EN54-23 Covering Visual Alerter’s Devices Assists Supplier Choice

There is a myriad of legislation and standards that govern the protection of buildings and its occupants and the consequences of not bringing all these together and ensuring the highest levels of fire detection, safety and evacuation can have tragic results. Paul Pope of Apollo Fire Detectors  considers a holistic fire hazard approach to evacuation as well as the recently introduced European standard covering visual alarms.

The process of safe evacuation from a building or area is complex and can require the input of fire safety specialists from the initial consultation and design stage through to the commissioning stage and finally the ongoing building management. The main point being that no one fire safety element works in isolation. The fire detection and alarm system provides the main method for the early warning and the evacuation strategy to begin. However, in addition a lot of work needs to be undertaken to ensure that all elements come together to ensure that occupants are given the best possible chance to exit the premises safely and quickly in the event of an emergency. Some of the different elements involved include ensuring that the buildings structural terrain and human sensory terrain are all designed and maintained correctly for the safe escape.  This would include a refuge strategy for each floor in the building that may be recognized as part of the normal "fire escape" process. It is important that all areas of the building are assessed to ensure the appropriate type of detection is used for the differing fire risks. Understanding the type of fire risk, materials present, fire load, environment, sensor technology and the best detector locations are critical for early and reliable fire detection.

Elementary Considerations
There are some elements of the evacuation strategy that are not quite so obvious. They may include ensuring that the fire detection system operates and monitors any fire protection measures correctly according to the fire evacuation strategy; for example simultaneous or phased evacuation, closing fire containment doors; grounding lifts to a safe area relative to the fire, fire and smoke damper control and fire suppression systems. Furthermore, occupants may not be familiar with their surroundings, possibly orientated to a different time zone and speaking different  languages - all these issues need to be provided for in the event of an emergency. It is therefore essential that fire detection and evacuation strategies provide simple and intelligible methods of notification and guidance to allow for a safe controlled evacuation in a timely manner. In some large buildings where members of the public are involved e.g. airport terminals, shopping centers the evacuation strategy can be quite complex and requires a lot of thought by all parties concerned before any evacuation strategy can evolve. The emergency evacuation plan should be the subject of frequent training so all employees are familiar with its contents and there should be regular evacuation drills with a review and record of the results. In order to assist disabled or sensory-impaired people to escape from fire additional provisions will be required and it may also be necessary for staff to be regularly trained in the correct procedures and adequately staffed to cope with this eventuality - all of which has to be thought through and managed.

Visible Solution
A mandatory European product standard (EN54-23: fire alarm devices - visual alarm devices) came into force on 31 December 2013. The aim of EN54-23 is to enable manufacturers to design, produce and have certified Visual Alarm Devices (VADs) to a specified visual coverage and mounting position to ensure that occupants are made aware of the need to evacuate whether they are deaf or have impaired hearing, including individuals whose hearing may be temporarily affected by external factors such as areas of high ambient background noise, the use of ear defenders, or even the intentional limiting of an audible alarm. In these situations, audible alarms - sounders - are not considered to be effective as the only primary means of warning  device. One solution which has become popular is a combination of audible and visual alarm devices - historically known as  sounder beacons. VADs are particularly useful in areas such as the public areas of hotels, hospitals, and shopping centers to name a few. Following a site/risk assessment, VADs should be positioned wherever hearing impaired individuals may be unaccompanied e.g. bathrooms, toilets and bedrooms. They are not, however, intended to waken people from sleep and in these situations should be used in conjunction with tactile alarms. Until as recently as 2010, no European product standard existed to determine the light output performance criteria and installation requirements of VADs, resulting in inconsistency across how manufacturers declared their products' performance. The introduction of EN54-23 clarifies the need to meet specific requirements, test methods and performance criteria for VADs. This enables those responsible for specifying systems to compare like with like, and identify the most suitable VAD for each application.