As members of the FIA, we thought we’d share this article with you which addresses the new European Standard for visual alarm devices. At Channel Safety Systems we have an extensive range of fire alarm systems and our LED Visual Indicator products can be found here. The LED Visual Indicators we offer our clients are versatile emergency indicators and are compatible with a variety of different alarm systems.
Normal hearing is taken for granted by most of us, but there are estimated to be nearly nine million people who are deaf or hard of hearing in the UK, equivalent to one in seven people. For these
people, reliance on audible alarms in the event of a fire is ineffective. In addition, increased concerns over health and safety are encouraging the greater use of ear defenders
in the work place and so there is a sizeable contingent of people who work in environments where alarm sounders are unlikely to be heard.
To overcome these issues, signalling needs to be broadened to stimulate senses other than hearing. Supplementing audible alarms with visual alarm devices (VAD’s) is the most effective way to achieve this
and VADs have been used to do so for many years. The trend continues to grow as they are suitable for many applications, either as a separate unit or integrated with the alarm sounders themselves.
Current building regulations and BS 8300, Design of buildings and their approaches to meet the needs of disabled people, recommends that a VAD is sited in any area where a deaf or hard of hearing person
may be left alone e.g. toilets or bedrooms. This, alongside the rising awareness of the Equality Act 2010 highlights the increasing importance that the industry is vigilant in designing fire systems
suitable for the deaf and hard of hearing. The question is what level of performance is required to ensure that a VAD provides a suitable level of coverage?
Prior to May 2010, there was no fire industry standard that determined the light output performance criteria and installation requirements of visual alarm devices. This gave rise to manufacturers rating their
products in a variety of different ways, leading to much confusion and misinformation. Now this has all changed with the release of standard BS EN54-23: Fire alarm devices – Visual alarm devices.
BS EN54-23 specifies the requirements, test methods and performance criteria for VAD’s in fire detection and fire alarm systems. Manufacturers must now present the products performance data in a uniform manner so that they can be directly compared and their suitability assessed for particular applications. All VAD’s sold for fire use in EU countries must be manufactured and certified to these requirements by 1st March
2013. For countries such as the UK which do not currently require CE marking to the CPD, compliance will be enforced from July 1st 2013 when the Construction Products Directive (CPD) is replaced by the
Construction Products Regulation (CPR).
The FIA and LPCB have jointly published COP0001 Code of Practice for Visual Alarm Devices used for Fire Warning, which directly compliments BS EN54-23 and BS 5839-1. It provides guidance and
recommendations on the planning, design, installation, commissioning and maintenance of VAD’s in and around buildings, other than single family dwellings.
VADs will now be classified into three categories based on their intended application, namely ceiling mounted, wall mounted and open class. Each of these categories has specific targets
for light distribution patterns in order to be compliant. The area of coverage determined by the testing is based on the distance at which the required illumination is achieved, which is 0.4 lumens/m2 on a surface perpendicular to the direction of the light emitted from the
It should be emphasised that achieving this requirement will demand light output to be significantly higher than today, when taking practical room size into consideration. The manufacturer must
specify the coverage volume with the device; therefore you should always look for the coverage volume specification code.
The wall and ceiling classes will require different light dispersion characteristics, the Wall format requiring the manufacturer to state a mounting height, minimum 2.4m and the width of a square
room over which the VAD will provide coverage. So the data with the VAD could read W-2.4-6, i.e. mounted at a height of 2.4m the VAD will cover a room 6m square. The VAD will therefore be required to cover
the volume below its mounting height. Any light going upwards will be wasted as far as this categorisation is concerned. (see figure 1, below)
Similarly the ceiling format will be assessed on the diameter of its coverage volume when mounted at a height of 3, 6 or 9m. The VAD in this case needs to radiate light in a cylinder below the
mounting point. (see figure 2, above).
The coverage volume of open class devices is fully specified by the manufacturer, but must have an illuminance of 0.4 lumens/m2 and specify the dimensions of the coverage volume.
COP 0001 advises that when designing systems incorporating VADs, a number of factors within the applications environment should be considered at the onset of design such as the
level of ambient light, the reflectivity of surfaces, effect of colour and the required field of view. It is important to assess and understand the types of surfaces involved as different materials will react differently to the emitted light. Consideration should also be given to the presence of an obstruction in the field of view as this could affect the VAD coverage.
When considering the siting and spacing of VADs in a room, it should be ensured that all occupants of the room have a clear line of sight of the device, but there should not be undue dependence on this in applications such as an office, where people predominantly spend their time looking at computer screens or focusing on a specific activity. Reflective surfaces can increase the field of vision by providing multiple paths for the light to attract their attention. Where the space to be covered is larger than the specified coverage volume of a device, a sufficient number of devices should be sited to ensure the required illumination levels are satisfied.
The flash rate of a VAD should be between 0.5Hz and 2Hz and should emit a white or red flash. COP 0001 specified that; ‘Generally white flashing light is more effective in alerting individuals as it includes a broader spectrum of colours’ and requires less power than red flashing light.
LED verses Xenon
To meet the requirements of BS EN54-23 and cover a practical room size encountered in most situations, VAD’s will be required to have higher light output levels than those generally used in the market.
Consequently, this means increased power will be required. LED technology can offer a breakthrough here, offering more efficient use of light and generally lower power requirements than Xenon tube devices, reducing the burden on control panel power supplies and cost of installation.
It is now up to the industry’s leading manufacturers to develop an innovative solution that meet the challenges of BS EN54-23 and makes the transition as easy as possible for risk assessors, installers and system designers operating within the industry.
You can refer to the original article from the FIA’s Focus, issue 23 here.
Channel Safety Systems can offer help and guidance with understanding the requirements of the new standard and its implications. Contact the team if you require further information on 0845 884 7000 or email@example.com