Airbag Containment Devices

[Guest Firediver]

Thanks Mike.

Yes Sir.

[JetPhoto 626]

I had gotten the information regarding "dual stage" airbags from a seminar I was at. It was said since some crashes involve hitting more than one obstacle a 2nd discharge in the airbag would occur to protect the occupant in the 2nd hit. It was later discussed that it was possible to go off a 2nd time during extrication.

This was a couple years ago so we have 2 separate opinions on the topic the bottom lines is to be aware anything can happen

[Guest Firediver]

Gonna have to go with no on that one until I see it written. I never heard of the same bag going off more than once only staying inflated a little longer to protect in case of roll over. If you can find your notes from the seminar check that again. I just checked multiple web sites and nothing of that is even mentioned. I'll keep checking on that. The link given clearly stated what a "dual stage" airbag/SRS is so its not really opinion more a fact.

Edited June 29, 2010 by Firediver

[Guest Firediver]

I search for as long as I can sit and have come up with 0 in regards to an airbag/SRS deploying more than once in the same accident. The only constant (that I found) was that airbags/SRS may deploy at different times during an accident (ie. front driver/passenger then side curtain).

Has anyone else found anything about it?

Edited June 29, 2010 by Firediver

[fyrlt17 13]

This is an example of a late-model dual Inflator. Depending on the threshold of the collision, one or both of the inflators will ignite. Even if the airbag has deployed, the second stage may still be live.

[Guest Firediver]

Ok there we have it. Now are the terms stage/inflater interchangeable? As in the link earlier it was stated that it may not deploy a full charge (say for a young adult) depending on a few factors of the crash, that being said, this second deployment will be the remaining energy left in the capacitor? So lets say 75% of the energy was discharged first so only 25% is left to discharge? Am I understanding this correctly Chief? Just so I am clear with this. Thanks

[antiquefirelt 994]

I am asking. What's the best approach?

My understanding is we should cut the battery, observe the 5-10-20 rule, think before we cut, and expose the posts on the inside be fore cutting.

Our approach is exactly as you've said here. On the second deployment, we've been told by the auto /repair/body/dealers/recovery folks that you "could" in fact have a second deployment of the same air bag. They explained that there are two separate charges, one full power, one at a lesser deployment charge. The same bag and deployment system is present. They explained that there is just as much chance of a secondary deployment as a primary deployment after the crash. The reason is that any deployment of a resting vehicle will indicate a failure of the redundant safety systems in the air bag deployment system. You need more than one sensor to be activated to deploy any bag (nowadays). Such as the crumple zone sensor and rapid deceleration. This is why actual post crash deployments are extremely rare, but given that we're dealing with a crashed vehicle, no one will guarantee anything due to the potential damage to anything and everything. Also the same folks strongly urge not to cut the deployed airbags as a secondary deployment would spew hot gas into the area directly in front of the bag.

[fyrlt17 13]

This is a compressed gas cylinder type inflator. High pressure gas is stored until the request for deployment is sent. At that time a disc inside the cylinder bursts and allows the gas to escape at high pressure to inflate the bag.

[antiquefirelt 994]

This is an example of a late-model dual Inflator. Depending on the threshold of the collision, one or both of the inflators will ignite. Even if the airbag has deployed, the second stage may still be live.

Just a question, but if both charges can go off at once or one or the other may discharge, does this make it a three stage system? Thanks for the pics, they help relay the story on how these operate.

Also to note what was said or asked earlier, word is that even with the capacitor drained the bags "could" deploy from any stored energy such as cellphone plug in or GPS plugged in, or even from a static charge from sliding across the seat! You can create one hell of a measured charge with static.

[Guest Firediver]

This is a compressed gas cylinder type inflator. High pressure gas is stored until the request for deployment is sent. At that time a disc inside the cylinder bursts and allows the gas to escape at high pressure to inflate the bag.

Thats crystal Chief. My question is is there something that will stop the gas flowing from the cylinder once the disc bursts? So there are 2 of these gas cylinders in a "dual stage"? Bottom line is be careful where we cut and why do not say "NEVER happen" in the Fire service. I was looking for hard evidence on a dual activation of the same bag but there has been enough word of mouth to convince me otherwise. Thanks Chief's

Jetphoto I stand corrected by word of mouth.

