Understanding the UL 924 standards
While shopping for emergency lighting fixtures or exit signs, you have probably seen that many products come with a label or description that says “UL 924 listed”. In this post, we’re going to briefly discuss what UL 924 means, what the UL 924 requirements are, and why Emergency Exit Signs and Lights with this certification are encouraged.
What does UL 924 mean?
The Underwriters Laboratory (UL) is an independent testing organization established in 1894 that provides testing and safety certifications for all types of products, components and materials. UL 924 is the Underwriters Laboratory “Standard for Safety of Emergency Lighting and Power Equipment.”
When you see “UL 924 Listed” or “UL Listed”, this means that a product and all of its components have been tested and reviewed by the Underwriters Laboratory, and has been certified to meet or exceed specific safety and fire hazard codes required for all commercial properties in the United States.*
What are the UL 924 requirements?
For emergency lighting to be considered UL 924 compliant, the light fixture must provide illumination for at least 90 minutes in the event of power failure due to an emergency or other situation. This is the time estimated to be long enough for the occupants of a building to safely evacuate in the event of a disaster, especially without any injury that could potentially make evacuation more challenging. In order for the emergency light to remain lit for at least 90 minutes, it must be connected to an internally hardwired backup battery.
In addition to that, it has been determined that the emergency lighting fixture should provide immediate and sufficient illumination in the event that there is a power outage.
Emergency exit signs also come under a similar set of regulations when it comes to UL 924 compliance standards. The hardwired battery backup systems inside exit signs, which provide illumination during power outages, also must provide at least 90 minutes emergency operation. Exit signs and combo units can also be directly connected to the building’s backup power supply. Underwriters Laboratory allows for the color of an emergency exit sign’s letters to either be green or red, and the letters will need to be at least six inches tall, with a letter thickness that measures ¾ of an inch. It should also have 3/8 of an inch in space between its letters.
In addition to all of this, the signs need to have at least 0.06 feet per lamberts in luminance, as well as the ability to be seen from at least 100 feet away. While there are some anomalies to the viewing distance rule, this will only be allowed if the emergency exit sign is marked with what the actual viewing distance is.
Why should you purchase UL 924 listed fixtures?
In short, peace of mind. The UL 924 label means that your life safety product is code compliant nationwide*, and has been thoroughly tested for reliability and performance.
*Except in certain jurisdictions, e.g., New York City and City of Chicago.