The D esign, Installation and Maintenance of Voice Alarm S ystems A guide to B S 5839-8: 01 The Design, Installation and Maintenance of Voice Alarm Systems A guide to B S 5839-8: 01 D o u gl a s F Ma s o n a n d Co l i n S To dd T h is third editio n p ub lis he d in the UK in by B S I S tandards L im ited C his wick H igh Ro ad L o ndo n W4 AL © T h e B ritis h S tandards I ns titu tio n F irs t e ditio n p ub lis he d b y C M P I nfo rm atio n Ltd in 0 S e co nd e ditio n p ub lis he d b y B S I in 0 All rights res e rved E xce p t as p erm itte d u nder th e a n d Pa te n ts Ac t 988, Co p y ri gh t, D e s i gn s no p art o f th is p ub licatio n m ay b e re p ro duced, s to re d in a retrie val s ys te m o r transm itte d in any fo rm o r b y any m e ans – ele ctro nic, p ho to co p ying, re co rding o r o th erwis e – with o ut p rio r p e rm is s io n in writing fro m the p ub lis h er Whils t eve ry care h as b ee n take n in de velo p ing and co m p iling this p ub licatio n, B S I accep ts no liab ility fo r any lo s s o r dam age caus e d, aris ing dire ctly o r indire ctly in co nnectio n with reliance o n its co ntents e xcep t to th e e xte nt that su ch liab ility m ay no t b e e xclude d in law While eve ry e ffo rt has b ee n m ade to trace all co p yrigh t h o lders , anyo ne claim ing co p yrigh t s h o u ld ge t in to uch with the B S I at the ab o ve addres s B S I h as no res p o ns ib ility fo r the p e rs is te nce o r accu racy o f URL s fo r external o r third- p arty interne t we b s ite s referre d to in this b o o k, and es no t guarante e th at any co nte nt o n s uch we b s ite s is , o r will rem ain, accurate o r ap p ro p riate T h e righ t o f D o u glas F M as o n and C o lin S T o dd to b e ide ntifie d as the autho rs o f this Wo rk h as b e en as s erted b y the m in acco rdance with s e ctio ns 7 and o f the Co p y ri gh t, D e s i gn s a n d Pa te n ts Ac t 988 T yp es e t in Gill S ans and C e ntury S cho o lb o o k b y H elius , B righ to n and Ro che s ter P rinte d in Gre at B ritain b y B e rfo rts Gro up www b e rfo rts co uk B ri ti s h L i b ry Ca ta l o gu i n g i n Pu b l i c a ti o n D a ta A catalo gue reco rd fo r this b o o k is availab le fro m the B ritis h L ib rary ISBN 978 80 8075 To my dear wife, E liz abeth D o u gl a s F Ma s o n To my three loving children, Keith, Jayne and Fiona (Little Boo) , because of whom I am blessed And to Karen for her everlasting love and support And to the cats of Hutton Roof (past and present) , for their loyal company as I write in the dead of night Co l i n S To d d Contents About the authors ix Introduction Voice alarm systems and standards – a short history The role of voice alarm systems in fire warning 15 Scope of BS 5839-8 21 C ontents of the C ode 25 Defining the terms 39 Types of systems and the evacuation plan 47 System planning considerations, including exchange of information and responsibilities and variations 53 Interface between the voice alarm system and the fire detection and fire alarm system 57 Fault monitoring, integrity and reliability of circuits external to the VAC IE 65 1 Typical arrangements of voice alarm systems 77 Voice alarm control and indicating equipment ( VAC IE ) 93 Power supplies 99 Use of voice alarm systems for purposes other than warning of fire 111 Loudspeakers, loudspeaker zones and loudspeaker circuits Power amplifiers 117 33 vii The design and installation of voice alarm systems Ambient noise sensing and compensation 39 E me rgency and non- e me rgency me ssage s 43 Audib ility and intelligib ility 53 E mergency message ge ne rato rs 65 E me rgency micro phone s 69 2 Wiring 77 Radio - linked systems 83 Vo ice sounde rs 89 C limatic and environme ntal conditions, radio and ele ctrical interference and electrical safety 93 Installation 95 C o mmissioning and handover 99 Mainte nance 03 User resp onsib ilities 09 viii About the authors Colin Todd graduated from Edinburgh University in 1974 with an honours degree in physics He then became one of the first four students in the United Kingdom to undertake a postgraduate Masters degree in fire safety engineering, thereby shaping his future career in fire protection After fire protection experience in industry, the