TAN 14- THE INSTALLATION OF SPRINKLER SYSTEMS IN HISTORIC BUILDINGS

No.1

Preparation and use of Lime Mortars (revised 1995)

N0.2

Conservation of Plastenvork (1994)

No. 3

Performance Standards for Timber Sash and Case Windows (1994)

N0.4

Thatch and Thatching Techniques: A gztide to cotzs-ng Scottisll tlmtclli~zgtrditiotzs (1996) The Hebridean Blackhouse: A glide to inaterinls, constnlctioit and nmintetmnce (1996) Earth Structuresand Construction in Scotland: A glide to tlze Recognition a i d Co~zsmtioilof Enrtll 7?c11~~ology ifzScottish B~tiuiizgs(1996) Access to the Built Heritage: Advice on the provision of accessfor people with disabilities to historic sites open to t/zepziblic (1996) Historic Scotland Guide to International Conservation Charters (1997) Stonedeaningof Granite Buildings (1997) Biological Growths on Sandstone Buildings: Control a t d Trearnlolt (1997) Fire Protection Measures in Scottish Historic Buildings (1997) Quarries of Scotland: A n illzatmtedgttide to ScottisIz geology and stone working methoch based on t l ~ British Geological Szlrvey Pl~otographicArchive of selected building stone qzawies (1997)

No. l3

The Archaeology of Scottish Thatch (1998)

No.14

The Installation of Sprinkler Systems in Historic Buildings (1998)

Available from: Historic Scotland Technical Conservation,Research and Education Division Scottish Conservation Bureau Longmore House Salisbury Place Edinburgh EH9 ISH Tel 0131 668 8668 Fax 0131 668 8669 email cbro~vnhs.scb@gtnetgov.uk.

by The Fire Pmtcction Association

l'ublishcd by Historic Scotland

ISIiN 1900168 63 4 @ Crown Copyright Ed~nburfih1998

G)mmiss~oncd by

TIK-INICAI, CONSEl?VATION, IIESEARCI-I AN11 EDUCATION I3IVISION

ACKNOWLEDGEMENTS The authors would like to acknowledge the assistance received from the following in the preparation of this Technical Advice Note: John Anderson, Principal Clerk of Judiciary and Session; lain Forbes, Forbes Leslie Network; Ian Hammond, General Accident Fire and Life Assurance Corporation plc; William Jackson, National Library of Scotland; Adair Lewis, Fire Protection Association; David Maclean, Scottish Court Service; Anthony McLaughlin; John Mair, Duff House; Matthew Hall Ltd.; Ove Arup and Partners; The Right Honourable Lord Rodger of Earlsferry, Lord President and Lord Justice General; John Stephens, Loss Prevention Council; Terry Watson, Gem Consultants.

PREFACE

This Technical Advice Note is part of an occasional series of notes on practical and technical issues concerning the care and conservation of historic buildings and monuments in Scotland. They provide guidance on the principles involved in a particular field and are not intended to be used as prescriptive documents or as specifications on site.

The 14th in the series, this particular Note is designed to inform Historic Scotland staff and others when considering fire protection issues and the option of installing sprinkler systems. The Note was prepared by the Fire Protection Association, following our own experience of the installation of a sprinkler system at Duff House, Banff.

The construction of Duff House commenced in 1735 to a design by William Adam. It was converted during 1994-95 into a Country House Gallery under a partnership agreement between Historic Scotland, The National Galleries of Scotland, Banff and Buchan District Council and Grampian Regional Council.

A fire risk assessment was carried out by Fire Safety Network, USA as part of the conversion project.

Improvenients to the fire protection of the structure and an automatic fire detection system were recommended as part of this assessment and installed during the conversion. The value of the house and its intended contents, the rural location and potential response from the fire brigade, greatly influenced the decision to install a fire suppression system with automatic sprinklers.

Sprinkler protection is a highly developed and reliable form of fire suppression, but its installation in an historic building can be complex. It has been in use for over one hundred years, yet has found little favour in providing fire protection in historic buildings in the United Kingdom.

In this publication the case for sprinkler systems is reviewed, the principles of sprinkler operation outlined and the risk assessment process described. The application of design standards and a specific design approach for historic buildings is addressed. The future care and maintenance needs of the installation are set out, and some thoughts given for future developments in this field.

Although its content touches on the subject of fire risk assessment in historic buildings, this has been covered in more detail in TAN I I, Fire Protection Measures in Scottish Historic Buildings. TAN 11 is also valuable in placing sprinkler systems in the wider context of fire protection measures that are applicable to historic buildings, and should be read in conjunction with this document.

Ingval Maxwell Director, Technical Conservation, Research and Education September 1998, Edinburgh

CONTENTS

1.

...

PREFACE

111

4.

CARE AND MAINTENANCE

SUMMARY AND ACKNOWLEDGEMENTS

vi

4.1

Staff training

4.2 Action in the event of fire

INTRODUCTION

4.3 Routine checks

1.1 History of sprinkler systems

4.4 Maintenance by sprinkler contractors

1.2 The effectiveness of sprinkler systems

4.5 Safety during sprinkler shutdown

1.3 The case for installing sprinkler systems in historic buildings

2

1.4 Sprinkler rules

5

1.S Hazard classification

5

1.6 Types of installation

7

1.7 The Bailey Report

4.6 Training exercises

APPENDICES Appendix A: Some serious fires in Scottish historic buildings since 1986 Appendix B: Case histories

1 .S Financial considerations

Appendix C: Training exercise Appendix D: Bibliography ..

- -

2.

COMPONENTS OF A SPRINKLER SYSTEM

2.1

Water supplies

I'

2.2 Pumps 2.3 Valve sets 2.4 Pipework 2.5 Sprinkler heads

3.

INSTALLING THE SYSTEM

18

3.1 Fire risk assessment

I8

3.2 Design guidance for the installation of a sprinkler system

19

3.3 Selecting a consultant enginecr

20

3.4 Selecting a sprinkler installation contractor 21 3.5 Installing water supply tanks

22

3.6 Housing pumps, generators and valve sets

25

3.7 Installing pipework

26

3.8 Installing sprinkler heads 3.9 Future developments

Appendix E: Organisations

List of Illustrations Plate I . Tllefire resi.stance of the door betrveen the ~rnsprinkleredSolicitors' Building and Parlianzerzt House, which is sprinklered, is enhanced by locating a sprinkler above the door; within the egg and dart corrzice. (p. 4 ) Plate 2. Tlze Box Corridor; High Co~lrts,Edinburgh.

(1). 4 ) Plate 3. Detail of sprinkler head and pipework in the Box Corridor; High Corrrts, Eclinb~rrgh.(p. 4 ) Plate 4. A recent CPVC pipe sprinkler irlstallation in progress. Fittings ancl firrnitrrre (protected by dust sheets) rerilained in the roorn througholrt the installation period. (p. 13)

Plate 30. Vertical pipe installation. (p. 34)

Figure I . Fire protectiorz of the thatclzed roof of the Globe Theatre. (Ill~rstratio~t courtesy of Gem Con.sultants) (p. 5 )

Plate 14. Detail of sprinkler head, h i g h Hall, High Co~rrts,Edinburgh. (p. 27)

Plate 31. Supply pipe in.stallation. (p. 34)

Figirre 2. Main eleiilerzts of a sprinkler system. (p. 7 )

Plate 15. Attic sprinkler pipe, protected by inslrlation and trace heating. (p. 27)

Plate 32. Quick response sprinkler /read i~zstalledirt a ceiling rose. (p. 35)

Figure 3. A \vet pipe s l ~ r i ~ ~ ksysterlt. ler (p. 8)

Plate 16. Sprinkler pipework, attic level positioning. (p. 28)

Plate 33. Extendecl coverage horizontal sidewall sprinkler irzstalled above the conlice. (p. 35)

Plate 13. Sidewall sprinklers and exposed pipework in the Laigh Hall. High Colrrts, Edinburgh. (p. 27)

Plate 17. Water supply-pipe i~zstallatiorzin a solid floor (P. 29) Plate 18. Pipe installation in a floor screed. (p. 29) Plate 19. The timber floor has been lifted to allorv tile integration of horizontal service r q s . (p. 29)

Plate 5. Sprinkler heads.

Lefi to right: Pendent Plate 20. Floor and ceiling (clirornefi~zislz), voids. (p. 30) Upright (brassfinish).

Horizontal (colo~~redfinish) Plate 21. Sider~~all sprinkler (P. 15) srrpply pipe. (17. 30) Plate 6. Recessed sprinkler Plate 22. The sprirlkler kend. (p. 17) supply pipe has been Plate 7. Concealed sprinkler installed beneath the joists.

Tlze sclrile care has not been head. (p. 17) taken to integrate the cable tray for electrical sen~ices Plate 8. Sidewall sprinkler and riser landing valve. Note witlzn~rtdamaging the historic fabric. (p. 31) tenlporaty signage and protectiorz to ~[~rirtkler head in place while constr~rction Plate 23. S~rpplypipe jlrnctiorts. (p. 31) vvork corltirures elsewhere.

(17. 22) Plate 24. Sprinkler slrpply pipe irlstallation. (p. 31) Plate 9. Plate 10. The resenloir and external plrmp ho~rsethclt provirle the bnck- Plate 25. Tin~herfloor 1rp water supply for a recent reinstr~tement.(p. 32) sprinUer insmllf~tion01 rrn Plate 26. I~tappropricrtely historic b~rildirzg.(1'. 23) locaterl acccs.s hatch. (p. 32) Plate 11. U~zdergrolrrldwater Plrlre 27. Verticnl ser~lice supply tanks and p ~ r n ~room p nrris. (p. 32) at Duff Holrse. (p. 24) Plate 12. Tank 1ar1clscal)irlg rrt Drrff Horrse irrclicates tlrat rnnre carefirl corlsidercrtion rrcec1.s to he gi\-erl to this aspect. (p. 25)

Plate 28. Vertical pipe irz.stallatio~z.([I.33)

Plate 29. Vertical pipe casework. (p. 33)

Figure 4. A dry pipe sprinkler systern. (p. 8 )

Figure 5. Vah.e set lr'ith sprinkler artcl water gong operating. (1ll~r.stratior1 Plate 34. Detail of side~c~all co~rrtesyof \Vor~i~alcl Fire Systems Lid) (p. 12) sprinkler above the cornice.

(P. 36) Figure 6. Constnrctiorz of a Plate 35. Side\r,all sprirzkler typical glass lxrlb sprirlkler pitjalls. (p. 36) head. (11. 14) Plate 36. 111stalledconcealed Figlrre 7. Distrib11tion sprinkler head, the Vestibule, patterns frorit spri~lkler heads. (p. 16) Duff Horrse. (p. 37) Plate 37. Fi~zisherlscl~enre inclrrdirlg concealed sprinkler installation, the Vestibrrle, D~rffHorrse.

(P. 37) Plate 38. Hole c~rtin ceiling, ready to receive concealerl sprinkler lzead tile kstil~lrle, Duff Holrse. (p. 37) Plate 39. Finished scheme including concealed sprinkler irz.stallntiorl,tlle Dirzirlg Roorzl, DlrfS Holrse.

(P. 37)

Figure 8. P1a11.snnrst he clear arzd legible, as \re11 ns showirig as rilrtclz rietrril as possible. (p. 20) Figure 9. Alter~lative nrrar~gerirerzt.~ cart be helpfir1 and di~neizsiorz.~ sholrll be ir~rlicaterliftl~rrnrbrrnil c1ra1virlg.sare not to the sarne scale as the rrlrrirl pl~trl.

(1'. 21)

Figirre 10. Tlle exact location ofsl7rirlkler Ireads shoirld be ri~nrkedor1 tlle plans ancl the alignrr~er~t of the yoke arrizs sho~rllalso he Plate 40. Sprinkler head if it rrlay rlot be molrnted \r.ithin a v e ~ l t i l a f i o ~irl(licated ~ obviolrs to the irl.stcrllirlg grille, High Courts, engirzeer (p. 21) Edirlbllrgh. (p. 37) Plate 41. Sidewvtrll sprirlllers km.e been in.smlled abo1.e the conzice in this co1lrtron1it in the High Colrrts, Eclirlblrrgh. (p. 38)

Figirre 11. Detrriled clrn,virlg.s of tlle sprinkler 11ecrcl.srrlrty be reqlriretl for ir~.stallrrtior~s in .serz.sitive areas. (p. 21)

spri~zkler Figure 12. Hot ~rorkpennit Plate 42. Si~letr~II form. (11. 23) hetrtl installed 1vithirz corrlice. (11. 39) Figjrre 13. Tl~preare nrnny Plrite 43. Front view of Drrff lrtrys of corlcetrlir~gpipelrorh in plaster rnorrlt1ir1g.s.(p. 26) Horrse, Bar$ (p. 46)

SUMMARY

Almost every year sees significant historic buildings in Scotland being destroyed by fire. TAN 11, Fire Protection ~ e a s u r e sin ~ c o t i i s hHistoric Buildings describes the range of measures which may be appropriate to protect an historic building from fire.

One of the most effective actions that can be taken to reduce the extent of fire damage is the installation of an automatic sprinkler installation and this should be considered alongside the more traditional alternatives when improvements to the fire protection of an historic building- are being- considered.

This Technical Advice Note is intended to introduce the concept of sprinkler installations, outline how they work and how they may be installed in an historic building with the minimum of disruption to the historic fabric. Sprinkler systems can be installed in even the finest buildings manner which need - in a sympathetic - not detract from their appearance. Indeed, in some instances even the sprinkler heads themselves may not be immediately visible to the untrained eye.

The first chapter of this Note describes the purpose of an automatic sprinkler installation, the various types of installation and outlines the principles of the codes of practice that determine their design. The second chapter discusses the components of the system in more detail and is designed to introduce the owners of historic buildings to the components and engineering decisions that will be necessary to enable an

Glossary of Abbreviations used AFD

Automatic fire detection

AMAO

Assumed maximum area of operation

C factor

Conduction factor

CEA

ComitC EuropCen des Assurances

CPVC

Chlorinated polyvinyl chloride

LPC

Loss Prevention Council

LPCB

Loss Prevention Certification Board

MTBF

Mean time between fires

NFPA

National Fire Protection Association

RTI

Response time index

installation suitable for a specific property to be designed.

Chapter three presents details relating to the practicalities of installing a system within an historic building and illustrates how many of the difficulties that may be anticipated can be overcome in practical ways with the minimum of intrusion to the fabric of the property.

Like any other equipment, once installed, a sprinkler system needs to be looked after to ensure that it will be in working order in case it ever has to operate. Routine maintenance has to be undertaken by specialist engineers but, more importantly, the owner or staff of the property in which it is installed must receive instruction in the actions that they need to take to keep the installation in readiness.

Finally a number of Appendices present a list of major historic building fires in Scotland, case histories, and other useful background information.

This publication is not intended to be a comprehensive technical guide, the material is introduced in everyday terms and is designed for the non-specialist. While it is hoped that the information will answer most of the questions that readers may have, it is recognised that not every set of circumstances can be addressed in a publication such as this. Further information can be obtained from the organisations listed in appendix E.

1. INTRODUCTION

An automatic sprinkler system consists of an array of sprinkler heads, normally at roof or ceiling level, connected by pipework to a water supply via a control valve. The sprinkler heads react to heat from a fire beneath them and automatically release water onto the fire. The flow of water causes an alarm to sound on the premises and a signal can be relayed to a central monitoring station. Thus: a fire is detected at any time of the day or night, an alarm is sounded to warn the occupants, water is released onto the fire, a call for outside assistance can be made.

It must be emphasised that only sprinkler heads above or adjacent to the fire will operate initially, releasing water onto the fire and wetting the area immediately surrounding the fire. Statistics reveal that 26 per cent of fires in buildings in which sprinklers are installed are controlled by the opening of a single head.

A sprinkler system is not intended to cope with a fully developed fire which enters the sprinkler protected area from an adjacent, unsprinklered part of the building.

Thus if sprinklers are to be installed, they should ideally be installed throughout the whole of the building in question.

Although experience has demonstrated the effectiveness of sprinkler systems, the fire brigade, property insurer, water company and, in the case of listed buildings, the Historic Buildings Inspectorate should be consulted at an early stage whenever sprinkler protection is being planned for an existing building. Sprinkler systems in historic buildings should be designed with painstaking care to respect fully the historic building fabric. This will mean that each system will have to be precisely engineered in order to be acceptable, both in terms of avoiding unnecessary damage to the fabric and also in terms of its appearance within the building.

Traditionally sprinkler systems have usually been installed to protect property. However, there is now an increasing trend to provide sprinkler protection in buildings to reduce the threat to life and assist means of escape in the event of a fire. Sprinkler systems should be considered as part of the overall strategy to protect the building, its contents and the lives of its occupants against fire. In some instances it may be possible to -

-

~

'trade off' other fire protection measures if a sprinkler system is installed, for example it may be permissible to have a larger compartment size. However, independent life safety features such as a fire alarm system should always be installed if required by the authorities. A sprinkler system should not, alone, be regarded as a panacea for all fire safety ills. Every historic building should be assessed individually, taking into account all of its intrinsic fire safety provisions. Guidance on the range of fire protection measures that may be appropriate can be found in TAN 11, Fire Protection Measures in Scottish Historic Buildings.

When considering the provision of sprinkler protection in a building it should be borne in mind that, whilst sprinklers are very effective at controlling fires, they will have no influence over whether or not ignition takes place. The presence of sprinkler protection does not eliminate the need for preventative measures to reduce the risk of a fire occurring. The managers and occupants of the sprinklered building should behave as though the building were not sprinklered.

1.1 The history of sprinkler systems One of the earliest sprinkler systems in the UK was installed in 1812 at the Theatre Royal, Drury Lane, London, and was designed to protect the audience.

Unlike present day systems, this was operated manually and the installation had no sprinkler heads but simply used pipework in which holes had been drilled, releasing water over the whole area in which the pipework was installed. The first practical sprinkler head was developed by an American, Henry Parmelee, following a fire in his Chicago piano factory in 1875.

Some 200,000 of these heads were installed by a company headed by Frederick Grinell who, in 1882 produced his own designs to give protection to New England cotton mills.

The first sprinkler to be recognised by insurers in the UK was the Parmelee model which was installed in the Edinburgh Rubber Works in 1881.

