A Guide To Fire Alarm Installations In Public Buildings

A Guide To Fire Alarm Installations In Public Buildings

If you’ve ever started a business then you’ll know that the installation of a fire alarm system should be undertaken in accordance with British Standard 5839 fire alarm regulations and should only ever be undertaken by a qualified installer.

Here’s a taste of what you’re up against…

Fire Alarm Installations In Public Buildings

There are a considerable number of regulations involved and in addition, there may be extra requirements of a local authority or fire authority.

Just to provide some idea of the fire alarm regulations complexities, we list here a sample of the requirements of BS5839.


To begin with, an AFD (Automatic Fire Detection) system may be designed to protect property or to protect human life. In order to protect property, an AFD may be installed either in all areas, or in specifically defined areas.

To protect life, the AFD may be installed in all areas, in defined areas at higher risk of fire, in escape routes and rooms leading to them, in corridors and stairways, or in areas where there is a specific fire risk. In addition, a manual fire alarm may also be required in certain circumstances.

Fire Alarm Sound Levels

The volume of a sounder device should be a minimum of 65 decibels, or 5db above any background noise if such noise continues for more than half a minute.

For instance, consider fire alarm regulations in a factory. Machinery may be operating all day so that needs to be taken into account. The maximum sound level should not exceed 120db. Cabling for sounders should be such that, in case of a fault, at least one sounder will operate in the area of the control panel.

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The maximum floor area of any individual zone is 2,000 square metres and a person searching for the source of a fire must not have to travel more than 60 metres from the entry point to find it. Equally, a person using an escape route should not have to travel more than 45 metres to reach a manual call point.

The centre of a manual call point should be positioned 1.4 metres from the floor, unless the first person likely to raise the alarm may be wheelchair bound. Fire alarm regulations say that visual alarms, such as flashing lights, should be mounted at a minimum of 2.1 metres from the floor and in a position where it is likely that they would attract attention.

Further Regulations For Fire Alarm Installations…

In areas where people sleep, the minimum volume of a sounder device should be 75 db at the head of the bed and, in buildings where there may be people with impaired hearing, both audio and visual alarms should be considered.

Loss of sound occurs through doors. In the case of a normal door, around 20 db will be lost and in the case of fire doors, around 30 db will be lost. It is suggested that, unless a sounder is sited in a bedroom, it is not likely that the minimum level of 75 db will be reached.

Fire alarm regulations also state that a smoke or heat detector device should not be mounted within 500 mm of an obstruction. If the top of a solid partition is less than 300 mm from the ceiling, it should be treated as a wall. Similarly, a beam on a ceiling that is deeper than 10% of the ceiling height should also be treated as a wall.

This is just a sample…

The foregoing is just a sample of some of the requirements. There are many others concerning lift shafts, stairways, smoke detectors, heat detectors and so on. However, it does give some idea of all the things that need to be taken into consideration when designing a fire alarm installation and why it is only ever a job for the trained professional who is BAFE registered.

Fire Alarm Installations – We Take The Headache Out Of It

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Here at Spy, we’re up to date with all the regulations and take the stress out of installing your fire alarm system, so you can get back to running your business.

We’re BAFE and IFA accredited, ensuring you get designs and installations certified to the BS5839 standard.



Don’t leave it to chance – Ensure your protected from fire with our help

Fire Alarms South London

Thousands of businesses across London and Kent rely on us to ensure their property, people and assets are safe from the threat of fire. Our methodical planning and in-depth installations have helped to ensure businesses are not only safe from fire, but also complying to the necessary legislation for their industry.