BS 5839-8:2023 Voice alarm systems that address life safety
The British Standard on voice alarm systems has been revised to bring it up to date with technology and regulatory requirements. This blog post explores what VASs are for and what the standard covers.
BS 5839-8:2023 Fire detection and fire alarm systems for buildings. Part 8: Code of practice for the design, installation, commissioning and maintenance of voice alarm systems is the newly revised British Standard on best practice in the deployment of voice alarm systems (VASs).
VASs are installed in buildings to aid the safe evacuation of occupants in the event of a fire. As such, they can play an essential part in protecting life. They’re typically deployed when the authority responsible for enforcing applicable fire safety codes or for fire risk assessments considers them appropriate, which is generally the case in buildings that are subject to a predetermined evacuation plan. In buildings where the occupants are adequately trained to respond effectively to a fire alarm and where trained fire warden are available to marshal an evacuation, traditional alarm devices such as bells or electronic sounders can be deemed sufficient, although a VAS 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, which in the standard are categorized by 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 system. The standard doesn’t recommend which type of system should be installed in any given premises: the categories are defined to help purchasers, specifiers and users understand what they’re getting.
To that end, the standard categorizes five types of system from Type V1 – which provides automatic operation of the VAS against a pre-programmed set of evacuation rules, and which may also have facilities for the manual selection of non-fire emergency messages – to Type V4 systems which provide for much more manual control and allow well trained and disciplined staff to follow a pre-planned evacuation strategy when the automatic mode needs to be overridden; to Type V5 which is for applications out-with the scope of Types 1 – 4 and covers tailored solutions based on the assessment of special or mutable risks.
Ambient noise sensing
Thereafter, the standard is broken down into five further sections, the first being an extensive section on Design Considerations. This notes that VAS 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 VAS.
Design Considerations also include consideration of such factors as the interface between fire detection and alarm systems and the VAS, systems in explosive gas or dust atmospheres, fault monitoring, loudspeakers and loudspeaker zones, and ambient noise sensing and compensation. The standard gives explanatory commentaries on clauses. For instance, the commentary on emergency messages states that these need to be immediately recognizable as such, intelligible, and must provoke urgent action.
The following section covers installation: including the responsibilities of installers, installation practices and workmanship and inspection and testing of wiring.
The next deals with commissioning and handover of VASs, including documentation, certification, acceptance and verification.
The final two sections respectively cover maintenance, including routine testing, inspection and servicing, and non-routine attention and user responsibilities which include 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.