Fire Offices’ Committee (which was later incorporated into the Loss Prevention Council) and a leading insurance broker, he founded the leading fire consultancy practice, C.S Todd & Associates, in 1982 The practice, of which Colin is managing director, provides consultancy services in all aspects of fire safety and fire engineering, but has always been able to offer specialist advice on fire detection and fire alarm matters, an area in which Colin specialized during his time with the Fire Offices’ Committee (FOC) Colin served for two years as a member of the Board of the Institution of Fire Engineers (IFE), and was the director responsible for technical matters He also served on the Board of the Engineering Council Division of the Institution, and, for many years chaired the Division’s Membership Committee He is, at the time of writing, Chairman of the Fire Risk Assessment Council of the Fire Industry Association Colin Todd is a chartered engineer, a Fellow of the Institution of Electrical Engineers, a Fellow of the Association of Building Engineers, a Fellow of the Institution of Engineering and Technology, a Fellow of the Institute of Physics, and a corporate member of the Society of Fire Protection Engineers and the Institute ofRisk Management He is also a standards associate of the British Standards Society For many years, Colin has served on national standards making committees, particularly those of BSI He is a member of the BSI Technical Committee that was responsible for the production of BS 5839-8, and he served on the BSI working group that prepared the final draft of the 1998 version of the standard ix The design and installation of voice alarm systems cooling requirements even when the equipment does not have its own internal cooling arrangements; it might be necessary to provide air conditioning of the room containing the VACIE Voice alarm equipment racks usually contain heavy batteries as well as heavy amplifiers; a further recommendation is therefore that the floor loading be assessed before the equipment is installed High-power loudspeakers can also be heavy and a recommendation reminds the installer/reader that, for example, a safety chain may be needed for a suspended loudspeaker There is a ‘ reminder’ recommendation that emergency microphones need to be installed in appropriate locations As explained in the commentary to clause 8, non-emergency use of such microphones is very common and the need to prevent access to a microphone’ s emergency mode has to be taken seriously This is not always easy to achieve because, while an ‘ emergency mode’ switch may readily be fitted, this needs to be operable quickly and reliably in an emergency Another ‘ reminder’ refers to the need for loudspeaker power tappings as installed to be recorded This makes it easier to assess the overall intelligibility/audibility pattern, particularly in a large building, for future reference, and could also help to avoid subsequent disputes (The commentary explains that loudspeakers are commonly provided with several power tappings that, if incorrectly set, can result in overloading of the amplifier circuit or difficulty in adj usting the system for intelligibility ) E nd of line devices of varying complexity are often required for monitoring loudspeaker circuit integrity (see Chapter 0) Sometimes these devices are mounted within loudspeakers but sometimes they are mounted in detached boxes; for maintenance purposes, it is obviously desirable that their locations are known As the commentary explains, there may be several such devices on each circuit, for example where individual loudspeaker circuit spurs are monitored Making these accessible and recording their locations on the as-fitted drawings, as recommended, should help minimiz e the cost of, for example, fault finding For obvious reasons, the positions of all VACIE , loudspeakers, microphones and equipment/devices requiring routine attention, such as end of line devices, should be recorded by the installer on the as-fitted drawings I n stal l ati on practi ces an d workm an sh i p This clause (3 ) reiterates the corresponding clause in BS 83 9-1 and therefore does not require any comment here 96 In s ta l l a ti o n I n specti on an d testi n g of