The first installation design guides (The 'Rules') were prepared in 1873 by the Mutual Fire Insurance Corporation in Manchester. In 1888 the first edition of the insurer's Fire Offices' Committee Rules was published.

HISTORIC SCOTLAND TAN 14 T ~ IINSTALLATIO E

The Ayrshire Association of Federated Bums Clubs, and their involvement in encouraging the fire protection of Burns' Cottage, provide an early example of Scottish interest in the protection of historic buildings from fire. In a report dated 1929 to the president of the association, a fire risk assessment of the property is described and recommendations made for suitable fire precautions. These include the introduction of a water drencher system in the roof to protect the thatch.

1.2 T h e effectiveness of sprinkler systems Sprinkler systems are successful in controlling and extinguishing fires in their early stages when they are still small. A high proportion of fires are controlled quickly by the operation of a single sprinkler head.

After the fire brigade have confirmed that the fire has been extinguished they will close the sprinkler installation control valve to stop the water flow. The sprinkler system may then be made operational again by replacing the sprinkler heads that have operated and any others in the immediate vicinity of the fire that have been exposed to heat.

Many statistics are available from sources world-wide to support the success of sprinklers. Unfortunately these are not available for historic buildings as a distinct group. However an analysis of fires for all classes of sprinklered buildings in the USA, UK, Australia and New Zealand (Nash and Young, 1991) indicates that:

-

26% are controlled by one head,

44% are controlled by up to 2 heads, 65% are controlled by up to 5 heads.

These figures may, however, be somewhat understated as a significant number of small fires extinguished successfully by a single sprinkler head may not have been recorded.

The most complete set of statistics for fires extinguished by sprinkler action alone are available for Australia and New Zealand, where records have been kept for all sizes and types of installation dating back to 1886. Their figures suggest 99.5 per cent effectiveness. In Europe there are ComitC EuropCen Des Assurances (CEA) statistics and in the USA both Factory Mutual International and the National Fire Protection Association collate performance statistics.

In the UK, the fire brigades report on all fires attended.

Where sprinklers are installed, details will be given in the report. The Home Office holds these reports, but the data they contain has not been collated to give statistics on fires in sprinklered buildings.

It has been estimated that the accidental failure rate for a sprinkler head is one in 14 million, hence the

possibility of damage being caused by the installed system can be considered to be low, although some residual risk relating to the water supply pipework remains. The scale of this risk, however, should be less than that for any other type of water supply installation, as the testing regimes for both the components and system are more rigorous than is the case with other installations. A sprinkler system has been installed in the category A listed Jenners department store, Princes Street, Edinburgh, since the mid 1950s. The implications of the accidental failure of a sprinkler head are very great in this context, in view of the value both of the building itself and of the merchandise on display, yet, apart from an instance where a head was accidentally broken by an employee, no failures have been reported.

1.3 T h e case for installing sprinkler systems in historic buildings The occurrence of serious fires in historic buildings has continued unabated for many years. A recent survey by the Fire Protection Association (FPA) found that a notable historic building is destroyed in the UK, on average, every two months. In addition there continue to be hundreds that suffer significant damage every year. The extent of the problem is illustrated in Appendix A, which lists some recent fires in historic buildings in Scotland. It should be remembered that although buildings can be rebuilt, original fabric is irreplaceable, and each of these fires represents a significant loss of Scotland's heritage.

This level of loss clearly demonstrates the need for improved fire protection in historic buildings. This subject has already been addressed in TAN I I, Fire Protection Measures in Scottish Historic Buildings.

Sprinkler systems have found little favour, to date, in the fire protection of historic buildings, but the case for their installation is reviewed here.

The FPA survey showed that 4 0 of the 54 serious fires (74 per cent) occurred during the night, at a time when few people may have been in the vicinity to detect the fire and fight the flames. In historic buildings, as in the case of other types of premises, automatic fire detection and suppression installations can be effective and should ensure that if a fire were to occur the extent of the loss would be minimised.

While an automatic fire detection and alarm installation can raise the alarm and call the fire brigade as soon as products of combustion reach certain predetermined levels, an automatic sprinkler installation can, in addition, control the fire. Fire detectors respond to heat, smoke or flame depending on the type of detector employed whilst sprinklers are operated by heat. It is often a point of conjecture whether the fire alarm or sprinklers will operate first in a fire. In reality

HISTORIC SCOTLAND TAN 14 TIE INSTALLATION OF SPRINKLER SYSTEMS IN HISTORIC BUILDINGS

which operates first is dependent on a number of variables such as the location of the fire relative to the nearest sprinkler head or fire detector, the nature of the burning materials and the rate at which flames develop.

Table 2 Fire brigade operations Number of appliances

Pumping rate per appliance 2000 Iitreslmin

Fires which develop very rapidly and are close to a sprinkler head may activate a sprinkler before the fire alarm responds. Fires which develop slowly, producing significant quantities of smoke only, are more likely to trigger a smoke detector before the sprinklers, with the time lag being in the order of two to three minutes. In many cases where a sprinkler system has been installed, a fire is found by the fire brigade to have been extinguished by the sprinklers prior to their arrival.

Where this has not happened, the fire spread had still been reduced, enabling the brigade to extinguish the remaining flames with greater ease than would otherwise have been the case.

A sprinkler system is economical in the use of water.

The use of limited quantities of water to extinguish a fire is particularly important in the case of historic buildings where the consequences of saturation by water of the fabric and contents of the building are great. In addition, environmental considerations in those historic buildings still in use for commercial or agricultural purposes may require fire fighting water to be contained, again favouring an economical application of water. Tables 1 and 2 indicate the volumes of water required for fire fighting and it can be seen that in the case of this typical scenario the quantity of water required by a sprinkler system is considerably less than that which would be needed by the fire brigade in fighting a fully developed fire.

Ordinary Hazard Installation

Flow rate from cach sprinkler

70 litreslmin

Water flow rate required

350 litreslmin

Typical running time

30 min

\Vater required

10.5m3(2310 galls)

8000 litreslmin

Typical running time

90 min

volume of water applied to the fire

720 m~(158 400 galls)

The provision of an automatic sprinkler alarm connection to a remote monitoring centre is usually proposed as an optional extra. In historic buildings which contain artefacts that are susceptible to both fire and water damage, such as books, paintings and wall hangings, the provision of such an alarm should be considered essential. Alarm connections to a monitoring centre ensure that both the fire brigade and the registered user of the sprinkler system are notified immediately of sprinkler operation even whilst the property is unoccupied. This facility enables the fire brigade to attend at an early stage in the development of the fire when the sprinklers will not have been running for long, and may result in a substantial reduction of fire, smoke and water damage to the property and its contents.

Table 1 Automatic sprinkler systems

5 (only 1 bead in 26% of fires)

Flow rate

Property insurers will often offer fire insurance premium reductions for buildings which are fully sprinkler protected. Since the disappearance of the Insurance Tariffs there are no fixed rates for insurance or rate reductions, and it may be necessary to seek quotations from a number of companies to determine what level of premium rate reduction can be obtained for a sprinklered building. Usually insurers will only recognise sprinkler protection for insurance purposes if a property is fully sprinklered in accordance with one of the recognised codes. If only part of a building or structure is protected by a sprinkler installation (often referred to as partial sprinkler protection) an insurance premium reduction is unlikely, although in some instances insurers may require specified forms of active fire suppression as a condition of insurance in some parts or areas of a property where there is a particular fire risk or assets of high value. If partial sprinkler protection is being considered, the advice of the property insurers and other authorities who have an interest should be sought at an early stage.

The ability of a sprinkler system to control a fire is of particular importance in rural areas where the building may be remote from the nearest fire station and this will lead to some delay in fire fighting operations being commenced by the brigade. Some of the fire stations may be manned by retained (part-time) fire crews which typically results in a delay of two and a half minutes when compared with stations manned by fulltime staff.

Number of sprinklers operating

4

Another benefit of a sprinkler installation is the increased protection afforded to elements of the con~tructionby sprinklers. Doors, for example, can provide an enhanced degree of fire protection if kept cool by being sprayed with water (see plate I). Suitably located sprinkler heads can thus assist in allowing original fittings to be left in place and maintaining the

3

1

HISTORIC SCOTLAND TAN 14 THEINSTALLATION OF SPRINKLER SYSTEMS I N HISTORIC BUILDINGS

original fabric of a building. A sprinkler system can alsa compenwte for the inadequacies of the building3s structure to resist fire. In the c m of the National Libmy of Scotlsmd, the cost, in both conmation and f w c i a l tern&,would have been grc3akr if it had been decided to upgrade the building's structure by traditional mehods to an appropriate 1e-l of fire resistance rather than install a life safety sprinkler system.

Xn some cases the instdlhan of sprinklm has beem a critical f@&r in maintaining the originallayout and use of an historic building and h m e preserving its histQlicd and cultural .-i@ficane. IQthe I-Ikgh Cants in Edinburgh, for instance, the box corridor is an escape route, lined wi& a w n woden baxea filled @ith legal p a p s . This arra@ament has b e n allowed to remain followiug the installation of a life safety s p M a sys-, despjte the obvious fire risk it past%, The installation is comprid of two rows of sprinklers that should drench any h smn after it exhibits established burning, and allow She &dor to -ontinwe to function as an escape row? (see plat$s 2 a d 3).

Plate 2 The Bm C o d o r ; High Couns, Rdinb~r~.

Plate I . Th~,fire resistunce of the door between the urzprinklered So1icitor.s' Building urzd Pc~rliurnentHouse, ~ ' h i c his sprinklerecl, is enhurzced b.v locuting cr .sl>rinkler above the door; within the e ~ und g dart cornice

Plate 3. Dew.1 afspri;nkde~hd and pipework in the BM Cfnrridor;High Court& Edift6iurgh.

HISTORICSCOTLAND TAN 14 THEINSTALLATION OF SPRINKLER SYSTEMS IN HISTORIC BUILDINGS

One recent project involved the installation of a water drencher system to protect the thatched roof of the reconstruction of the Globe Theatre in London, the first building to be built in the area with a thatched roof since the Great Fire in 1666. The sedge and water reed thatch has been protected by a system of open drencher heads installed on the apex of the roof (see figure I).

The water supply to the heads is controlled by a linear heat detection cable, which zigzags through the thatch.

Factors such as the length of the cable that is detecting heat and the temperature detected determine the operation of the zone control valves. This is an example of an installation in a new building, but similar installations may be appropriate in historic buildings.

D m n r h o h r u L on

&rd

"'<pp

--.-+

b"nAll tmorrd ",;,h

Thrrrh ~pproxinz.~,<+ 30ornm dirk

Figlrre I . Fire protectinrl r$tlre thatched roofofthe Globe Tllmtre. (Illlrstrotior~courtesy of Cerrl Corls~rltcrr~ts)

1.4 T h c sprinkler rulcs The installation standards most commonly used in the UK are: British Standards Institution - BS 5306: Fire extinguishing installations and equipment on premises: Part 2: Specification for sprinkler systems Loss Prevention Council - RLS6: Rules for Automatic sprinkler installation (The LPC rilles use BS 5306: Part 2 as the core document and supplement it with additional information and new requirements and developments in the form of Technical Bulletins) There are many other national and insurance standards for sprinkler systems throughout the world such as: National Fire Protection Association - NFPA 13 Instiillation of sprinkler systems (USA national standard) Comitt Europten Des Assurances (CEA) Sprinkler System Planning and Installation (European insurers standard)

Factory Mutual - Loss Prevention Data Sheet 28N (a USA mutual insurance company sprinkler standard) Although sprinkler installations in the UK are usually installed in accordance with the British Standard or LPC rules, other installation codes may be used.

However, if other codes are employed the end user is sometimes faced with the duty of proving equivalence to the British codes if the fire or building control authorities request this.

Systems should be installed and maintained by competent sprinkler installation contractors certificated by the Loss Prevention Certification Board (LPCB) under Loss Prevention Standard 1048: Requirements for certificated sprinkler installers, supervising bodies and supervised installers.

Regulations for the installation of sprinklers were developed for the protection of industrial and commercial property. It will be appreciated that the installation of fire protection systems is most easily carried out whilst buildings are being constructed. The protection of historic buildings presents different problems to the sprinkler protection of modern buildings and strict application of the rules is therefore not always appropriate.

There are a growing number of historic buildings which have been sprinkler protected with systems engineered to suit the particular building. In some instances it may be necessary to employ special techniques and equipment which are sympathetic to the building fabric. For example, in an eighteenth century house in Northern Ireland horizontal sidewall sprinklers were installed in rooms having deep cornices. The sprinklers were located above the ledge near the base of the cornice so that the pipework and sprinklers were concealed from view. Mathematical modelling techniques were used to ensure that the time taken to operate the sprinkler heads would not be excessive despite their non-standard location.

However, the extent to which computational modelling techniques may be used is limited, as it is only possible to estimate the time taken to operate the first sprinkler.

At the moment these methods are not sophisticated enough to determine the time of sprinkler operation after the activation of the first head, or to predict the outcome of a sprinkler controlled fire. The involvement of a consultant engineer experienced in the installation of sprinkler systems is clearly vital to assess the effectiveness of any proposed layout.

1.S Hazard classification The design of a sprinkler system is mainly influenced by the fire hazard within the building. Most sprinkler rules have highly developed hazard classification

HISTORIC SCOTLAND TAN 14 THEINSTALLATION OF SPRINKLER SYSTEMS IN HISTORIC BUILDINGS

systems which define the level of sprinkler protection required. The hazard classification is mainly a function of the likely heat release rate (the units of which are kW) which in turn is related to the heat of combustion of the contents (and in many historic buildings, parts of the structure) (measured in KJlkg) and the rate at which these combustible materials will burn (measured in Kgls). Factors such as the building structure, structural fire resistance, height of ceilings and adequacy of heating will influence the sprinkler installation design and the performance required.

Crucial design factors for a sprinkler system incIude details relating to the:

occupancies where the amount of combustible material is low, and is suitable for rooms and corridors not more than 126 m? in area bounded by fire resisting construction of not less than 30 minutes duration. This level of protection is now seldom used because of the area limitation and due to the fact that many occupancies for which it was originally intended now contain fire loads which exceed its capability (for example schools which have fire loadings which justify a higher hazard rating).

The level of sprinkler protection provided by Light Hazard is: Assumed maximum area of operation - 84 m2 (AMAO)

assumed maximum area of operation (AMAO): this a worst case assumption about the number of sprinklers that may operate in a fire, expressed in m', minimum discharge density: the minimum allowed water application rate at the assumed maximum area of operation, expressed in mmlmin, the duration of the water supplies, maximum and minimum distances between the sprinkler heads, expressed in m, maximum distance of the heads from the boundary of the area, expressed in m, maximum area protected by a sprinkler head, expressed in m', clearance between the sprinkler heads and any obstructions such as joists or light fittings.

In addition, in historic properties the installation should: involve the minimum of disruption to the fabric and structure of the building, have an aesthetically acceptable appearance,

To designate the hazard by BS 5306: Part 2 and the LPC sprinkler rules, the following classification system is used:

Light Hazard Light

Hazard

is

intended for non

industrial

- 2.25 mm/min

Water supply duration

- 3 0 minutes

Allowable sprinkler spacings - 21 m2/sprinkler

Ordiitary Hazard The Ordinary Hazard classification includes nonindustrial occupancies where the fire loading is greater than that allowed in Light Hazard. It is also suitable for commercial and industrial occupancies such as manufacturing, and includes limited amounts of storage, providing they are not likely to develop intense fires early in the initial stages of combustion.

The following design features are common to all Ordinary Hazard sprinkler systems:

.

Discharge Density

- 5 mmlmin

water supply - duration

- 60 minutes

A

-

Allowable sprinkler spacings - 12 m2/sprinkler Ordinary Hazard is subdivided into four sub groups, and the level of hazard that may be protected increases with increasing Group number:

be safe from all forms of accidental discharge.

None of these latter points are addressed in the sprinkler rules, yet they are of vital importance when considering the installation of a sprinkler system in an historic building and should be uppermost in the minds of the clients, consultants and contractors involved.

Constructive assistance may be provided by insurers in the form of advice and checking of initial proposals and design drawings.

Discharge Density

S

ordinary ~~~~~dcroup 1 AMAO

72 m?

Ordinary Hazard Group 2

AMAO

144 m?

Ordinary Hazard Group 3

AMAO

2 16 m'

Ordinary Hazard Group 3 s (Group 3 Special)

AMAO

360 m'

High Hazard High Hazard occupancies include those that are the most difficult to protect such as process and storage risks where fires may develop rapidly. High Hazard protection of storage risks involves the use of a materials categorisation system that is also used where storage is found in Ordinary Hazard situations. It is

HISTORIC SCOTLAND TAN 14 THEINSTALLATION OF SPRINKLER SYSTEMS IN HISTORIC BUILDINGS

unlikely that historic buildings will require High Hazard protection, so only the briefest details will be shown here: AMAO

- 260 m'

Discharge Density

- 7.5 to 3 0 m d m i n

Water supply duration

- 90 minutes

Allowable sprinkler spacing -

9 m2/sprinkler

Expensive mistakes can be made at the design stage so it is essential to obtain the correct advice, for example BS 5306: Part 2 suggests that libraries may be protected by a Light Hazard system providing the~floor area does not exceed 126 m'. This level of protection would be satisfactory for many village libraries.

However, libraries greater than 126 m' in area should be protected by an Ordinary Hazard Sprinkler system which provides a higher level of protection. For many high street libraries, Ordinary Hazard sprinkler protection may be appropriate but it should not be .. . assumed to be sufficient without a review of the fire hazard. Libraries now store large quantities of video tapes and C D ROMs in solid shelving which could be a serious challenge to an Ordinary Hazard system.

National libraries and many large county libraries often have book and document storage areas which are in fact book warehouses and should be classified as High Hazard areas.

-

occupants whilst escaping from the fire and does not assume that the property itself will also be protected.

TB24 Water storage capacities for sprirzkler installations The LPC introduced this Technical Bulletin in 1997 to allow water storage capacities to be reduced if certain advantageous design features were present. The water supply duration for Ordinary Hazard wet pipe systems may be reduced from 60 minutes to 30 minutes if the following are present:

-

Determining the level of sprinkler protection to be employed to protect a building is the single most important decision to be made at the design stage and this decision should only be made after consultation with a consulting engineer experienced in the installation of sprinkler systems. Where sprinkler protection has been required as a condition of insurance, or suggested as a means to obtain a fire insurance premium discount, the insurance company may provide technical advice on the level of protection required.

