Branch Reports

ONE NEW STANDARD DOES IT

A single British Standard for portable fire extinguishers, based on performance requirements, will eventually replace seven separate standards in BSI's catalogue. J. Mills, chairman of the drafting committee, gives the history of the standard. So many types of sophisticated fire fighting apparatus are available today that it is surprising to reflect that it is little more than 50 years ago that the first British Standard for portable fire extinguishers was published, in 1922. This was BS 138 for extinguishers of the water type (soda-acid) which was the predominant type at the time.

Water type (soda-acid) extinguishers contain a solution in water of sodium carbonate together with a bottle of acid. When the extinguisher is operated, the acid mixes with the solution generating carbon-dioxide gas. The gas forces the solution through a nozzle which the Operator aims at the fire. This type of extinguisher is still in use Widely today and it is effective on wood, paper, textile and similar carbonaceous fires.

This specification was followed in 1937 by a standard for extinguishers of the foam type (chemical) which are similar to the water type (soda-acid) but more suitable for liquid fires. At the same time a standard was introduced for extinguishers of the halogenated hYdrocarbon type, which are capable of dealing not only with liquid fires but with fires in electric al equipment, becaUse the extinguishing medium is non-conductive. The halogenated hydrocarbon is expelled either by a hand pump, or by pressure stor ed internally in the extinguisher or in a small cylinder.

Interest in fi r e fighting and fi r e preVention was considerably stimilated during the Second World War. After the war a standard was published for water type extingui sher s in which the water is expelled by gas stored in a small cylinder. This was followed by a specif ication for extinguishers of the foam t ype in which the foam is expelled f rom B S I News ... - March 1977

similarly. Subsequent standards covered ., carbon-d10x1de .' shers ext1ngu1 (which . are . part1cularly f 1 use u for fires 1n is

electrical equipment because the. gas non-conducting and leaves no res1due when the fire is out) and the dry extinguishers . Wh1Ch use an extingu1S J_ng medium of dry powder expelled by a gafs. Powder extinguishers were developed or liquid fires in . 1 electr1ca equipment and for burning metal. In all seven standards were published over the years. They were largely constructional standards reflecting proven . exper1ence. However, . t this type of standard t ds en to restr1c the introduction of new . ns des1g and new _. extinguishing med1a. W rk 0 on rev1s1ng since

these standards has been in progress . N 70 . 1970 in conjunct10n · W1 th ork w 1n CE Portable fire . h extingu1s ers, wi th the .' h . intention of al1gn1ng th e neW Br1t1s Standard with international work. Unfortunately, . ser10US delayS have k in meant that the 1 t comp elon of wor _ is CEN on portable fire t- gU1shers ex 1n d-ng not yet in sight, d an correspon d 1 work in ISO has not t ye starte _ _ tion for Accordingly BS 5423 being - ishers 1 portable fire ext1ngu _ the d to reV1Se published in or er -le at the same existing standards wh1 - - uch t1me embodY1ng as m as 0 ossible P Work will of the work of CEN/ WG 7. _ the hope continue t interna - nally ln 10 The earlier of reaching agreement . ithdrastandards will be w at wn has a later expired. date when their usefulnesS

Identification - hed leaves open BS 5423 as publ1S _ extinguishers - of flre the identificat10n D aft for Deve- t of r which is the subJec SI NeWS March 1976 ) lopment DD 48 The Draft for (see B 1 meDeve op t '! • proposes that painted wi th an extinguisher hou1d s be identify the a par ticular colour to _ h it contains d - WhlC extinguishing me lum favours - - Europe However pr actlce 1n _ red and - U1Shers painting all ext1ng h - view as wel l . there i s support for t 1S try It is as opposition in this coun hoped it will be possible to reach

international agreement on the of colours and incorporate the result into BS 5423. In the absence of such agreement, DD 48 is to be withdrawn and a recommendation inserted in BS 5423 that all extinguishers should be predominantiy red, with an additional colour code marking to identify the extinguishing medium, BS 5423 as published also leaves open the written classification of DD 48 which suggests how extinguishers should be marked to indicate the types of fire for which the extinguisher is most suited to BS 5423 to cover colour coding and the written classification is in preparation.

As far as possible BS 5423 is based on performance requirements. It includes requirements for minimum performance in extinguishing a test fire of either type A or B classification of BS 4547 Classification of fire.

