John Mittendorf

Stored Energy

When discussing modern personal protective equipment (PPE) and its impact on current fireground operations, would the term “stored energy” sound familiar or result in a strong “say what?” Several months ago, I was accidentally introduced to this phrase, which, interestingly, has remained relatively unknown to most of the American Fire Service. As a result, allow me to use this article as a brief overview of the phrase “stored energy.”

Recently, I was attending a national fire service conference and happened to spot a friend of mine who is employed by a large manufacturer of fabric for PPE. As this friend was not a speaker at the conference, I asked why he was attending the conference. He replied that a firefighter employed by a local fire department had been seriously burned in a recent fire and he was investigating the incident for his company. He then went on to explain the firefighter had suffered third-degree burns to his thighs, hands, and back; and he specifically wanted to inspect the fabric (made by his company) used in the firefighters PPE. My friend then asked me if I was familiar with the incident, and I said, “No.”

My friend then explained the incident as follows:

“The firefighter was semi-crouched at the end of a hoseline in a hallway of a fire in a commercial building while waiting for his partner to ensure there was enough slack in the line to facilitate their advance in the hallway. When it was determined there was sufficient slack and no kinks, the partner then took a position directly behind the lead firefighter. Prior to advancing the line, the lead firefighter bent over to retrieve the attack line. At this point, the firefighter was suddenly aware of being very warm and decided to retreat and exit the building. After exiting the building, his PPE was quickly removed, which revealed that he had sustained third-degree burns to his thighs, back, and the back of his hands. Interestingly, there was no visible burns/damage to the exterior fabric of his PPE.”

At this point, you are probably wondering how a firefighter can receive third-degree burns with no visible damage to the exterior of his PPE. My friend then explained how this happened.

“As the firefighter was semi-crouched in the hallway, the temperature between his PPE and body steadily increased. Because this rise in temperature was not rapid/instantaneous, the firefighter was unaware of the increasing temperature (similar to the familiar story of placing a frog in a bowl with cool water on a stove over a low flame. The frog will ultimately be in serious trouble because the slowly rising temperature goes undetected). When the firefighter bent over to retrieve the hose line, he eliminated the gap (or air space) between his body and PPE, and also minimized the layering of the fabric of his PPE. These actions compressed the fabric of his PPE, while simultaneously drawing his PPE tight against his back, thighs, and hands, causing third-degree burns to these areas.”

My friend went on to explain that there was no visible damage to the exterior of his PPE, but visible damage occurred to the inner fabric layer of the PPE.

I then asked the following questions:

How many PPE manufacturers are aware of this problem? Answer: “All of them.”
How long have the PPE manufacturers been aware of this problem? Answer: “About three to five years.”
Why has there been a lack of information on this problem/subject in the fire magazines/journals? Answer: “Good question.”
What is the solution or answer to this problem? Answer: “Currently, there is not a definite solution. PPE could be cut tighter, but that would be unacceptable for freedom of movement for personnel.”

So in conclusion, is there an answer to this story? From this author’s perspective, this story is another subtle warning that the modern firefighter needs to be aware of the following factors:

The fireground of 2003 is vastly different than the fireground of several years ago. Consider that building construction offers less fireground time than yesterday.
The thermal layer of today is primarily a result of fire involving synthetic materials (plastics) instead of conventional materials (wood, wool, paper, cotton, etc). This translates into an environment that can flash and burn two to three times hotter and faster than the fire environment of yesterday!
Modern protective equipment is very good. Stated from another perspective, it is very, very, very, good! In fact, it is so good that it can easily mask common fireground indicators and give a false sense of security, allowing a firefighter to either remain in a fire environment for a longer period of time or rapidly advance to the seat/area of a fire.

Therefore, a wise firefighter will constantly evaluate his fireground environment and not solely depend on his protective equipment as the only source of feedback/information regarding the changing environment. Before entering a fire environment, consider the following method to evaluate your “length of stay” and determine appropriate actions:

First, before entering a structure, determine the interior conditions. This will give you a “baseline comparison” to refer to. So, five, ten, fifteen minutes later, the environment will either be worse, the same, or better.
Secondly, always consider the “3-strike rule” as follows:

Do you have smoke with heat? Cool smoke offers a low chance of flashover, and smoke with heat is more likely to flashover.

Do you have less than acceptable visibility? What is your definition of acceptable visibility? My definition is “your ability to get out of the structure in a timely manner”! So, if visibility is minimal or nonexistent and you are not happy with the environment that you are committed to, ask yourself, “How is my ability to get outside in a timely manner?”

Your environment is not improving! This consideration is dependent upon you developing a baseline before (or as) you entered the structure. If you developed a baseline that can be used for comparative purposes, then you should be able to determine the status of your present environment compared to the environment that was present when you entered the structure. Either it is better, the same, or worse. So, if you are in a hot environment that has not improved (or is going downhill) and you are not sure of your exit point, you should start thinking about your length of stay in the structure!

In conclusion, remember to use your PPE as a defensive weapon, not an offensive weapon, and continually monitor your fireground environment. Do not allow your PPE to give you a false sense of security.

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