9.2 Vehicle Fires, Exterior Class A & Ground Cover Fires (JPR 4.3.7, 4.3.8)

9.2 Vehicle Fires, Exterior Class A & Ground Cover Fires (JPR 4.3.7, 4.3.8)

Passenger Vehicle Fires

NFPA 1001 Firefighter I requires the candidate to attack a passenger vehicle fire operating as a member of a team. A passenger vehicle fire is a Class B/C hybrid: the fuel system (gasoline, diesel, or alternative fuels) presents a flammable liquid and energized electrical hazard, while the tires, plastics, and upholstery burn as Class A fuels. The attack is staged using a 1.5-inch or 1.75-inch handline flowing 95 to 200 gpm, and the crew operates with full structural PPE and SCBA on air because the smoke is toxic.

Approach and Standoff

1. Approach the vehicle from a 30-degree angle, never from directly in front of or behind the vehicle. The bumpers, struts, and hood are pressurized components that can launch projectiles when heated.
2. Maintain a 30-foot standoff distance until the seat of the fire is identified.
3. Identify the fuel type (gasoline, diesel, hybrid, EV, CNG) from badging or the location of the charge port. Alternative fuel vehicles introduce electrical and lithium-ion battery hazards.
4. Position the apparatus to shield the crew from traffic.
5. Charge the handline and advance from the unburned side of the vehicle.

Attack Sequence

1. Cool the passenger compartment and exterior with a straight stream or narrow fog from the 30-foot standoff.
2. Once the visible fire is darkened, move closer and apply a straight stream to the undercarriage, fuel tank area, and tire wells.
3. Open the hood only after the engine compartment is darkened; releasing the hood latch from the side keeps the firefighter out of the path of any flare-up.
4. Apply a narrow fog to the engine compartment to cool it without scattering hot oil.
5. overhaul the tires, wheel wells, trunk, and undercarriage to confirm extinguishment; tires can re-ignite.

Vehicle Fire Dangers

• Bumper projectiles: Hydraulic bumpers and gas struts can launch the bumper 50 feet or more when overheated.
• Hood strut launch: Hood lift struts can fire the strut rod 30 feet.
• Tire explosion: Tires can blow out and launch the sidewall fragments at high velocity.
• Airbag deployment: Undeployed airbags can deploy forcefully if the canister is heated. Maintain 10 to 15 inches of clearance from any airbag module.
• Alternative fuel hazards: Lithium-ion battery fires can release hydrogen fluoride and re-ignite hours later. CNG tanks are pressure vessels that can BLEVE (boiling liquid expanding vapor explosion). Maintain a 50-foot buffer from a burning lithium-ion EV and use copious water for cooling.

Exterior Class A Fires

NFPA 1001 Firefighter I requires the candidate to extinguish fires in exterior Class A materials such as storage containers, brush piles, and unattached structures. The principle is to attack from the unburned side toward the burned side, protecting exposures and preventing extension.

Operational Sequence

1. Identify the fuel: storage container contents, brush pile size, or structure type.
2. Identify exposures: nearby buildings, vehicles, vegetation, or property that the fire can reach.
3. Charge the appropriate handline (typically a 1.5-inch for storage containers, a 1.75-inch for unattached structures, or a booster line for small brush fires).
4. Attack from the unburned side, applying water to cool the fuel between the fire and the exposure.
5. Work around the perimeter to fully surround the fire before overhaul.
6. Overhaul the fuel pile with a pike pole or Halligan to find hidden fire, then apply water to cool the interior.
7. Establish a watch line to prevent rekindle.

Ground Cover (Wildland) Fires

A ground cover fire is a wildland or brush fire that burns across surface fuels such as grass, leaves, brush, and light slash. Firefighter I operations on a ground cover fire are limited to the initial attack of small fires and support of larger operations; complex wildland operations are Firefighter II and wildland certification territory.

Fire Behavior on Ground Cover

Ground cover fires spread by following the lay of the land and the wind. Fire moves fastest uphill (preheated fuel and rising convection) and with the wind. The fire is described in three parts:

• Head: The leading edge moving in the direction of spread. This is the most dangerous part.
• Flanks: The sides of the fire, moving perpendicular to the wind.
• Heel (or tail): The back of the fire, moving against the wind and downhill.

Attack Strategy

The standard Firefighter I attack strategy on a small ground cover fire is:

1. Anchor the attack at a safe point such as a road, creek, or burned area so the fire cannot outflank the crew.
2. Flank the fire by attacking along the sides from the heel toward the head, working in tandem with the second crew on the opposite flank.
3. Break the fire line by scraping fuel down to mineral soil with a pulaski, shovel, or McLeod.
4. Wet line the edge with a booster line or forestry hose to prevent the fire from crossing back.
5. Mop up the entire perimeter to a depth of at least 30 feet before declaring the fire out.

Safety on Ground Cover Fires

• Maintain a 10-standard-fire-order watch and observe LCES (Lookouts, Communication, Escape routes, Safety zones).
• Identify an escape route to a safety zone that can hold the entire crew without sheltering.
• Never attack the head of a fire from above unless there is a clear safety zone.
• Watch for changes in wind direction that can turn a flank into a head and put the crew in the path of the fire.
• Carry a fire shelter and know how to deploy it.

Common Considerations Across Exterior Fires

• Water supply: Exterior fires may require a rural water shuttle or draft from a portable tank because hydrants may not be available.
• PPE: Wildland PPE is lighter than structural turnouts and is designed for heat stress reduction. Structural PPE on a wildland fire is exhausting and dangerous.
• Communications: Maintain radio contact with command and the other flank crew. Report any change in fire behavior immediately.