BS 5839-8:2023 on voice alarm systems published by British Standards Institution

Voice alarm systems are installed in buildings to aid the safe evacuation of occupants in the event of a fire episode. As such, they can play an essential role in protecting life.

Such systems are typically deployed when the authority responsible for enforcing applicable fire safety Codes of Practice or fire risk assessments considers them appropriate, which is generally the case in buildings that are subject to a predetermined evacuation plan.

In those buildings where the occupants are adequately trained to respond effectively to a fire alarm, and where trained fire wardens are available to marshal an evacuation, traditional alarm devices such as bells or electronic sounders can be deemed sufficient, although a voice alarm system might still be appropriate to enhance the management of an evacuation.

System types 1 to 5

BS 5839-8 deals with a wide variety of different types of system. In the British Standard, these are categorised by the degree of manual control required. The degree of manual control should be appropriate to the risk and the availability of trained personnel to operate a given system.

The British Standard doesn’t recommend which type of system should be installed in any given premises: the categories are defined to help purchasers, specifiers and end users understand what they’re dealing with.

To that end, the British Standard categorises five types of system from Type V1 – which provides automatic operation of the voice alarm system against a pre-programmed set of evacuation rules, and which may also have facilities for the manual selection of non-fire emergency messages – through to Type V4 systems, which provide for much more manual control and allow trained and disciplined staff to follow a pre-planned evacuation strategy when the automatic mode needs to be overridden.

Type V5 is aimed at those applications outwith the scope of Types 1-4 and covers tailored solutions based on the assessment of special or mutable risks.

Ambient noise sensing

Thereafter, the British Standard is broken down into five further sections, the first of these being an extensive section on design considerations. This notes that voice alarm system designs must be based on the results of a risk assessment. For larger and more complex buildings, one result of a risk assessment will be an evacuation plan for the building – or parts of it – that will govern the degree of manual control required and, therefore, the type of voice alarm system.

Design considerations also include consideration of such factors as the interface between fire detection and alarm systems and the voice alarm system, systems in explosive gas or dust atmospheres, fault monitoring, loudspeakers and loudspeaker zones and ambient noise sensing and compensation.

The British Standard details explanatory commentaries on clauses. For instance, the commentary on emergency messages states that these need to be immediately recognisable as such, intelligible and must provoke urgent action.

The following section covers system installation (including the responsibilities of installers, installation practices and workmanship and the inspection and testing of wiring). The next deals with commissioning and handover of voice alarm systems, including documentation, certification, acceptance and verification.

Maintenance and user responsibilities

The final two sections cover (respectively) maintenance, including routine testing, inspection and servicing, and non-routine attention and user responsibilities. The latter encompass premises management and a logbook.

Emergency voice communication systems are used in connection with life safety and are therefore subject to high standards of design, manufacture, installation, commissioning and maintenance. BS 5839-8:2023 is important because it can help ensure that the latest standards of reliability, safety and security are achieved, leading to acceptably high standards of performance.

*Copies of BS 5839-8:2023 are available to purchase online in digital and hard copy format by visiting the BSI Knowledge website