Sequential Firing of Airbags/Curtains

To my knowledge up to date, I understand that some airbags will fire in a sequence. Not necassarily an actual sequence, but if the angle of impact, and if it is in the crush zone far enought to set off sensors, they multiple deployment will happen. Does this occur with window curtains also? How are they wired and if impact is in the front or rear of the vehicle does the deployment of other bags affect curtains automatically? Since they are basically designed for a roll, and to stay inflated during one, will they fire on a side impact without a roll? My other question is a safety issue. If we decide to flop a roof, where in the "B" post should we cut? Or should we not at all? (Alternative manuever?) I understand that the fuel canister is usually in the head liner area just rear of that post in most vehicles.

To assist you in your questions you might try going to this link, it is an alternative method I developed to use with side impact curtains: Modified Dashroll
http://www.extrication.com/modifiedash.htm

The method also works well with jacking of the dash.

With regards to your question on the deployment of the airbags/curtain. The frontal and side impact systems are independent of each other with regards to firing. A direct frontal impact will not activate the SIPS. Conversly, the SIPS will not active the fronal when there is a 90 degree impact. If the angle of the crash involves both front and side impacts at once then you could anticipate the two systems deploying. Mostly likely one will deploy fractions of a second before the other sensors are tripped.

If the left side impact deploys the right side will not be activated unless that senorary system is activated as well.

As far as the side impact curtain being designed for rollover, it was orginially designed to protect the occupants from side impact collision. It also protects the occupant from glass fragments and forces created from the whip lash effect, and to some degree in a rollover if seat belts are worn. There are crash test videos available from Volvo or other agencies, Ron Moore can supply you with the names and addresses.

I have a inert side impact curtain to be used in training, it is aproximately 6 feet long not including the anchor and inflator. Volvo and Mercedes mount the inflator in the rear pillar, the airbag (curtain) extends up along the interior roof rail to the A-pillar, the anchor point is bolted mid A-pillar. If you go to the link shown you will see a Volvo with the interior trim removed. Also notice that there is a pretensioner in the B-pillar, the inflator extends aproximately 2 inches beyond the sill line of the window. Where do you make your cuts?

Toyota is coming out with a side impact curtain next year, the inflator will be mounted in the A-pillar. BMW's HIPS (sausage airbag) is also mounted in the A-pillar.

Also remember that Autoliv one of the makers of the side impact curtain, states do not cut the airbag or it's components. This will make you think, but the answer is simple and works well.

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Ron Shaw
http://www.extrication.com