12-28-1998, 06:52 PM #1georgeFirehouse.com Guest
vehicle fires & airbags/hydraulic bumper systems
Looking for some advice/direction on how best to handle vehicles on fire which have potential for airbag or bumpers with hydraulic shocks?? Anything out of the normal??
12-29-1998, 06:16 AM #2adartyFirehouse.com Guest
From what I have read airbag equipped vehicles under fire conditions offer no additional hazards. I have yet to see an airbag deploy under these conditions, but don't bet that it can't happen. Train your people to recognize that a "possible" hazard exists of deployment under fire conditions.
As far as bumpers, thats a totally different story. Gas filled shocks and struts exposed to fire can and do rupture. Many vehicles now have front & rear "impact absorbing bumpers" which are attached to shocks. Many hoods, trunk lids, and lift doors have smaller gas filled struts which also pose a hazard. Drive shafts can rupture under fire conditions, and it would suprise most of us to see the force exhibited when a grease cap from an axle pops off from fire conditions.
I always try to approach from an angle, hitting the fire as I approach. Spot your apparatus at an angle from the vehicle, use a line that will allow you to cool and knock down the fire quickly(no line smaller than 1 1/2"), and have all your people in full protective gear, including SCBA. Use foam if available, or if your rig is equipped for it hit the fire with the deck gun as you roll up.
12-30-1998, 12:40 AM #3LtDave44Firehouse.com Guest
Our Department moved to 1 1/2 to 1 3/4 in the car fire bin about 4 years ago for this very reason. It is always better to be safe than sorry. A water curtin can provide some additional protection from anything that may be in that car in addition to the factory gas filled shocks. Always approach from the side of the car, never from the front. I once had a stolen Mustang 5.0 start to role on a hill while still on fire. Gas shock or not, an aggressive approach from the side of the vehical could never hurt!
Lt. Dave DeLibro
Trumbull Center FD
12-31-1998, 03:02 AM #4fcfdFirehouse.com Guest
We drive in with a deck gun going from 150 to 200 feet away. Take the heat out then move in with hand lines and scba. Seehttp://www.geocities.com/Baja/Trails/6658/cars.html for a step by step pictorial
01-01-1999, 09:42 PM #5rmooreFirehouse.com Guest
Reply posting from Ron Moore, Forum Moderator <email@example.com>
Regarding vehicle fires, airbags and energy absorbing bumpers, there are some safety concerns that emergency responders must be aware. Fluid-filled bumper pistons, originally appearing with the 1973-model year vehicles, are still used today on brand new vehicles. In addition, as one responder has noted, smaller hydraulic lifters are used for items such as hoods and trunks.
If an intact bumper piston unit is exposed to heat, under the right conditions it may violently explode, propelling loose parts off the vehicle. The entire bumper may even detach itself and move a considerable distance away from the vehicle. Emergency service personnel must be constantly on the alert for the sudden "launching" of any portion of an energy-absorbing bumper system. A burning vehicle should be approached from a vantage point other than the front or rear of the vehicle. The area directly in front of or behind a burning vehicle is called the bumper 'strike zone'. It presents the greatest risk if a bumper system component should rupture and launch off the vehicle.
Launching of bumper components because of heat exposure is further complicated when the automobile is an older model. As the vehicle ages, rust and corrosion can develop at the mounting brackets connecting the piston tube to the bumper of the auto. In an accident situation, the mechanical impact of a collision may be strong enough to fracture this mounting bracket assembly, mechanically disconnecting the bumper from the piston tube. If the vehicle were to be involved in fire, the heat could launch the unrestrained piston tube assembly, with a potential travel distance of over 300 feet.
Regarding today's generally accepted vehicle fire procedures, I agree with the information provided by others posting to this forum. Position your rig and attack from a safe distance (100 ft.+), remaining uphill and upwind if possible. Wear full protective clothing including SCBA for the attack and the fire overhaul. Flow 100 gpm+ to be safe; 1&1/2" or 1&3/4" line at least. Class A foam will work well in this attack also. One posting even suggested a 'blitz' from a deck gun for initial knockdown.
I have a personal saying about how to begin a car fire attack with a handline. I always remember the phrase "get the upper hand on the lower foot". This reminds firefighters that nearly all immediate explosion hazards on a burning vehicle are found within the lower 12 inches, somewhere between the front bumper and the rear bumper.
It is critical that the firefighting crews take the time as they initially attack a fire to "buy a life insurance policy". Apply a few seconds of cooling water spray from the hoseline along the entire undercarriage area to get the upper hand on the situation.
After this initial cooling sweep, the fire attack line can be moved into proper position to combat the body of fire; engine compartment, interior, etc.
The electrical power of a vehicle that has been involved in a fire should be shut off. As soon as the fire has been extinguished, the negative battery cables should be cut if the battery is still intact and capable of developing an electrical charge. Personnel must be wary of melted battery casings that expose the acid still contained within the cells.
As the fire attack gets underway, consideration should be given to chocking the front and back of one wheel of the burned vehicle when safe to do so. This procedure is intended to minimize the chance of vehicle movement along the ground.
One member of the fire attack crew should have simple forcible-entry tools during fire combat. With a tool such as a Halligan type of pry bar readily available, the crew can immediately vent automobile windows, move hot metal, or hold or prop hoods or trunk lids in the open position.
Remember, if there is a fire of sufficient magnitude burning in a vehicle when you arrive on-scene, that vehicle is considered "dead on arrival." It will be "written off" by the insurance company for its salvage value. The safety of the firefighting crew members must therefore be paramount. To risk exposure to the fire and its products of combustion would be suicidal; it is an attitude that cannot be tolerated.
How to airbags react during a vehicle fire? The current version of frontal airbags are designed to self-deploy when exposed to temperatures in excess of 330 degrees F. What is supposed to happen is that the sodium azide in the airbag canister module reacts, deploys the bag and the inflated nylon bag melts away. This has been my personal experience at working car fires.
What has actually happened however in just a few cases ( I know of three but I've been told there are more documented cases than that) is that the container holding the chemical violently explodes. In one Florida case, mounting bolts from the module blasted into the rear wall of a pickup truck. In the Long Island NY area, the airbag and its module exploded through a glass sunroof landing out on the driveway behind the vehicle.
Airbags in vehicles on fire are just one more safety concern for responders to be aware of as we calculate the risks of our jobs. Airbags simply reinforce the reason why recommendations about car fire attack presented here should be followed.
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