An Introduction to EN 54 Part 23 and Visual Alarm Devices

Originally scheduled for commencement on 31 March 2013, a lack of product availability from manufacturers delayed the introduction of EN 54-23. A key stimulus for its introduction proved to be the Equalities Act 2010.

Fire detection and alarm systems are intended to alert occupants of a fire within the building.  It’s common to use a mix of audible and visual alarms to do so, with compliant VADs ensuring that the system generates an effective warning for all occupants of a building.

If the primary warning is a visual alarm regime, then that regime must be effective in alerting hearing impaired or hard of hearing individuals as well as those personnel working in environments with a high level of ambient noise. For example, areas where wearing ear defenders is required.

EN 54-23 is not intended to cover visual indicators (for example, those found on detectors or on the control and indicating equipment). Typically, they would not be as bright as a VAD. It may be appropriate to have visual indicating devices (VIDs) for providing supplementary indication or information to the building occupants (at a nursing station, for instance).

VAD selection

When selecting a VAD for a specific application, it’s important that consideration is given to its mounting requirements, as well as to the illumination coverage volume needed to provide an effective warning for building occupants.

Three classes of device are specified. These are as follows:

*Category ‘C’ for ceiling-mounted devices

*Category ‘W’ for wall-mounted devices

*Category ‘O’ (open) for manufacturer-specified performance

For categories ‘C’ and ‘W’, both the mounting requirements and coverage volume are clearly specified. The correct application of Category ‘O’ VADs relies on the data supplied by the manufacturer.

VAD bases in the ‘Open’ category may have a specific dispersion pattern (it’s Best Practice to refer to the manufacturer guidance) due to having a detector or cap fitted in the centre of the device.

VADs and VIDs

VADs and VIDs may be stand-alone devices or may be incorporated in other devices such as sounders and smoke detectors. While VIDs and VADs can look similar and be used together, there’s a difference between them.

VADs are tested and certified to comply with BS EN 54-23 and have marking requirements defining their use. The manufacturer must declare the latter, which are ceiling, wall or open. The marking also identifies the coverage of their light output.

The flash rates of VADs are between 0.5 Hz and 2 Hz. VADs may include a synchronisation function to eliminate the possibility of a flash frequency that could result in adverse effects, such as inducing epileptic fits, when devices are in close proximity.

In order to avoid discrimination, BS EN 54-23 compliant VADs may be installed in all sanitary accommodation (not just WCs) and all hotel bedrooms, student accommodation and similar properties, in addition to anywhere where people with impaired hearing are likely to be on their own (such as in an isolated office).

Of course, in the example of a hotel bedroom, VADs will not wake an individual so, if required, they should ask for vibrating pillow pads or alarm pagers.

Where a specification calls for visual devices, it should be assumed that all devices are BS EN 54-23 VADs unless specifically indicated to the contrary in the specification.

Building Regulations 2000

In England and Wales, Part M of Schedule 1 to the Building Regulations 2000 requires that ‘reasonable provision’ shall be made for people to gain access to – and subsequently use – a building and its facilities. This may necessitate the provision of VADs such that buildings are safely accessible for disabled people, including means of evacuation for those who are deaf or hard of hearing.

Non-compliant VIDs may assist as auxiliary indicators that are not intended as the primary means of alarm warning.

Mike Sutton is Regional Sales Manager at Apollo Fire Detectors

*Further information is available online at www.apollo-fire.co.uk