Updating Emergency Plans
Emergency plans must be reviewed at least annually. The next time you review yours, pay attention to details, especially those sections that may have been lifted from templates or other sources.
I recently reviewed plans from four different workplaces, and found at least one common problem with each. When I pointed out the section to the clients, each confirmed that it had been part of the template they used, and they had accepted it at face value. Chances are, you’ll find it in yours as well.
The passage usually goes something like this:
“When evacuating a smoke-filled room, crawl or stay as close to the floor as possible and move quickly to the nearest exit.”
Great advice.. for 1960.
In the modern workplace, remaining close tothe floor is just as dangerous as standing upright when traversing a smoke filled environment. Back when that statement was first published, office furniture was primariy made of wood or other similar material. When burned, the smoke and heat rose toward the ceiling, leaving clean, breathable air along the floor.
In the modern office, the majority of furnishings and contents are made of plastics, polymers, foam rubber and other similar materials. When these materials are burned, heavy smoke is generated that rises with the heat towards the ceiling- just like the older wood furnishings. The twist here is that smoke is only part of the problem.
Burning plastics and other similar material also produces another dangerous by-product- deadly gasses such as cyanide. Other toxic chemicals released during burning include nitrogen oxides, sulfur dioxide, volatile organic chemicals (VOCs), and polycyclic organic matter (POMs), carbon monoxide, methyl methacrylate, butyl acrylate and aldehydes. Burning plastic (such as PVC) and treated wood may also release heavy metals and toxic chemicals such as dioxin.
Most of the gasses released by these materials in a fire are heavier than air- they sink rather than rise. They are also invisible, unlike smoke, so those evacuating would not normally be aware of their presence as much as they wold be of the smoke overhead. The problem with the instruction to “crawl or stay as close to the floor as possible” should be apparent.
Studies conducted by UL and others have determined that the level of these heavy gasses during the first few minutes of a fire – the period during which an evacuation would be taking place – is usually between 24-30 inches above floor level. Two to two-and-a-half feet.
The “danger zone” for the hot air and smoke above is harder to determine, since there are several factors involved that are location specific. Height of the ceiling, type and condition of ceiling tiles (if present) are facors that affect the location of the lower limit of this hazard.
Generally speaking, the “good air” that evacuees should remain in while leaving the area can be found approximately waist to chest level (3 to 4 feet above the floor). Obviously, this is a general statement. People come in different heights, so being specific isn’t very practical.
The annual emergency plan review should always be followed by reminding employees of the evacuation procedures in case of a fire. By explaining the concept of “finding the middle ground”, each employee will have a better understanding of where the good air is, and will be able to safely and quickly evacuate while avoiding the danger zones above and below.
Central Florida Safety Academy