Automatic alarm transmission to an LPCB approved central station; -.

The maximum height of sprinklers above the floor does not exceed 5m; Maintenance of the sprinkler protection is under contract to a LPCB certificated or registered company; -

-

Quick response sprinklers are used.

1.6 Types of installation There are several types of sprinkler installation, the main elements of which are shown in figure 2. The type chosen should depend on the nature of the probable fire and the ambient conditions in which the system will be installed.

Recent developmer~tsin tlie LPC spri~zklerrules The LPC sprinkler rules include developments that are not yet included in BS 5306: Part 2, for example:

TB 14 Sprirzkler s~stenzsfor d~vellirzghoirses This LPC Technical Bulletin details how a house or flat may be sprinkler protected without using the hazard classification system described above. The design Parameters are that a d ~ m e s t i csprinkler system should be capable of providing a flow of at least 60 Llmin when any one sprinkler head operates and a flow of 42 L/min through any two sprinklers operating simultaneously. The assumption is that the domestic sprinkler system will provide protection for the

Figure 2. Main elenzents of n sprirzkler systenz.

Most systems are of the wet pipe type, but the options are as follows: A wet pipe system, (figure 3), allows water to be applied to the fire as soon as a sprinkler head operates. This type of system has all pipework

HISTORIC SCOTLAND TAN 14 THEINSTALLATION OF SPRINKLER SYSTEMS IN HISTORIC BUILDINGS

and Range Pipes

D

Water Supply

Wet Pipe Installation Control Valves

Water Motor and Gong

Figure 3. A wet pipe sprinkler system.

from the water supply to the sprinkler heads permanently filled with water under pressure and is the only type of system that should be installed for life safety purposes.

Wet pipe systems should only be installed where the ambient temperature does not exceed 70째C (high temperatures accelerate corrosion and calcification of the pipework) and there is no danger of the water in the pipework freezing.

Where the temperature in part of the premises may be outside these limits a 'tail end alternate extension', which allows a part of the system to operate as an alternate wet and dry system (see below), or similar arrangement may be installed.

Applying trace heating to pipework liable to freezing is an alternative solution.

A dry pipe system (figure 4), is designed for areas where there is a danger of water in pipes freezing or where temperatures above 70째C may occur. In these cases the pipes would normally be filled with air under pressure. The disadvantage of this type of installation is that when a sprinkler

head operates there is a delay while the air in the system is expelled before water is released.

Additional equipment, taking the form of accelerators and exhausters, on the valve set can go some way to reducing the delay.

In a dry pipe system the valve set, part of which is always filled with water, must always be protected from extremes of temperature.

Alternate wet and dry, which is a system designed to be operated as a wet pipe installation in the summer and a dry pipe installation in winter.

Pre-action systems are dry pipe systems (or an alternate system operating in the dry mode) linked to the automatic fire detection (AFD) system. There are several types of pre-action system, the purpose of which is to apply water from the system in less time than would be possible from a standard dry pipe system, and to prevent water release from mechanically damaged sprinklers or pipe work when there is no fire. The operation of the various types of pre-

Figure 4. A dry pipe sprinkler system.

Dry Pipe Installation Control Valves

Water Motor and Gong

HISTORIC SCOTLAND TAN 14 THEINSTALLATION OF SPRINKLER SYSTEMS I N HISTORIC BUILDINGS

action system are based on the principle that the AFD system is electrically connected to a control system on the pre-action installation control valve. The design of the control valve and its sub-systems determines how the preaction system reacts to the activation of fire detection or sprinkler heads.

Due to their added complexity, pre-action systems have more potential failure modes, and hence require more maintenance than the other sprinkler systems. The AFD and electrical systems tend to be the dominant factors determining the fault rate for pre-action systems.

Their complexity also tends to make pre-action systems more expensive than wet or dry pipe installations.

Where protection against radiation and flames from a fire in an adjacent area is required for openings such as the doors, windows and skylights, the roof of the building, or for tanks of flammable liquid or liquefied petroleum gas (LPG), a spray system using either automatic or open spray heads is often employed.

1.7 The Bailey report

locating sprinkler heads on painted and decorative plaster ceilings. The report also considered that the installation of pipework would be a problem quoting riser dimensions of up to 150 mm internal diameter.

The report weighed these costs against the risk of accidental water damage. The probability of accidental damage was considered to be low. Reference was made to sprinkler heads being fully tested 'so that the risk of failure is negligible'. The report referred in particular to a pre-action system requiring operation of the AFD installation to charge the sprinkler system. In the event of fire, 'generally no more than four sprinkler heads operate'.

Water is discharged from a sprinkler head at a rate of 'between 30 and 100 litres per minute'. This rate of discharge compares with about 600 litres per minute from a hand-held fire brigade hose and about 1100 litres per minute from a monitor operated from a hydraulic platform or turntable ladder. If a fire is allowed to develop, considerable quantities of water will be required to extinguish it by the fire brigade. The 31 jets and 2 hydraulic platform monitors used at the height of the Windsor Castle fire would have applied some 20,000 litres of water per minute to the fire.

to take all practicable 'passive' measures, such as compartmentation, to check fire spread,

The report concluded that 'in the particular case of the Royal Palaces, and given the adoption of the full range of recommendations we have made, the costs in money and heritage terms of additionally installing a modem sprinkler system throughout any Palace building have not yet been shown to be justified by equivalent savings in fire risk. So we are not recommending that sprinklers are installed throughout the Palaces', but the report left open for consideration their installation in small confined areas 'if a detailed survey demonstrates that this would achieve a worthwhile reduction in risk'.

to install a full analogue addressable automatic fire detection (AFD) and alarm system,

1.8 Financial considerations

Following the disastrous fire at Windsor Castle, a report by Sir Alan Bailey 'Fire Protection Measures for the Royal Palaces' outlined a strategy to minimise fire risks. The strategy included the need: to carry out a detailed fire risk assessment of each building, to eliminate as far as possible the causes of fires,

to ensure that the local fire brigade is called immediately to all fire alerts (with the minimising of 'unwanted' warnings), so that the brigade can fight the fire with minimum delay, to provide training so that staff on-site can use fire extinguishers and hose-reels to tackle outbreaks of fire effectively and safely.

The report indicated the cost of installing sprinklers: 'a rough cost estimate of approximately ÂŁ25-35 per square metre for a relatively straightforward building, though the costs could be much higher than this given the architectural complications'. The report went on to say that the cash cost was not the only cost to consider.

'The main reason for not installing sprinkler systems in historic buildings has been concern about damage to their fabric.' Attention was drawn to the difficulties of

The cost of installing a sprinkler system in an historic building varies depending on the type and size of the building, its form of construction and use, its location, the type of sprinkler system to be installed, and the ease of access to areas in which pipes and sprinkler heads are to be installed. It will be more economical, and less disruptive to the fabric of the building, if the installation of sprinklers can be carried out at the same time as other services are being renewed. Thus the installation of the system may well be phased to suit a planned general refurbishment programme.

Accurate data to confirm or repudiate the financial wisdom of installing sprinkler protection is difficult to obtain, and such data as can be determined may be valid under certain circumstances only.

HISTORIC SCOTLAND TAN 14 THEINSTALLATION OF SPRINKLER SYSTEMS IN HISTORIC BUILDINGS

Benefits may be achieved by reducing the costs of a fire incident, including less easily quantifiable costs such as loss of life, injury, subsequent legal action, loss of irreplaceable artefacts and building structure, the impact on the operation of the premises and possible negative publicity. Where historic buildings operate as businesses, any loss through fire will have a drastic effect on income generation, an effect that may persist even after the building is returned to full use. To take an example, interesting though the reconstructed Globe Theatre is, it does not have the appeal the original building would have had, had it survived to the twentieth century. Finally, there is the intangible area of benefits which will accrue to the reputation of the premises and its owners.

The cost benefit will be the difference between the potential loss associated with the unsprinklered building and the reduced loss associated with the sprinklered building. In both instances it is necessary to estimate the rate at which fire incidents occur and the average cost per incident.

It is assumed that the fire incidence rate will be the same for both scenarios, since the presence of a sprinkler installation does not influence whether ignition occurs (although clearly the attitudes of staff and management towards fire safety will affect this, and the installation of sprinklers is one factor which would indicate a positive attitude towards fire safety).

The estimated average cost of a serious fire incident divided by the mean time between fires (MTBF) yields the annual loss, expressed in & per annum.

It must be emphasised that the following figures are incbrcled for deinonstratiorz piirposes only and are not intended to be acciirate figlires relating to any particcrlar type of installation or any speciJic location.

There may be alternative valid ways to calciilate jnancial benefits.

As an example, if a fire incident is estimated to result in an average loss in the unsprinklered building of, say, £2m and £100 000 in the sprinklered building and the MTBF is estimated to be 100 years, then assuming that: estimated average loss / MTBF = estimated average annual loss then the average annual loss in the unsprinklered building will be: £2 000 000 / l00 = £20 000 per annum; and the average annual loss in the sprinklered building will be: £1 00 000 / 100 = £1000 per annum

The direct benefit from installing sprinkler protection could therefore be: £20 000 - £1000 = £19 000 per annum

The cost of installing sprinkler protection consists mainly of a large one-off sum and is difficult to compare with the calculated benefit derived. A better comparison can be made if the cost of capital expenditure is converted to an equivalent annual expenditure, which should include financing charges and the costs of maintaining the system.

As an example, the installation of an appropriate system may indicate the following figures: Installation of system

£40 000

Civil works and making good

£17 000

Water supply connection

£ 2 000

Total Installation Cost

£59 000

--------The annual calculation could be shown as fol[ows: Cost of capital employed (assuming an installation life of 30 years)

£4 720

Maintenance

& 800

Total

£5 520

So as the sprinkler installation capital cost is £59,000 and the annual cost will be £5,520 over the 30 year life of the system the annualised cost, to include finance charges, is estimated at £7,486. No doubt different accounting conventions may yield differing results but these should be of the same order. It should therefore be seen immediately that there is already a notional benefit when comparing the potential costs of fire with the cost of the system.

It is also likely that the insurers of the buildings and contents will offer a premium rate reduction for the sprinklered building, especially if the system is s the work done by an LPCB designed to LPC ~ u l e anJ certified contractor. Premium reductions can amount to substantial sums, particularly in areas where there is high risk of deliberately set fires. (In schools, for example, premium reduction suggests a pay back period of only 8 - I0 years.) No estimate of the order of discount that insurers may be prepared to give on their . . premium can be given, but we would be disappointed if an insurer was not able to offer a discount.

2. COMPONENTS OF A SPRINKLER SYSTEM

A sprinkler system consists of a number of components, all of which require careful consideration when the system is being designed and installed in an historic building.

Fire protection is provided by ensuring that the level of risk identified in the fire risk assessment can be counteracted by the delivery of a matching level of fire suppressant, in the case of sprinkler systems, water.

Other fire protection measures introduced in the building will obviously contribute to this equation. A number of factors affect the quantity of water delivered. These include the volume of water delivered to each head by the sprinkler distribution pipework, the number of heads and the floor coverage pattern of the head type chosen.

2.1 Water supplies Water supplies for sprinkler installations need to be reliable, at a suitable pressure and ideally be able to supply a sufficient flow of water for long enough to fight the largest fire anticipated. They should also be: under the control of the occupier of the building, (or their right of use should be guaranteed), free from solid material which may cause a blockage in the installation.

A number of different types of water supplies are identified in sprinkler rules publications, enabling users to grade and select the supplies in terms of their reliability. For insurance purposes the quality of the water supply will have a direct influence on any premium discount the insurer may offer for the sprinkler protection. The following are typical examples of water supply: Single supply - This type of supply is usually considered suitable for Light and Ordinary Hazard applications where the estimated maximum loss is not considered excessive. A town main connection of at least 100 mm diameter may be used depending on the pressure/flow characteristics and capacity of the source. Town mains are increasingly prone to the leakage reduction strategies of thc water supply companies which may make them i~nsuitablefor sprinkler protection purposes. A single storage tank and pump is also an acceptable supply.

Superior supply - This type of supply is usually considered suitable for Ordinary Hazard applications and in some instances insurers may allow the use of a superior supply to protect High Hazard risks. A superior supply is an improved form of single supply which typically consists of one of the following: a more reliable town main, two suction pumps drawing from a single tank or two booster pumps drawing from town mains.

Duplicate supply - As the name suggests this is typically two independent supplies connected to a sprinkler system. Duplicate supplies are considered suitable for properties where either the estimated maximum loss is large or where the fire risk is high. It is most often used for Ordinary Hazard applications such as high rise buildings or High Hazard warehouse or process risks. Two independent town mains are allowed but this is an unlikely solution due to the specified performance requirements. The most common arrangement of a duplicate supply is two pumps, one of which must be diesel driven, drawing water from one or two storage tanks, depending on their capacity.

It may be possible to draw water, if filtered, to supply the sprinkler system from canals, rivers or reservoirs and there are limited provisions for the use of elevated private reservoirs, gravity tanks and air pressure tanks.

Water supply requirements for life safety systems are still evolving and some of the guidance documents are confusing. Most of the life safety requirements for sprinklers have been developed around the needs of properties such as shopping complexes and high rise buildings and will not necessarily translate into historic building applications. Additionally it should not be assumed that water supply requirements for life safety will be satisfactory for protecting property. For instance LPC and NFPA publish guidance on domestic sprinkler protection (LPC TB14 and NFPA 13D and 13R). The purpose of these systems is to allow the occupants to escape from a burning house or flat and the water supply and level of protection is sized to achieve this objective. It is not intended that this level of protection will save the property from eventual destruction, although in some instances this might be achieved. It should be noted that according to

HISTORIC SCOTLAND TAN 14 THEINSTALLATION OF SPRINKLER SYSTEMS I N HISTORIC BUILDINGS

BS 5306: Part 2: 1990, all life safety sprinkler systems must have a duplicate water supply.

2.2 Pumps Usually a pump draws water from a suction tank capable of supplying the maximum demand for at least 30-90 minutes depending on the type of risk being protected.

Pumps are usually diesel or electrically operated with characteristics designed to meet the requirements of the installation. In some installations more than one pump may be required to improve the security of the water supply. Power for pumps must be available at all times, thus fuel tanks of diesel pumps, as well as the generator plant fuel tanks, should be kept full. Where the electricity supply is not taken from the public supply, details of the generator should be made known to the designer of the intended installation.

The pumps should be arranged to start automatically when a sprinkler head opens, this is normally accomplished by means of a pressure switch in the installation pipework. Manual start buttons are required for testing and maintenance procedures.

2.3 Valve sets Each sprinkler system has an installation control valve set which is the main control for the installation. The valves are of different designs depending on the type of system installed (see section 1.6), but all incorporate a main stop valve and a sprinkler valve which includes an alarm function. The valve set should be easily accessible so that the fire brigade can turn the water off as soon as rewired. The room or compartment in which the valves are housed should be signed 'Sprinkler stop valve inside'. After a fire, the main stop valve should only be turned off at the command of the officer in charge of fighting a fire on the premises (and only then when the fire is under control or extinguished). If maintenance or repair work is to be carried out on the system, it is essential that it is appropriately authorised and the water is turned on again after the works have been completed.

The period when the system is out of action should be kept to the absolute minimum and the fire brigade and insurer for the building should be notified before the installation is shut down, and as soon as it is operational again. If the sprinkler system is a life safety one, there should be a full bore by-pass around the installation control valves, thus alleviating the need for the installation to be completely isolated, but in the event of a complete shut down, staff o r public may not be allowed in the building.

Figure 5. k l v e set wit11 sprinkler and ,vater gong operating.

(Ill~rstrationcourtesy of Wor~nnldFire Systen1.s Ltd)

The main components of an installation control valve set are as follows: (see figure 5) The main stop valve, which is operated manually and should normally be strapped and padlocked in the open position. If the valve is monitored, a microswitch assembly, which may be termed an anti-tamper switch, can raise the alarm at a sprinkler system monitoring and control panel if attempts are made to tamper with the valve.

The alarm valve, which is designed to prevent back-flow and allows water to flow to a water motor alarm gong to raise a local alarm. In addition, a pressure or flow switch can be linked to a sprinkler system monitoring and control panel to raise the alarm and, in some cases, send a signal to a central monitoring station.

2.4 Pipework The sprinkler system will require relatively large diameter pipes to carry the water from the pumps to the valves. Further pipes of varying diameter convey the water from the valves to the 'range pipes' to which the sprinkler heads are connected. Vertical pipes are known as 'risers' as distinct from the horizontal 'distribution pipes'.

Pipe sizes are determined at the design stage either by a process of hydraulic calculation or by use of pre-

HISTOI<I~.

