In recent years, health and safety experts in the fire service have increasingly begun to explore the role of heat stress on firefighters, and how it contributes to line-of-duty deaths from cardiac arrest. Most of this research, however, has focused on the conditions firefighters face on the fireground.
But what about in the training academy? After all, an instructor in charge of live-burn training is repeatedly exposed to heated environments. Do such conditions increase their risk for adverse health effects?
Fire service leaders in Sweden have studied that exact question–and changed their training practices as a result of what they found. One of those studying this issue is Dr. Stefan Svensson. As he puts it, Svensson is “a scientist with a day job, but I’m more firefighter than scientist.” Currently, he works for Lund University, but he has been working for the Swedish Civil Contingencies Agency for 22 years, which he describes as a combination of FEMA, NIST and a fire academy. Svensson is also a 27-year fire service veteran, currently serving as a part-time firefighter at the battalion chief level. His PhD is in fire science, and he’s also an associate professor.
We recently spoke with Dr. Svensson to get his perspective on the effects of live-burn training on instructors, and how this might influence U.S. training practices.
FireRescue magazine (FRM): How much exposure does the average Swedish fire instructor get to hot environments?
Dr. Stefan Svensson (SS): That is a very hard question. An average instructor at a fire brigade would probably not get as much exposure as some of the instructors at one of our national fire academies. To put a number to it, I would say that an average instructor at a fire academy would probably get about four to six hot sessions in a day, and that each session would be anywhere between 30 minutes and an hour. This includes everything from preparing a session (adding fuel, putting dummies in the training facility and setting the fire) to addressing the students (teaching, supervising), adding more fuel and finally closing the session. On a hectic week, this means that an instructor could have as many as 30 sessions. Some of the sessions might very well be really hot and really tough. And these instructors do this several weeks every year.
Also, it should be noted that these sessions might be anything from being inside a flashover container, to nozzle training in a training facility where radiation from the flames is really high, to following the students during their training in an environment that’s 175—300 degrees F and where humidity also might be very high.
Instructors at a fire brigade might get just as much exposure, but not as frequently.
FRM: What’s the basic problem with repeated/prolonged exposure to heated environments such as those found in live-fire training?
SS: There are several problems with it. However, it seems as if the loss of liquid from sweating is the largest problem. This loss of liquid affects several functions in the body, such as creating imbalance within and between cells. In addition, being exposed to heat raises the core temperature of the body. Basically, this is similar to having a fever several times every day. And I guess most of us know how it feels to have a fever and what this does to the body.
FRM: What are the symptoms of over-exposure to heated environments?
SS: The human body is a fantastic mechanism, but it’s also very complex. Most bodily functions affect each other in different ways. However, some very simple and easy-to-detect symptoms are increased rate of pulse, increased rate of breathing and increased volume of each breath. To Scandinavians, these are well-known symptoms; we experience them just by sitting in a sauna. If you add hard work to it, the symptoms will come earlier and will probably be more significant.
A few things should be noted: A heated environment is an environment with a temperature higher than body temperature (i.e., above 98.6 degrees F). And just by putting on personal protective equipment (PPE), you might find yourself in such a temperature. Also, by putting on the PPE, you will add some degree of hard work to your body even when you’re just walking around.
FRM: Describe how you studied this problem.
SS: A couple of years ago, we made a small study of this problem. We had a number of instructors going through a simulated session, which was supposed to emulate a standard live-fire training session (but without the students). Each session took 30 minutes to complete, of which 12 minutes was inside a 212—302 degrees F environment. Also, each session included setting fire to a number of fuel beds, adding fuel and carrying dummies.
Before and after each test, or every morning and every evening, we took samples of blood and urine for analysis. We measured pulse rate, body temperature, skin temperature, intake of fluid, reaction time, motor skills and a number of other things. It was a fun week!
FRM: What were the results of the study? What recommendations came as a result?
SS: One of the interesting findings was that body temperature didn’t start to increase until the end of a session–or several minutes after a session. Consequently, when an instructor started the next session after about a 45-minute rest, the body temperature was still increasing as a result of the session before.