wi ri n g The text of this clause (3 4) again closely follows BS 83 9-1 O ne of the recommendations, however, calls for a test of the kHz impedance of each loudspeaker circuit This measured impedance can be compared with the calculated parallel impedance of the loudspeakers and should confirm, for example, that all loudspeakers are present and connected The recommendation, ‘ Continuity of all circuits should be tested’ appears to be quite correct but, perhaps as an oversight, has been omitted from the corresponding Subclause of BS 83 9-1 97 27 C om m i ssi on i n g an d h an d over T h e rele vant S e ctio n o f th e revise d C o de is divided into five clau s es , , , , and , co vering diffe re nt as p ects o f co m m is s io ning and hando ve r As in S e ctio n , reite ratio ns m o s t o f th e reco m m e ndatio ns in this s e ctio n are o f reco m m e ndatio ns m ade p re vio us ly in S ectio n o f th e C o de b ut will b e im m ediately ap p arent to p o tential p ro j ect o r co m m iss io ning engine ers reading o nly S ectio n C om m i ssi on i n g T h is claus e is alm o st a dire ct re p e at o f C lau se in B S - O nly o ne co m m ent ap p e ars nece s s ary T h ere is a reco m m e ndatio n th at ‘ the co nfo rm s to th e s ys te m sp ecificatio n’ fo rgiven co ve red fo r by no t BS realiz ing 5839-8 co m m entary to C lau se 1 given ab o u t, fo r th at T h ere e xam p le , vis ual, are p ro vis io n o f any vis ual alarm s T h e re ade r o f the C o de co u ld b e as o nly well two as audib le , refere nces and in th is re co m m endatio n fault m o nito ring o f vis ual to alarm s th is : are in th e N o guidance is alarm circuits or whe re /wh en the y s h o u ld b e u s ed P erhap s s o m e re co m m e ndatio ns co uld b e give n at th e tim e o f a revis io n o f th e C o de D ocu m en tati on T h is claus e is alm o s t a direct re p eat o f C laus e 40 in BS 5839-1 and requires no maj or comment T he recommendations of the C ode relating to information needed on as- fitted drawings substitute loudspeakers, microp ho ne s , etc fo r th e detecto rs and s o unders referred to in B S - 99 The design and installation of voice alarm systems Certification O nce again, there is great s im ilarity b e twee n C laus e o f the C o de and C laus e o f B S - M o del ce rtificate s fo r the vario us m o dule s ( de s ign, ins tallatio n, co m m i s s i o n i n g, ac c e p t an c e , m o dificatio n) are v e r i fi c at i o n , include d in Anne x ins p e ctio n D In an d p ractice, s e r vi c i n g, m any vo ice an d alarm co m p anie s will no t us e thes e exact m o de ls , u s ually p re fe rring the ir o wn vers io ns T his is p erfe ctly acce p tab le , p ro vided that they co ntain all the require d info rm atio n and are s igne d as ap p ro p riate A no te to reco m m endatio n 37 m ake s it cle ar that ‘ Whe re a s ingle o rganiz atio n is res p o ns ib le fo r the ap p ro p riate de s ign, ins tallatio n and/ o r co m m is s io ning o f b o th the fire de tectio n and fire alarm s ys tem and the VA s ys te m , it is acce p tab le fo r B S - and B S - m o dular ce rtificates to be co m b ine d ’ T his is a s ensib le way of cu tting wn on p ap erwo rk! Acceptance T e xt has b ee n take n fro m B S - and m o difie d and exte nded to co ve r VA s ys te m s T he re co m m e ndatio ns in this C laus e ( ) relating s p ecifi- cally to VA s ys tem s are dis cu s s ed b e lo w In additio n gency to m e s s age s accep ting that co rrectly, the the u se r s ys tem or b ro adcas ts p urchas er is re co rde d em er- reco m m e nded to ens ure that live vo ice b ro adcas ts are s atis facto ry fro m all ins talle d em erge ncy m icro p ho ne s ; inte lligib ility this sho uld o f em ergency include b ro adcas ts che cking m ee t the that audib ility and reco m m e ndatio ns of C lau s es and 2 o f the C o de T he agree d p rio rity structu re fo r e m e rgency b ro adcas ts s ho uld als o b e checke d b y the u s er o r p urchas e r, e g that live vo ice m es s age s fro m the e m e rgency m icro p ho ne( s ) o ve rride any p re- reco rded e m e rgency m es s age b ro adcas t F o r thes e j udge m ents to b e m ade , there will generally b e s o m e fo rm o f dem o ns tratio n o f the s