Fire tactic: Offensive vs. defensive fire attack
When the goal is to extinguish a fire, the incident commander must decide on an offensive, transitional or defensive fire attack
I can't tell you how often I have heard, "We are an aggressive interior firefighting department." Does this mean they are unable to make any other decision when faced with a fire?
I often wonder if we have brainwashed our new personnel so that regardless of how safe the scene is, we will enter any structure to put the fire out. My worst nightmare is the day I may have to tell one of my firefighters' significant others that their loved one will not be coming home because I gambled with their lives.
I will try my best to err on the side of safety and make sure that the number one priority on the fire scene — my guys and ladies — are not placed in a situation where common sense is traded for tradition. Our corporate culture must be the concept that no property is worth a firefighter's life. We should also not be in a situation of potentially trading the lives of firefighters for the lives of victims who may not be savable.
When the goal is to extinguish a fire, the incident commander must decide on an offensive, transitional or defensive fire attack.
The operation must first begin with size-up to enable the incident commander to decide which mode to operate in — offensive or defensive. A marginal or transitional attack is used to focus tactics on saving lives. In a transitional attack, hose lines are used to protect crews for rescue support, not for fire extinguishment. The purpose is to accomplish a known rescue and get out, which may force a change in the two-in-two-out thinking mentality.
It's important to note that OSHA's two-in, two-out regulation requires that prior to a team entering an IDLH environment, there must be a two-person initial rapid intervention team on the exterior of the hazard zone. The only time this rule may be set aside is if there is a reasonable confirmation of a live victim that can be saved if a crew immediately enters the IDLH without an exterior rescue crew.
The defensive mode is chosen to isolate or stabilize and incident to ensure it does not get any worse. This may mean sacrificing the building on fire to save others that are not involved.
A defensive operation should be initiated when fire conditions prevent an interior attack such as when the structure is unsafe for firefighters to enter and no civilian lives can be saved and when the fire is beyond the control of hand lines.
During the defensive operation, place large exterior fire streams between the fire and the exposures to prevent fire extension. When possible deploy master streams and control perimeter to prevent firefighter entry into collapse area.
To ensure firefighter safety near or around structures that may collapse, collapse zones should be established based on the vertical collapse danger zone that is minimally the full height of the wall and a horizontal collapse danger zone that is minimally the full length of the wall.
Factors to consider when establishing collapse potential include:
- Building class/construction
- Type of occupancy
- Fire duration
- Fire location/size
- Bulges in walls
- Cracks in walls, either exterior or interior
- Sounds of structural movement
- Water flowing through exterior masonry walls
- Water run-off is smaller in quantity than amount being pumped by apparatus
- Truss construction with direct fire involvement for longer than 5-10 minutes
You should consider the placement of apparatus to prevent injury or damage when the initial or subsequent structures collapse. Attempt to place apparatus in a position that allows for safety should the fire location impinge upon apparatus. And the first defensive line should be placed to protect life, and emergency egress, then placed to protect the most endangered exposure. The second line will be placed using the same criteria.
In addition, consider hazardous processes when deploying initial lines; they may endanger multiple occupancies. Exposure lines work best by cooling the exterior of the exposure being protected, then additional lines may be effective when water is put on the original fire. Also, use the most appropriate appliance to deliver the amount of water required to control the fire in the most effective fashion, such as blitz nozzles for a rapid ground level attack.
Offensive and defensive modes are separate tactics. A defensive attack may be used to set up for a quick interior attack (transitional attack), but they should not occur at the same time. The incident commander must announce the strategy when changing from offensive to defensive and ensure all personnel are aware of the fact and that a PAR is completed prior to a complete tactical shift.
An offensive mode involves taking direct action to mitigate the problem. This means an aggressive interior attack will be used because initial crews believe there is a chance that occupants may be inside the structure and conditions may be such that they could still be alive.
In addition, ensure that initial risk assessment has confirmed that the structure is not so involved that collapse is imminent, fire dynamics are understood, truss impingement times can be estimated with some accuracy, OSHA's two-in-two-out policy is adhered to and that sufficient resources are present to deal with both fire attack and rescue tactics.
More lives are saved by putting the fire out as swiftly as possible. And the rapid location, confinement and extinguishment of the fire depend on proper hose selection and placement.
Here are some other considerations for an offensive atttack.
- Coordinated and communicated ventilation.
- Company officers must direct the activities of the crew, not operate the nozzle.
- The second line stretched should be a back-up line of the same size or larger than the first line deployed.
- Fighting the fire from the unburned side is not always an option; select the option that allows for the largest amount of fire extinguishment.
- Never stretch a dry line into the fire compartment.
- If the next in engine may not get on scene before your water tank is empty, get your own water supply line when possible.
- Advise ability to obtain a water supply line with initial size-up report.
- When possible, protect the main areas of egress, both for victims and firefighters.
You should always check for hidden fires. A fire will burn on six sides, four walls, a ceiling and a floor. Make sure fire is extinguished in all sides. Finally, always coordinate interior fire attacks with exterior operations.
This article, originally published in 2009, has been updated.