Heading for the Exits

Photoluminescent egress markings increase the safety and efficiency of emergency plant evacuations.

• By Susan Larson
• Feb 01, 2003

SAFE evacuation of your facility in emergencies such as power outages, fires, natural disasters, or other crisis situations requires advance preparation. The safety of all people in the plant depends on a detailed plan and site preparation, including explicit marking of egress routes.

NFPA and OSHA (at 29 CFR 1910.38) mandate a written plan and procedures and recommend clear marking of exit routes. Other national and local codes, such as California's, may demand more. Plant preparation now avoids serious problems later. Plant managers are finding that photoluminescent signs and markers provide explicit directions for egress, in lighted conditions or in complete darkness, with minimal outlay and maintenance.

The pressure of a crisis situation makes it harder for all of us to think clearly, making on-site instructions even more valuable to plant occupants. Keep in mind that you want to mark clearly what the occupants need to avoid, as well as the safest, most efficient egress route. Long-time employees may be perfectly familiar with your facility's layout, but new employees, contractors, and visitors will require more detailed help. You need in-plant signs and markers to guide people along evacuation routes to appropriate exits, and outdoor assembly points.

Why Use Photoluminescent Markings?
Photoluminescent signs absorb and store energy from normal ambient light in the room, then release this energy in the form of light when the room is darkened. Some new signs incorporating the latest technology glow for 24 hours.

The new photoluminescent materials take advantage of strontium aluminate in their compounds and have better performance. These improved materials glow brighter and longer, making them a fast-growing solution for reliable egress marking. Their value becomes apparent in the case of power outage or fire--especially in smoke-filled areas.

Because photoluminescent markings require no electricity, they have lower installation costs (no rewiring) and no operating cost (no electricity or batteries). They're maintenance-free, saving the time of monthly checks that can be sizeable in large facilities. And their expected life is more than 25 years for some types.

Photoluminescent markings are suitable even in hazardous environments because they will not generate an electrical spark to set off an explosion. They are non-toxic and non-radioactive for environmentally friendly operation and disposal, unlike the older tritium signs that are radioactive, considered hazardous material, and require expensive disposal.

The maritime industry has long, well-developed experience in marking exit routes. Larger ships, with their multiple decks and sometimes complex exit routes, need clear instructions that can be followed in any emergency situation, including complete darkness or smoky conditions. Photoluminescent markings are frequently used to convey instructions and clearly mark evacuation routes and exits. The International Maritime Organization and International Organization for Standardizaton (ISO) have issued several resolutions and standards covering both their recommended application and minimum performance standards.

Shopping for Photoluminescent Signs and Markings
A recommended guide, E2030, from ASTM International (formerly named the American Society for Testing and Materials) addresses use of photoluminescent markings. Used to supplement emergency lighting, mark evacuation routes, and identify exit doors, they can eliminate confusion and help facilitate an orderly evacuation in a time of crisis.

When choosing your signs and markings, look for "Safety Grade" materials. Make sure they at least meet, and preferably exceed, ASTM standards E2072-00/E2073-00 governing luminescent values for safety markings. Some materials perform 10 times longer than the standards require. Look for materials that retain their luminescence for more than 10 hours. Primary exit signs must meet UL924, NFPA 101, and OSHA 1910 requirements.

Get the best-quality markings and signs you can for an assurance of longer life. Compared to your sign cost, your greater costs are in specifying, ordering, and installing the signs, so it isn't cost effective to compromise on sign quality.

For printed floor markings, choose an over laminated polyester for longer life and a non-slip surface. Polyester materials are preferable to vinyl because vinyl gives off toxic chlorine gas when burned. Make sure all markings have industrial-grade adhesives, to prevent skidding.

If you have a diverse ethnic workforce, you may need multilingual signs and signs with pictograms to help clarify the message or instruction. Service temperatures of the products may be important for very cold or warm environments.

Key Marking Tips
Use photoluminescent markings for anything that is important to locate, especially in complete darkness. For example, firefighting equipment, exit route maps, critical shutdown procedures, valves, switches, and exit routes should be clearly perceptible for emergency access. Potential hazards and obstructions along the route also should be illuminated to avoid injuries. Other tips:

• Place "You are Here" evacuation maps at strategic locations throughout the facility for those who are not familiar with the facility layout. Low-location egress pathway markings are effective even in smoke-filled rooms and corridors. Floor-level directional markings make finding a way out simple and intuitive--just follow the arrows.
• Firefighting equipment, and directions to its location, should be clearly marked for fast reaction in an emergency.
• Easy-to-locate exit doors and emergency exits can literally mean the difference between life and death. Just as important, all non-exit doors should be identified to avoid confusion and prevent evacuees from choosing wrong pathways. Highly visible markings on handrails, treads and risers on stairs, and ramps will help prevent accidents in the rush to evacuate.

Planning + Preparation = Prevention
When seconds count, having equipment and pipe shut-off valves properly labeled and visible even in complete darkness can help avert a major disaster. A well-thought-out evacuation plan, combined with clear egress marking, can greatly improve the safety and well-being of your workforce in the event of an emergency. It provides everyone with the means to a way out.

By putting the necessary information where it is needed throughout your plant, you can help to facilitate an orderly, efficient evacuation.

This article originally appeared in the February 2003 issue of Occupational Health & Safety.