SCO'I'I.ANI) TAN 14 TI~I;INS.[-:\I.L.ATION Or: SPRINKI.I:RSYSI'EMS IN Hlsro~l(' BLIII~I)IN(IS

calculated pipe size tables which are published in some the pipe or the fitting to be rotated to make the joint. sprinkler codes, Hydraulically ealeulated pipe systems The initial discharge frsm the sprinkler heads m y be will allow the use of smaller diameter pipework than contaminated with iron oxide, and so this type of the ptecdculared pipe sizing methds specify. The pipework may not be appropriare where books or other disadvantage of using hydraulically calculated fragile mefacts m being atmd. pipework is that should any modifications be required In recent yeas, W C (chl~rinatexiPVC) plastic tp a system designed in this way, full calculations of all plpework has gained approval for use in eertain the element8 would again be required to ensure the Ordinary H& and domestic risk dtusr;tions. It has a m d i f i d system will perform effectively. number of advantages (see Plate 45. Lt can, far example In the case of Duff House, Banff, hydraulic be cut to length e&ly on sire and joints and fittin&sbe ctzlculations allowed the main feed pipes to be reduced secured with a specially fsrmulated acbsive, thus from 100 mm to 80 mm diameter, risers from 100 mm diminating the- need far tim wnsuming threading or to 50 mm and final distribution pipework from 65 m growing of steel pipes. In addition, tl.1.e p i p have same flexibility, whi~hmay assist when installing Ehm to 32 mm and 25 mm. in confmed spikes. ~ o w G e rthe , p i p &mld never be Steel is the industry standard for sprinkler pipework, left in a permanently stressed condition. It is g& but the full implications of installing â&#x201A;Źhis 'hard pipe' practice to install the p i p behind a suitable fire byatem should be ccmsidad before specifying it fos w resistim barrier, such as gypsum bard, to give added histodc building. Each deviation in the pipe run has ro fire pr~mtion.Should the need arise, CPVC pipe W be jdnted, which can mean a pr~liferationof jaints in tw painted, but only with emulsioa ar w a t e r - b d a complex retro-fit project. Suffi~ientworking space paints, as oil-based piain& will cause making, a point for joinring to take plae-e needs to be allowed when that will need t s be highlighted in the maintenance plans m drawn up. A l t h q h screwed pipe fittings are a m u d for the building. It also follows that the the: most common a d fhe c h e a w f m af pipe pipework should not be exposed m m.ivents or other jsinting method, thm are also many LPGB approved deleterious chemials. mdunical pipe couplings and fittings which can be used with s i pipes. These forms of pipe fittings do CPVC plastic piping is mt dmays h e appropriate n& rely on threaded pipes or fitting to make a joht but choice and the agreement of i n s u m ahodd lie sought wualIy rely on a groove which is either cut or rolled before a contractor is engaged to btdl a system. In into the pipe end. The d v a n t q e that these mwhanicd addition the installation must be und%rt&en by pipe couplings offer is that the fittings .s uusually properly trained staff. bolted or fastened around the pipe and do not require

Plate 4. A recent CPVC pipe sprinkler installation in progress. Fittings undfurniture (protected by dust sheets) remained in the room thmugho~ttthe installation period.

H ~ S T ~ SCOTLAND RIC TAN 14 THEIN~TAI.I.ATION OF SPRINKLER SYSTEMS I N HISTORIC BUILDINGS

Stainless steel pipe is more expensive than the other types of pipework listed here. It has occasionally been specified for some installations where, for example, the aesthetic of exposed stainless steel is appropriate to the building or where the building or where contents are sensitive to the contaminants which may be present in water discharged from carbon steel pipes. It is for the latter reason that stainless steel piping was specified for critical areas of the National Library of Scotland.

Copper pipe may be used in Light and some Ordinary Hazard systems and is suitable for both commercial and historic buildings. However, hot work such as brazing or soldering should not be allowed to take place on site. Hot work cannot be condoned in the UK, in view of the many fires caused by such activities in historic buildings. The practice of bending copper pipe is not allowed by any of the European sprinkler codes due to the possibility that the waterway might be narrowed.

P F' Tension Screw

l ~ e aSensitive t I

Assembly

U

All pipes need to be supported, thus pipe hangers may have to be installed at regularly spaced intervals. The sprinkler heads are supported by the pipework.

Figure 6. Co~zstr~lction of a typical glass b ~ l l bsprillkler head.

2.5 Sprinkler heads Heads are manufactured with 10, 15, and 20 mm thread sizes. Each of the sizes has a differing waterway dimension and therefore has a different water flow rate capability. These are respectively 57, 80 and 115 litreslminute at 1 bar pressure. A sprinkler head has a heat-sensitive element which holds the waterway valve closed. The element fuses or ruptures at a specific temperature, opening the valve and releasing water.

There are two commonly used heat-sensitive elements: those operating by the rupture of a glass bulb, illustrated in figure 6, and those incorporating a fusible element where the valve components are held in place by a eutectic alloy component (similar to solder).

At normal temperatures a sprinkler head glass bulb contains a coloured liquid which expands under the influence of heat, and a small air bubble may also be discernible. As heat is applied, the liquid expands and the size of the bubble reduces as the glass bulb internal pressure increases. Continued heating increases this pressure until the bulb shatters. This releases the valve covering the waterway, and the water that is released is broken up into droplets and distributed by a deflector.

The temperature rating of fusible element sprinkler heads is determined by the composition of the eutectic alloy used. The fusible link components are arranged to drop free and open the waterway when the appropriate temperature is reached.

2.5.1 Temperature rating A sprinkler head will not operate until the heatsensitive element reaches a predetermined temperature. The table overleaf indicates typical operating temperatures of glass bulb sprinkler heads.

The temperature rating is identified by the colour of the fluid in the bulb and is also marked on the sprinkler assembly. A range of temperature ratings is also available for fusible element sprinklers, although the nominal temperature ratings available are determined by the properties of the eutectic alloys used and differ slightly from the glass bulb ratings. The temperature ratings of fusible element sprinklers are marked on them and a colour coding system also exists whereby the colour code is painted on the sprinkler frame.

Colour coding paint is not usually applied on fusible element sprinklers with decorative finishes.

The selection criterion for sprinkler heads is that the nominal operating temperature should be more than 30째C above the highest anticipated ambient temperature conditions. For normal environments the 6S째C glass bulb and the 74째C fusible element temperature ratings are most frequently used. Care should be taken to select the appropriate temperature rating in rooms, compartments or localised areas where there may be a build-up of heat from machinery or equipment such as boilers or where there may be solar gain beneath roof lights or beside windows.

Table 3 Colour coding of glass bulbs sprinkler heads Nominal operating temperature

Colour of fluid

57OC

orange

6S째C

Red

The advantage of using quick response sprinklers is that they operate at an earlier stage in the development of the fire than standard response sprinklers. In many instances this should result in better fire control, with fewer sprinklers operating and hence less water discharged during a fire. Quick response sprinklers are also generally smaller than the other types, lessening isual impact in historic interiors.

Yellow

Green 14loC

Blue

182OC

Mauve

-

--.W

--

2.5.2 Response Time Under fire conditions a hot gas layer forms at the ceiling and by the time a sprinkler operates the gas temperature will always be higher than the nominal temperature rating of the sprinkler head. The time taken for the sprinkler to operate is a function of a number of variables. Sprinkler equipment approval authorities measure the thermal sensitivity of sprinklers and rate the sprinklers according to their performance. The rate at which the sprinkler heat sensitive element takes up heat from its surrounds is measured and calculated as a Response Time Index (RTI) (the RTI scale used is 0 to 350, the higher the value the slower the sprinkler is to operate).

Measurement and calculation also determine the rate at which the heat sensitive element dissipates heat, (usually to its supporting pans, which are at a lower temperatures,). This is called the Conduction Factor (C) (the C scale used is 0 to 2, the higher the C value the greater the heat dissipation). Although the RTI and C are measured accurately, providing the sprinklers fall within the specified limits they are classified as one of the following thermal sensitivity ratings: standard response (RTI >80 -200) (C >0 -2) special response (RT 1 >50 -80)

(C >0 - l )

quick response

(C >O - l )

(RTI >0 -50)

The trend in recent years has been to manufacture sprinklers which operate more quickly. In the 1960s and 1970s glass bulb sprinklers usually had RTIs of 300 or more. Many are now classified as 'Quick Response' and have RTIs of less than 50.

2.5.3 Sprinkler orientation Sprinklers heads are designed, manufactured and assessed for use in specified orientations: pendent, upright and horizontal (related to the direction in which the sprinkler heads are mounted), see plate 5. The orientation for which they are suited is marked on the deflector. The orientation marking is usually combined with the sprinkler head type marking, for example Spray Sprinkler Upright will usually be identified SSU. Conventional sprinkler heads can usually be used in both the upright and pendent orientation and will therefore be marked CUIP. Sprinklers should only be used in the orientation for which they have been made and approved. It is sometimes necessary to install pendent sprinklers beneath sloping ceilings or the undersides of staircases. Not all pendent sprinklers are suitable for use on an incline, for example some flush and concealed sprinklers may have ceiling slope limitations. The manufacturer's data sheet should therefore be consulted and any restrictions adhered to.

2.5.4 Sprinkler types Sprinkler heads are arranged in an array at ceiling or roof level, designed to provide an even distribution of water onto the goods, furniture or floor beneath. The following sprinkler types are available (see figure 7):

1

Plrrte 5.

Sprinkler heads. kfi to right: Pendent (chromefinish), Upright (brassfinish), and Horizontal (colouredfinish) sprinkler heads.

Figure 7. Disrriblrtiorz patterns from sprinkler heads.

Distribution patterns Conventional Conventional sprinklers produce a spherical discharge pattern with some of the water being thrown up towards the ceiling.

Spray sprinklers produce a hemispherical discharge below the sprinkler with little or no water reaching the ceiling.

Conventional pattern sprinkler heads project about 50% of the discharge downwards and 50% upwards to the roof or ceiling and may produce comparatively large droplets.

Conventional sprinkler heads may be installed in an upright or pendent position. Traditionally they have found most use where the ceiling and its supporting structure are combustible.

Spray pattern sprinkler heads produce a hemispherical discharge pattern with at least 80% of the water directed downwards from the deflector, so little or no water reaches the ceiling. Different spray heads are manufactured for installing in upright and pendent positions.

Sidewall pattern sprinkler heads are designed to be installed close to walls. They project the water downwards and away from the wall. Sidewall heads are used where it is necessary to keep the ceiling or ceiling void free from fittings or pipework. Sidewall sprinklers are manufactured in upright, pendent and horizontal version and are often used to protect corridors, narrow rooms and lobbies.

Ceiling and flush pattern sprinklers are variations on the pendent spray pattern sprinklers and they

Upr~ghthead

U w ~ h head t

Pendent head

Pendent head

are designed to fit closely to the ceiling line, and may therefore be appropriate in some historic interiors. However, there is a compromise on performance as a result of their low profile.

When a hot gas layer forms at a ceiling during a fire, the gas temperatures and velocities close to the ceiling are relatively low. The highest temperatures and gas velocities occur about 150 mm below the ceiling line and sprinklers will be most efficient if the heat sensitive element is at this position below the ceiling line.

Recessed pattern sprinkler heads are another variation on the pendent spray pattern sprinkler.

These sprinklers are recessed in the ceiling in a metal cup with the deflector protruding below the ceiling line (see plate 6). The same comments apply to the recessed sprinkler as were made about the ceiling and flush pattern sprinklers.

Recessing sprinklers will however make the sprinkler even less responsive to the fire. If quick response heat sensitive elements are used this will improve the performance of the sprinklers, but at best they are likely to achieve the performance equivalent to a standard response exposed sprinkler head.

l

1

HISTORIC SCOTLAND TAN 14 THEINSTALLATION OF SPRINKLER SYSTEMSI N HISTORICBUILDINGS

1

T L eiling

level

4.5cni

L

3.5crn

Ceiling level

Conamled pattern sprinkler heads are messed into the ceiling and a cireular plate avers the sprinkler (this is comorrly called a a o n d e r plate) (see plate 75. From below only the conceder plate cm be seen. The concealerplam are attached to the sprinkler assembly by law mslting point eukxtic alloy tabs. When subjected to hot fire gma, the tabs fuse and the concealer plate falls away. Only whm the c m c d e r plate has fallen wiIl the sprinkler head heat-wnsitive element iwlf be mbjwtal to he hot gases.B w m s e of the design and gasition dative to the ceiling, conmalexi pattern s p W w heads will be compatatively s l m to operate and should therefore be used with caution. They also

h&%more eritical camponen& than a stmdmi sprinkler and this will influence their mliability and &ult rate%@oncedar phks can be pravided in a rang&of different w l o m to suit the howewer they should srtfy b pzlinted by the manuktumr.

Where the q e r n is af ;lfthw dryTp a l t t : a~ pr& wtian types, the h& should he, inrstalIe4 in the upright p i t i o n to ensure the compl&e of the pipwwk and thua eliminate the p b l e m smnetima by msidud water M 1 6 in thR sprinkler barn

3. INSTALLING THE SYSTEM

3.1 Fire risk assessment To managers of commercial and industrial buildings the concept of fire risk assessment will not be new, as it is a requirement of the Fire Precautions (Workplace) Regulations 1997 that a fire risk assessment is carried out for these types of properties. The Regulations implemented the European Community's Framework and Workplace Directives in respect of fire safety. Both Directives firmly placed the primary responsibility for ensuring health and safety in the workplace with the employer or the person who has control of the Workplace. They must be in possession of an assessment of the risks, including the risks from fire, to health and safety at work.

3)

eliminating the hazard, controlling the hazard, avoiding or transferring the hazard.

If desired, a form of rating may now be assigned to the building as a whole, or various areas within it. For example the fire risk assessment for an historic house may show that: Low fire hazard areas are corridors, stairways and exhibition galleries (it must be remembered that while exhibition galleries may be of low hazard, their contents will be of high value, and hence these spaces will be of high risk). Attic spaces may also be low hazard areas provided they are not used for storage or for services. A fire may, however, spread rapidly in a loft or attic area and these spaces may be difficult to access for fire fighting, so compartmentation or sprinkling of these spaces is critical.

Although there are a number of 'accepted' workplaces to which the Regulations do not apply, in general they must be observed by employers in all workplaces other than private dwellings. The need for a fire risk assessment to be carried out thus applies to many historic premises.

There are many ways of carrying out a risk assessment and it is important to remember that there is no wrong and no right way. More comprehensive guidance on this matter can be found in TAN 11, Fire Protection Measures in Scottish Historic Buildings. However the risk assessment is carried out, a number of points have to be taken into consideration. A typical risk assessment would involve: 1)

Normal fire hazard areas generally include rooms used as offices, retail shop or tea room.

Higher fire hazard areas are plant and storage rooms, sleeping accommodation and kitchens.

Rapid action response would be necessary to prevent fire spreading from these areas to adjacent rooms.

Identifying all the fire hazards, that is to say: all possible sources of ignition, all combustible or highly flammable materials present in each area. These will include the furniture and furnishings, parts of the structure and fittings, and any materials used during business operations, craftwork and so on. any unsatisfactory structural features.

Identifying people who could be at risk, including:

-

people with disabilities, people who may be sleeping, large numbers of members of the public, contractors.

After completing the first two steps, consideration should be given to:

4)

Having reduced the fire hazard as far as is practicable (in the light of the normal usage of the premises) consideration has to be given to whether the existing fire safety provisions are adequate or need improvement. It is at this stage that the installation of a sprinkler system may be investigated. Although it is normal practice to install sprinklers throughout a building there may be circumstances where partial installations would be appropriate, especially in those areas of the building that the fire hazard has been found to be higher than normal. Thus kitchens, tea-rooms and offices could be protected by fire detection and sprinklers. The principal rooms may be protected by fire detection alone, most discreetly by air sampling for smoke. The decision on the

HISTORIC SCOTLAND TAN 14 THEINSTALLATION OF SPRINKLER SYSTEMS IN HISTORIC BUILDINGS

installation proposed should be based on the response that the room warrants.

5)

Having decided how to manage the residual fire risk, the findings of the fire risk assessment should be recorded. This is a legal requirement of any fire risk assessment required under the Workplace Regulations if five or more people are employed in the premises.

6)

The sixth step is to prepare contingency plans.

These should include provisions for damage limitation and salvage as well as the steps necessary to protect the historic fabric of the building and minimise business losses.

7)

Having carried out a fire risk assessment it should be reviewed periodically.

During the exercise the historically important construction, finishes and detail of the building should be fully documented, if this has not already been done.

This is especially the case in a building which has been extended over time, as it is possible that earlier features are hidden behind more recent work, for example, painted joists and ceilings may survive above later plaster ceilings or an early external stone wall with moulded openings may be concealed by strapping.

Reference should be made to original building records to aid understanding the history of the development of the building, which may give clues to possible hidden features and structural discontinuities. Sources of this material include the Royal Commission on the Ancient and Historic Monuments of Scotland, the Scottish Record Office, original architect's offices or the client's records. The building survey and documentary search will serve to establish: The nature and importance of the fire resistance of walls, floors and ceilings. This will suggest routes for pipework and the nature of the fittings which can be used.

The historic relevance and fire resistance of doors and glazing to ensure that they are consistent with the fire resisting properties of the building elements in which they are located.

That all holes around existing pipes, cables and other services are fire stopped to an appropriate standard.

The locations of voids within the construction of walls, behind panelling and above ceilings or below floors. These may be considered as areas through which pipework may be run. Where voids are large, it may be necessary to install sprinklers to protect them.

Compartmentation possibilities and difficulties.

The temperature extremes in areas through which pipes may run should be estimated so that the types of sprinkler systems and temperature rating of sprinkler heads which might be installed can be determined.

3.2 Design guidance for the installation of a sprinkler system No design guidance for work in historic buildings can be prescriptive, as each building presents a different challenge. The starting point must be to carry out a comprehensive survey of both the physical fabric and documentary sources of information, which will allow an assessment of the importance of the building to be made. Following the survey, which may have been carried out as part of the fire risk assessment, a framework can be set for acceptable intervention, protecting those qualities that have been recognised as central to the building's importance.

The fire risk assessment will highlight where the risk of fire is most acute. As indicated in the previous section, the next stage is to translate this analysis into a strategy for the building. A range of solutions should be considered, and all the options judged against the framework of acceptable intervention set for the particular building.

Thus in an eighteenth century building with fine unaltered interiors, the aesthetics of these interiors will be paramount and it may be decided that any disruption of these, even to install the smallest of recessed sprinkler heads and their associated pipework will be unacceptable. Passive measures to reduce the fire risk, such as improved compartmentation and automatic fire detection may represent the minimal intervention strategy that should be adopted in this case. Each case must, however, be considered on its own merits. In some buildings, works required to improve, for example, compartmentation, could be highly damaging to original fabric and fittings. Management procedures, such as increased vigilance, provide another way of improving the fire protection of a historic building, with no impact on its fabric.

By contrast, in the case of an early industrial building, the social and historic significance of the building and the lessons it can teach us about the work and life of our forefathers are likely to be of greatest interest. The installation of a sympathetically designed surface mountcd system of sprinklers could have a major, but acceptable, visual impact on a building of this type.

Listed building consent will be required for all installations within listed buildings. Liaison with the Historic Buildings Inspectorate should be carried out at an early stage, in order to highlight any possible problem areas early in the process.

