Fire alarm strobe requirements: everything you need to knowMayara
When you think of a fire alarm, the first picture that comes to mind is loud horns going off all around, right? Regarding it comes to properly alert people in an emergency, though, there is another type of device that plays an important role: the visual notification appliances. Where should you install strobes, and how do they work in the event of a fire? Learn more about fire alarm strobe requirements and find out if you are really prepared for any emergency.
Introduction to fire alarm strobes
Technicians usually install alarm strobes in combination with horns and speakers to make people aware of an emergency. In 1970, the first visual notification appliance ever used was a Space Age Electronics AV32. The technicians installed it over an existing horn. Six years later, Eaton’s Wheelock introduced the first horn-strobe notification appliance with the 700x series.
Over the years, more constructions began to require visual signals, and more strobes started to appear. Also, the 1990 Americans with Disabilities Act (ADA) required changes in evacuation signals, to assist the hearing impaired. ADA codes demanded strobes with at least 15 candelas and with a flash rate of at least 60 flashes per minute.
Such conditions made companies like Wheelock and Simplex discontinue their translucid strobes. They replaced these for new, bright, high-intensity devices. Nowadays, some buildings have strobe synchronization devices, which sync strobes into a uniform pattern.
Different types of fire alarm strobes
A strobe coverage area depends on the strobe’s intensity, which you can measure by the candela rating. Therefore, when choosing the right strobe for your building, you must consider the dimensions and layout of the area you want to cover.
Standard strobes have candela ratings that can vary between 15 cd and 110 cd. Extended coverage strobes typically have candela ratings of 177 cd and 185 cd. You can check a complete guideline of maximum coverage areas for strobes at the National Fire Alarm and Signaling Code (NFPA 72).
Besides having different candela ratings, strobes can also differ between wall-mounted or ceiling-mounted.
These devices are perfect for rooms with a high ceiling, generally above 40 feet. Ceiling-mounted strobes can’t be mounted higher than 30 feet above the floor. In this case, the best solution would be wall-mounted devices.
Ceiling-mounted strobes are perfect for coverage between aisles, while also covering other areas of the room. Libraries, department stores, locker rooms, and other places where there might be obstacles in the light path require this type of device.
Where should I install fire alarm strobes?
NFPA 72’ guidelines state that occupants of a building should be notified by a visual notification appliance, either directly or indirectly. Consequently, you don’t need to be facing a fire alarm strobe light directly, from all possible orientations, at all times. Indirect coverage happens when walls, floors, and furniture receive enough light to warn people in their surroundings.
Fire legislation and legal documents, such as the NFPA 72 and ADA, stand that public areas require the installation of strobes. If so, you should see this type of device in hallways, lobbies, restrooms, classrooms, cafeterias, conference rooms, and other public spaces. In the event of an emergency, a hearing-impaired person should be aware of what is happening, in order to look for the nearest exit.
For sleeping areas, NFPA 72 requires the installation of fire alarm strobe lights with an intensity of 110 candelas, at least 24 inches from the ceiling. In non-sleeping areas, however, you must install strobes six inches from the ceiling. The size of the room determines the ideal number of strobes.
When talking about hallways and corridors, NFPA 72 requires strobes installation in a way that they can be visible from anywhere. The devices must be no further than 100 feet apart from each other and must be within 15 feet of the end of the hallway.
More fire alarm strobe requirements
Considering the height requirements for wall-mounting strobes, the installation should be between 80 to 96 inches above the floor. This standard takes into consideration the typical occupant viewing height.
There is also a parameter for ceiling-mounted strobes, considering that the fire alarm strobe height decreases the candela intensity. Therefore, as the mounting height increases, the minimum compliant candela rating also increases.
For the most effective visual coverage, technicians usually recommend fewer strobes set to a higher candela rating. When setting the strobe placement, the first thing to think about is the layout of the room and any possible obstruction of the light.
Sequentially, you should consider the candela rating. When a room is too big for one device only, it would be best to break the coverage area into smaller squares.
Horn strobes and speaker strobes
Technicians usually use visual and audible notification devices in combination to provide the occupants of a building a higher chance of being aware in an emergency. In this case, many manufacturers offer devices that include both types of notification, such as horn strobes and speaker strobes.
To comply with requirements for both visual and audible notifications, the best protocol is to locate the devices considering the visual requirements first. Once that is done, you can then adapt the devices for audible coverage and intelligibility. To know more about strobes, horn strobes, and speaker strobes, you can contact The Fire Alarm Supplier. We have a wide range of products from the most reliable brands. Just let us know what you are looking for, and we’ll be happy to help.