Edited June 29, 2010 by Firediver

[mfc2257 464]

On a side note... Any departments use either books or computer programs that show you where to cut on specific vehicles?

Yes... Although I'm not sure if they are still in service, but we equipped Rescue 36 with a vehicle specific reference guide and the annual refresher/update guide. A copy also went on E248. If someone with radio communications on scene (Chief, PD, etc) could relay the vehicle make, model, year back to one of the extraction units while they were in route, the officer could begin to look up the specific info regarding restraint systems in the vehicles.

I'm not sure if these manuals have been updated in the 6 years that I've been gone, but they were valuable at the time we equipped the extraction units with them. E247 is now equipped with extrication equipment as well. If they are still in use, I'm assuming (hoping) a copy went on E247 as well.

[fyrlt17 13]

Sorry had to go on a run:

There are to types of infators 1) inflation system is not unlike a solid rocket booster. The air bag system ignites a solid propellant, which burns extremely rapidly to create a large volume of gas to inflate the bag. The bag then literally bursts from its storage site at up to 200 mph -- faster than the blink of an eye! A second later, the gas quickly dissipates through tiny holes in the bag, thus deflating the bag so you can move. Even though the whole process happens in only one-twenty-fifth of a second (250 ms) the additional time is enough to help prevent serious injury.

Sodium Azide

Class C Explosive

Self Ignites When Heated To 600 Degrees.

2) compressed gas cylinder type inflator. High pressure gas is stored until the request for deployment is sent. At that time a disc inside the cylinder bursts and allows the gas to escape at high pressure to inflate the bag.

Contains 3000 PSI

[Guest Firediver]

Chief, I'm gonna be a little persistent here so I can pass this info along with full understanding when the time comes so bear with me.

Young petite adult in front passenger seat, front impact accident, dual stage has sensed that it is not a large adult and we'll say the lesser of the 2 discharge (small charge for argument sake), the crumple sensors have detected this, car spins around 360 hits a jersey barrier front end again. Now from what antiquefire has said he was told there is a full and a much less than full charge. The less than full charge has deployed initally, now we are left with the full charge for this barrier impact. Since the sensors have already detected what charge was initially needed for the young adult, wouldn't a deployment of the full charge on 2nd impact to the young adult open up a can of worms with law suits?(I'm sure if they did not get seriously hurt it would be obsolete) Yes, I am going with the airbag/SRS could possibly deploy again but if this was something that has happened more than a freak time there would be much more accessible literature out about this for OUR safety other than word of mouth no? Thanks Chief

Edited June 29, 2010 by Firediver

[fyrlt17 13]

I don't want to confuse everyone but all the gas is released or ignited. With new Smart Bag Technology The airbag controller controls how hot to burn creating more or less gas and for the stored pressure how fast the gas is released.

Confused yet?

The problem lies with the us being able to determine if the secondary charge has deployed.

COPIED FROM GM website: Avanced airbag technologies are being developed to tailor airbag deployment to the severity of the crash, the size and posture of the vehicle occupant, belt usage, and how close that person is to the actual airbag. Many of these systems use multi-stage inflators that deploy less forcefully in stages in moderate crashes than in very severe crashes. Occupant sensing devices let the airbag control unit know if someone is occupying a seat adjacent to an airbag, the mass/weight of the person, whether a seat belt or child restraint is being used, and whether the person is forward in the seat and close to the airbag. Based on this information and crash severity information, the airbag is deployed at either a high force level, a less forceful level, or not at all.

Adaptive airbag systems may utilize multi-stage airbags to adjust the pressure within the airbag. The greater the pressure within the airbag, the more force the airbag will exert on the occupants as they come in contact with it. These adjustments allow the system to deploy the airbag with a moderate force for most collisions; reserving the maximum force airbag only for the severest of collisions. Additional sensors to determine the location, weight or relative size of the occupants may also be used. Information regarding the occupants and the severity of the crash are used by the airbag control unit, to determine whether airbags should be suppressed or deployed, and if so, at various output levels.