Type A fires involve solid materials, and are usually of an organic nature in which combustion takes the place with . the formation ofgiowing · embers, a typical example being a wood fire. Type B involves liquids or liquefiable solids, for instance petrol or cooking fat. Two series of standard test fires, both in geometrical progression of size, cover the ranges of performance likely to be expected from portable fire extinguishers. Because a high test performance can sometimes be achieved by a rapid discharge, minimum discharge times are specified in order that the inexperienced operator should not be caught unprepared by too rapid a discharge. Helping the user Careful consideration has been given to other ways of improving the ease with which an inexperienced operator can use an extinguisher. Extinguishers which have to be inverted to operate are now excluded and this removes one possible cause of confusion In addition it should not be necessary to repeat any of the movements, necessary to operate an extinguisher. The provision of means for interrupting the discharge is now specified in order to assist the operator, a feature which was frowned on in the past. The hand pump type of extinguisher has been omitted. All types covered by BS 5423 contain a source of energy to expel the extinguishing medium. Further standardization of the method of operating portable fire extinguishers is under international consideration and may be introduced in BS 5423 when agreement is reached. CP 402 Fire fighting installations and equipment Part 3 Portable fire extinguishers for building and plant, is being revised and in due course will be published as BS 5306 Code of practice for fire extinguish1ng installations and equipment Part 3 Portable fire extinguishers. The revision will take account of BS 5423 and give recommendations for the siting and distribution of extinguishers, the suitability of various types for use on fires of different substances, the intervals between routine inspections details of the maintenance to be carried out at stated intervals and recommended intervals between periodic testing by discharge.

EASTERN

Minutes of the Meeting of the Eastern Branch held at the Cambridgeshire County Council Fire and Rescue Service, Divisional Headquarters, Parkside, Cambridge, on Wednesday, 15th December 1976.

Introduction

The Meeting was opened by Mr. B.O. Lowe, Bedfordshire County Council in th e absence of Mr. J.W. Frid, ' who was unable to attend. Mr. Lowe thanked the 13 members and 1 guest for attending in the prevailing bad weather. Apologies

Apologies were received from 5 members.

Minutes

The minutes of the July meeting of the Branch (previously circulated), were confirmed.

Matters Arising The matter of the question of whether Branch members need to be members of the National Association was raised. Also the difficulty within some fire authorities was mentioned, whereby the authority would wish to become a member but Would wish to nominate varioUS officers to attend meetings. The Honorary Secretary felt that this latter problem could be overcome by the authority becoming an associate member. The Chairman asked that the former matter be put down as a qUestion for the agenda of the Association A.G.M. This was agreed.

Correspondence The letters sent to the Health and Safety Executive and the Metrication Board as a result of the members' concern over the question of metric deliveries of petr oleum spirit to garages equiped only with dipsticks graduated in quantities were circulated, together with repl i es . General concern was felt amongst member s that the matter was s t i ll not resolved. It was mentioned that conversion charts issued by at least one petrol company were inaccurate . Any other business Copies of Branch Rules Vlere circulated to those present, and a branch fee of fifty pence was charged to those not present at the inaugural meeting of the branch. L.J. Brooks (Cambridgeshire) asked if in future correspondence to members within one authority could not be sent in one envelope to the office address, in order to save on postage charges. This was agreed.

Discussion The Chairman raised the question of disused tanks, and the growing numbers which are now becoming disused for temnorary periods, pending a change in the economic climate. He asked members what steps their authorities insisted upon to. make these tanks safe. A lively ensued, which various methods of maktng safe temporarily were put forward frOM filling with water, to sealing the tan};: off. It was suggested that until a had been made safe by some means , the site should continue to be licensed by the local authority. After lunch a very , t· interes and informative talk was given by Mr. F.E. McCarthy, Senior Sales Engineer , EmcO Wheaton U.K. Limited , on the fittings for vehicles engaged in the conveyance of petroleum spirit. This was accompanied by a film on fire engulfment tests on carrying tanks for petroleum spirit, and by a display of the various fittings manufactured by Emco Wheaton. Mr McCarthy was warmly thanked on behalf of the Branch by Mr. L.J . Brooks .

SOUTH EASTERN

Minutes of the Annual Gene r al Meeting of the Branch held at Slough Town Hall , Bath Road , Slough, Berkshire at 10.00 am on 9th March 1977 .

Prior to the A. G.M . the Branch endorsed the secretary's action in preparing and submitting notices of motion to the Association A.G.M. via the Hon . General Secretary in accordance with instructions given on 24th November 1976 .