It is very important for firefighters to understand how their personal protective equipment (PPE) protects them from burns, and it is crucial to know its limitations. Ironically, the insulating properties of modern PPE mask the most reliable indication of impending burns: heat. Firefighters wearing state-of-the-art PPE can be exposed to dangerous levels of heat for a few seconds without feeling a thing, provided that the gear is dry and there is no exposed skin. This begs the question: How deep can firefighters penetrate into dangerously hot conditions before they realize that they are in trouble? Since PPE absorbs heat, another way to phrase the question is, how much heat can firefighters’ PPE absorb before it starts to burn from the inside out?
Thermal Saturation: The “Empty Glass” Analogy
Oakland (CA) Fire Department Captain (Ret.) Dennis LeGear teaches firefighters the limitations of PPE with this analogy: Consider that a firefighter’s PPE is an empty glass. As soon as he enters a heated environment, his PPE begins to absorb heat, signified by pouring hot water (energy) into the glass. As the firefighter moves down the hallway closer to the fire, more heat is absorbed, and more hot water is poured into the glass. Once the firefighter feels the heat and starts to squirm to change his position, most of the glass is full of hot water. He doesn’t realize his glass is about to overflow, rapidly.
Once he reaches the fire compartment, he is hit with a blast of radiant and convective heat, his PPE has reached the point of thermal saturation, and his glass overflows. Heat has totally saturated the outer shell, the vapor barrier, the thermal barrier, and the firefighter’s station uniform. At this point, any additional heat absorbed is transferred directly to his skin, which, at 125⁰F, will cause full thickness burns in as little as 30 seconds. Now, with pain and panic overriding rational thought, the firefighter dives over other firefighters in the hallway to escape his perilous situation.
PPE Inspection and Cleaning
Inspect for damage and thermal degradation of any PPE that is subjected to extreme temperatures. How well PPE protects firefighters is directly related to its moisture content and cleanliness. Ideally, firefighters would “bag and tag “their dirty, wet gear and change into their second set.
The most vulnerable component of an SCBA is the lens of the face piece. Although lenses of modern SCBA can withstand more heat than older models, they will still start to develop small cracks and soften when exposed to temperatures at or above 280⁰F. Additional heat exposure can result in holes developing in the lens.
“I’m Burning!”
On his first day out of the fire academy, a probationary firefighter responds to his first structure fire, and he is assigned to the nozzle position. This new firefighter’s “baptism by fire” is challenging, but he is looking forward to the challenge. The fire is in a well-involved wood-frame house. This is a perfect opportunity to prove himself to his officer and crew.
On returning to quarters, his officer notices that the probie has sustained a deep second-degree burn to his knee. When the officer asks him, “Why didn’t you tell me you were burning?” His reply is that he didn’t want the reputation of backing out of his first fire.
The following are takeaways from this incident:
- Officers, realize that personnel can be in physical contact with each other and receive different levels of heat. For example, a nozzle firefighter may shield the officer directly behind him from radiant heat. Conversely, the officer may be in a position that compresses his PPE, reducing the air gap in between layers of his PPE, his station uniform, and his skin. As a result, he gets burned while the nozzle firefighter does not. Additionally, improperly donned hoods or gloves can leave skin exposed, resulting in burns at relatively low temperatures.
- Officers, encourage crew members to advise you when they are burning. Remember, it will only get worse as their PPE becomes closer to saturation. You will be the one filling out the injury report for their burns, and it may result in an investigation.
- Firefighters, don’t hesitate to advise your officer and crew members that you have to back out because you are being burned or having problems with your SCBA.
Stay Low
Before hoods and ear flaps, firefighters didn’t hesitate to get as low as possible to avoid the heat. The motivation? Extreme pain from burning their ears and neck. Back in the 1970s and early 1980s, large blisters on the ears and neck were accepted as the price you paid for an aggressive interior attack.
Today, firefighters, insulated with a hood and ear flaps, don’t immediately feel the pain. Additionally, firefighters using thermal imaging cameras (TICs) can be burned if they use them improperly. With TICs, firefighters don’t have to get low to see under the smoke and, consequently, can expose their heads and upper bodies to the thermal layer above the floor. Remember, get low enough to see your feet.
