Voice Alarm System Refurbishment
Voice alarm systems first became very popular back in the late 1980 & 1990’s. Early systems were bespoke using equipment adapted from public address system equipment. However, as industry standards such as BS5839 & BS7443 became the required level to make a fully integrated life safety monitoring voice alarm system, manufacturers started to design purpose-built products compliant with these standards.
Some of these early systems are actually still in use, however they are well past their optimum life cycle and thus failure rates will increase.
British standard 5839 Pt8 from 1988 recommends a minimum life cycle for voice alarm main equipment of 15 years including full support from the manufacture. (Some manufactures can still support equipment older than 15 years).
Due to the environment where some of these voice alarm systems are located, such as storerooms, offices and security offices. The heat build up can cause premature ageing of equipment such as amplifier’s and control routers.
This can obviously affect the systems reliability. Therefore as a guideline, voice alarm systems over 15 years old should be replaced.
Voice Alarm System Field Wiring
In general the voice alarm field wiring consists of fire rated cabling which has a good level of mechanical protection as well as protection from heat, therefore it is not usually necessary to replace the field wiring.
This has the great advantage of reducing system replacement costs as rewiring an existing building which is in use by staff and/or the general public would be very inconvenient and costly.
Loudspeakers for voice alarm systems
Loudspeaker’s for voice alarm system come in various different designs, however as from 1988 all voice alarm ceiling loudspeakers were fitted with fire rated enclosures as per the requirements of BS5839 pt8.
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Ceiling loudspeakers with fire rated enclosures.
The fire rated enclosure can protect each individual loudspeaker from fire and limit the spread of fire or smoke from above or below the ceiling.
Prior to 1988 ceiling loudspeakers had Nylon terminal block, no thermal fuse and Aluminum enclosures. Steel enclosures were introduced in 1995 to increase the enclosure melting point to 800 degrees C.
Ceramic terminal block
Changing the loudspeaker connections from plastic terminal block to ceramic terminal block helps to isolate the field wiring from short circuits if a loudspeaker were to catch fire.
Loudspeaker thermal fuse protection/isolation
The next addition to loudspeaker circuit protection was to add a thermal fuse in line with the loudspeaker connections.
This would enable a loudspeaker to isolate its connections from the field wiring in the event of a short circuit and thus keeping all other loudspeakers in the associated areas fully operational.
Latest standard EN54-24
Since the new standard EN54, not much has changed with loudspeaker design compliancy apart from the types of paint used on loudspeakers with low toxicity and coping with ingress of moisture.
Summary
Taking the considerations for loudspeaker field circuit wiring and loudspeakers into account, it is practical to refurbish all voice alarm main equipment including microphones, end of line monitoring and fire alarm interface equipment.
New system main equipment can be installed compliant to the current regulations.
Tech X have carried out such works at various sites throughout the UK using tried and tested manufactures solutions where the main equipment microphones, end of line monitoring and fire alarm interface are compliant with EN54.
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