HISTORIC SCOTLAND TAN 14 THEINSTALLATION OF SPRINKLER SYSTEMS I N HISTORIC BUILDINGS

minimum and is sympathetic to the aesthetic dimension of designing within historic interiors is vital to the success of the project. The consultant engineer should be made aware of the distinction between fine and service areas of the building and the locations of these. Detailed plans of the building should be made available and these should show the locations of voids where these are known. The spaces required in building cavities for crossovers of pipework and cables must be accurately assessed at the design stage.

Detailed layout drawings showing all proposed pipework should be drawn up by the consultant engineer, and the scheme discussed at all stages with those responsible for electrical, heating and other installations, who should also be required to produce

In the following sections, the various elements of the installation are considered, and lessons learnt from the case studies are presented. Further information on the case studies can be found in Appendix B.

3.3 Selecting a consultant engineer It is important to employ only consultants who are experienced in the installation of sprinkler systems in historic buildings. It is appropriate that an experienced conservation architect oversees and ensures the coordination of the work of all other specialist consultants. The selection of an appropriately experienced consultant engineer, who understands the need to reduce intervention in the fabric to the

Figure 8. Plans must be clear and legible, as well as showirlg as much detail as possible.

20

HISTORIC SCOTLAND TAN 14 THEINSTALLATION OF SPRINKLER SYSTEMS IN HISTORIC BUILDINGS

P&

P+ P a t tb.4215-037

Figure 11. Detailed drawings of the sprinkler heads may be required for installations in sensitive areas.

P

-

m

~

e

d

b

!

Figure 9. Alternative arrangements can be helpjirl and dimensions shorrld be indicated ifth~intbnaildrawings are not to the same scale as the main plan.

C-iiq/L*"PlastaRm

lmcrGlrq/Lk#ttth

Tender documentation must be prepared that specifies the exact locations of the water supply (where appropriate), pumps, alarm valves, the intended location of all pipework runs and the type, layout and position of the sprinkler heads to the sprinkler installation contractor. A part of a plan is shown in figure 8 and details are shown in figures 9 to l l. Any deviations from the LPC Rules, and thus BS 5306: Part 2 should also be detailed. If these details appear to be extensive it may be wise to seek the advice of the insurer's specialist.

3.4 Selecting a sprinkler installation contractor

S;rl*b-wtkd

mW 1Unrq Rmn 5 d e

Nqnmtofydcc mns

Figure 10. The exact location of sprinkler heads should be of the yoke arms marked on the plans and the aligni~~ent should also be indicated ifit may not be obvious to the installing enginee~

drawings of similar accuracy. The installation of sprinkler systems is just one service installation, and, as with all service installations in historic buildings, should be carried out as conservatively as possible.

Those responsible for commissioning the sprinkler installation should ensure that they see and approve the detailed plans of the installation before work commences. They should not assume that the consultant engineer will understand all the intricacies of working on historic buildings, or the constraints that this will bring. In sensitive areas of a building the suggested route of every pipe and location of each sprinkler head should be checked before the final design is agreed. The approval of the planning or fire authority and Historic Buildings Inspectorate may also be required.

The selection of the sprinkler installation contractor is of vital importance to the success of the project. The chosen contractor must be able to demonstrate that they have experience of work in historic buildings, and all operatives too must be selected for their individual experience of working in historic buildings and their understanding of conservation issues.

The installing company should meet the requirements of Loss Prevention Standard 1048: Requirements for certificated sprinkler installers, supervising bodies and sripervised installers, published by the Loss Prevention Council (LPC). Firms listed in this standard are authorised by the Loss Prevention Certification Board (LPCB) to design, install and certify sprinkler installations to the LPC Rules. The LPCB assess LPS 1048 installers to the appropriate technical and quality standards, but do not carry out financial assessments with regard to their ability to finance contracts.

Representatives of the chosen companies should be invited to visit and be shown the full extent of the premises so that suitable protection may be designed.

Any restrictions that will have to be observed during the installation should also be described.

The contractor should be made aware that, in historic buildings, service runs need to be carefully coordinated so that minimal disruption is caused to the

HISTORIC SCOTLAND TAN 14 THEINSTALLATION OF SPRINKLER SYSTEMS IN HISTORIC BUILDINGS

building fabric. This requires close communication between all the individuals responsible for the various service installations.

3.4.1 Work in progress Close monitoring of the work in progress is required ta ensure that all systems are installed to the highest standards of workmanship, especially that all pipework joints are correctly made. A quality control regime should be incorporated into the contract to ensure this is the case.

A location for temporary accommodation for the installation contractor should be agreed. If this is to take the form of a temporary cabin it should be located at least 10m from the historic premises. The contractors should be required to observe other relevant recommendations in the Code of Practice for Fire Prevention on Construction Sites published jointly by the LPC and the Building Employers Confederation. Failure to do so could result in the insurer withdrawing cover.

If installation in some areas of a building is to be undertaken while members of the public are being admitted elsewhere, suitable routes into the premises for the contractors will have to be agreed. Security measures may also have to be reviewed while contractors are at work.

Plans should also be drawn up for the protection of furniture, carpets, pictures and fittings as necessary.

Suitable, safe, storage must be found for any valuable items temporarily relocated. The fire load of storage areas used may have to be reassessed and additional fire extinguishers purchased or obtained on loan from a supplier.

Many fires occur while contractors are working in buildings. A large proportion of these result from changes in well established management procedures necessitated by the work in hand. Thus close liaison should be maintained with contractors and if changes to routines are necessary great care should be exercised. Staff should also be suitably instructed and advised to be vigilant. The guidance contained in the HSE Fire Safety in Construction Work should be followed. A large proportion of fires occur when hot work is being camed out. The contractor should therefore be required to assure those responsible for the property that suitable precautions are observed if welding, cutting or similar operations are undertaken.

Hot work should only be used if there is no other suitable technique available. A hot work permit system should be implemented and adherence to this scheme should be a written requirement within the work contract. An example of a hot work permit is shown in figure 12.

Plate 8. Sidewall \ / v 111I.ler and riser ltr~rclingvalve. Note temporary signagc, c~ndprotection to sprinkler head in place while construction work continues elsewhere.

Any modification to other fire safety provisions made at this time (see plate g), such as the temporary covering of automatic fire detectors, should be for as short a period as possible, and only be carried out after consultation with the local authority Fire Safety Officer. It may also be necessary to erect temporary fire exit signs.

3.5 Installing water supply tanks Water supply tanks will be necessary if mains pressure is insufficient to supply the sprinkler system, yet the provision of water supply tanks will often be impossible within an historic building. Ingenuity is then required to find a suitable location for these, and some compromise on their capacity may have to be accepted. This was the case at Coleridge Cottage, a National Trust property in Somerset, where only 1400 litres of water are stored. This is sufficient to supply two sprinklers for 10 minutes. Thus any fire will be controlled while it is still small, and in the event of the fire not being extinguished by the sprinklers, it is intended that the fire brigade (the nearest full time fire station is 15 miles away) should arrive before serious

HISTORIC SCOTLAND TAN 14 THEINSTALLATION

l

OF SPRINKLER SYSTEMS IN HISTORIC BUILDINGS

HOT WORK PERMIT

HISTORIC SCOTLAND CODE No

MONUMENT DEPOT Permlsslon 1s Granted to

Date

To Use

In the

Between.

am

And

PERMIT No

(Val~d tor Day of Issue Only) (Exact Locat~on)

am

pm

And

Pm

TO BE COMPLETED WITH THE CONTRACTOR IN AlTENDANCE a) The above locallon has been exam~ned

bJ There are no combusl~bleItqulds, vapours. gases or dusts

c) All combustible materials have ellher been removed or suttably protected agalnsl heat and sparks lnclud~ng levels underneathibelow

0 0

m

d) Su~lableextlngulshers are locally available and at adlolnlng rtsk areas particularly below e) He and the operatives have had the nearest f~realarm1 telephone pointed out to them and have been told what to do In the evenl of a fire I)

Addltnonal supervlslon IS requ~redby Ihe contraclor as lhere s a r#sulo areas below

g) A metal bucket of water 1s requlred and 16ava~lable .. .

Slgnalure of Person lssulng the Permft

. .

..

...

.. .

. .

.

YesiNo H~stor~c Scotland Manager

ihe IOllOWlng Inspecllonsof the work area have taken place durlng the course ol the operallons and the proper procedures are belng followed

Time

S~gnalure

T~me

Signature

Ttme

Slgnalure

T~me

S~gnalure

The conlraclor responstble for the works conflrms that the works are complete, that the work area and the adjacent areas to wh~chheat and sparks mlght have spread have been thoroughly ~nspected Slgnalure

Tlme

Name Pr~nted

for

(contractor)

AFlER SIGNING THE CONTRACTOR IS TO IMMEDIATELY RETURN THIS PERMIT TO THE ISSUING HISTORIC SCOTLAND MANAGER The area has been thoroughly Inspectedby Ihe H~storlcScotland Superv~soragaln 30 mlnutesafter the work betng completedto ensure no smouldering has taken place and that lhere IS no rask of a Ire startang S~gnature

T~me

Name Prlnted

NOTE: Thls permit 16requlred for all operallons ~nvolvtngIlame, hot alr or arc weldlng and cunlng equtprnenl. brazlng and soldering equtpmenl, blow lamps. blturnen Wders and other equlpmenl produc~ngheal or havlng naked llarnes Plus all dcsc cunlng and grlndlng works In wh~chsparks are emlned

Figure 12. Hot work pet-mit,fort?z.

damage is done. In other situations, it may be appropriate to consider the existing domestic water tanks as sprinkler storage tanks to supply sprinkler heads for a limited amount of time. In another recent sprinkler installation in an historic building, a small water tank filled with clean water was installed within the house. hi^ serves as a first response supply only, with back-up provided by a connection to an existing reservoir (see plates 9 and 10).

Plate 9. Plute 10. The reservoir and externcil pump house that provide the back-up water supply for a recent sprinkler installation in an historic building.

HISTORIC SCOTI.AND TAN 14 THEINSTALLATION

The National Library of Scotland has mently installed a sprinkler system in the bookstacks of its headquarters building in Edinburgh. The tight city-cenm site gave little room for manoeuvre, but 130,000 litres of water storage was inserted in three large tanks under the arches of the adjacent George TV Bridge. The newly inrjtalld sprinkler systems in Farliammt House and the Faculty of Advocates have also beeu connected into this storage facility, 90 considerably reducing the need for disruption of their fabrie. The buildings grouped mound the National Library of Seotland have thus effectively established a district water storage facility,

OF SPKINKI.F.U SYSTEMS IN

HIS~ORIC BUII-DINGS

a eoncept that is of relevance in historic tom centres throughout Scotland.

It may be ntoessary to consider the prevision caf underground water storage tanks and associated pumps, as at DuffHouse, Banff. a n sedtive sites, this approach could require an archaeological investigation in advance, Normal design and structural considerations should apply during the inception, cens.truction and finishing stages of the worlr, employing sheet piling, surface Wabr pumping and tanking as appropriate (plata 11). Care needs to be

Plate 11. U n d e g m d water suppiy tank a& pump mon stt I)*

House.

in other cases, where a generator in an outbuilding can be installed with minimal disruption to the historic fabric of n property.

P h t e 12. Tunk ltmdscctping (it Duf House indicates that more corejirl c.onsiderzction n r d s to he given to this (ISPC~I.

Any valve sets which need to be installed in the historic building should have their location identified by appropriate signs so that they may readily be found by the fire brigade on their arrival. As well as a sign on the door of the cupboard or room in which they are positioned, a sign should be displayed on the external wall adjacent to the entrance nearest the valves. Listed building consent may be required for the signage, and this will need very careful consideration so that functional needs are adequately balanced by sympathetic design and positioning.Suitable lighting should be provided in pump rooms and if these have to be accessed via a ladder or stairs. the light switches should. for safety, be located at the start of the route.

3.6.1 Electric pumps exercised when determining the position of the storage facility to ensure that it both functions appropriately and integrates well with the site; there is a need to fully consider the visual effect of the finished scheme. Vent pipes, manhole covers. or breather pipes may be required above ground. and the presence of these elements should be anticipated and steps taken during the design process to minimise their visual impact. The finished level should avoid unnecessary above-ground intrusions on backfilling. In the case of Duff House, where the effect of the above-ground plant room paraphernalia is further compounded by floodlighting fittings, the visual consequences are considerable (plate 12). Often it is the failure to consider small points of detail that can negate the entire effect of an otherwise well executed installation.

3.6 Housing pumps, generators and valve sets Pumps and generators are unsightly items which need to be housed discreetly but easy access will also be required for maintenance. They may be installed in peripheral areas or outbuildings where they will be less noticeable, though care should be exercised in their design and detailing, and, if the building is listed, their installation will require listed building consent.

Fail-safe power supplies must be provided for electrically driven sprinkler pumps. At the National Library of Scotland, electrically driven pumps were installed in a small room beside the water storage tanks; there was no space, nor sufficient ventilation to install a diesel pump. The solution was to house a diesel generator, with sufficient capacity to serve the entire building's needs in the event of a power failure, in a separate location. This approach may be applicable

Electric pumps should be correctly installed and wired in accordance with the requirements of BS 7671: Requirenunt.~for rlrc'mccll instullutions (The Institution of Electrical Engineers Wiring Regulations). The wiring practices for electrically driven sprinkler pumps are described in detail in the LPC sprinkler rules and it is important to follow the advice given to make sure that electrical power is available to the pumps in a fire. One of the first actions that the fire brigade will take when attending a fire is to isolate the power supplies to the property to protect tire fighters from electrocution. If the wiring circuits are incorrectly configured the sprinkler punips niay be switched off unintentionally.

When using diesel generators as a power source for electric pumps it is essential that the power output of the generator is correctly estimated. The power requirements for properties have a tendency to grow with time. Overloading a generator during a fire may result in a total power failure of the sprinkler system.

3.6.2 Diesel pumps Diesel pumps are generally considered to be the preferred pumping equipment for sprinkler systems and for certain risks and combinations of water supplies insurers may insist on at least one diesel driven pump. They have their own self contained power source and have proved to be dependable and are immune from the problems associated with the reliability of electrical power supplies during fires. The disadvantages of using diesel driven pumps are that they are more costly than comparable electrically driven pumps, are noisier and require more maintenance. Diesel pumps require a purpose built pump house with adequate heating and ventilation.

HISTORIC SCOTLAND TAN 14 THEINSTALLATION OF SPRINKLER SYSTEMS IN HISTORIC BUILDINGS

Ideally the pump house should be external to the building and easily accessible to the fire brigade during a fire.

3.7 Installing pipework All of the fabric of an historic building is valuable as each part, whether concealed or on show, unadorned or splendid, contributes to the authenticity of the building.

Any decision to disrupt any part of the fabric should therefore be considered carefully at all locations throughout the property. Ways of reducing the amount of pipework needed, possibly through combining systems, should be considered. This could take the form of having joint fire brigade and sprinkler risers, as at the Parliament Hall, Edinburgh, or combining the heating and sprinkler systems by running hot water through exposed sprinkler pipes, as in the bookstacks of the National Library of Scotland in Edinburgh.

A wide variety of structural conditions is liable to be met when an historic building is surveyed prior to the insertion of modern services. Working with the alignments of the historic construction will permit more straightforward and sympathetic installations.

the installation can be 'painted out' to blend with the background decor (for example the dark painted sprinkler pipework in the elaborate hammerbeam roof of Parliament Hall, Edinburgh (see cover illustration), or the light painted pipework of the Laigh Hall in the High Courts, Edinburgh (see plates 13 and 14).

In some historic interiors, it may be possible to run exposed pipework out of sight above existing cornices.

Some examples showing how this may be detailed are shown in figure 13.

Reversibility is one of the criteria that should be applied to all proposals for intervention in historic buildings to test their suitability. Even though a sprinkler system should remain serviceable for up to 50 years, consideration should be given to the need for its removal and renewal as the life of any historic building is likely to be considerably greater than that of any service installation. An exposed sprinkler system is more readily removed due to the ease of access to its

Because historic buildings encompass such a large variety of different types of structures and uses it is difficult to establish a code of practice for the installation of automatic sprinkler installations in such premises. Every sprinkler installation in an historic building is unique and few general rules can be provided. Every proposed system must be considered from first principles on its own merits. This makes it especially important to build the appropriate team of experienced professionals who understand the unique problems that historic buildings pose.

3.7.1 Exposed pipework systems This approach minimises the degree of disturbance to the structure of the historic building, and, in this respect, is the preferred installation system.

Exposed pipework will, however, have a major visual impact on the space in which it is inserted, and this will not be appropriate in all historic interiors, especially those where the importance of the room rests in its precise geometry or fine detailing.

Care will always need to be exercised in the design of the exposed pipework to ensure its appearance is appropriate to the historic interior to be protected. Two approaches can be taken to the installation of exposed pipework systems in historic buildings: the installation is frankly expressed as a new insertion whose aesthetics are appropriate to the building in question,

Figure 13. There are many ways of concealir~gpipework in plaster mo~rldings.

HISTORIC SCOTLAND TAN 14 THEINSTALLATIONOF SPRINKLER SYSTEMS IN HISTORIC BUILDINGS

Plate 13. Sidewall sprinklers and exposed pipework in the Laigh Hall, High Courts. Edinburgh.

constituent parts, a characteristic that will also facilitate the maintenance of pipework during the life of the system.

Exposed pipework should be used in all unoccupied areas of the historic building, such as attic spaces, where ease of access for maintenance will be important and the appearance of the system less significant.

All water sprinkler pipes in unheated areas should be adequately protected from frost. Even in a well-heated

Plate 14. Detuil c?ff'sprinkler head Lc~ighHull, High Courts, Edinburgh.

house, the ambient temperature in roof voids in winter can fall below freezing point. Particular care needs to be taken with fully charged water sprinkler system pipework, which should be fully protected by an adequate thickness of insulation. For added protection the pipework could be trace-heated, with junction boxes positioned on the vertical cheek of rafters for ease of access and maintenance. (plate 15). An alternative arrangement circulates warm water, this facilitates inspection of pipework and may be appropriate in some cases.

Plate 15. Attic sprinkler pipe, protected by insulation and trace hearing.

