Automobile Airbag Identification Issues

by Bob Brown

In my previous article, the various styles of side impact and head protection airbag systems were discussed. As a follow up to that article, we will have a look at the challenge of determining what vehicles are equipped with these systems, as well as identifying related challenges such as battery locations, seatbelt pretensioners and break resistant glass.

To date, there are no standards in place requiring a uniform identification method when a manufacturer makes the decision to equip a vehicle with more than just the dual front airbags. In fact, it is not mandated to identify the driver or passenger front airbag and, although thankfully rare, there are examples of these identifications lacking. Also, to date, there is not a single manufacturer providing a visible identification indicating the presence of a pyrotechnic seatbelt pretensioner (and currently these are available on approximately 75 models of cars, vans and sport ute’s).

The good news on the identification front happened in May at a meeting between the author and 3 major auto manufacturers. The topic of discussion revolved around the complication for the rescuer in identifying the following:
1. What is the make, model and year of this car?
2. Where is the battery located?
3. What types of airbag systems are in this specific vehicle (front, side, head, or knee)?
4. Are there seatbelt pretensioners?

I would like to complement General Motors, BMW, and Mercedes Benz for their participation in, and enthusiasm for this project, along with the Society of Automotive Engineers for their help in carrying this project forward. All understood the many challenges the rescuer finds on an extrication scene and are considering options for a method of answering the above questions in some user-friendly format. We received great input from a gentleman deeply involved in the EMS side of the profession, Paul Maniscalco, Adjunct Assistant Professor GWU and Deputy Chief FDNY EMS. Fire Rescue Magazine will keep you informed of the progress of this committee.

In researching what vehicles are equipped with side impact airbags or head protection systems, one will quickly discover the lack of uniformity for the location of the various tags, stickers, plates or embossed identifiers. In situations where the side impact airbag is located in the door as is the case with BMW, Mercedes, Porsche, and the Cadillac DeVille Concours and D’Elegance, the identification will be found somewhere on the inside door panel. However, identifiers will not necessarily be easy to see. Walk into the showrooms of some of the above mentioned car manufacturers and have a look at the passenger door from outside the driver’s door. With 20/20 vision you will likely be able to make out a small area where “AIRBAG”, “SRS Side Airbag” or just “SRS” is stamped or embossed into the door. Now fast forward yourself to the incident in the middle of the night, in the rain, patients pleading with you to make their world all better again, adrenaline coursing through your veins, and oh, by the way, did you notice that little I.D. tag on the door? Probably not, unless you were aware that this is one of the 15 or so models of cars available with door mounted side bags (and providing you can even figure out what this smoking pile of wreckage used to be). Remember too that if there are patients in the seat, the identification area will likely be blocked from view.

The more common side impact airbag is mounted in the seat, and deploys forward (and in some cases upward) from the seam of the seat between the occupant and the door. Again, the challenge exists in locating the identifier. Have a look at the variety of locations in the accompanying photos and take note of the small size and lack of contrasting colors for the labels. Will you actually be able to see these labels even if scanning the interior of the vehicle during your initial scene survey? If both front seat positions are occupied you are out of luck, with very few exceptions (such as when labels are on the seat side as in the photo above, although again with the seat in its normal position this area is hidden by the “B” pillar).

If you’re not yet stressing out about the locators for side impact airbags, look at the three manufacturers (soon to include a fourth and major American manufacturer) installing head protection systems. The first, BMW, uses the tubular style bag extending from the lower “A” pillar to the roof rail behind the front seat occupants’ head. If you know what you are looking for, this system is easy to identify. Look at the “A” pillar from outside the windshield and scan thoroughly. The ID will either be a tab in the upper area of the pillar (in the 5 & 7 series) or embossed midway in the plastic strip running up the center of the pillar (3 series). The letters HPS will tell you that this BMW is equipped with a Head Protection System. Precautionary measures should include avoiding the deployment zone during extrication activity. An accidental triggering of this device could be a nasty surprise for the rescuer leaning though the front windows. (The pyrotechnic device is at the lower end of the "A“ pillar approximately where the top hinge is located).

The next two manufacturers to use head protection systems are Mercedes (“E-class and “S-class) and Volvo S80. This technology uses a curtain style airbag to cover the inside area of the occupant compartment from the “A” pillar to the “C”pillar. Inflation is accomplished with the use of a compressed gas cylinder (see example in diagram 1). This cylinder is located in the “C” pillar and should be avoided during roof removal. A very high cut (at the roofline of the pillar) should get you around the gas cylinder. If you do cut through the cylinder the rush of escaping gas and the potential for cylinder failure should do a good job of tightening your sphincter. The gas is harmless (95% Argon, 5% Helium), however the addition of a pyrotechnic charge and flammable liquid or gas chamber complicate matters. These are added to heat and expand the escaping gas, since escaping compressed gasses cool and would not provide enough expansion to fill the airbag in time to do its job. Again, I strongly recommend a visit to Mercedes and Volvo dealers as the identifiers for the curtain style airbags are very difficult to see.

There are other side impact airbags which also provide head protection, such as the Ford head thorax bag introduced in the ’99 Mercury Couger and available in the Explorer, Windstar, and Lincoln’s. Unfortunately, the identifiers for side bags give no indication of the size of the bag. With this in mind, it would be wise to get to know the various systems available in order to understand what areas of the vehicle pose a potential hazard during your extrication activity.

