scotland's literary heritage", Fire Prevention, No 265, Dec 1993, pp. 10. Editors (1993), Fire 93 "Heritage Under Fire", "Security - the first 3.4 line of defence against fire", Fire Prevention, No 265, Dec 1993, pp. 12.

117


Appendix V111

4

Behaviour of historic buildings in fires

4.1 Fisher, R. W. and Barbara F. W. Rogowski, (1974), "Results Surface Spread of Flame Tests on Building Products", Department of the Environment, London, HMSO 4.2 Drysdale, D. D. (1985), "An introduction to fire dynamics", Chichester, John Wiley and Sons. (Second edition in press at July 1997).

Stollard, P. and L. Johnston, (1995), "Design against fire", 2nd 4.3 edition, London, E & F N Spon, Chapman and Hall.

5

Fire Safety Management and Fire Precautions

English Heritage, "Model Fire Safety Manual", draft May 1996 5.1 (private communication). National Trust for Scotland, "Emergency Procedures Manual", in 5.2 house publication, July 1991. National Trust (1991), "Manual of Building 12191- Guidance for 5.3 Safe Building Operations", London, The Trust. 5.4 National Trust (1991), "Manual of Building 12191- General Requirements for Building Works", London, The Trust. Building Employers Federation; Loss Prevention Council; National 5.5 Contractors Group, "Fire Prevention on Construction Sites - the joint code of practice on the protection from fire of construction sites and buildings undergoing renovation", Second impression, (with amendment) July 1993 London, Loss Prevention Council 1992, Birmingham, Building Employers Federation; 1992. 8 pp. Health & Safety Executive (draft 1996), "Guide to Fire Precautions 5.6 on Construction Sites", HSE (to be published in September 1997). Department of National Heritage (1993), "Fire Protection Methods 5.7 for the Royal Palaces", London, HMSO.

Porter, A., ( 1996), "Fire Safety in Cathedrals", London, English 5.8 Heritage.

Part I1 6

Compartmentation

Kidd, S. (Editor) (1995), "Heritage Under Fire" (Second Edition), 6.1 London, Fire Protection Association


Bibliography Malhotra, H. L. (1993), "Fire Compartmentation - Needs and 6.2 Specification", Fire Surveyor, Vol22, No 2, April 1993, p 4 - 9. Loss Prevention Council (1996), "LPC design guide for the fire 6.3 protection of buildings", Borehamwood, Herts. National Fire Protection Association (USA) (1994), "Recommended 6.4 practice for fire protection in historic structures", Quincy, MA, USA; NFPA. 6.5 British Standards Institution (1987), BS 476 "Fire tests on building materials and structures; Part 20 Method for the determination of the fire resistance of elements of construction (General principles)", London, BSI. British Standards Institution (1987), BS 476 "Fire tests on building 6.6 materials and structures; Part 21 Methods for the determination of the fire resistance of load bearing elements of construction", London, BSI. 6.7 British Standards Institution (1987), BS 476 "Fire tests on building materials and structures; Part 22 Methods for the determination of the fue resistance of non - load bearing elements of construction", London, BSI. 6.8 National Audit Office (1996), "Ministry of Defence: Management of fire risks", Report by the Comptroller and Auditor General, HC 129, London, HMSO. 6.9 Donaldson, Peter (1996), "Conservation case study: The Duff House Project", Architectural Heritage V1 - The Journal of the Architectural Heritage Society of Scotland, 1996, pp 33 - 48. 6.10 Building Research Establishment (1978), "Cavity barriers and fire stops: Part l", BRE Digest No. 214, BRE, HMSO. 6.1 l Building Research Establishment (1978), "Cavity barriers and fire stops: Part 2", BRE Digest No. 215, BRE, HMSO. 6.12 Shields, T. J. and G. W. H. Silcock (1987), "Buildings and fire", London, Longman, Scientific and Technical. 6.13 The Scottish Office (1990), "Technical Standards" for compliance with the Building Standards (Scotland) Regulations 1990 with amendments, Edinburgh, HMSO 6.14 Building Research Establishment, "Increasing the fire resistance of existing timber floors", BRE Digest 208, Garston, Watford, BRE, 1988. 6.15 Department of National Heritage: Bailey, Sir Alan, D. Insall and P. Kilshaw, (1993), "Fire protection measures for the Royal Palaces", London, HMSO. 6.16 Waldron, B. (1996), "Understanding the glass specification process", Fire Safety Engineering, Vol. 3, June 1996, pp. 18 - 21. 6.17 Welsh, P. A. (1995), "Flow resistance and wind performance of some common ventilation terminals", Information Paper, IP 6/95, Building Research Establishment, Garston, Watford.

