The following will provide, courtesy of GloBrite Systems, how weatherproof exit signs need to be operated and maintained in order to keep within OSHA (Occupational Safety and Health Administration). In general, weatherproof exit signs should only need to be replaced every eight to ten years (considered optimal lifespan). However, some users of exit signs will place indoor exit sign models outdoors, causing these exit signs to degrade much faster due to the exposure of harsh weather elements, such as extreme heat, snow, heavy wind, and rain. Those organizations in practice of this unsafe usage of exit signs need to invest in weatherproof exit signs, which are designed and built for such purposes.
Similar to all exit sign fixtures, weatherproof exit signs placed in wet locations must remain lit at all times so personnel can follow egress points to a safe location at all times in the event of an emergency. Weatherproof exit signs need to be able to light brightly for at least ninety minutes after power expires.
Features of Weatherproof exit signs include the ability to be hermetically sealed, constructed with complete weatherproof design and functionality, LED units must consume less than five watts of electricity daily, push button backup battery testing ability, listed on the UL 924 mandate for approved components, and provided with a minimum five year warranty. Weatherproof exit signs can be employed in exterior locations exposed to extreme heat, arid conditions, rain, sleet, snow, cold weather conditions, and heavy wind. Weatherproof units may be fitted with an internal battery heater for freezing or below freezing conditions.
External specifications include the implementation of a corrosion resistant ABS (Acrylonitrile Butadiene Styrene) plastic housing and a clear polycarbonate faceplate to protect the lettering of the exit sign. The faceplate needs to be shatter resistant and lined with a gasket to form an airtight seal when fastened. Internal specifications include either green or red color lettering (you can specify which style you prefer when ordering) that is lit by LED (Light Emitting Diode) strips that consume less than five watts of electricity each day. The internal nickel cadmium (NiCad) battery should be able to power the exit sign for at least ninety minutes after external power expires.
Electrical specifications include a 120 to 277 volt connection, which can be customized to 220 and 240 voltages if necessary, an alternating current lockout component to prevent battery discharge, and a low voltage disconnect component to protect the battery during lengthy discharge periods. Code compliance for weatherproof exit signs must include UL 924 – the exit sign is placed in or near a damp location, CS860, the NFPA: Life Safety 101, and NEMA 4x – rated for all weather conditions.
For weatherproof exit signs with battery backup, OSHA requires it tested at least once a month, without fail. This diagnostic is performed by way of a sealed test switch. Backup batteries should be drained and refilled every six months to extend its lifespan.