Why Are Emergency Exit Signs an Important Part of Building Safety?
Large commercial and residential buildings have one big thing in common. They both have multiple floors, sets of stairs, and exit paths. The ICC created codes that require emergency exit signs and other materials to be used for marking paths to these exits. These items are meant to help occupants of a building find their way out any time lighting fails. This could be during a fire, electrical outage, or a major disaster. Typically, buildings have to have some sort of signs and markings to be in compliance. Over the years, most owners have used signs that run off of electricity in combination with backup lighting. The generators kick on when the power goes out and ensure the backup lighting comes on in the hallways and stairwells so that individuals can find their way out of the building. Past emergencies have proven that this does not always work as planned.
Past Events Trigger the Need for More Reliable Exit Identification
A good example of a common building emergency with unplanned complications involves the 2003 blackout in New York. The high rises were set up to have backup generators. Many of these generators failed in less than an hour from when the electricity stopped. These generator failures occurred for many reasons with the top one being maintenance. Fuel supplies were bad. They were unable to handle the full capacity needed to power the building areas. The additional capacity needed caused them to blow and become non-functional. Electrical failure can occur and in some cases it occurs when other catastrophic events are happening at the same time. This can create panic and confusion that could be avoided if better precautions were implemented.
Buildings were forty stories or higher. If the electricity failed, a large generator was set to power emergency lighting and safety systems. This included stairwells, exit lighting, public address systems, fire panels, and exhaust fans. The buildings immediately went to automatic backup power. Main generators experienced a power surge that created a large voltage drop. This drop made elevators fail and caused people to be trapped in them. Operators could not access the generator which was located on the top floor. The increased load, reduced air pressure, and activated sprinkler heads resulted in the generator overheating and then shutting down. All lighting went out and remaining occupants had to exit the building in complete darkness. There were no luminous stripes, signs, or other visual aids to follow. Occupants stumbled on steps, ran into each other, and complete chaos resulted. People got hurt and the entire situation was far worse than it should have been.
A lesson was learned from this event and many similar ones. Older technology and safety methods are not the best way to keep building occupants out of harms way. Emergency exit signs and visible markings are a must for egress path identification. Previous building emergencies have shown that luminous identifiers are safer. While backup generators and lighting are beneficial and meet building code requirements, in some situations they are not enough. Owners can ensure occupant safety by taking precautions and adding these safety elements to their egress strategy.