Wednesday, November 20, 2013

They’re Not Oxygen Masks!

In the past year, I have run across at least three instances in which a writer incorrectly called the air masks firefighters wear into fires “oxygen” masks. One was in a news report, the other two appeared in novels; all were incorrect. Here’s the latest occurrence from a novel:

“Only then did he remove his [firefighting] helmet, and then the oxygen mask.”

Firefighters use Self-Contained Breathing Apparatus (SCBA) which are similar to the Self-Contained Underwater Breathing Apparatus (SCUBA) many people are familiar with. SCUBA gear is designed specifically for underwater use. Firefighting SCBAs are designed for hazardous environments such as fires. They can withstand high temperatures and a certain amount of day-to-day abuse, but are not suitable for use underwater.

Here’s what SCBAs look like on a couple of firefighters preparing for search and rescue training:

Photo by Robin Widmar. Copyright 2012.
SCBAs utilize air cylinders that are filled with filtered compressed air – regular old air, just like we breathe every day – not pure oxygen. Normal air consists of 21% oxygen, 78% nitrogen, and 1% other gases.

The air passes from the cylinder, which is clipped into a frame outfitted with shoulder straps and belt, through a regulator to reduce the high-pressure air from the cylinder to a breathable level. Air moves from the regulator to a full-face mask, which seals to the firefighter’s face and keeps the good air in while keeping the bad air out. Most of today’s SCBAs use positive pressure, meaning the pressure of the constant air flow also helps to keep contaminants at bay if the mask seal happens to leak.

SCBAs are equipped with alarms that sound when air runs low, allowing firefighters time to exit the hazardous environment. Personal Alert Safety Systems (PASS) are integrated into newer models of SCBA. PASS devices sound a piercing alarm when a firefighter is motionless for a short period of time, alerting others that a firefighter is down and needs help.

That’s the long way to simply say firefighters do not wear oxygen tanks/masks into fires. 

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