There is one side impact airbag system that warrants individual attention. In 1995 Volvo was the auto manufacturer to bring the first side impact airbag system to market. This bag was designed to activate mechanically rather than electronically. (The only other mechanically activated airbags this author is aware of were the driver front airbags installed in the older Jeep Cherokee and Jaguar’s). The sensor in the side of the seat is actually a compression sensor. When depressed far enough, it activates a charge in the tube, which flashes up to the airbag canister and inflates the bag. Volvo actually wrote instructions for the rescuer showing how to disable this system in the event of the need to force the door, displace the seat, etc. I give Volvo all due credit for thinking of the challenge we face when working around these systems (for a copy of the 4 page Emergency Protocols written by Volvo, contact Holmatro or Volvo). Now for the bad news. As of the 1999 model year this system has changed and so have the rules! As with all other side impact airbag systems, this one is now electronically activated. You should not reach in to access and cut the ribbed black plastic cable (wire loom) as of the ’99 model year.. The reason is that there is now an electric wire running up to the airbag module in place of the pyrotechnic tube and as with any electronic airbag wiring it should not be cut. To help clarify the difference between these systems, view the video available from Holmatro entitled New Vehicle Safety Systems for the Rescuer. It contains a bundle of valuable information on new vehicle technologies and will help clarify many of the challenges being faced in modern car rescue hazards.

If you missed the opportunity in the November issue of Fire Rescue, a current list of vehicles with side impact and other pyrotechnically activated technology, such as seatbelt pretensioners, is available. It also contains many of the unusual battery locations that may thwart our efforts to remove the power to the airbag system.

All current literature available from auto manufacturers and the National Highway Traffic Safety Administration strongly recommend the disconnection of the battery to reduce the potential for accidental deployment of a pyrotechnic system during rescue. I stress the word reduce since there will always be the potential for static electricity to foul your plan. The growing problem with battery disconnection is accessibility. It is now becoming common practice for the auto manufacturer to locate the battery under the rear seat, in the trunk, or in the left or right front wheel well. I just had the opportunity to borrow a model year 2000 Buick LeSabre for a class, and much to my surprise the battery moves to the under rear seat location for this car. Why? It seems the most logical reason, according to the manufacturer, is to increase the longevity of the battery by avoiding the high heat and vibration typical to the under the hood location. There are also center of gravity issues and space considerations. Here are some vehicles with unusual battery locations:

Battery Under Rear Seat
Buick Riviera, Park Avenue, Le Sabre
Cadillac Eldorado
Mercedes E-Class
Oldsmobile Aurora
BMW 7-series pre ‘97
Battery In Trunk
BMW-all models since ’97
Jaguar XJ, XK, &VDP
Mercedes C,S,SL,& SLK-Class
Porsche 928
Volvo S80

Battery In Wheel Well
Chrysler LHS, Concord, &M300 (right front well)
Dodge Stratus & Cirrus (left front well)
Plymouth Breeze (left front well)

Other battery access challenges will include the under-ride situation in car versus truck crashes, and rollovers. Whenever you must work a crash where you are unable to disconnect the battery, increase your level of caution and awareness of body position relative to the airbag deployment zone. Due to the huge variety of airbag sizes there really are no specific guidelines for a “safety zone” where you can be sure of avoiding the explosive force of a deploying bag. It is also important to re-position your patient away from the deployment path whenever practical. In situations where there is a seat mounted side impact airbag move the patient toward the inside of the vehicle (away from the outboard edge of the seat). With door mounted side bags, tilting the seat back will help avoid the deployment zone (in addition to getting them away from the front bags.
With the ever-popular sport of urban (typically) carjackings things are heating up a bit in reference to the break resistant glass issues. BMW offers what they refer to as “Security Glass” in the side windows of the 7-series. This stuff is 6 layers and 9mm thick, the center layer being impact resistant polycarbonate. If you bump into it don’t bother with an attempt at side glass removal. Simply go to the rear window with your punch since it remains tempered. Other manufacturers are beginning to use laminated side and/or rear glass, which will mean more glass cutting in the future. One disturbing development is the possibility for allowance of impact resistant polycarbonate glass for all non-windshield locations. In testing by TERC, this material thwarted most efforts at quick removal, and the most effective method turned out to be a router. Oh boy. As we all know, in many cases immediate access to the patient in a car crash is critical to their survival. The practicality issue of adding a router to your cache of rescue tools must be questioned. So far this material is being used only in non-retractable windows for cars, but it is not uncommon to find it in busses and trains.

Again, keeping abreast of the ever-changing automobile design is a constant challenge. Get out to your local car dealers and snoop around. Look for the variety of airbag locations and identifications, battery locations, gas struts under the hood and trunk, and check the sticker for seatbelt pretensioners. Holmatro will continue to develop the database containing most of the hazards to the rescuer, and will soon have a comprehensive guideline available for field reference. Stay in touch!

- Look for seat bag identifications on the seat side, tag sewn into the seam, or lower seat edge
- Look for door bag identification on the door panel
- On BMW’s, check the “A” pillar for the HPS label
- ON Mercedes, look at the top of the “B” pillar for “SRS-Airbag” identifying the Window Curtain
- On Volvo, look at the top of the “C” pillar for “IC/ Inflatable Curtain” identification
- There are no identification locations for the seatbelt pretensioner
- Re-position your patient away from the potential airbag deployment path whenever possible
- Turn ignition switch to the off position after taking advantage of the electric door lock releases, windows, and seats
- Disconnect battery, negative first
- If you don’t find the battery under the hood, remember the wheel well, trunk, and rear seat locations
- Respect the potential for static electricity deployments

PLEASE NOTE
If you have experienced the deployment of an airbag or seatbelt pretensioner during a rescue, please contact the author. It is extremely important information to aid in training your fellow rescuers regarding the potential hazards of live pyrotechnics. I am also in the process of gathering information on fires starting from airbag deployments and gas strut failures during car fire scenes.