Photoluminescent (PL) egress systems are non-electric, illuminated routing markers that provide an intuitive path that can be easily followed during an emergency evacuation of high-rise buildings, stadiums, arenas, medical facilities, hotels, multi-story buildings, parking garages and more. They played a key role in aiding survivors during the 9/11 World Trade Center attack by providing a lighted evacuation route when all power was lost. PL systems are now considered critical components in an effective egress system. Here are the top five things you need to know about PL today:
The notion PL products might someday qualify as an emergency electric lighting alternative demonstrates the technology has come a long way. 25 years ago the convention of PL was copper-activated zinc sulfide. Today, most modern PL products use the patented phosphorescent chemical, strontium aluminate oxide. It is ten times brighter and lasts ten times longer than its predecessor. The PL pigment is charged by storing light photons from natural or artificial light. It then slowly releases the charge as light emission (or “glow-in-the-dark”) over extended periods of time. It can continually be charged and recharged by light sources without loss in performance. PL systems are now considered critical components in an effective egress system as they instantaneously glow bright enough to lead occupants out of a facility when light sources fail.
2) Tested to standards
The glow duration and brightness of PL products depend on the length and intensity of the light exposure. For this reason, the International Building Code (IBC) has adopted two test standards to set the bar for performance of PL products in egress applications. Products must meet either Underwriters Laboratories (UL) 1994, Luminous Egress Path-marking Systems, or ASTM E2072, Standard Specification for Photoluminescent (Phosphorescent) Safety Markings. These standards dictate the brightness and exposure time of the charging light, the decay time once the charging light is removed, and the performance expectations of the product at the end of this time. Though they differ slightly, both standards require a 60-minute exposure to an 11-lux (1-footcandle) light source and a 90-minute decay time.
3) Required by building codes
Important building code sections requiring PL exit path markings are:
- International Building Code (IBC) 1023. 9, “Floor ID Signs” – Photoluminescent stairway identification signs shall be included in interior exit stairways. This is effective from January 2009.
- IBC 1025, “Egress Path Products” – Photoluminescent markings shall be provided in interior exit stairways of building types A, B, E, I, M, and R-1. This section became effective in January 2009.
- National Fire Protection Association (NFPA) 101, Life Safety Code, and 5000, Building Construction and Safety Code, Sections 18.104.22.168.5, “Exit Stair Path Markings” and 7.10, “Marking of Means of Egress.” – Effective from January 2009, the section makes photoluminescent exit stair path markings optional for all buildings, new and existing, regardless of height.
- California Building Standards Code (CBSC), Chapter 10, “Means of Egress in Group A, E, I, R-1, R-2, and R-3” – Required in occupancies in exit corridors leading to emergency exit stairwells. This was made effective in January 2008.
- General Services Administration (GSA) P-100, Facilities Standards for the Public Buildings Service, Section 7. 8, “Exit Path Markings” – Required in all new and existing buildings, and effective from March 2005.
In 1993, the World Trade Center bombing provided a sobering indication that electrical systems alone were insufficient because the building’s emergency lighting system was damaged, impeding egress for occupants. It became clear egress routes needed to be designated with markings not reliant on external power sources. Consequently, the World Trade Center was one of the first facilities to employ PL as an egress path marker in the late 1990s following the advancements in PL technology. On 9/11, 2001, the World Trade Center attack put the PL system to the real test. Survivors listed the PL markings as one of the top three things that helped them exit the building safely. In contrast, at the Pentagon where PL demarcation was not yet in use, survivors reported difficulty exiting. (See A Brief History of Photoluminescent Markings). The events of the 9/11 attack are what prompted a number of PL installations and requirements for the material in building codes.
If people are to exit a building safely years after PL products have been installed, then the durability of the specified product has a major impact on occupant safety. Unfortunately, life-safety products are often downgraded as a part of larger efforts to reduce total project cost. While looking for cost-saving opportunities is good from a project management standpoint, it should never compromise a building’s life-safety systems. For example, the use of products that wear much quicker under foot traffic, such as tape or film, can result in worn or missing markings, which leaves the intended PL egress pathway poorly defined and subject to a potential code violation and liability. In contrast, coated aluminum strips provide a much stronger, longer-lasting marking system for the daily abuse of foot traffic applications. Quality path markings are an essential aspect of every egress system, because they help ensure code-compliance, promote the safe egress of occupants during power loss and provide an overall peace of mind.
Find out more about Balco’s complete PL egress product line, IllumiTread™.