Fire attack: New methods for new threats

Structures are weaker and fuel loads burn hotter, which requires a transitional fire attack

It is no longer your father's structure fire. Floors and roofs are no longer safe places to be. Even gusset plates are no longer new.

Many of the rules that used to apply to firefighting no longer apply.

That means fireground strategies and tactics must change. And that was the underlying message from the Chicago Fire Department's James Dolton and Peter Van Dorpe during an FRI seminar on basement fires.

Their presentation was about more than basement fires; it was about how modern houses burn, the science that bears that out and how to attack those fires.

Mass extinction
Van Dorpe, the city's director of fire training, said not to focus on the components of lightweight construction, such as gusset plates, but to focus on the loss of mass. Things are changing so fast that gusset plates are now the most massive, robust things used in lightweight construction. Everything else is worse than gusset plates and trusses.

"We can engineer extra mass out of buildings and will continue to do so because it saves cost," Van Dorpe said. "We're going to have more fuel and less mass and we're just going to have to learn to deal with it; that's our job."

Dealing with it means more than just determining if the building can be saved. It's a life-and-death issue.

The two leading causes of firefighter deaths — heart attacks and vehicle crashes — are both trending down, Van Dorpe said. Deaths from catastrophic failure or building collapse are trending way up.

Applied science
Part of learning how to deal with it has been a five-year-long relationship between Chicago Fire and Underwriters Laboratory. They've been studying effects fire has on modern construction and fuel loads by burning things down. And the science is proving out what is being seen in the field, Van Dorpe said.

One thing they are finding is that even something as simple as wood is not the same as it once was. A piece of 2 x 10 dimensional lumber from a 40-year-old home lasted 18 minutes under fire, while the same size piece from Home Depot lasted 7 minutes, Dolton said.

"Do not become over complacent in dimensional-lumber buildings because materials have inherently changed and so will the fire performance times," Dolton said.

Dolton, Chicago's coordinator of research and development, knows what he's talking about when it comes to building construction. He was an architect and structural engineer before joining the fire service.

A floor built using lightweight construction becomes unstable after being exposed to fire for 3 minutes. And when these fail, Dolton said, it is not a 2-foot hole opening up, it is a section large enough to take out a five-member crew.

Starts with education
The first solution to this problem is educating new firefighters. The three things needed to survive a firefighting or officer career are fire behavior, building construction, and tools and equipment, Van Dorpe said.

"We spend all of our time on tools and equipment and breaking stuff; that's fun," Van Dorpe said. "Two of those knowledge bases that we really have to master, we spend no time on because we don't build it into our curriculums."

In the six months that Van Dorpe has his recruit class, they will only get two hours of fire behavior; that's based on national Firefighter I and II standards. An officer candidate is not required to study anything regarding building construction according to the national curriculum.

"That's within our ability to change as fire chief or training officer," Van Dorpe said.

Most departments don't have SOPs for lightweight construction buildings, Van Dorpe said. Looking at what we are going to do differently and putting it on paper is an important step.

"The first thing that happens in a modern-fuel environment when you ventilate is that temperatures go up; they don't go up a little bit, they go up to flashover conditions," Van Dorpe said.

Yet, new firefighters are still taught that the reason to ventilate is to remove heat.

"It's not so much that that is wrong, it is that it is dangerously incomplete," Van Dorpe said. "You are removing hot gasses, but you are also bringing in a lot of air that allows this fire to accelerate."

Another critical approach is to assume every building is lightweight construction until proven otherwise. Also, anything with exposed wood is inherently dangerous. Even legacy buildings were not engineered to withstand today's fuel loads.

Van Dorpe also advises to upgrade the response early and not wait to call for auto aid.

Transitional attack
Modern houses also demand different tactics. The fire service has a tendency to move from aggressive interior attack to surround and drown.

"There's a whole lot of room between aggressive interior attack and surround and drown," Van Dorpe said. "We have to look at occupying that middle ground. That does not mean you have to abandon ship. You have to retreat and regroup enough to get a better assessment of what's going on."

This may involve starting an interior attack from the exterior. Bust a window and put water on the fire before sending a crew inside, Van Dorpe said. This also can be done using the deck gun.

"Put some water on the fire to back this thing up a little bit before you commit your limited crews too far into these buildings," Van Dorpe said.

The fire-push myth
The fear that this tactic will push fire into unburned portions of the structure is unfounded, Van Dorpe said. "You can't push fire with water."

A fog stream pattern will change the flow pattern, so Van Dorpe said to use a tight stream and bank it off the ceiling to replicate sprinkler action.

"The lesson is it is not where the nozzle is located, it is stream selection and technique," Van Dorpe said. "Understanding the science a little better can help you make better decisions on the fireground."

Another tactic is to expose void spaces. Thermal imaging cameras cannot be relied upon for floor stability because coverings like carpet or tile will mask the heat.

"The first guy through the door should be putting one hole in the floor and one in the ceiling to expose the void spaces," Van Dorpe said. "Fire has to go to a low-pressure area and you created a low-pressure area (with the inspection hole); it has to come to you. We want to see it; then we can do something about it."

Fire control
The hardest decisions will involve when and how to perform rescues. Van Dorpe said that even when there is a high probability of a victim, a crew with limited manpower must make controlling the fire its top priority.

"It is faster to remove the hazard from the victim than it is the victim from the hazard," he said. "Rescue is your first priority on the fireground, without a doubt. It is a strategic priority, not a tactical priority. Sometimes I'm going to recognize that putting water on the fire is the best way to accomplish that strategic goal."

It is critical to keep in mind when the clock starts, Dolton said. If the average response time is 10 minutes, a crew is likely to find a structure already compromised upon arrival.

Time is not on the firefighter's side. There are new, ever-present dangers that require new thinking and new tactics.

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