119


Appendix V111 6.18 Welsh, P. A. (1995), Testing the performance of terminals for ventilation systems, chimneys and flues", Information Paper, IP 5/95, Building Research Establishment, Garston, Watford.

7

Doors and door closers

7.1 Mohamed, N. (1993), "Ironmongery for frre resisting and emergency doors", Fire Surveyor, December 1993, pp. 18 - 20.

Vibert, J. (1995), "Heritage door upgrading and testing", Fire 7.2 Prevention, No. 284, pp. 30 - 32. Godwin, R. (1995), "Upgrading of doors at the Palace of 7.3 Westminster", Fire Prevention, No. 284, November 1995, pp. 28 - 29. IFSA (1989), "The role of intumescent materials in the design and 7.4 manufacture of timber based fire resisting doorsets". Information sheet No. 1, High Wycombe, The Intumescent Fire Seals Association, March 1989. English Heritage, "Timber panelled doors and fire, Upgrading the 7.5 fire resistance performance of timber panelled doors and frames". English Heritage, 23 Savile Row, London W1X 1AB, May 1997.

8

The Performance of Building Materials in Fire

8.1 "Fire and the Structural Use of Timber in Buildings" (1970), Proceedings of Symposium No 3, Fire Research Station, London, HMSO.

Kirby; B. R., D. J. Lapwood, and G. Thomson (1986) "The 8.2 Reinstatement of Fire Damaged Steel and Iron Framed Structures". Swindon, British Steel Corporation. The Steel Construction Institute, (1991) "Investigation of Broadgate 8.3 Phase 8 Fire" Ascot SCI. Scottish Ofice (1993) "Investigation into Heavily Painted Surfaces 8.4 in Existing Buildings" Scottish Prison Service February 1993. English Heritage, "The use of intumescent products in historic 8.5 buildings". English Heritage, 23 Savile Row, London W1X lAB, May 1997.

9

Detection

9.1 British Standards Institution (1988), Fire Detection and Alarm Systems for Buildings, BS 5839 : Part 1 - Code of Practice for System Design and Servicing", London, BSI.


Bibliography Burry, P. (1996), "Fire detection and alarm systems - a guide to the 9.2 BS code - 5839 Part l", 2nd Edition, Borehamwood, Herts, Paramount Publishing Limited. Lister, E. (1995), "An introduction to multisensor technology", Fire 9.3 Safety Engineering, Vol2, No 3, June 1995, pp. 14 - 17. Smithies, N. (1995), "Fire detection in heritage buildings", pre-print 9.4 of paper given at the conference of the Fire Protection Association "Heritage Protection '95 held on the Isle of Wight, May 1995. DEGW - ETL (1996), "Heritage and technology - new ways of 9.5 working with historic buildings", London, Lucent Technologies, Bell Labs Innovations. Todd, C. S. (1992), "Protecting historic buildings", Fire Prevention, 9.6 No 246, JanuaryJFebruary 1992, pp. 29 - 32. 9.7 British Standards Institution (1996), BS 5839 : Part 6, "Fire detection and alarm systems for buildings. Code of practice for the design and installation of fire detection and alarm systems in dwellings", London, BSI. 9.8 Todd, C. S. (1996), "The design of fire detection installations for dwellings" - a guide to the BS Code BS 5839 : Part 6, Paramount Publishing Ltd., Borehamwood, Hertfordshire.

10

Alarm, Escape, Lighting and Signs

10.1 British Standards Institution (1988), Fire Detection and Alarm Systems for Buildings, BS 5839 : Part l - Code of Practice for System Design and Servicing", London, BSI. 10.2 British Standards Institution (1988) "Emergency Lighting - Part 1 Code of practice for the Emergency Lighting of Premises other than Cinemas and certain other specified premises used for entertainment", BS 5266 : Part l , London, BSI. 10.3 British Standards Institution, "Fire safety signs, Notices and Graphical Symbols, BS 5499 Part I : 1990 - Specification for fire safety signs, Part 2 : 1986 - Specification for self luminous fire safety signs, Part 3 : 1990 - Specification for internally illuminated fire safety signs see also EC Directive 92/58/EEC "Means of Escape (Fire Exit) Signs". 10.4 Jerome, I. (1996),"Guide to fire safety signs", The Loss Prevention Council Library of Fire Safety, Volume 4, The Fire Protection Association, Borehamwood, Herts.