[Guest Firediver]

Nope not confused at all, I found all that info last night just nothing about an airbag/SRS being deployed 2x's. I even found myself on a web site that had all kinds of lawsuits against the manufacture for airbag/SRS defects, misfires, early deployment etc. but nothing on the 2nd ignition. The more knowledge the better

Edited June 29, 2010 by Firediver

[fyrlt17 13]

I forgot to mention that there are systems that don't have Smart Bag Technology. Making it Hard for us to determine which vehicle have controlled inflators .

The writing on the airbag warns

"Risk of Injury"

"Two stage airbag system. Airbag could trigger a second time"

Holmatro's Rescuer's Guide to Vehicle Safety Systems and HURST Crash Recovery System

Are excellent resources. You put in the Year, make and model of a car and all the hidden hazards of that model are displayed

[Guest Firediver]

Wish ya would have chimed in yesterday before I strained my eyes looking for that. Yup, hit all the tool manufactures(I could think of) sites too and came up dry. With your permission I would like to save a few pics for myself. Don't worry, I have no plans on teaching VET. You have it covered extremely well. Thanks again Chief.

Edited June 29, 2010 by Firediver

[antiquefirelt 994]

Chief, I'm gonna be a little persistent here so I can pass this info along with full understanding when the time comes so bear with me.

Young petite adult in front passenger seat, front impact accident, dual stage has sensed that it is not a large adult and we'll say the lesser of the 2 discharge (small charge for argument sake), the crumple sensors have detected this, car spins around 360 hits a jersey barrier front end again. Now from what antiquefire has said he was told there is a full and a much less than full charge. The less than full charge has deployed initally, now we are left with the full charge for this barrier impact. Since the sensors have already detected what charge was initially needed for the young adult, wouldn't a deployment of the full charge on 2nd impact to the young adult open up a can of worms with law suits?(I'm sure if they did not get seriously hurt it would be obsolete) Yes, I am going with the airbag/SRS could possibly deploy again but if this was something that has happened more than a freak time there would be much more accessible literature out about this for OUR safety other than word of mouth no? Thanks Chief

I'd add the concern relayed to us for a very similar situation, is when the bag senses the smaller passenger, then after any impacts, a would-be rescuer applies his/her additional weight to the seat while assessing/accessing the patient allowing that portion of the deployment sequence to arm for the higher un-deployed charge.

I think the reason for few lawsuits regarding secondary deployments are that the likelihood of an actual post impact deployment is still very rare, yet they're unable to guarantee it won't happen, thus our precautionary posture. Anyone have any actual numbers of airbag deployments during extrication ops? Short of the Akron incident I cannot recall another. I know Ron Moore and others have been asking for any information of any post crash deployments for some time now.

[Guest Firediver]

I'd add the concern relayed to us for a very similar situation, is when the bag senses the smaller passenger, then after any impacts, a would-be rescuer applies his/her additional weight to the seat while assessing/accessing the patient allowing that portion of the deployment sequence to arm for the higher un-deployed charge.

Understood. I think I'm trying to break down the process too much. I do still have a question about the steering wheel cover in that pic. Is the TOP relative to space or the TOP of the steering wheel (ie wheels are turned to the right a little)? and was the failure because of that or the steering wheel material?

Edited June 30, 2010 by Firediver

[efdcapt115 1,511]

bump: for great content.

[16fire5 693]

Anyone have any actual numbers of airbag deployments during extrication ops? Short of the Akron incident I cannot recall another. I know Ron Moore and others have been asking for any information of any post crash deployments for some time now.

On the same note I'm interested in the consequences of cutting through cylinders that have not deployed. I bet it's happened a lot (unintentionally).

Thanks to the posters here passing on some good practical field knowledge and procedures to follow for the safety of our crews.

[FiftyOnePride 100]

On the same note I'm interested in the consequences of cutting through cylinders that have not deployed. I bet it's happened a lot (unintentionally).

Thanks to the posters here passing on some good practical field knowledge and procedures to follow for the safety of our crews.

There is a video out there from Europe of an accident cylinder cut, I'll have to find it, it basically blew up in their faces if I remember correctly.