ys tem to that p e rso n b y the co m m iss io ning engine er An additio n to the trans fe rred wis m o f C laus e o f B S - is a reco m m e ndatio n that the u s er o r p urchas e r s ho uld b e satis fie d that ‘ the s ys te m fully o p e rates whe n the p rim ary p o we r su p p ly is re m o ve d’ T his is an adm irab le reco m m e ndatio n b u t, in the ab s e nce o f a te chnical rep re s entative, e g a co ns ultant em p lo ye d wo nders if this check will b e m ade! 200 by the u s er or p u rchas e r, o ne Co m m i s s i o n i n g an d h a n v e r Verification This clause (3 9) has a much shorter commentary than the BS 83 9-1 (Clause 43 ) equivalent The suggested reasons for the user or purchaser deciding to have a verification undertaken are the division of work elements between different organiz ations, the evolution of the building design during construction and/or the lack of detailed information at the time of design It is worth pointing out that, while these reasons would make a verificatio n almost essential, independent co nsultants are o ften requested to undertake verifications because the user or purchaser has perhaps felt remote from the technicalities of the design and installation and therefore is not sufficiently confident to accept the system on the basis of their own knowledge and understanding of the system The larger the system, the more likely such a verification would be undertaken 201 28 M n ten an ce Rou ti n e testi n g In the revised Code, the clauses on maintenance have been expanded considerably compared with those in its previous version This is once again because it was decided to give the section similar treatment to that in BS 83 9-1 Obviously, emergency b roadcasts replace alarm signals in the text However, in a VA system, there may be more than j ust one alert and one evacuate message to be broadcast during the testing For example, phased evacuation or a building of complex or unusual design will often require a number of emergency messages; also, nd sequence alert messages are commonly employed in b uildings with phased or staged evacuation (see Chapter 8) All these messages need to be checked regularly In VA systems other than those of Type V1 , emergency microphones will be included; these also need to be tested for live voice announcements Likewise, the facilities in Type V4 and possibly V5 VA systems for manually starting and stopping recorded emergency messages from the VACIE require to be checked regularly for correct operation A note to recommendation 40 a) makes it clear that, when carrying out a weekly test on a VA system, it is not satisfactory for emergency broadcasts to be initiated directly from the VACIE This would not test that there is a working link from the associated fire detection and fire alarm system; therefore a manual call point needs to be operated to start the broadcast The recommendations (40 b) ) for testing various types of system not include testing all possib le comb inations of b roadcast messages and loudspeaker z ones, e g ‘ for Type V3 and V4 systems, check that the live message is broadcast correctly in at least one z one’ Unfortunately, this may lead to one combination only of broadcast and z one being repetitively tested each week; in some ways it would have been 203 The design and installation of voice alarm systems b e tte r if the C o de had reco m m e nded that a different co m b inatio n was tes ted each wee k, so that all co m b inatio ns wo uld b e tes ted o ve r a s p e cific p erio d P erhap s this co uld be co nside re d by the ap p ro p riate wo rking gro up at the tim e o f the next am e ndm ent o r revis io n o f the C o de T he re is some anecdo tal e vide nce that o ccup ants o f a b uilding m ay tend to dis re gard a ge nuine e m e rgency m es s age if they are exp o s e d to o regularly to tes t b ro adcas ts that us e that s am e m es s age So, fo r a fire de te ctio n and alarm s ys tem us ing a VA sys te m fo r e m e rge ncy s ignalling, the re are co nflicting nee ds : the ne ed to he ar and le arn e m e rge ncy m e s s age s ( fro m regu lar tes ting) and the nee d no t to b e exp o s ed to s uch tes ts so o fte n that they are no t lis te ned to tho ro ughly – a ge nuine alarm co uld be m