The Modern Fireground Environment

By John W. Mittendorf

Of no great surprise to the firefighter of 2002 is the fact that the modern fireground environment does not provide the FIREGROUND TIME of just a few short years ago. Although most firefighters are aware of lightweight building construction (that has been around since 1960), it is easy for firefighters to allow their protective equipment to give them a “false sense of security” inside a burning structure because of the advanced technology of their safety equipment. As a result, it is easy for a firefighter to quickly advance into a hostile environment that is more willing to collapse and “flash over” by using their protective equipment as an “offensive” weapon instead of a “defensive” weapon. Remember that safety equipment is not to be used as an aggressive firefighting tool.

One of the most prevalent hazards in the modern fireground is “flashover.” Tests have shown that this condition can result in the following conditions:

• Immediate drop in the oxygen level from 21 percent to four percent.
• Immediate increase in the carbon monoxide level from low levels to 40,000 parts per million (levels in the range of 4,000 ppm can be fatal).
• Immediate increase in the temperature level to more than 1,000°F at the five-foot level and more than 800°F at the ceiling level (eight-foot room).

Obviously, these conditions are immediately untenable for suppression personnel and may result in significant injury or death regardless of the type of safety equipment being utilized. Due to the fact that modern protective equipment has the ability to “mask” fireground indicators, every firefighter should quickly review the following question prior to entering a burning structure: “What do I use as a fireground indicator while I am inside this building?”

It is imperative that personnel engaged in interior suppression operations be aware of and constantly monitor their fireground environment. Therefore, when entering a structure, make a mental note of conditions. This gives personnel a baseline to evaluate an environment that will be degrading or improving as they advance into the structure. With this simple operation, personnel can then implement the “3 Strike Rule”:

• Is there smoke with no heat, or smoke and heat? An absence of heat would indicate a reduced chance of a problem (food on the stove, etc), while smoke with heat increases the chances for a problem (structure fire, etc).
• Is there acceptable visibility? Acceptable visibility is defined as “being capable of exiting the structure in an acceptable period of time.” If personnel are going to push the envelope at an incident, at the minimum, they should be able to exit the structure in a timely manner.
• Are conditions improving or not improving? If conditions are not improving, this is an indicator there is a lack of effective fire suppression and/or ventilation operations, and personnel should begin to evaluate their length of commitment.

John W. Mittendorf joined the Los Angeles City Fire Department in 1963, rising to the rank of Captain II, Task Force Commander. In 1981, he was promoted to battalion chief and in the year following became the commander of the In-Service Training Section. In 1993, he retired from LAFD after 30 years of service.
Mittendorf has been a member of the National Fire Protection Research Foundation on Engineered Lightweight Construction Technical Advisory Committee. He has provided training programs for the National Fire Academy in Emmitsburg, Maryland; the University of California at Los Angeles; and the British Fire Academy at Morton-in-Marsh, England. He is a member of the editorial advisory board of Fire Engineering and author of the book Truck Company Operations (Fire Engineering, 1998).