Avoid “Death on the Nozzle”: Slow Down, Assess Conditions, and Cool the Overhead
At a vacant house fire, firefighters narrowly missed serious injury as a result of being caught in a flashover. The house was very small, with boards covering the doors and windows. Like racehorses at the starting gate, these undisciplined firefighters were eager to rapidly advance their hoseline the moment the front door was forced open. As a result of their haste, they did not feel the heat in their PPE until it became saturated, causing them to bail out of the house. Imagine the embarrassment of going to the hospital for burns in a ridiculously small house.
On entry, disciplined firefighters take a moment to perform a three-level scan with a TIC; determine the height of the neutral plane; and, if they can, determine if they are in the intake or exhaust of the fire. Firefighters feeling heat in their PPE should never hesitate to open the nozzle and cool overhead. No fire department should experience “death on the nozzle” —the loss of firefighters on a charged hoseline. The days of not opening a nozzle until you encounter fire are long gone.
Searching Without the Protection of a Hoseline
Years ago, fires would reach the decay stage because they ran out of fuel (consisting of “legacy” materials, wood, wool, cotton, and steel coil springs in upholstery). As a result, fires in legacy contents took almost 30 minutes to reach flashover.
Today, just about all the contents of a modern American household consist of synthetic petrochemical-based materials (plastics) that can reach flashover in four minutes. Today’s fires are not going to take a “time out” while firefighters search for occupants. Petroleum-based materials burn with a voracious appetite for oxygen, resulting in fires rapidly becoming “fuel rich” with flammable fire gases but with insufficient oxygen. Firefighters entering a structure to perform a search may bring with them sufficient oxygen to transition a fire to flashover.
The Miami-Dade (FL) Fire/Rescue Training Division is training ladder and medic-rescue companies in TIC-directed search. A fundamental component of this training is to stress the danger of searching without the protection of a hoseline. This is not to discourage companies from doing so but to teach why it is crucial to conduct search operations in accordance with a continuous risk-benefit analysis and a constant awareness of fire conditions.
When Engine Companies and Companies Performing Search Operations Arrive Together
Engine companies have a critical mission in search and rescue operations: advance a hoseline to achieve control of the fire. The engine company protects occupants and the firefighters searching for them. Additionally, the engine company can search the immediate fire area and along the hoseline. It is crucial, however, to keep the nozzle firefighter on the nozzle to provide orientation for crew members and to control any flareups. Once fire control is achieved, firefighters can aggressively search areas beyond or above the fire with greater confidence, knowing that they are protected. It is critical however, that firefighters searching above a fire inform the engine company before they ascend because their safety depends on the engine’s ability to control the fire. Accordingly, the incident commander and companies operating above the fire floor must be notified immediately in the event that anything interferes with the engine’s ability to maintain control of the fire, such as a burst length of hose.
“Salty” Gear Is No Longer a Badge of Honor
Up until recently, soot-stained turnouts and heat damaged helmets were admired. Young firefighters couldn’t wait to “season” their new PPE. Dirty, heat-damaged gear smelling of smoke was a sign of a “salty” firefighter who fought a lot of fire. Some of the favorites were melted flip-down eye shields as seen in photo 1 and molten asphalt stains on light-colored turnouts and yellow helmets. Fortunately, those days are over.
1. The firefighters wearing these heat-damaged helmets may have nothing to be proud of. Investigate burned PPE. It may be an indication of improper or overly aggressive tactics, such as firefighters moving toward a fire too quickly without assessing conditions, failure to stay low, or not opening the nozzle to cool the overhead. (Photo by Eric Goodman.)
Today, dirty turnouts and heat-damaged helmets are no longer admired; in fact, they may be considered a sign of ignorance. Investigate incidents of burned firefighters and PPE to determine the cause and how to prevent them; do not automatically dismiss them as the cost of doing business.
Bill Gustin is a 51-year veteran of the fire service and a captain with Miami-Dade (FL) Fire/Rescue. He began his fire service career in the Chicago area and is a lead instructor in Miami-Dade’s Officer Development Program. He is a technical editor of Fire Engineering and an advisory board member of FDIC International. He is the recipient of the 2024 Fire Engineering/ISFSI George D. Post Instructor of the Year Award.
