So, How do firefighters keep cool? With the extreme heat experienced inside a structure fire and the layers of protective gear firefighters must wear, how do firefighters not overheat? What about if it’s 100 degrees out?
Firefighters keep from overheating by wearing the proper protective gear when firefighting. They also have guidelines to make sure they manage how much time they spend exposed to high heat, as well as a rehab protocol to re-hydrate and recover from the heat stress.
How hot does it get in a fire? Is firefighting gear fireproof? How long do firefighters stay in a fire? What is the firefighting rehab protocol? Can firefighters get heat stroke? We have some interesting information answering these questions below.
Firefighting Personal Protective Equipment
In order for a firefighter to be able to withstand the heat of going inside a structure fire, they must have the proper personal protective equipment (PPE).
Firefighters PPE is usually referred to as “Bunker Gear” or “Turnout Gear” in the U.S. and as a “Fire Kit” in the U.K. and Ireland. Despite what you have seen in the movies, firefighter turnouts have a limit to the amount of heat they can protect the firefighter from.
The technology has come quite a long way with firefighting protective gear; the equipment that firefighters use today is more comfortable and breathable while offering more heat protection than ever before.
In order for these turnouts to do their job, they are built with three different layers that work together synergistically to allow the firefighter to do his or her job. These layers are the Thermal Liner, the Moisture Barrier, and the Outer Shell.
The Thermal Liner is the innermost layer, closest to the wearer and is the layer that provides most of the heat protection (hence the name).
Together with the moisture barrier, the thermal liner provides about 75% of the thermal protection (protection from heat) of the complete turnout coat or jacket. This layer is designed to trap air in between the quilted material, which acts as insulation from the heat. (This is similar to how a thermos works).
The Moisture Barrier works to protect all the inner parts of the gear (and the firefighter) from water, chemicals and infectious agents (germs). This layer is more at risk of being damaged than the others and needs to be inspected frequently.
Lastly, the Outer Shell is what you see when someone is wearing the gear. It uses material like a Nomex/Kevlar combination to offer resistance to direct flames (not fireproof, but should not catch fire unless under extreme conditions). Though it only provides 25% of the thermal protection, it shields the inner layers and allows them to work effectively. It also protects from scrapes or cuts and usually has beefed up padding in the knees.
Together, these three layers of the turnout coat and pants allow the firefighters the protection they need to do there job. Firefighters also wear boots, protective “flash hoods”, helmets, gloves and air packs with face masks (SCBAs) to have complete coverage of all skin.
This is crucial for being able to withstand the heat of a structure fire. The turnout pants are usually folded down over the boots, so when the call comes in, the firefighter can step into the boots and pull up the pants very quickly.
FUN FACT: Turnouts are named due to firefighters rolling them down over the boots or “turning them out”. Bunkers got the name as they used to be kept right by the firefighter’s bedside (Bunk) for quick access (This is no longer common practice as the chemicals from smoke can off-gas after they are exposed and are not good for firefighters to breath)
Firefighting protective gear helps and hurts firefighters when it comes to heat stress or overheating. While it offers protection from flames and thermal protection from the outside heat, it also traps body heat inside, as well as fluid loss, which can cause overheating very quickly.
But it is obviously very necessary for firefighters to wear their PPE, so they must use other methods to prevent overheating.
How Hot Does It Get in a Structure Fire?
When we go into fires, we carry a camera that sees differences in heat (called a thermal imaging camera or TIC). It also has a readout that will tell you the temperature of the area you point it at.
I have personally seen readings of 900 degrees F at the ceiling (the hottest area in any fire in an enclosed space, because heat rises) during training fires. I’m sure others have seen even hotter temps.
Now it maybe 900 degrees at the ceiling but on the floor, it might be 350 degrees. That’s one of the reasons firefighters stay low and crawl. So the firefighters aren’t directly exposed to the 900 degrees (you can tell when it’s too hot cause everyone gets really low and it may be time to back out). But even at 200-300 degrees, that puts a ton of stress on the firefighters. The temperature inside the turnouts can be up to 160 degrees!
In the Fire Service, there are regulations and protocols set up to protect firefighters from heat stress.
These procedures can vary, but the goals of firefighter rehab, based on NFPA (National Fire Protection Association) standard 1584, are:
- Relief from the temperature and conditions of the fire
- A chance to rest and recover
- Active (using fans, water, ice packs) or passive cooling (depending on the severity of the conditions as well as outside temperatures) to return body temps back to normal
- Re-hydrating and electrolyte replacement (turnouts and fires cause you to lose fluid and electrolytes very quickly)
- Medical monitoring (a procedure to check vital signs and make sure personnel are good to go back to work)
In my department, when working at a fire, once you go through 2 air bottles (each bottle usually lasts 15-35 minutes during hard work), you must go to the firefighter rehab area. This procedure is put in place to protect firefighters from overheating. It allows a chance to cool off, rest and get some water so that you can go back to work without getting yourself or someone else hurt.
Here is a video of firefighters in Arizona discussing how they rehab from the heat:
When exposed to heat, the body can become stressed and firefighters are especially susceptible. These are the things that can happen if firefighters don’t manage the heat they are exposed to properly. There are three types of heat stress, in order of severity, they are: Heat Cramps, Heat Exhaustion and Heat Stroke.
Heat Cramps are just muscle pain or tightness (like any other cramps) but they are brought on by heat.
Heat Exhaustion is the next level of heat stress. It can include: headache, dizziness, extreme thirst, rapid heart rate, nausea, pale skin, and heavy sweating.
With Heat Stroke, the individual can be confused, have temperatures over 104 degrees F, dry skin, seizures, or even lose consciousness (pass out).
As you can see, heat can be a very serious concern for firefighters and must be managed appropriately (including medical monitoring) to prevent overheating and injury.
What Is the Leading Cause of Firefighter Injuries?
According to a National Fire Protection Association (NFPA) report in 2017, the leading cause of firefighter injury on the fire-ground (not at the station) was overexertion (29% of all fire-ground injuries). The overall leading cause of injury was muscle strains and sprains (56%). https://www.nfpa.org/News-and-Research/Data-research-and-tools/Emergency-Responders/Firefighter-injuries-in-the-United-States
How Heavy Is a Firefighter Suit?
A complete set of firefighting protective gear (including turnouts, boots, helmet and SCBA (air pack)) weighs 35 to 60 pounds. Added tools and equipment may increase the weight that must be carried.