H I S T ~ R ISCOTLAND C TAN 14 THEINSTAI.LA'I-ION

1

16. Sprinkler pipework, attic level positioning.

Suspending, or cheek securing, to the timber roof structure are simple methods of fixing new services in place with minimal damage to the original fabric (plate 16). All sprinkler pipework should be installed away from roof timbers so maintaining a free air flow, and protecting the timbers from rot. If a lage number of securing points are required, it may be best to consider installing a separate plate to which the larger number of fixings can be made.

3.7.2 Concealed pipework systems In order to keep intrusion to a minimum and maintain the aesthetic detail and historic quality of the building, it is likely that pipes will have to take circuitous routes to reach their destinations. For example. in the installation illustrated in plate 4, pipes were installed in the timber floor. These follow the route of earlier heating pipes in order to minimise disruption 01' the fabric, and supply the sprinkler head illustrated in plale 42 from below. This is entirely acceptable from an engineering point of view provided that hydraulic calculations have been carried out to ensure thal adequate flow and water pressure is provided at the sprinkler heads. Designers should be encouraged to rise to this challenge.

In order to conceal pipework from view it may be run: under floors, between joists, above ceilings, in voids, such as those behind panelling, or up redundant chimney flues. along the top o i wide cornices.

OF

SPRINKI.LR SYSTE.MS IN H I S T O R I C

Bll~l.DlN(iS

along the walls of adjacent service areas, along previously disturbed, but redundant, service routes.

Ideally, all new pipework should be located within existing voids and service routes through the building.

However, for a full installation, some hard structure raggling may need to be accepted, but the actual extent of disturbance should be kept to a minimum. Full testing of installed pipework should be carried out before the recreation of finishes.

If compartment walls are breached to allow sprinkler pipes to be installed, they must be fully fire stopped on completion of the works to maintain fire integrity.

3.7.3 The integration of pipework in solid floors In many installations, the main supply pipework will enter the building at the basement floor. It may be appropriate to chase the pipework into the solid floor at this level, (plate 17) and this can be easily achieved with plastic pipe, which can be laid directly into a chase lined with tanking material and screeded over. If steel piping is to be used, it will require protection from corrosion by additional tanking wrapped around the pipework itself. If a general refurbishment is taking place, lined recesses can also be created to house conduit, electrical cabling and plug outlets.

Sprinkler water supply pipes can also be accommodated within existing floor screeds if these are of sufficient depth (plate 18). Care needs to be taken to keep the overall size of the pipe slot to the minimum so that the re-laid tlooring can span the installed pipe without damage through detlection, or lack of support.

Plate 17. Water supply-pipe installation in a solidflool:

Plate 19. The timber floor has been lijled to allow the integration of horizontal service ways.

3.7.4 The integration of pipework in timber floors

If ma-jor conservation works are required, or the historic building is being refurbished due to a change of use, it is likely that entire floors will be lifted allowing the opportunity for a range of services to be comprehensively detailed and installed (plate 19). This approach creates additional demands on the design team and on-site contractors, especially when the topside of the underlying ceiling is exposed.

Additional protection should be installed to prevent damage to those features exposed by the lifting of floorboards and this should be maintained in a satisfactory condition throughout. Temporary movable flooring may be required to provide safe working areas. and to prevent operatives, tools and materials falling onto, or through, the exposed plasterwork below. Appropriate fire precautions must also be taken at all stages of the work. (See section 3.4.1 Work in Progress).

Plate, I N . Pipe, in.srallutio~~ in cr ,poor sc.reed

When lifting an historic timber floor, it is imperative that all floorboards are individually identified prior to work starting. One method of achieving this is to lay masking tape over the floorboards, and mark on each a unique reference number. The tape is cut as the boards are lifted, but on re-laying the tape alignment will allow accurate repositioning of the boards. Bundling of adjacent boards before storage will further aid their accurate reinstatement. A detailed plan should be

Following the removal of the floor-boards, a detailed analysis of possible service-ways should be made.

Useful voids can usually be found above the lath and plasterwork of coved or combed ceilings. In the example shown in plate 20 the laths are fixed to formers. These, in turn, are cheek-nailed to the face of the floor joists to create a common profile. The void created provides a horizontal "duct" space, ringing the room below. The void can accommodate a wide range of services, pipes, cables, apparatus and sensors, installed from the floor above. However, maintaining a free airflow in this zone will be critical to ensure dry rot does not break out, especially crucial if the floor joists bear on an external masonry wall. In the example shown in plate 2 1 pipes installed in the void behind the falsework of a combed ceiling are secured directly to the masonry with brackets. Right-angled pipework bends allow direct connections to the horizontal runs.

A more sympathetic integration in this situation would have located the horizontal pipe run below the joists, so avoiding notching into them.

Plate 20. Floor and ceiling voids.

drawn showing the position of each board and they should be carefully stored in appropriate environmental conditions for the duration of the work.

Care will be required during lifting and re-laying to avoid damage and splitting of the boards, helpful guidance can be found in SPAB Information Sheet 10, Patching Old Floorboards. flute 21. Sidewall sprinkler supply pipe.

The onus lies with the architect working with the consultant engineer to avoid creating situations that will require the removal of any part of the structure and fabric of the building. Thus, . pipes should be set . between the joists, running parallel to them, whenever possible. When laying pipework within an existing timbered floor space, it can either be laid around the timber members resulting in a large number of closely spaced pipework joints or longer lengths of straight pipe can be used resulting in extensive timber notching (plate 22). In the context of a historic building the services should be adapted to suit the building and not vice-versa, and the pipework laid around the structural timbers wherever possible. Provided stringent quality control checking is in place and a competent company

HIS~OKIC SCOTLAND TAN 14 THEINSTALLATION OF SPRINKLERSYSTEMSIN HISTORIC BUILDINGS

Plate 23. Supply pipe junctions.

Plate 22. The sprinkler supp1.v pipe has been installed beneuth the joists. The sume care has not been taken to integrate the cable tray jhr electrical services without damaging the historic fabric.

is installing the pipework, the increased jointing of pipework should not increase the risk of leakage from the system. With recent developments in sprinkler technology permitting the use of CPVC pipes, which are more flexible than steel, longer lengths of pipe may be routed through the structure with minimal notching of timbers.

Top or bottom notching of structural floor timbers greatly reduces their strength. Some historic structures have been over-designed, so that it may be possible to reduce the section of timber without impairing its performance, though the advice of a structural engineer should always be sought before this is contemplated. In addition to considering the strength of the timber to be notched, the impact of the change on the wider structural system of the building should always be considered. Many practitioners do not take this holistic view, and unacceptable loss of structural stability can result.

Where it is necessary to notch the uppermost surfaces of floor joists, the pipework should be designed so that jointing pieces do not occur at these timbers, so minimising the depth of the notch required (plate 23).

Plate 24. Sprinkler supply pipe installation.

Where a sprinkler head position has been determined by the ceiling design, it is possible that this will coincide with a structural floor member above (plate 24). Removal of timber can be minimised through the use of a hole saw, though precautions will need to be taken to avoid the saw wandering off a true vertical alignment. It may be necessary to carry out local strengthening of the structural timber so that the sprinkler head can be accommodated within it if a recessed or concealed type is to be used. Any strengthening steelwork inserted into the structure should be protected to give the required level of fire

HISTORIC SCOTLANDTAN 14 THEINSTALLATION OF SPRINKLERSYSTEMSIN HISTORIC BUILDINGS

Plate 26. Inappropriately located access hatch.

3.7.5 The integration of riser pipework Ingenuity will be required to design a system that has minimal impact. For example, if no shafts or existing service routes exist to house sprinkler pipework risers, it may be possible to install these within a series of vertically-aligned wall cupboards. In this case, it will only be necessary to make physical connections at each floor in order to provide a continuous vertical rising duct (plate 27).

Plate 25. Timberfloor reinstatement.

resistance, this may be most simply achieved with an appropriate intumescent paint.

Once work is completed, any floorboards that have been uplifted should be replaced in their original position (plate 25). Care needs to be taken when refixing the boards not to puncture any underlying cables or pipes with securing nails.

Access covers will need to be provided at appropriate locations, and these should be noted on any drawings submitted for listed building consent. The design process should be geared towards an effective integration of the service installation with the original finishes at the outset (plate 26). This should mean that the shape and size of access ways align with naturallyoccumng joints in the floor patterns. The provision of access panels may involve rebating the flooring to enable a frame to be inserted to give the panel strength.

Panels should be screw-fixed to avoid puncturing the underlying installations when re-fixing after routine inspection or maintenance work. Floor plans showing the location of access and inspection covers should be available to maintenance contractors at all times.

Exposed pipework is preferred as its installation will cause the minimum possible damage to the fabric of the building. and allow the pipework to be easily accessed for any future maintenance. Should it be decided that riser pipework must be concealed within the structure, pipe and cable-ways need to be carefully secured into raggled internal masonry. Pipe holdfasts should be fixed directly into the bodies of the larger stones that are encountered (plate 28).

Plate 27. Vertical service runs.

Hlsro~rcS ~ O . ~ I . A TAN N I )14 THEINSTAI.LATI~N OF SPRINKL.ER SYSTEMS IN HISTORIC BUILDINGS

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hi;

Plate 28. Vertic.~rIpipe insrrrllarion.

Plate 29. 1

Care should be taken to ensure that walls are thick enough to accept ducts safely. Only ducts of adequate, but restricted, dimensions should be cut into walls or solid floors, of sufficient depth to allow for all pipework and joints and for the sensible recreation of the room's plaster or other finishes. Should inspection panels be needed, these should be carefully detailed so that they integrate with the completed decor of the room.

Before covering up, water supply and sprinkler pipes should be lagged with fibre insulation (plate 30). This helps to protect the assembly from any possible interactions that might occur after the wall has been replastered. Banding of grouped cable runs also helps to minimise interference, as long as the electrical installation has been designed to allow cables to be bunched or covered in this way. The lagging of the pipes provides protection from frost and should prevent mechanical damage occumng after the wall has been plastered. Care needs to be taken to avoid over-lagging the pipework as this could reduce the depth available for re-plastering (plate 3 I).

Disc tool cutting equipment greatly assists in minimising the amount of disruption to historic fabric that can occur whilst inserting services but must be used by skilled operatives only. In the example shown in plate 29, a series of four vertical cuts shape the vertical duct and hose reel recess. A series of five cross cuts further define the recess and allow the segmented pieces to be extracted with little further distress to the fabric. The wall plaster spanning across a solid stone wall and timber stud partition ably demonstrates how structural discontinuity and hence fire route risks can be hidden within the structure of an historic building.

Wherever vertical routes through the building are created, additional care will be required to ensure that the floors are fully fire-sealed on completion of the work. Failure to do so will create a weakness in the fire compartmentation of the building. Intumescent bags, granules and blocks can be used if it is not possible to create a suitable hard fire stopping at breakthrough positions.

HISTORICSCOTLAND TAN 14 THEINSTALLATION

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SPRINKLER SYSTEMS I N HISTORIC BIJILDINGS

Plate 30. Vertical pipe installation.

Plate 31. Supply pipe installation.

3.8 Installing sprinkler heads

In the last decade or so quick-response sprinkler heads have been developed. These sprinkler heads are able to react more swiftly to fire, thus minimising fire, smoke and water damage, they also tend to be smaller than other sprinkler head types. When painted by the manufacturer to suit the decoration, they may be combined with an existing decorative feature to become almost invisible to the casual observer (plate 32).

BS 5306: Part 2 (the LPC Rules for Automatic Sprinkler Installations) recommends head spacings for sprinklers to achieve the correct water discharge density. In historic buildings the visual impact of the sprinkler heads must also be taken into account, and this will invariably lead to a non-standard pattern of sprinkler heads being adopted to achieve the necessary coverage. However, the maximum and minimum spacing requirements should be adhered to, otherwise fire protection may be compromised either by inadequate water coverage or by sprinkler heads causing excessive cooling at adjacent sprinkler head locations.

Each room should be considered individually since each will uresent a different challenge.

Heads can be exposed or concealed, depending on the strategy agreed for the building. In either case their finished appearance and visual impact should be considered at the outset.

Quick response, horizontally-mounted extendedcoverage sprinklers have also been developed and these are capable of distributing water horizontally over a distance of up to 7m. It is therefore possible to protect some rooms, galleries or similar areas without the need for ceiling-mounted sprinklers. One such installation is shown in plates 33 and 34.

The effectiveness of the sprinkler will depend upon its ability to detect and suppress a fire. Thus any obstructions to the head and its spray pattern, should be avoided. This may require the co-operation of other

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HISTORIC SCOTLAND TAN 14 THEINSTALLATION

OF SPRINKLER SYSTEMS IN

Plate 33. Extended coverage horizontal sidewall sprinkler installed above the cornice.

HISTORIC BUILDINGS

service disciplines and the curator of the building who oversees the arrangement of furniture.

The example illustrated in plate 35 shows the sidewall sprinkler, detection head and fluorescent light fitting all installed to a common alignment. Unfortunately, the projecting cowl of the light fitting extends below the uppermost boundary of the sprinkler head spray range.

Should the head be activated, the effective range of the spray will be greatly reduced. A pendent light bulb, rather than a strip light, would have been more appropriate in this location. Any storage on the uppermost shelf will also interfere with the intended spray pattern, greatly reducing the coverage of the sidewall sprinkler. Greater attention to design detail and subsequent housekeeping management is necessary.

Plate 34. Detail of sidewall sprinkler above the cornice.

3.8.1 The imtdlation of &ling-mo~ntdsprinkler heads Through eoreful integration with the design of ornate ceiling wmk it is passible to gmitly d u c e the visual impact d sptinkler hmds. When viewed obliqwly, the

Plate 36. Sidewall sprinkler pitfcrlls.

Plote 36. Itlstolled corzce~ilerl.sl~ritzklcr-11ctrd.rhc. Vc..stihirle.

D L House. < ~

l

Hlsroalc SCOTLAND TAN 14 THEINSTALLATION 01; SPRINKLER SYSTEMSI N HISTORIC BLIILDINGS

Plate 37. Finished scheme inclua conceale in.stullation, the Vestibule, Duff House.

raised modelling of the ceiling will further obscure them, see plates 36, 37, 38 and 39.

In the example illustrated in plate 36, the concealed sprinkler head is located along the centre line of the ceiling design, between the bird's head and the surrounding frame, below the vase base. Using a circular hole-saw it is possible to cut the lath and flat

Plate 38. Hole cut in ceiling, ready to receive concealed sprinkler head. the Vestibule. DuffHouse.

Plate 39. Finished scheme including concealed sprinkler installation, the Dining Room, Duff House.

plasterwork of the ceiling with minimal damage (plate 38). The hole should be tightly sized to the head assembly dimensions, as the screw-on cap will then completely cover the opening.

Plate 40. Sprinkler head mounted within a ventilation grille, High Courts, Edinburgh.

HISTORIC SCOTLAND TAN 14 THEINSTALLATION OF SPRINKLER SYSTEMS IN HISTORIC BUILDINGS

The opportunity to use any existing ceiling openings should be seized. In the example shown in plate 40, the sprinkler head has been effectively concealed by mounting it within the existing ornate ventilation grille.

Care must be exercised when carrying out repainting work as concealed sprinklers should not be overpainted. This would affect their performance through creating an 'insulated' layer that will interfere with the response mechanism and timing. In addition, the paint could 'glue' the concealer plate to the ceiling. Such restrictions dictate that the concealer plate's finished colour be factory applied by the manufacturer. In order to specify the colour when ordering, a detailed historic paint analysis may be required.

Sprinkler heads recently installed in Windsor Castle were factory-finished in gilt to suit the surrounding decoration. and manufacturers should be consulted early in the design process to ensure their co-operation in the production of appropriately finished sprinklers.

Increasingly better colour matches are available, although some manufacturers may restrict the actual colour supplied to a near match of the historic hue. In some sensitive historic interiors this approach is inappropriate. Suppliers need to be aware of the need to improve the provision of coloured concealer plates if they wish to support a greater use of sprinkler systems in historic properties.

In some cases, sprinkler heads can be hand painted but this must be carried out under the close control of the consultant engineer.

From a practical point of view, sprinkler heads should be located where they can best detect and suppress a fire. In roof spaces, a location in the apex of each void is likely to provide the optimum situation.

Protective guards can be installed on sprinkler heads to offer some protection from accidental knocks. These may be necessary in areas where ladders and other tall items are moved around. The guards will not interfere with the water flow patterns should the head be activated, but they do considerably increase the visual bulk of the sprinkler head, and should be deployed only where appropriate, i.e. in storage and service areas.

3.8.2 The installation of wall-mounted sprinkler heads The horizontal mounting of sidewall sprinklers brings advantages in that the pipes may be introduced through a wall from an adjacent area or from a void formed by coving. It may also be possible to run exposed pipework out of sight on top of cornices. The visual intrusion of the sprinkler heads can also be reduced by locating them above a projecting cornice, concealing some of their bulk (plate 41). Alternatively, sprinklers

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HISTORIC SCOTLAND TAN 14 THEINSTALLATION OF SPRINKLER SYSTEMS IN HISTORIC BUILDINGS

must occur either locally to the frre or throughout the protected room Some of the techniques that must be employed will be the same as those used with gaseous extinguishing systems, for example the gas holding integrity of the enclosure is important if the water supply is not continuous.

The use of water mist is at present confined to specialist applications where a suitable alternative for halon is being sought. However, currently there is no standard for the design of such systems; installations often evolving from a series of experiments.

Phte 42. Sidewull .rl,rinkler head installed within cornice.

may be mounted within a cornice, incorporated within the decorative pattern (plate 42). The inipact of the projecting head can be further reduced if its colour is matched to that of its surroundings.

3.9 Future developments It may be thought that. after 100 years since their introduction, there are few developments to be made in the design and installation of sprinkler systems. This is far from the truth and currently developments are being made in several areas. The three outlined below have particular relevance to the tire protection of historic buildings.

3.9.1 Plastic pipework CPVC plastic pipework has been used in a large number of recent fire sprinkler installations. In the future other, more flexible pipework may be available, using technology developed for other industries. These have not, as yet, been approved for general use by organisations such as the LPCB.

3.9.2 Water mist systems As their name implies, water mist systems are simply sprinkler installations designed to produce water droplets of a very small but well defined size. Such systems are now available commercially.