Appendix V111 11

Suppression

11.1 Nash, P. (1977), "Performance of Portable and Installed Fire Fighting Equipment in Buildings", CP 3/77, Building Research Establishment, The Fire Research Station, Garston, Herts. 11.2 Hoare, J. (1996), "Carbon dioxide fire extinguishing systems", Fire Safety Engineering, Vol3, No l , pp. 15 - 17. 11.3 Loss Prevention Council, "Halon Alternatives" - A report on the extinguishing performance characteristics of some gaseous alternatives to Halon 1301, Borehamwood, Herts., (LPC), 1996,47pp. 11.4 Meland, O.G. Jensen and S. Helseth (1996), "Water mist to protect wooden historic structures", Conference presented papers , pp. 169.- 180. 11.5 British Standards Institution (1976), "Hydrant systems, hose reels and foam inlets", BS 5306 : Part 1, BSI, London, BSI. 11.6 British Standards Institution (1990), "Rules for automatic sprinkler installations", BS 5306 : Part 2, BSI, London, BSI. 11.7 British Standards Institution (1985), "Code of practice for the selection, installation and maintenance of portable fire extinguishers", BS 5306 : Part 3, London, BSI. 11.8 British Standards Institution (1986),"Specification for carbon dioxide systems", BS 5306 : Part 4, London, BSI. 11.9 British Standards Institution (1988), "Specification for low expansion foam systems", BS 5306 : Part 4, Section 6.1, London, BSI. 11.10 British Standards Institution (1989), "Specification for medium and high expansion foam systems", ES 5306 : Part 4, Section 6.2, London, BSI. 11.1 1 British Standards Institution (1988), "Specification for powder systems", BS 5306 : Part 7, London, BSI. 11.12 Young, R.(1995), "Sprinkler protection - the basics for all risks", pre print, conference proceedings, Isle of Wight, May 1995. 11.13 Donaldson, P. (1996), "Conservation Case Study, Duff House, Banff', Journal of the Architectural Heritage Society of Scotland, Architectural Heritage VI, Edinburgh. 11.14 Cash, T. (1995), "Fighting fires with foam - Part 2", Fire Safety Engineering, Vol2, No 4, August 1995, pp. 9 - 14. 11.15 Cash, T. (1995), "Fighting fires with foam - Part 3", Fire Safety Engineering, Vol2, No 5, October 1995, pp. 10 - 16. 11.16 Ove Arup and Partners (1995), "Use and benefits of incorporating sprinklers in buildings and structures", London, British Automatic Sprinkler Association.


Bibliography 12

Smoke and its Control

12.1 Building Research Establishment (1994), "Smoke control in buildings" BRE Digest 396, BRE, Garston, Watford, Herts. 12.2 Marchant, E. W. (1990), "Fire engineering and smoke control" in "Fire engineering" supplement to Building Control, MarchJApril 1990, pp 6 - 19. 12.3 Morgan, H P and J P Gardner (1990), "Design principles for smoke ventilation in enclosed shopping centres" BRE Report 186, BRE, Garston, Watford, Herts. 12.4 British Standards Institution (1978), "Code of practice for Fire precautions in the design of buildings. Part 4. Smoke control in protected escape routes using pressurization" BS 5588 : Part 4 BSI. London, BSI. 12.5 Hansell G. 0. and H. P. Morgan (1994), "Design approached for smoke control in atrium buildings", BRE Report 258, BRE, Garston, Watford, Herts. 12.6 Morgan, H. P. (1985), "A simplified approach to smoke-ventilation calculations" IP 19/85, BRE, Garston, Watford, Herts.

13

Fire Engineering

13.1 The Department of the Environment (1990), "Fire safety Approved document "B"", HMSO, Edinburgh. 13.2 The Scottish Ofice (1990), "The Technical Standards for compliance with the Building Standards (Scotland) Regulations 1990 and amendments". HMSO, Edinburgh. 13.3 Cooke, G. (1996), "Fire Safety Engineering - the UK approach", Prevention 288, April, pp 25 - 28. 13.4 Butcher, E. G. and A. C. Parnell (1996), "Fire safety engineering - What performance standard is acceptable and what does it mean?", Fire Safety Engineering, Vol. 3, No 3. 13.5 Marchant, Eric W. (1996) "Levels of practice", Fire Safety Engineering, V013 No 4, 1996, pp 30 -31. 13.6 British Standards Institution (1994), (DC/94/340340), "Draft code of practice for the application of fire engineering principles to fire safety in buildings", London, BSI. 13.7 Marchant, E. W. (1991), "Fire engineering strategies", Fire Science and Technology, (1991), Vol 11, Nos 1 + 2. 13.8

Fire Safety Journal, Vol23, No. 2, (1994) whole issue


Appendix V111 Appendix V Insurance a Ecclesiastical Insurance Group (1994); "Insurance valuation for churches", Gloucester. b Thames Valley Fire Protection (1994), "A guide to the insurance of listed buildings and their contents", TVF.

Lees, C. and I. Wainwright (1995), "Churches - a burning issue", Fire Prevention, issue 284, ,pp 14 - 17. C

d Loss Prevention Council (1995), "Code of practice for the protection of unoccupied buildings", London, LPC.


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