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Under emergency conditions, its important to evacuate a building as quickly and safely as possible. In the absence of interior lighting due to an interruption in the normal power supply, the NFPA 101 Life Safety Code calls for illumination of the egress pathway using an emergency lighting source. Specific designated egress pathway areas are targeted for emergency illumination - stairs, aisles, corridors, ramps, escalators, walkways, and exit passages.
These designated egress pathways, along with appropriate directional egress markings (exit signage), are intended to safely guide and direct building occupants to the "public way".
The NFPA 101 Para. 3.3.193 defines "public way" as:
"A street, alley, or other similar parcel of land essentially open to the outside air deeded, dedicated, or otherwise appropriated to the public, for public use and having a clear width and height of not less than 10ft (3050 mm)."
Deciding what is, or is not, the "public way" is a question that continually puzzles lighting designers, electrical contractors and building owners. Could it be the area first encountered when evacuees pass through the last designated building "exit way", or is it located some undefined distance away from the building?
Code Interpretation
Ultimately, it is up to the local authority having jurisdiction (AHJ) to interpret the code and determine what and where the public way actually is. This is a challenge for manufacturers. If all inspectors interpreted the code similarly, it would be simple to create a single, catch-all solution. Since interpretations vary wildly, Hubbell Lighting Inc. has responded by creating various solutions to capture a variety of applications.
Even though the final decision rests with the AHJ on what the public way actually is, one thing, however, is clearly defined: the requirement for an emergency lighting source now includes the building exterior as well as the interior.
Interior vs. Exterior Considerations
Incorporating emergency lighting inside a building's conditioned space is fairly straight forward.On the other hand, emergency lighting on the exterior of a building is exposed to extreme temperatures and wet weather conditions such as rain, sleet, and snow.
Keep in mind when considering an emergency lighting product for a building exterior:
- Temperature negatively effects both battery life and capacity.
- Elements such as rain, sleet, and snow can damage the batteries and electronics of a unit.
Related Literature
Solution 1
Remote Lighting Heads
Indoor emergency lighting or combination units with remote capacity that power outdoor remote heads.
Solution 2
Outdoor Emergency Lighting
Outdoor, wet location listed emergency lighting unit with optional battery heater.
Solution 3
CFL Outdoor Lighting Fixtures
Simple single fixture solution from Hubbell Outdoor, Kim Lighting or Dual-Lite. Temperature range to 0°C.
Solution 4
Bollards, Outdoor Lighting
Solutions from AAL with no temperature constraints.
Solution 5
Normally On LED Sconce and Decorative Remote
Normally on operation powered by line voltage (120/277VAC) and/or emergencyoperation powered by a remote 6 or 12V DC source such as an emergencylighting unit or combo unit with at least 12 watts of remote capacity. Low profile housing available in four powder coat finishes; platinum silver, black, dark bronze or white..
Solution 6
Central Lighting Inverters
This solution from Dual-Lite provides the highest light output over a large area and centralized maintenance while keeping the attractive appearance of the lighting design.
