January-February 2010 Issue

	January-February 2010

Flashover and Backdraft, Seconds to Disaster

By Mike Healy

It’s 3 a.m. and the alarm sounds for a reported structure fire in a single-family residence. All units respond according to your department’s standard operating procedures, and upon arrival you find a 2½-story wood frame house with heavy black smoke pushing out of every crack and crevice in the building. There are two cars in the driveway and no residents outside the house.

The first firefighters off the apparatus take the appropriate tools and see to our first tactical priority, search for life. The door is forced, and the team heads to the second-floor bedroom area searching for victims and the seat of the fire. Smoke and heat are down to the floor level and a dim orange glow can be seen towards the end of the hallway. The team heads for the seat of the fire to begin the search and get control of the fire room door while continuing the search for those in peril. As the team proceeds, they hear a sound of a window breaking behind them, the heat increases tenfold and within seconds, FLASHOVER.

During the natural evolution of today’s residential fires, flashover will occur, sometimes aided by the actions or inactions of firefighters on the scene. Why? In a word, plastics. The high heat production of these burning products of petroleum which now decorate our homes, invite early occurring flashovers that trap, injure, and kill our firefighters.

The ongoing question remains: how do we avoid these disfiguring, painful, and sometimes fatal events? Our stock answer that firefighters will always be injured and perish in burning buildings is not an acceptable answer. It’s time to reevaluate our procedures and actions in the early stages of structural firefighting.

Action, position, and timing will always be our menu for a successful operation, but how do we accomplish this especially in today’s manpower starved fire service. The answer first and foremost is training.

In today’s departments it is imperative to have all your personnel skilled in every facet of search, fire attack, and ventilation. We are often asked where we think the fire department is most deficient in early structural operations. Our answer is always our inability to properly ventilate the building allowing the heat and gases to escape prior to flashover or backdraft.

You may have noticed that we said “properly ventilate” the building. When teaching the “Flashover Survival” course for the last fifteen years, we always start the class by asking the students to describe the difference between flashover and backdraft. On a few occasions the correct answer pops up, but most of the time our question is answered with incorrect answers or blank stares. After drawing the time-temperature curve on the blackboard, most students recall that flashover occurs at the full growth peak of the curve, while backdraft occurs on the decay side. At this point we ask, "Which one would you associate flashover with?" The answer is always “heat,” and when asked the same question of backdraft, it is always “oxygen.” Our task for the rest of the class is to show just how important of a part oxygen plays in flashover, and heat in a backdraft.

Introduction of oxygen to a growing fire in its early stages along with the re-radiation of heat from the walls and ceilings into the flammable gases within the smoke, is the combination that causes flashover. Upon entering the burning structure, we introduce oxygen which immediately heads for the seat of the fire.

The team that usually becomes cut off and trapped in flashovers is the primary search team. As we tell our students, once you enter the building, you are in danger of becoming a victim yourselves. You are in a burning structure without the protection of a hand line on the fire, and you must remain aware of that fact. The primary search has to be carried out as quickly and efficiently as possible, and the proper tools have to be with you to carry out this vital task. A flathead axe, halligan tool, six-foot hook, and a 2½-gallon water can are essential for a successful search for life.

All other operations on the fireground during the primary search should be in support of that search, and the stretching of the first line to the seat of the fire.

VENTILATION

As the search team is starting their task, the vertical and horizontal ventilation teams should be in action to get the heat and gases out of the structure. Each member of the department should be trained in this task, and drills should be held on roof props allowing frequent use of the power saws. For every inch the heat and gases are lifted off the floor, the more chance that a ceiling to floor flashover or backdraft will not occur.

HOSE ADVANCEMENT

As the two above tasks are being carried out, our initial line must be stretched, and as the saying goes, "The fire goes as the first line goes.” The proper line must be stretched with enough lengths to do the job. The speed in which this line is stretched may be the difference necessary for the search team to make that last bedroom in search of a missing victim. Proper line size and proper nozzle selection are necessary for the proper delivery of water on the fire. Straight streams, delivered by smooth bore nozzles, in our opinion, are the best tool for the job. Our friend and brother Andy Fredericks spent years proving this theory in engine classes all over the country. Large droplets of water are needed to knock down these violent flashovers. Engine companies, operating their lines in structural fires, have never been killed by flashovers. Those in a couple of cases who abandoned their lines in an attempt to flee the building have been caught in fatal flashovers. In the old days, we taught firefighters not to operate lines on smoke. In today’s fires, if you are in an area that is pushing you down to the floor with increasing heat, it is advisable that you operate the line immediately to the floors, walls, and ceilings, clockwise motion.

PORTABLE LADDERS

Another area that needs attention early in the incident is the use of portable ladders. If the search team runs into trouble, there will have to be a safe means of egress if they become cut off by the fire. Too many times our big, beautiful ladder trucks sit in front of the building with their full compliment of ladders still on board. Waiting for the firefighters to start screaming maydays is not a good strategy, and it is probably too late to start calling for ladders to the rear of the building. Having ladders placed on all four sides of the building will assure that if a firefighter has to get out, a ladder will already be on that exposure. A ladder raised against a building can be easily moved by one firefighter. FAST or RIT team members can and should be used for this task if necessary. (See NFPA 1910.134.)

FAST / RIT TEAMS

The recent use of FAST / RIT teams has been a giant step in firefighter safety. Unfortunately, valuable time is often wasted before calling for these teams. Whenever a member is placed in a dangerous, life-threatening situation, the FAST / RIT team should be in place or at least on the way. Some forward-thinking departments are having their teams dispatched on the initial alarm. It only makes sense.

INCIDENT COMMAND SYSTEM

Now naturally, a properly coordinated group of operations as stated above, along with all the other tasks that will have to be taken care of, will need an incident management system properly in place. If your department does not have the necessary manpower to cover all the tasks necessary to support your firefighters, you must take whatever means necessary to assure the safety of our firefighters by providing that manpower and other resources needed. Calling for mutual aid after the search team is missing is too late.

Case studies show us that, although flashovers and backdrafts can happen at any time, they usually happen at the early moments of the alarm. Temperatures that reach over 1,500 degrees will blind a firefighter with pain and disorientation in a room fully involved in flame. Survival is non-existent without the immediate means to get out of harm's way.

A proper incident management system fueled by department standard operating procedures will ensure a safer fireground for all. Some tragedies on the fireground cannot be avoided, but selling our brothers short with no strategic plan is nothing less than negligent.

ACCOUNTABILITY

We all know the difficulty in accountability in the early stages of the fire. In many departments, accountability tags are used and hung on a ring in the rig en route to the alarm. The safety officer when possible then collects the tags and hopefully finds out where their owners are operating on the fireground. As we stated, this is not an easy task; but it must be done. Recently a FAST team was put to work after a partial collapse of the building, and after 90 minutes, Command did not know for sure who was missing.

SUMMARY

As we instruct the flashover course and we’re asked how we can prevent flashover and backdraft injuries and fatalities, our answer will always be the same, TRAINING, TRAINING, TRAINING! We can’t say it enough. Examine your SOP’s, or better yet, see if you have any. Be honest with yourself as to your commitment to dong the job right. Never put yourself in the position of standing in front of a coffin saying to yourself, this could have been avoided. Make sure the basics of firefighting are being taken care of and that your troops are ready for battle. Most departments are 10 percent fires and 90 percent preparing for fires. Whether you are a chief or a probationary firefighter, commit yourself to doing things right. Be safe.

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