Standard Advice
Don’t fall behind on the latest fire regulations – make sure you are up to date with the latest EN54-23 product standard, says Neil Baldwin, sales director with ESP.
BS EN 54-23 stipulates the requirements, test methods and performance criteria for Visual Alarm Devices in fire detection and fire alarm systems. In order to comply, manufacturers now need to present their products’ performance data in a uniform manner so that they can be directly compared and their suitability assessed for particular applications.
EN54-23 gives an independent assessment of a beacon’s performance in the same way that EN53-3 does for sounders. With this standard, systems designers, risk assessors and installers can assess what the requirement of a beacon must be in order to deal with a particular application and then have confidence in choosing the right device for the job. For example, compliant beacons and sounder beacons are designed for areas where people with hearing difficulties may be alone, environments with high levels of ambient noise, and areas with restricted access.
The development of EN54-23 required a fundamental change in visible alarm technology to ensure that the light output from warning beacons is sufficiently bright to attract attention. EN 54-23 allows for three product classifications: W (wall); C (ceiling); and O (open). The key performance indicators are that the output of the device must be greater than one candela (cd) and less than 500 cd; the flash rate must be between 0.5 and 2.0Hz.
The critical requirement from a manufacturer’s point of view is that each model must be tested to demonstrate compliance with the standard’s requirements. For ceiling-mounted devices, the manufacturer must define the maximum height at which it can be installed, set by the standard 3, 6, or 9 metres. A wall-mounted device must be installed at a minimum of 2.4m from the floor in the same way a sounder is today. The coverage volume, defined by the manufacturer, is that in which the output meets the minimum illumination requirement of 0.4 lumens/m2 (lux) on a perpendicular surface.
To avoid having to install an unacceptably large number of beacons, manufacturers are typically designing to meet smoke detector spacings. The result is that W class devices are assessed in terms of the dimensions of the cube of light they cover and C devices are assessed as the diameter of a cylinder of light. The coverage of an O class device is a cuboid of light, defined by the manufacturer as independent of the EN54-23 height/placement requirements.
A further important consideration is that if the risk assessment does not specify a VAD for a particular area, it will still be acceptable to install a non-compliant beacon as a supplementary indicator to a sounder.
Red or white flash?
The fire industry has traditionally used a red flash to denote an alarm condition. This presented a challenge under EN 54-23, as the light intensity drops as it is filtered through a red lens, requiring more power to achieve the required coverage. This loss can be as much as 80%. Installers and specifiers need to be aware of this when selecting a VAD. If an existing installation has VADs with red flash then the colour of the flash has to remain the same on any replacements or extensions to the system.
Specifying
When selecting a beacon, room coverage, flash colour and current consumption are the key measures. The milliamp per metre specification of a product offers a good guide to selecting the most efficient VAD possible.
The introduction of EN 54-23 has led to growth in the use of VADs and this is set to continue. They offer the reassurance of a visual indication to a fire alarm and help to mitigate the risk to the building occupants. Fully automated and highly reliable, used as part of a comprehensive fire detection system, VADs remove any human error associated with systems that rely on human interaction or the requirement to ensure that portable tactile devices are working and that the batteries are charged. The standard enforces a specific illumination level, ensuring that any visual alarm is meaningful and inclusive to all.
Article can be viewed here: http://www.ewnews.co.uk/index.php/getting-acquainted-with-en54-23-product-standard/