The instructors also reported tiredness, muscular weakness, headache and muscular pains, and their urine samples showed protein leakage. Blood samples revealed no values outside the ordinary reference values; however, daily and weekly changes were noticed concerning several parameters that may indicate long-term effects.
FRM: What recommendations came as a result?
SS: As a consequence of this study, we developed some recommendations for the instructors. These recommendations can be summarized by stating that work in hot environments should be followed by rest periods. We tried to quantify this by saying that such work should be limited to:
- Approximately six sessions per day
- Every other day only
- Every two weeks only
- A maximum of approximately 25 sessions per month
- A maximum of approximately 120 sessions per year
FRM: How are you implementing these regulations? What’s been the reaction to them among fire instructors?
SS: The problem is really how to define a session. But we have put some effort into giving the instructors sufficient knowledge on how to assess their situation. We aren’t strictly enforcing the regulations. In fact, I believe the most important thing is that we are talking about this. Consequently, if an individual instructor believes they’re doing too many sessions, they can speak up and know that the other instructors and the coordinator will support them. And it’s the other way around as well: If other instructors think that you’re working too much, they will tell you.
Also, we try to make this practical; the purpose is not to make things harder for anyone. The purpose is to make sure that the instructors can have a safe workplace and to make sure that they remain safe and healthy over the short and long term.
FRM: Do you think U.S. fire instructors should follow similar recommendations?
SS: Yes, of course. Although we speak different languages, we are all humans with exactly the same bodily functions. However, U.S. departments shouldn’t just adopt our exact numbers or even our definitions. Instead, they need to create a policy that works locally. Also, it’s very much dependent on how training is performed, what kind of training facilities you have, competency of the instructor, etc.
FRM: How are you evaluating the effectiveness of the recommendations?
SS: In the beginning we tried to keep a log for the instructors, but that didn’t turn out very well. I guess we forget things just like anyone else! Today, I believe it’s more of a collegial thing. Basically, you keep an eye on your buddy. If someone starts talking about not feeling well after a couple of days of hot training sessions, we talk about this and try to find a solution, such as more/other instructors, moving around in the work schedule or cancelling classes. And, above all, our study made everyone aware of the problem, which increases the level of knowledge among the instructors.
FRM: How is the general health and fitness of a fire instructor/firefighter related to their stamina for live-fire training?
SS: Good health and good fitness are basic presumptions for any Swedish firefighter, not only instructors. If you’re in good health and work out regularly, which most (all?) Swedish firefighters do, being an instructor is not a problem. But you still need to limit the number of hot training sessions.
FRM: What requirements does the Swedish fire service have for ensuring firefighter fitness?
SS: For structural firefighting (working inside buildings with a breathing apparatus), no matter if they are career or part-time firefighters, we require a medical examination every other year (no cardiovascular, lung, phalanx or limb problems, etc.). In addition, all firefighters must complete an annual treadmill test in which they walk at 2.8 mph at an 8-degree inclination, for six minutes (plus a two-minute warm-up), wearing full PPE including SCBA. If you’re in reasonably good shape, this test is pretty easy. And we have the same requirements for instructors.
Most Swedish firefighters can spend some of their shift on fitness training, perhaps one or two hours every shift. As a part-time firefighter I get paid an hour every week for fitness training, although I spend a few more in the gym or running.
FRM: What do you think about U.S. requirements for firefighter fitness?
SS: The tests I’ve seen focus more on firefighting ability than physical ability. Being able to do firefighting stuff is not the same as being in good shape. My point is that if you have a correct technique, you can probably pass the test and still be in not-so-good physical shape. But I also believe that physical fitness tests are secondary. If your body is in good condition from a medical point of view, you’re good for firefighting. If you can meet requirements for medical examinations, you’re probably good. And even if you don’t pass such an examination, you can still be a firefighter. But there are probably some things that you shouldn’t be doing as a firefighter.
The fire service, both in Sweden and in the United States, will need to keep evaluating the effect of heat stress on firefighters and instructors and, where necessary, making modifications in the way we train and in our personal protective equipment to minimize harmful effects. Although change is difficult, if we pursue such changes from a practical mindset and with flexibility, we can gain the acceptance we need to make firefighters safer.