is taken fo r ‘ ye t ano ther tes t’ ! T here is no o b vio us way of achie ving b o th the s e ne e ds b ut changes have b e en m ade to this C laus e in the C o de to effect a co m p ro m is e T he co m m entary has b ee n alte re d to p lace les s em p has is o n the ne ed fo r b ro adcas ting o f m u ltip le e m e rge ncy m e s s age s during te sts and a s ho rt p as s age o n s ys tem s u s ing p hase d e vacuatio n has no w b e en o m itte d A new p as s age , 40 b) , has also b e en adde d; this re co m m e nds that, ‘ … a m inim um num b e r o f s taff and p u b lic are exp o s ed to the em e rge ncy m e s s age during the wee kly tes ting o f the VAS reco m m ende d in a) , exce p t that, at inte rvals o f no t m o re than three m o nths , b ut p referab ly m o nthly, de p ending up o n an ap p ro p riate risk as s ess m e nt fo r the b u ilding, the VAS te s t re co m m ended in a) s ho u ld b e carrie d o ut in no rm al wo rking ho urs , s o that all o r m o s t b uilding o ccup ants he ar the em ergency m es s age s taff ( at leas t) b ro adcas t; ’ wo u ld hear an T his actu al m e ans , in p ractice , em erge ncy that s e curity m es s age every we ek, b ro adcas t o u t o f ho urs , as p art o f the fire alarm te s t; all b uilding o ccu p ants wo uld he ar that m e s s age ge nerally o nce p er m o nth, during no rm al wo rking ho u rs , u nle s s a ris k ass e s s m ent fo u nd that a lo nge r p e rio d, o f u p to three m o nths , was ap p ro p riate b etwe en s uch te s ts Additio nally, no nem erge ncy te s t m es s ages co uld, of co u rs e , be b ro adcas t to te s t fo r co ve rage and inte lligib ility at o the r tim es , b ut no sp ecific re co m m e ndatio ns fo r re gular tes ting o f this kind are given in the C o de Appropriate messages should be broadcast before and after routine tests ( s ee als o C hap te r ) to e ns ure that p e o p le no t evacu ate the b uilding unne ce s s arily N o te has b e en adde d to a) to re info rce this p o int, altho ugh co ntains the actual re co m m e ndatio n I n a no te to , it is s uggeste d that ‘ the “ tes t o ve r” announcement may also ask that any lack of intelligibility is reported to the resp o ns ib le p erso n’ T his re qu est is alre ady s o m etim e s inco rp o rate d into P A m e s sage s re lating to tes ts o f fire de te ctio n and fire alarm s ys tem s 204 Ma i n te n a n c e I n specti on an d servi ci n g Since the recommendations are following those in BS 83 9-1 , only those referring specifically to VA systems are the subj ect of comment below (where necessary) There is a recommendation that vented b atteries be attended to on a three-monthly b asis, as in BS 83 9-1 , but, additionally, that ‘ the date of installation of the batteries should be checked against the battery life recommended by the supplier and replacement batteries installed, if appropriate’ This latter recommendation refers to any battery type and to the lab els referred to in of the Code Because of the need for intelligibility as well as audibility, it is, if anything, even more important than for fire detection and fire alarm systems that areas of a building are not devoid of adequate broadcast messages because of structural changes that might occur between maintenance visits It is therefore recommended that a check be made that loudspeaker locations are all as they should be Likewise, it needs to b e checked that ambient noise has not increased in an area because, for example, of a change of use A point is made in the recommendations that the company normally handling maintenance of a VA system might not be sufficiently competent to carry out modifications necessary because of changes of use, structural alterations, etc This would b e particularly true in a large, complex building with, for example, ‘ difficult’ acoustic surfaces that could have excessively high reverberation times The services of an electro-acoustic designer might then be required Another recommendation not applicable to fire detection and fire alarm systems is that ‘ all emergency microphones should be visually examined for damage and tested to check that the selected areas receive an intelligible broadcast’ This is particularly important for hand-held microphones