The mist produced depends on the water pressure and the configuration of the nozzle. Water mist systems operate by cooling the surroundings and structure whist the extinguishing process takes place, which is achieved primarily by reducing the oxygen level below that which will sustain a fire. The oxygen depletion

In theory water mist installations are attractive because limited quantities of water are applied, and hence the water storage needs and pipework sizes are much reduced. The mist does not, however, appear to have the same penetrating power as other forms of suppression.

3.9.3 Hot water systems Combined heating and sprinkler pipework has been used in a novel installation in the National Library of Scotland. Edinburgh. Combined systems have been used for many years in the USA by the General Services Administration (a Federal agency) for chilled ceilings in hospitals. Hot water is as effective as cold water when used to tight a tire and the combining of the systems may lead to reduced installation costs as well as to a reduced level of damage to the fabric of the building caused by the installation.

4. CARE AND MAINTENANCE

As part of the installation contract the installation contractor should design and produce a maintenance manual including a comprehensive maintenance and test schedule for the equipment that has been installed.

Although the basic maintenance routines should be common for all systems some of the details will vary depending on the equipment employed and the use of the system. The maintenance schedule should be strictly observed; the system is liable to be inspected by the local fire brigade as well as the insurers of the property. The installer should support this on handover by providing an intensive equipment familiarisation and training programme for those members of staff who have been nominated to look after the installation.

A designated member of staff, who may be called the fire safety manager, should be made responsible for the day to day care of the sprinkler system. The individual may be the building- owner or a member of the volunteer staff where this is appropriate, and they should be trained to carry out the daily, weekly and quarterly checks outlined below. (These are explained in detail in Technical Bulletin 6 of the LPC Rules for A~itor7znticSprirzkler bzstallations).

The sprinkler installation contractor should hand over drawings of the installation as it was fitted and records should be kept of all modifications to the system. A quality assurance scheme for documentation should be operated for this purpose.

4.1 Staff training Everyone who works in a building protected by a sprinkler system should be aware of the installation, its purpose and how it operates. They should be instructed about the care that they should exercise when undertaking maintenance or cleaning work in the vicinity of sprinkler heads. Staff training should also include instruction on: the purpose of the system, the need to keep sprinkler heads unobstructed at all times, the need to avoid damage to sprinkler heads and other components of the system, pumps and back up testing, water supply matters,

the action they should take if the system operates as a result of a fire.

Staff should be made aware that they should not tamper with the control valves and only operate them under close supervision. Pipes should not be used to support ladders and items should not be hung from them.

Specialist staff require more detailed training, depending on their role in the organisation. These personnel include security staff, maintenance staff and the fire safety manager. The member of staff designated as being responsible for the installation should receive in-depth training so that he or she understands the system fully and is competent to carry out or supervise the regular inspections and authorise any follow up requirements. Back up personnel should be instructed in the emergency operation of the system so that a trained member of staff is always available.

The system should ideally be maintained by the installing company as part of a regularly reviewed contract. This arrangement has the advantage that the company should be certified (or supervised by a company that is certified) by the Loss Prevention Certification Board (LPCB). The engineer from the company should carry out the half-yearly, annual and longer term maintenance work.

Painters must be warned not to paint over the sprinkler heads, and cleaners should carefully keep them free of accumulations of dust and fluff.

All staff should be instructed to report any incident of unauthorised tampering with the sprinkler system. All such incidents should be fully logged.

4.2 Action in the event of fire In almost all circumstances staff should react to a fire alarm in the same manner whether a sprinkler system is installed or not. The primary response must be to call the fire brigade and evacuate the premises. The brigade should be called even if a n automatic brigade connection is fitted as this will confirm that the call has been received.

Only after calling the brigade and evacuating the building should the cause of the fire be investigated if it is safe to do so. The sprinkler stop valve should not be shut except on instruction from a fire officer. Even

HISTORIC SCOTLAND TAN 14 THEINSTALLATION OF SPRINKLER SYSTEMS I N HISTORIC BUILDINGS

if it appears that a fire is out the sprinklers should remain operating until the building has been searched to ensure that there is not more than one fire.

After a fire, the sprinkler system should be reinstated as soon as possible, with sprinkler heads that have operated replaced by spares. If a number of heads have operated it is advisable to call the maintenance contractor to inspect the system, but this should not be regarded as a reason for delaying putting the system back into full working order as soon as possible after the incident.

testing the automatic pumps, checking the water levels on storage tanks.

If a serious fault is found, the fire brigade and insurers should be informed immediately and the maintenance company engaged as soon as possible to effect repairs.

The fire brigade or central monitoring station should be informed before any directly connected alarms are tested.

The quarterly checklist should in addition include reference to:

In the case of a false alarm the cause should be established and the system reinstated. The insurer should be informed of all incidents, whether a claim is made or not.

unstrapping and exercising valves,

4.3 Routine checks

checking batteries and chargers.

The following sections are based on advice given in Technical Bulletin 6 of the LPC Rtlles for Alltotnrltic Spritlkler I~zstrrllatiotls,to which reference should be made.

Routine security patrols should be provided with a simple checklist which should enable them to make an easy and effective inspection as part of their normal duties. If the premises are not patrolled the member of staff responsible for fire safety should delegate the duty, which should include reporting: any leaks found,

reviewing the hazard classification, checking the condition of sprinkler heads, pipework and hangers,

A stock of spare sprinkler heads should be kept on the premises s o that the system can be reinstated without delay in the event of a fire or of a head being broken.

A proper sprinkler head spanner should be kept with the spares to ensure that they are not damaged when being fitted.

Spare fuel filters, oil filters, belts, gaskets, hoses and injector nozzles for diesel engine driven pumps should also be kept available.

Spare parts that are used should be replaced immediately.

obstn~ctedsprinkler heads, obvious tampering with control valves, such as the straps being removed or unbuckled, incorrect pressures in the system (gauges should be marked with their correct pressures), lack of heating in pump and valve rooms, materials stored in pump and valve rooms.

The regular inspections carried out by the fire safety manager should be in accordance with a series of more detailed checklists. The topics to be covered on the weekly list should include: unmonitored fire brigade alarm connections, adequacy of heating, recording the readings of pressure gauges, checking the positions of valves, tests at alarm valves, drain and test valve checks, checks for leaks,

4.4 Maintenance by sprinkler contractors The exact maintenance undertaken by the contractor will depend on the type of system installed but will generally include: changing alternate systems from wet to dry operation (or vice versa) as appropriate, greasing and exercising valves, inspecting and testing fire brigade connections, servicing and changing the oil in diesel engines, testing water flows and pressures, checking pressure gauges against a standard for accuracy, checking batteries with a hydrometer and topping up if necessary, checking the condition of pipework, hangers and sprinkler heads, The contractor should provide a complete report of all work carried out and should certify that the system has been left in an operable condition.

HISTORIC SCOTLAND TAN 14 THEINSTALLATION OF SPRINKLER SYSTEMS IN HISTORIC BUILDINGS

4.5 Safety during sprinkler shutdown Before a sprinkler system is wholly or partly shut down, all interested parties should be informed, in particular the fire brigade, insurers and central monitoring station. Indeed, it would be wise to obtain permission from insurers, where possible, before shutting down the system. If the system becomes inoperative or has to be turned off as a matter of urgency the fire brigade and insurers should be informed as soon as possible. In the case of a life safety sprinkler system, additional measures will also be necessary.

Work should be planned so that there is the least possible interruption to the protection provided by the sprinkler system: if possible sprinklers should not be left inoperative overnight, alterations and repairs should be carried out during normal working hours as far as practicable, sprinkler contractors should make sure that the staff involved are ready to do the work and that they have the materials and tools needed to complete the task beforc sprinklers are shut off, in the case of manufacturing premises extensive alterations o r maintenance should be deferred until machinery and plant are idle.

When it is impossible to complete the work in one day, as much of the system as practicable should be made operative before the sprinkler contractors leave and special attention paid to parts of the premises where the system is inoperative. It is particularly important to make sure that fire doors and shutters are closed.

As many sprinkler heads as is practicable should be kept in service while work on the system is in progress: where there are large systems made up of more than one installation or suitably zoned into areas, each with its own stop valve andlor alarm valve, only the installation being worked on need be shut down, sections of an installation on which work is being carried out can be blanked off so that the remainder of the installation is kept in operation.

This may involve temporary connections to hydrants or to other sprinkler installations. in some cases shutting down a system can be avoided entirely by the use of pipe tapping machines with which connections can be made to underground mains without shutting off the water. (This technique should only be undertaken by appropriate specialists).

In order to reduce fire dangers during shut down, a number of precautions should be assiduously taken: before turning off sprinklers check thoroughly that there are no signs of fire in any part of the buildings, suspend all operations which could give rise to fire including:

- processes known from past experience to be hazardous,

- burning of rubbish, - hot work. prohibit smoking in all affected areas at all times, rigorously enforce normal fire safety requirements such as the removal of combustible waste and the closure of fire doors, ensure that all extinguishers are in position and ready for use, with trained staff available, arrange for continuous patrolling of areas in order to detect any signs of fire and to maintain good standards of housekeeping, display bold 'valve closed' notices on closed valves as a reminder to open them when work is complete, close the building to members of the public or increase supervision.

On completion of the work, ensure that all valves are reopened fully and restore the system to normal operating conditions. Secure the valves open by padlocked chain or straps. In sprinkler systems in historic buildings it is appropriate that stop valves be electronically monitored to indicate when they are fully open.

If the mains water supply to a sprinkler system is cut off because of burst pipework or any other reason beyond your control, pay special attention to maintaining any alternative water supplies and observe the precautions indicated above as if the sprinkler system had been shut down.

4.6 Training exercises When fire safety training exercises are being designed, the sprinkler system should not be overlooked. A case history of such an exercise is presented as Appendix C. The aim of the exercise should be to test: the operation of the hydraulic water alarm gong, the reaction of staff to the sound of the alarm gong and any other associated alarms

HISTORIC SCOTLAND TAN 14 THEINSTALLATION 01; SPRINKLER SYSTEMS IN HISTORIC BUILDINGS

the cut-in of the main pumps and the back-up facilities, the correct operation of other parts of the installation.

The fire brigade should be informed before the exercise is carried out and may be asked to participate if a salvage and disaster limitation exercise is being carried out. This allows staff to practice working alongside local authority fire fighters in a scenario that is safe, but one in which pressure may be placed on the available manpower.

It would also be of benefit if the member of staff responsible for the sprinkler installation was able to witness a sprinkler head operating and the distribution pattern of the water released. This form of training should not, however, be undertaken in the historic building itself. It is not recommended that sprinkler heads are broken deliberately for training or any other purpose.

APPENDIX A: Some serious fires in Scottish Historic Buildings since 1986 This list has been compiled from a number of sources, including the Buildings at Risk Register, Historic Buildings Council reports and newspaper clippings.

1986 St Machar's Cathedral, Aberdeen Dunmore Castle, Tarbert Edinburgh Castle Piping School Charleton House, Montrose Elgin Sheriff Court House, Elgin Aberdeen Grammar School, Aberdeen

1991 Grand Theatre (Cinderella's), Stockbridge, Edinburgh Portmore House, Eddlestone, Palace Hotel, Edinburgh Ascog House, Rothesay West George Street Building, Glasgow Knockando Church, Moray

1987 Cullen House, Banff Ca d'Oro Building, Glasgow Dunbar Parish Church Bellevue Hotel, Dunbar Greenmount Hotel, Burntisland Tarbat House, Kildary, Near Invergordon

1992 Ferryhill North Church, Aberdeen.

1988 Liberton House, Edinburgh Bmidwood Castle, Strathclyde Logie House, Dunfermline, Fife

Wrangholm Hall, Motherwell Strathleven House, Alexandria Seafield Arms Hotel, Keith

1989 Chalmers Memorial Church, Anstruther 6-14 John Finnie Street, Kilmarnock

Old Corn Exchange (Marina Cinema), Hawick Butler's Lodge, Glasserton, Whithorn

Broughton House, Kirkcudbright Old Court House, Dunfermline, Fife Newton House, Dunfermline, Fife Torsonce House, Stow, Borders Nicolson Square tenement, Edinburgh Queensgate Hotel, Inverness

Kilnside House, Paisley Newton House, Moray

Former Counting House, Anchor Mills, Paisley

Bellevue Hotel, Dunbar 1990 Old House of Orchill, Dunblane York Place tenement, Edinburgh Mar Lodge, Braemar Edinburgh University Students Union, Teviot Row, Edinburgh Lomond Castle Hotel, Balloch Netherkirkton House, Neilston

1993 A and S Henry Building, Dundee Beach Ballroom, Aberdeen Chapel Works, Montrose 1, 2 and 3 Park Gardens, Glasgow Linside Mill, Anchor Mills, Paisley Mid Dykebar, Paisley Strathleven House, Alexandria

HISTORIC SCOTLAND TAN 14 THEINSTALLATION OF SPRINKLER SYSTEMS IN HISTORIC BUILDINGS

1994 Scotstoun West Parish Church, Glasgow

1997 Inverbervie Castle, Mearns

Aberuchill Castle, Comrie Lanrick Castle, Doune Kilkerran House, Maybole Lochailort Inn, Highlands Sherbrooke St Gilberts Church, Glasgow Kilmarnock Infirmary Stiroke House, Wick

The Heckling Shop, Robert Bums House, Irvine Lennoxlove House, Haddington, East Lothian Stewart Park Pavilion, Aberdeen Hallgreen Castle, Kincardineshire Newhall House, Penicuik Bankend Farm, Cumnock Lennoxlove House, Haddington Loch Lomond Distillery Bonded Warehouse, Alexandria Poultry, Castle Avenue, Bothwell

St Peter's College, Cardross Foley House, Isle of Bute Skibo Castle. Domoch 1995 Greens Playhouse, Dundee Caldwell House, Uplawmoor North Church, Dumbarton Hunter House, East Kilbride Rockvilla School, Glasgow Moy House, Moray 1050 Great Western Road, Glasgow Stanley Mills, Perthshire Ferguslie Threadworks stables, Paisley

Coats Girl's Hostel (Memorial Home), Paisley Half Time School, Paisley Templars Hall, Irvine Granton Country House Hotel, Moffat Meldrum House Hotel, Oldmeldrum Scotstoun Church, Glasgow Cullen House, Banffshire 1998 Peoples' Palace, Glasgow Larbert House stables, Larbert

Knightsbridge Hotel, Livingston British Ropes Factory, Rutherglen

Caledonian Hotel, Lanark Crescent Hotel, Aberdeen Luscar House, Dunfermline

1996 Middleton House, Midlothian Towans Hotel, Prestwick Mitchell Library, Glasgow

Joiners shop, Gateside Place, Kilbarchan Arnage Castle, Ellon New Inn Hotel, Ellon

Vennel Museum, Irvine Mill Inn Hotel, Stonehaven Garthsherrie Academy, Coatbridge Philipsburn House, Selkirk Duke of Gordon Hotel, Kingussie Hallside School, Rutherglen Kiltarchan School, Renfrewshire Potterton House, Grampian Kirkoswald Parish Church, Ayrshire Woodbank Hotel, Balloch, Dumbarton Kinfauns Parish Church

6 Rhughasinish, South Uist

APPENDIX B: Case histories

B.l DUFF HOUSE

Plate 43. Front view of Duff House, Bang

History Construction of Duff House commenced in 1735 to a design by William Adam ( 1 669-1748) for William Duff MP (Lord Braco, Earl of Fife) (1697-1763).

However, the period 1736-43 was one of disagreement and subsequent litigation, the outcome of which was that the building was not built as originally designed and illustrated in Vitruvius Scoticus (1735). Only the central block was completed (plate 43).

In 1870 a single wing designed by David Bryce Junior was added to the east. This wing was bomb damaged during World War I1 and later demolished. 1906 saw the end of the occupation by the Fife Family when the house and 140 acres were gifted to the joint Burghs of Banff and Macduff.

In the period 1906 to 1935 the house was used as an hotel, a Sanatorium, and again as an hotel prior to being unoccupied from 1935 to 1939. From 1939 to 1945 the War Department used the building as a billet

and then accomodation for prisoners of war after which it was unoccupied until taken into State Care in 1956.

From 1956 to 1990 various conservation works made the House secure, wind and watertight. The interior decoration was also partially restored. The period 1990 to 1995 encompasses the present scheme to convert the House for use as a Country House Gallery. (Detailed information is set out in 'A Guide to the History, Architecture und decoration of Duff House' by Ian Cow and Timothy Clifford, published by the National Galleries of Scotland in 1995.)

The Duff House project At a total cost of &21/rm,the project involved major works to strengthen the floors and undertake a complete reservicing. The house has been entirely redecorated, rewired, replumbed and equipped with heat and smoke detectors, a lift, closed circuit

HISTORIC SCOTLAND TAN 14 THEINSTALLATION OF SPRINKLER SYSTEMS I N HISTORIC BUILDINGS

television and other security devices. The result is a series of gallery rooms with associated lecture room, audio-visual room. kitchen, restaurant, shop, cloakrooms, toilets and a staff flat. To aid this comprehensive programme of work, the decision was taken that all the existing floorboards would be uplifted and re-laid in their original position once the structural and services work was complete. Although each floorboard was individually identified by room number and laying sequence, the intention to adopt this approach was eased by the knowledge that a considerable number of apartments had already been fitted out with replacement boards.

Through opening-up the structure in this way, both structural and service engineers and contractors, were better placed to undertake the design and installation work for a sprinkler system with minimal damage to the original fabric.

The procedure demanded stringent work method statements. Temporary storage for bundled flooring had to be found and, because the upper surface of the underlying lathed plaster ceiling was exposed, care had to be adopted while working on the supporting timber beams and joists.

Primary and secondary floor beams were strengthened with intumescent painted steel plates, beams and joists were notched for cable service trays and pipework (which, as far as possible, was run between structural timbers and in ceiling comb voids) and some 38km of cabling was installed. Fire stop barriers were strengthened, particularly in the roof space where the heads of the service stairs were partitioned off and under floor loose laid intumescent bags were set into the cable trays where they crossed from one protected zone to another.

A comprehensive smoke detection system, involving a mix of air sampling and point detectors, together with a manual fire alarm call system was also installed.

The sprinkler installation In the case of Duff House the potential fire brigade response time with local appliances was estimated at 17 minutes. Back-up provision was available from Aberdeen within an estimated 45 minutes. Risk assessment considerations therefore demanded that in addition to upgrading the structure and installing an automatic fire detection system, a full fire suppression system using automatic water sprinklers would be installed.

