Purelux Catalog 2018

emergency lighting 101
Legal requirements and guidelines
It is important to be aware of legal requirements before undertaking an emergency escape lighting design. Two main instruments are of
interest to emergency lighting:
> The occupational health and safety act (OHS Act)
> South African Bureau of Standards (SABS) specifications
The OHS Act (85 of 1993), and act of parliament basically states that it is illegal not to have emergency lighting in the work place in areas
where failure of the normal mains supply may present a danger through low visability.
The compulsary specification (VC 8055) has been issued that calls various safety standards (including SANS 1464 part 22) making it illegal
for emergency lighting products not to comply with certain levels of safety and performance. Interestingly, because the emergency lighting
forms part of safety equipment, it must not only be designed to prevent shock or a fire hazard, it must also provide correct lighting
levels, lighting duration and other technical levels of performance.
The SABS offers internationally acceptable design guidelines to ensure the functionality and, probably more importantly for cash strapped
budgets, cost effectiveness of an emergency lighting solution.
In the event of an emergency, the emergency lighting systems must provide continuous illumination for a minimum of 90 minutes to allow
the occupants to safely exit the building. Emergency lighting systems must meet stringent criteria for construction and performance
against the occupational health and safety act (OHS Act). However, even though emergency lighting systems must meet these standards,
not all systems are created equally. There are applications in which certain systems should not be used. The mounting height, light source
and environment are very important to consider during installations. Some environmental issues to consider are temperature, dust, damp
or a wet location and a hazardous area.
The OHS Act requires an average of 1foot-candle upon initial illumination of the emergency light, and an average of not less than 0.6
foot-candle after a 90minute illumination period. Keeping that in mind, the proper choice of unit must be made to meet the foot-candle
requirement. The unit source of the unit used in an office with a mounting height of 7 - 9 feet will not work in a situation where the emergency
light is mounted 18 feet above the floor.
Many emergency lighting systems have lead acid batteries. These batteries generally have a 5 - 7 year life expectancy as long as it is
maintained in an operating temperature range of 60 - 80°F. As the temperature increases above 80°F, the life of the battery decreases dramatically.
When the temperature decreases, the battery life will increase, but the run-time of the battery will decrease, thus not allowing
the system to maintain the required 90 minute illumination. The sealed Nickel Cadmium maintenance-free battery is an alternate option
when it comes to temperature. These batteries offer a 12 to 15 year life with an operating range of -4 to 158°F. There are also re-fillable
lead acid and Nickel Cadmium batteries. These batteries require maintenance, but are great batteries to consider for temperature issues.
The lead acid battery has an expected life of 8 to 12 years if maintained in an operating environment of 32 to 105°F. The Nickel Cadmium
battery will have a life of 20 to 25 years, with an operating range of -22 to 140°F.
There are emergency lighting units that are specifically designed for dusty, damp and wet environments.An installer can not place any unit
into these situations and expect them to function as designed. Standard metal emergency lighting units will allow moisture and dust into
the enclosure. There have been situations where this has occured and the result is a shorter printed circuit board because the moisture
accumulated and dripped on the board components, or the dust from a metal grinding operation accumulated over time in the enclosure
that created a connection between components.
Hazardous environment units are again designed for their particular applications. The NEC developed Classes, Divisions and Groups for
these situations. Class I refers to areas where inflammable gases or vapours may be present in sufficient quantities to produce explosive
or flammable mixtures. Class II units are for areas where combustable dusts are present. Class III systems are for areas where ignitable
fibers are present in sufficient quantities to produce ignitable mixtures. Division I indicates an area where the hazardous condition is normally
present either continuously or periodically. Division II are areas where the hazardous condition is present due to accidental rupture,
breakage or unusual faulty operation of a dosed container or system. The groups are broken down by particular categories based on class.
Under Class I, Group A is for Acetylene, Group B for Hydrogen, Group C for Ether, Group D for Gasoline. Class II has Group E for Metal Dust,
Group F for Coal Dust and Group G for Grain Dust.
Emergency conversions are available for most Purelux luminaires. The advantages of using our fittings with factory fitted emergency
lighting equipment include the peace of mind that comes with the guarantee that applies to the entire luminaire and factory fitted units
installed under our quality assurance systems meeting the requirements of ICEL, BS and EN standards.
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