where a microphone is regularly clipped and unclipped fo r test p u rp o ses and fo r m icro p ho nes , b o th h and- held and de sk- mounted, that are used for non-emergency announcements as well as in emergencies The recommended recording of sound pressure levels in the logbooks, so that they can b e compared with previous test results carried out at the same locations, is a good idea, since it will highlight any fall-off in performance of loudspeakers, changes in acoustics because of structural modifications, etc It is very important in a VA system that a check is made on the system’ s performance on primary (mains) power only and, separately, on standby power only Sometimes, in the past (it is to b e hoped) , cost- 205 The design and installation of voice alarm systems reduced design of power amplifiers could include using the batteries to supplement the primary power supply to cope with maximum loudspeaker loading at high volume; a similar design shortcoming often resulted in a considerable drop in average power output capability on operating from batteries as compared with that from mains power operation For some reason, these design practices were tolerated for a long time but it is believed that the situation is now much improved Recommendations 41.2h) and k) now specifically disallow such malpractice ‘All ancillary functions ofthe control and indicating equipment should be tested’ is another recommendation This, at first sight, might appear to be a mistaken import from BS 5839-1 In fact, there are ancillary functions that can apply to VA systems: visual alarm devices can be controlled via voice alarm as can shutdown of ancillary systems such as third-party sound systems, e.g for entertainment or non-emergency announcements The servicing work to be carried out at intervals not exceeding 12 months is an extension of the equivalent text in BS 5839-1 In addition to these latter recommendations, orientation of loudspeakers is recommended to be checked where necessary; this would apply to, for example, projection loudspeakers mounted along a wall, directional horn loudspeakers and multi-driver unit column loudspeakers Now that the revised Code covers radio-linked VA systems, it is recognized that electromagnetic field strengths need to be checked N on -routin e attention Without repeating the recommendations in the Code (which closely follow those in BS 5839-1 once again), it is worth commenting on 42.3, which relates to system tests after modifications Often, modifications to a system may be very minor and it is therefore ‘over the top’ to issue a modification certificate in these circumstances Usefully, the Code now tries to quantify when a certificate is needed in a note advising that a …modification certificate will generally be necessary where the system changes include addition or removal of e.g more than 5% of the loudspeakers or voice sounders, addition or removal of any emergency microphone or power amplifier, any change to the number of emergency loudspeaker zones, or any change to the VACIE that will alter the previously agreed “cause and effect” requirements 206 Ma i n te n a n c e T he re m ay b e co m p laints fro m tho s e who have to fill o ut ce rtificate s fo r m o dificatio ns m arginally ab o ve tho s e lim its b ut at leas t this re m o ve s an o the rwis e to tally s ub j ective ide a o f what co ns titutes a m o dificatio n! 207 29 U ser respon si bi l i ti es These responsibilities are naturally very much the same as the familiar equivalents in BS 83 9-1 Because VA systems replace fire detection and fire alarm systems, the duties of the member of the premises management ‘ appointed to supervise all matters pertaining to the VAS’ include training in the use of the microphone (in VA systems other than those of Type V1 ) It is really important to ensure that appropriate new staff members in an organiz ation can make clear announcements in an emergency The recommendations for a logbook also parallel those in BS 83 9-1 A recommendation in the Code makes it clear that a combined fire detection and fire alarm system and voice alarm system logbook is permitted but adds the rider, to avoid confusion, that the dual purpose of the book should be clearly indicated in/on it 209