BRE research into the effectiveness of visual alarm devices
Conducted in partnership with industry, BRE research into the warning effectiveness of visual alarm devices (VADs) has supported the development of the product test standard, EN 54-23, and led to the publication of guidance for manufacturers and a code of practice for specifiers and installers.
VAD product test standard
Developing a robust test standard for assessing the performance of VADs, required two key tests:
- a reproducible test to measure the total integrated light output from a flashing device, and
- an operational performance test to quantify the absolute light output in different directions.
As a member of the CEN TC72 working group drafting this EN standard, BRE developed the fundamental experimental tests that form Annex A and B of the now published standard, EN 54-23:2010 (available from BSI online).
Manufacturer’s guidance
EN 54-23 proved to be a challenging standard as the performance requirements of VADs are significantly more demanding than those of the Visual Indicating Devices (VIDs) that manufacturers had been accustomed to producing. To provide manufacturers with guidance on complying with the standard and optimising the performance of their VADs, BRE performed an investigative study and produced an Information Paper.
Code of practice
With the product standard and guidance for manufacturers in place, and approved VADs about to enter the market, the Fire Industry Association (FIA) and BRE agreed that guidance was needed for specifiers, installers and maintainers of fire detection systems.
In partnership with the FIA and a number of its members, BRE performed a series of tests in the BRE test rooms and at on-site installations, to understand the factors (such as ambient light levels and room sizes) that influence VADs’ ability to deliver effective visual warnings. This led to publication of the code of practice, LPCB CoP0001, which is referenced in the BS5839-1 code for fire detection systems.
Further research
Following this wide ranging work in support of VADs, a private research study has been performed to assess how the pulse duration of LED VADs influence the effectiveness of warnings. Further work is currently in progress to identify how factors such as ambient light levels, colours of VADs and orientation of people relative to VADs, all contribute to providing effective visual warning.
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