Just completed a drill in which dealt with new vehicle safety systems. It answered a lot of questions and like all good training, it raised a few more. One question I have yet to get answered is regarding impact curtains(HPS, IC). On the BMW and Toyota systems with the gas generator located low in the A-post, does cutting the A-post during the Modified dash roll compromise the venting of hot gases (in the case accidental deployment) directed at the rescuer? If so, what precuations should be taken, and how far would gas vent?
Modified Dash Roll
I don't believe that will be a problem for you if you are doing a Modified Dash Roll. The Toyota inflator, from what I have been told and understand, will actually be located in the dash, not directly inside the A-pillar which runs from the roof rail down to the wield flange/rocker channel. The BMW inflator for the HPS, from what I have been told is also in the dash area not in the cutting zone of the A-pillar. However things can change at anytime during a production run or from year to year. What might be a safe cutting zone today, may change 6 months from now.
If you cut the A-pillar close to the dash, the airbag will be inoperative from that point on to the rear pillar. However you still have the problem of the inflator firing off and venting through the open but. Don't forget the pretensioner and sensors which are mounted in the B-pillar of some vehicles.
Once you have started your roll, the dash and remaining pillar will be through the windshield line pointing away from the rescuer and patient.
If the inflator then blows off, hopefully it will be directed upward and away from personnel and near the pillar. You only need to do one side of the vehicle, this manuveer works well. And I suggest leaving the doors on, just bend them back to 90 degrees or better. This will help give strength to your A-pillar. If you sever the pillar above the bottom hinge, you will have to remove the door, the two hinges will then fight against each other during your roll.
This is my personal opinion, unfortunately we have not been offered the opertunity to be allowed to cut into a new vehicle to test the theory out. But it has been brought to the attenion of Autoliv, who just finish their second set of tests cutting side impact curtain inflators (hybrid) 11/99. Test results have not been made public, nor how the test were conducted. A foreign auto maker requested the test be conducted, Holmatro provided the equipment for the test and advisor.
I was called prior to the testing by an official for comments to passed along. It was my suggestion that a vehicle with side impact curtains be used, while cutting in the normal cutting zones for a roof displacement, the inflators should be fired off to see what exactly will happen.
The first tests in Sweeden had multiple failures resulting in projectiles, sources have told me that only one failure was reported during the second test. No information has been made public on the first test either. All that was allowed to be told was that hydraulic cutters were used to cut into the inflators and that aproximately 6 out of 8 inflators failed resulting in projectiles.
The Modified Dash Roll seems to be the lesser of evils. With inflators mounted in the rear pillar, there are no problems you completely avoid cutting any of the inflators, IC, and pretensioner systems. With the forward mounting of an inflator, it is impossible to roll/jack a dash without compromising safety to a degree. Keep personnel away from the open butt, just incase there is a deployment. If possible use a self-stick colored tape to warn of a hazard. Do not try to block the end, let the gas vent! Do not try to disconnect the leads to any inflator, there is a shunting device to prevent static discharge from deploying the inflator.
If you flapped the roof foward without cutting the impact curtain/window bag, if deployed there is no telling what could happen, and who could get hurt.
This is the only time that I would suggest cutting an airbag, only because it is virtually impossible to roll the dash with out creating a greater risk of injury.
Unfortunately there is no standard for SRS devices with regards to mounting locations, there is no commitee with an extrication specialist sitting in on discussions and offering our imput.
Until the US government steps in and tell the auto industry to make a fire department kill switch, which would shut the entire car down, we have to educate ourselves and train to protect ourselves from safety devices!
You may contact me by email if you have further questions.