Full hydraulic calculation was carried out to determine the minimum pipe sizes necessary for the installation in order to minimise the disturbance to the fabric of the building. Having established the design procedure, the physical routes for pipework had to be identified prior

to detailed hydraulic calculations being carried out.

The sprinkler main traverses the ground floor corridor concealed beneath removable floor slabs. Risers are taken to the attic from which pipework drops to serve individual rooms. The up and over layout overcame the potential problem of driving pipework through masonry up to 1200 mm in thickness. To further reduce damage to the sensitive historic interiors, risers were located in the former service areas of the building with horizontal pipe runs above ground floor level situated as far as possible between joists in the ceiling spaces.

To avoid the risk of frost damage, all pipework in the attic was wrapped in insulation and fitted with electric trace element heating. Coverage extended over the entire attic space with horizontal runs set at ridge and eaves level. To avoid the risk of accidental damage to the sprinkler heads, standard wire guards were installed over those most at risk from knocks.

Water supply and storage LPC rules require the provision of a reliable supply of clean uncontaminated water at the designed volume.

For Duff House this requirement was calculated at 500 litres per minute at a pressure of 7.5 bar. As this demand was not available from the mains supply, it was deemed necessary to provide a storage tank with a capacity of 10 cubic metres. The required volume and weight of water was such that the installation of tanks in the building was readily ruled out at the beginning of the design process. It was therefore decided to install storage tanks with associated high pressure pumps, and back-up facilities, in a purpose built underground chamber external to the building.

The minimum requirement for a risk of this nature would be a single pump and tank. However, in the circumstances of Duff House and in view of the value of its contents, the attendance time of the fire brigade and the possibility of an electrical power failure, it was also considered essential to provide a diesel engine driven fire pump set for standby purposes. This failsafe approach resulted in the need to construct a considerable underground facility to accommodate all of the plant.

Such a solution would be relevant in other similar sensitive circumstances, but can only be achieved at a cost. Being positioned underground there is a need to ensure it cannot be flooded, and that it is kept free from water penetrating through the structure. The solution adopted also creates additional visual complexities, given that access hatches, vent pipes and air intakes are evident at ground level. These have a greater visual impact because of their location near to the house, a decision determined by the need to maintain the effectiveness of the plant by reducing unnecessarily long pipe runs.

HISTORIC SCOTLAND TAN 14 THEINSTALLATION OF SPRINKLER SYSTEMS IN HISTORIC BUILDINGS

Project management and contractual arrangements The design and installation of the water sprinkler system at Duff House was carried out as part of the conversion work at an estimated cost of ÂŁ120,000.

Project management was by Historic Scotland, assisted by a design team of appointed consultants experienced in work in historic buildings.

When the decision to install sprinkler systems was taken, a sprinkler system designer, certificated by the Loss Prevention Certification Board (LPCB) was appointed to the design team, reporting through the mechanical and electrical engineer. The sprinkler installation contractor was then appointed as a nominated sub-contractor. This process was devised to allow the project management to retain control over coordination of the sprinkler system components within the historic fabric.

HISTORIC SCOTLAND TAN 14 THEINSTALLATION OF SPRINKLER SYSTEMS IN HISTORIC BUILDINGS

B.2 COLERIDGE COTTAGE History Coleridge Cottage is steeped in history; it was here that Samuel Taylor Coleridge lived when he wrote 'The Rime of the Ancient Mariner' and other poems between the years 1797 and 1800. The Cottage comprises a building within a building, in which the original structure has been extended with a more modern outer structure, and the thatched roof which originally formed part of the 'two-up-two-down' building has been replaced with tiles.

The sprinkler installation Coleridge Cottage, at Nether Stowey, Somerset, has become the first property in the care of the National Trust to be protected from fire by a unique automatic sprinkler system. The move follows concerns that, as the 350 year old cottage is 15 miles from the nearest full time fire station at Bridgwater, any fire could potentially destroy the building before sufficient fire fighting resources arrived.

Because of the historic importance of the building, great care was needed to produce a system that would not only be effective, but also not be intrusive or damaging during installation or as a completed system.

For ease of installation the basic design concept for the sprinkler system was to install a wet-pipe system of CPVC pipework in varying sizes ranging from 40 mm down to 20 mm nominal diameter. The size of pipework was based on hydraulic calculations specific to the building, using the criteria for domestic sprinkler systems as detailed in Loss Preverztion Col~rzcil Teclzrlical B~rlletinNo. 14 1990.

Fifty quick response sprinkler heads, designed to operate at 68"C, protect all rooms. The sprinkler heads employed in the system react to heat and fire much quicker than conventional heads, ensuring that any outbreak is quickly dealt with. Virtually total concealment of pipework was possible with only 5 per cent of the pipework needing additional camouflage through boxing in or painting out, none of which was in the historical part of the building.

Water supply and storage In designing the water supply route, the appearance of Lime Street, the narrow road where the cottage stands, was taken into consideration. External ground works would have been disruptive, and any pipework entering the cottage from outside could have intruded on the most historical rooms of the house.

As a result, it was decided that the system should use domestic water available at the rear of the cottage. This was supplied to the system via automatic controls, a water tank with an effective capacity of 1400 litres, and a pump arrangement specifically designed for this project.

The water supply allowed is based on a maximum of two sprinklers operating in any fire situation, as described in the LPC Technical Bulletin No. 14 1990, and will supply two sprinklers for ten minutes.

Activation of any sprinkler head will automatically sound a local alarm and transmit a call to the fire brigade.

APPENDIX C: Training Exercise

This report of a fire safety training exercise which took place at Duff House illustrates some of the features which may be incorporated into any such exercise and the value of lessons which may be learned.

It should be emphasised that the deliberate breaking of sprinkler head as part of an exercise such as this is not recommended in normal circumstances.

The aim of the exercise was to test the integrity of the fire sprinkler system and this was achieved by setting off a sprinkler head in a Kitchen Dry Store which had been designated as requiring serious remedial work under the indemnity of the renovation contract. This room also had an impervious floor which featured a drain. The kitchen stores were removed for the duration of the exercise Four fire-fighters with breathing apparatus were present in the room to monitor the exercise and set off the sprinkler head. Along with the fire fighters were located two oil paintings, one approximately 40 years old, the other perhaps 10 to 15. All electrical supplies had been isolated and items such as the heaters had been sealed to avoid water contamination. When the sprinkler head was broken the small jockey pump located in the pump house responded immediately.

This was monitored by engineers from the sprinkler installing company and the M & E Engineer of Historic Scotland. It was significant to note that while the jockey pump was trying to cope with the demand there was no fire siren sounding anywhere in the building.

Water instantly appeared from the sprinkler head when it broke but whilst the jockey pump was running its flow was similar to that from a water hose. After approximately 20-25 seconds the main electric pump was triggered by the sensor monitoring the pressure in the system to satisfy the demand for water. This gave far greater water pressure and flow from the sprinkler head increased, the fire alarm, emergency lighting and automatic door closing were also initiated. The addressable fire alarm panel was checked to ensure that it was giving the correct information.

The main electric pump was allowed to run for two and a half minutes, after which it was switched off and the diesel pump (the back-up facility in the event of the failure of the main electric pump) was run. The diesel pump was allowed to run for a further two and a half minutes before the fire sprinkler system was turned off by the main stop valve.

The fire-fighters reported that the sprinkler had been extremely effective but the flow from the head had been deflected by the position of the smoke detector and the ceiling-mounted strip light housing. This resulted in a lack of water reaching the back wall of the room at above five feet above floor level. This could be easily rectified by re-positioning services but demonstrates the requirement for the various engineering disciplines to liaise closely over the siting of sprinkler heads. It was also learned that if any kitchen stores were placed on the top shelves it would be detrimental to the spray pattern from the sprinkler head. The drain in the floor could not cope with the supply of water and there were four inches of water remaining when the stop valve was closed. This was extracted by the fire brigade's disaster team very quickly. The paintings were removed and placed in the corridor and thirty minutes later were inspected. There were no noticeable cracks or tears and the paintings had virtually dried out.

The installing company's technicians immediately drained the complete system and reinstated the sprinkler protection. They then tested the system to ensure that the installation was fully operational. The smoke detector, electrical wiring and fittings in the room were inspected and reinstated. All facilities were functional 20 minutes after the test.

It was noticed the morning after the test that some black dirt had come from the sprinkler head with the water. This had dried out on the ceiling and the walls in the form of small spots, but was easily cleaned off the paintwork with soapy water.

The exercise ran extremely well with no mechanical or technical failure. This instilled confidence both in the local authority fire-fighters (who had never been in an active fire sprinkler environment) and in the staff.

Immediately prior to the fire sprinkler exercise the integrity of the house dry-riser system was also tested.

This proved to be faultless and worked extremely well under test. This exercise was also completed under the control of the installing company's technicians and representatives of Historic Scotland.

APPENDIX D: Bibliography

Fire protection, including sprinkler systems Ackland, A, Custodians of the past, Fire Prevention, No.267, March 1994, p.25-27.

BS 5306: Fire Extinguishing installations and equipment on premises: Part 2: Specification for sprinkler systems.

Chevin, D, Scotch Mist, Building, Vol. CCLVIII, No. 7783, 26 February 1993, Building, p.60-61.

Loss Prevention Council, Technical Bulletin 16: Consultation and acceptance for sprinkler system approval by fire insurers, 1992.

Factory Mutual International 1990, Preserving today's treasures for tomorrow, Fire Prevention, No.229, May 1990, p.20-23.

Loss Prevention Council, Recommendations for frost protection measures for sprinklers WP7, 1993.

Factory Mutual Loss Prevention Data Sheet 2-8N.

Loss Prevention Council, Power supplies for electrically driven sprinkler pumps, TB22, LPC, 1996.

Fire Protection Association, Automatic sprinklers: design and installation.

Fire Safety Data PE1 1, 1989.

Fire Protection Association, Fire protection equipment, Fire Prevention Design Guide FPDG 6, 1991.

Fire Protection Association, Automatic sprinklers: components of a system, Fire Safety Data PEIO, 1981.

Fire Protection Association, Automatic sprinklers: design and installation, Fire Safety Data PE1 l , 1985.

Fire Protection Association, Automatic sprinklers: safety during sprinkler shut-down, Fire Safety Data PE13, 1985.

Fire Protection Association, Automatic sprinklers: care and maintenance, Fire Safety Data PE12, 1985.

Grant, CC, Tales of fire and ice at the Wayside Inn, NFPA Journal, Vo1.88, No.6, NovemberIDecember 1994, p.75-82.

HSE, Fire Safety in Construction Work, HSG 168, 1998.

Lougheed, GD; Mawhinney, JR; O'Neill, J, Full-scale fire tests and the development of design criteria for sprinkler protection of mobile shelving units, Fire Technology, Vo1.30, No.1, First Quarter 1994, p.98133.

Nash P and Young RA, Automatic sprinkler systems for fire protection, Paramount Publications, 1991.

NFPA 13 1994, Standard for the installation of sprinkler systems, National Fire Protection Association, Quincy, Mass, USA. NFPA 13D 1994, Standard for the installation of sprinkler systems in one and two family dwellings, National Fire Protection Association, Quincy, Mass, USA. NFPA 13R 1994, Standard for the installation of sprinkler systems in residential accommodation of up to and including four stories in height, National Fire Protection Association, Quincy, Mass, USA. NFPA 909 1997, Standards for the Protection of Cultural Resources including Museums, Libraries, Places of Worship and Historic Projects.

Kidd AS, Heritage Under Fire, Fire Protection Association, 1995.

NFPA 914 1994, Recommended Practice for Fire Protection in Historic Structures.

Loss Prevention Certification Board, Requirements for certificated sprinkler installers, supervising bodies and supervised installers, LPS 1048 : issue 2, i993.

National Heritage, Department of, 1993, Fire Protection Measures for the Royal Palaces, HMSO.

Loss Prevention Council, Rules for automatic sprinkler installations, LPC, 1998. This document incorporates

Mayhew-Smith, A, Fire Protection in the Round, Fire Prevention 300, June 1997, P. 8-10.

General conservation issues Davey A et al, The Care and Conservation of Georgian Houses, Butterworth, 1995.

Glasgow West Conservation Trust, The West End Conservation Manual.

Historic Scotland, Simpson and Brown, Conservation of Plasterwork, TAN 4, 1994.

Historic Scotland, Fire protection Measures in Scottish Historic Buildings, TAN 11, 1997.

Historic Scotland, Memorandum of Guidance on Listed Buildings and Conservation Areas, 1998.

Hughes P, Patching Old Floorboards, Information Sheet 10, SPAB.

APPENDIX E: Organisations

The Architectural Heritage Society of Scotland.

The Glasite Meeting House, 33 Barony Street, Edinburgh EH3 6NX Tel0131 557 0019; Fax 013 1 5570049 Association of British Insurers, 5 1 Gresham Street, London EC2V 7HQ Tel0171 600 3333; Fax 0171 696 8999 British Automatic Sprinkler Association, Carlyle House, 235 - 237, Vauxhall Bridge Road, London SWIV IEJ Tel0171 233 7022; Fax 0171 828 0667 British Fire Protection Systems Association, 55 Eden Street, Kingston-upon-Thames, Surrey KT I IBW Tel0181 459 5855; Fax 0181 547 1564 British Standards Institution, 389 Chiswick High Road, London W4 4AL Tel0181 996 9000; Fax 018 1 996 7400 Chartered Institution of Building Services Engineers, Scottish Region, c10 Steensen, Varming Mulcahy and Partners, The Matrix, 64 Newhaven Road, Edinburgh EH6 5QB TelO13 1 554 3666; Fax 013 1 555 1723 Chiltern International Fire Limited, Stocking Lane, Hughenden Valley, High Wycombe, Bucks. HP14 4ND Tel01494 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 5575222;Fax0131 5566355 Edinburgh Old Town Renewal Trust, 343 High Street, Edinburgh EH1 IPS Tel0131 225 8818; Fax 0131 225 8636

English Heritage, 23 Savile Row, London WIX IAB Tel0171 973 3000; Fax 0171 973 3001 Fire Extinguishing Trades Association, Neville House. 55 Eden Street, Kingston-upon-Thames, Surrey KT1 IBW Tel0181 549 8839; Fax 0181547 1564 Fire Protection Association, Melrose Avenue, Borehamwood, Herts WD6 2BJ Tel0181 207 2345; Fax 0181 236 9701 Building Research Establishment Ltd, Bucknall's Lane, Garston, Watford, Herts WD2 7JR Tel01923 69 4000; Fax 01923 66 49 10 Glass and Glazing Federation, Fire Resistant Glazing Group, 44 - 48, Borough High Street, London, SE I IXB Tel0171 403 7177; Fax 0171 357 7458 Guild of Architectural Ironmongers, 8 Stepney Green, London El 3JU Tel0171 790 3431; Fax 0171 790 8517 Health and Safety Executive, Belford House, 59 Belford Road, Edinburgh EH4 3UE Tel0131 247 2000; Fax 0131 247 2121 Historic Scotland, Longmore House, Salisbury Place, Edinburgh EH9 I SH Tel0131 668 8600; Fax 0131 668 8788 Institute of Public Loss Assessors Limited, 14 Red Lion Street, Chesham, Bucks HPS IHB Tel01494 782 342; Fax 01494 774 928 Institution of Fire Engineers, 148 Upper New Walk, Leicester LE1 7QB Tel0116 255 3654; Fax 0116 247 1231 E mail: <info@ife.org.uk>

HISTORIC SCOTLAND TAN 14 THEINSTALLATION OF SPRINKLER SYSTEMS IN HISTORIC BUILDINGS

Institution of Structural Engineers, Scottish Branch, c/o D J Nicoll, 4 Dixon Road, Helensburgh, Dumbartonshire G84 9DW TelO1436 675 100.

International Council on Monuments and Sites (ICOMOS), 10 Barley Mow Passage, London W4 4PH Tel018 1 994 6477; Fax 0181 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 TelO181 207 2345; Fax 0181 236 9701 National Fire Protection Association (NFPA), 1 Battery March Park, PO Box 9101, Quincy, Mass, USA 02269-910 1 National Library of Scotland, George IV Bridge, Edinburgh EH1 IEW Tel013 1 226 453 1; Fax 013 1 220 6662.

National Trust, 36, Queen Ann's Gate, London SW l H 9AS TelO171 222 9251 National Trust for Scotland, 5 Charlotte Square, Edinburgh EH2 4DU Tel0131 226 5922; Fax 0131 243 9501 Royal Commission on the Ancient and Historical Monuments of Scotland, John Sinclair House, 16 Bernard Terrace, Edinburgh EH8 9NX Tel0131 662 1456; Fax 013 1 662 147711499 Royal Fine Art Commission for Scotland, Bakehouse Close, 146 Canongate, Edinburgh EH8 8DD Tel013 I556 6699; Fax 01311 556 6633

Royal Incorporation of Architects in Scotland, 15 Rutland Square. Edinburgh EH1 2BE Tel0131 229 7545; Fax 0131 228 2188.

Royal Institution of Chartered Surveyors in Scotland, 9 Manor Place, Edinburgh EH3 7DN Tel013 1 225 7078; Fax 013 1 226 3599.

Scottish Conservation Bureau, Historic Scotland, Longmore House, Salisbury Place, Edinburgh EH9 I SH Tel0131 668 8668. Fax 0131 668 8669; E-mail: <cbrown.hs.scb@gtnet.gov.uk> Scottish Office, Victoria Quay, Edinburgh EH6 6QQ. Tel0131 556 8400; Fax 0131 244 7454 Scottish Society for Conservation and Restoration, The Glasite Meeting House, 33 Barony Street, Edinburgh EH3 6NX Tel0131 557 0019; Fax 0131 557 0049.

Smoke Ventilation Association, Sterling House, 6 Furlong Road, Boume End, Bucks. SL8 SDG Tel01628 531 186; Fax 01628 810 423; E-mail infor@feta.co.uk; Internet: http:/lwww.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 UKIC (United Kingdom Institute for Conservation of Historic and Artistic Works), 6 Whitehorse Mews, Westminster Bridge Road, London SE I 7QD Tel0171 620 3371; Fax 0171 620 3761