Eli5: why do firefighters wear oxygen masks when fighting a building fire, but often not in a wildfire? You’re still breathing in smoke…
In: 483
Pretty sure they do wear mask outdoors when going in close.
They always put masks on indoors because that’s where smoke is the most dangerous as it spreads horizontally and vertically.
We wear compressed air cylinders and positive pressure air masks. They are bulky and weigh about 30 pounds (15kg). The air lasts from 20-45 minutes, depending on the size of the bottle. Most structural fires are shorter events than wildfires but the smoke can be more contained and concentrated, increasing the risk of carbon monoxide poisoning and modern fuels (the stuff in your house) can give off other toxins as well.
I only fought smaller outside fires as a municipal firefighters. I believe some wildland firefighters have special filter masks they wear in heavy smoke, their firefighter gear is also less bulky. Wildland firefighters also have to be more mobile than we do as shifts in the wind can quickly trap them, making SCBA undesirable.
Wildland firefighting includes walking miles while doing things like clearing brush and cutting down trees. Air packs weigh 40-50 pounds. In addition to that wildland firefighters shouldn’t actually be close to fire. It consists mainly of creating brush lines to try and slow/stop the fire. Finally when you’re not in an enclosed space the smoke mostly rises, opposed to in a house where it fills the space.
As a Wildland Firefighter, we simply don’t have any masks.
Fortunately we are outside with lots of oxygen available to us, and smoke will just rise to the sky.
However there are situations where the wind might not be in our favor and we can get smoked out, making it incredibly hard to breath and see. I’ve personally experienced situations like this in grass fires, and it’s hard on The lungs, but ideally, you want to be working the fire in such a way that you can avoid smoke inhalation.
In structural fires you’re in an enclosed area where the fire is sucking all the oxygen out of the air, hence the need for heavy oxygen tanks and masks, that just wouldn’t be ideal for all the walking and laborous tasks we have to do in wildfires, and if the wildfire is big enough to be sucking oxygen out of the air around you, then you wouldn’t even be there in the first place. Big fires require other methods of attack such as water bombers or back burning, but not ground personnel directly attacking it.
Edit: this is coming from central Canada, I’m sure other departments across the world have their own gear but this is my personal experience
Wildland firefighting is a misnomer, there’s a lot less “fighting” than you’d think for those on the ground.
For those on the ground the name of the game is containment. Most wildland firefighters are experts on clearing out 20ft+ wide tracts of forest for tens of miles at a time.
Clearing is more than just cutting down trees/brush, the teams usually have a train of people behind the chainsaws with Pulaskis ripping out any burnable fuel from the topsoil.
Most of the actual fighting is done by water planes and helos. Although there are Smokejumpers who are inserted much closer to remote fires as initial attack crews.
I fought forest fires. A few things.
You’re hiking into wilderness, so you don’t want to carry heavy stuff.
You’re usually a ways from any major flames, cutting fire lines, clearing brush, etc.
You’re outside, so smoke it much less dense and contained. Fires make their own weather, so it’s often windy to dissipate smoke.
A lot of time is spent “hot spotting” to make sure the fire isn’t still burning underground. So there’s little smoke during all that time.
Most simply wear a bandana as a filter.
You do end up blowing soot out your nose for several days after.
Self contained breathing apparatus (SCBA) delivers smoke-free air to the wearer in all conditions. Its purpose is to protect firefighters from fatal atmospheres by providing a constant supply of fresh air.
A tank worn on the back supplies compressed air to a regulator that can either deliver the air on demand with each breath, or delivers air as a constsnt stream.
The regulator feeds a mask which forms an airtight seal around the face, preventing smoke ingress.
Some SCBA systems are designed to deliver breathable air even if the wearer is submerged in shallow water (to a depth of about 1 meter or so).
Practicality
House fires are far more hazardous, are usually contained before firefighters breach, and require shorter times inside the fire itself. Wildfires are worse in every way but the hazardous gas part. Mobility and longevity are more essential against wildfires and a 40-min air tank isn’t going to help if it takes hours to fight.
First, they’re not oxygen tanks, they’re just atmospheric air. Oxygen tanks have the risk of exploding when exposed to fire cause more problems. Structural fire fighters wear air tanks because they’re in a confined space and run the risk of coming across super heated gases and other non-breathable toxic fumes (which might not actually be smoke in some cases). They use the tanks to provide clean air to breath while working inside those confined spaces.
Wild land firefighters, while exposed to smoke, it’s in a far less concentrated form than structural firefighters are exposed to. Some wild land firefighters will wear masks or bandannas tied over their face to help filter some of the smoke particulate out though. It’s also not feasible to easily refill tanks when they’re hiking miles into the wilderness to get to where they work. Typically they also don’t work directly on top of the fire. Their primary objective is to actually just contain the fire more than extinguish it. So they’ll do things like “cutting line” which is basically creating a fire break by clearing all of the brush and combustible material in a line around the fire in a safe distance so that the fire can keep burning upto that point and then put itself out when there’s no more fuel to burn. The areas they do that in, while they might be slightly smoky, aren’t as dangerous as being exposed to concentrated and super heated smoke like you’ll find inside a burning structure.
[deleted]
Latest Answers