Emergency Rescuer's Guide to Cars Fitted with Airbag Supplemental Restraint Systems (Airbag SRS)
How an airbag SRS works
An airbag SRS may be an electrical or mechanical type, with some or all of the following elements;
The airbag SRS module - includes an inflator, an airbag, and a trim cover
The electronic diagnostic module - monitors the airbag SRS electrical system for faults and disables the system when certain faults are detected
Crash sensors - detect sudden deceleration. Internal sensors are integral with the airbag SRS module, resulting in a self-contained system. External sensors are located elsewhere on the vehicle.
A back-up power supply - provides power to the system in case the battery is damaged before the crash sensors operate.
The driver-side airbag SRS module is located in the hub of the steering wheel. The passenger-side airbag SRS module (if the vehicle is so equipped) is in the dashboard above the glove compartment. The side-impact airbag SRS module (if the vehicle is so equipped) is in either the door panel or the seat and may not be visually identifiable.
The airbag SRS inflator contains a solid chemical gas generant consisting of:
solid pellets or disks of sodium azide and an oxidiser, such as copper oxide or,
a solid cylinder of nitrocellulose.
The solid chemicals are safely stored in a metal chamber inside the airbag SRS module. Each inflator is sealed to keep out moisture.
An airbag SRS is designed to deploy in moderate to major frontal crashes. The following four steps show how the airbag SRS works:
(i) In a frontal impact, sensor(s) in the vehicle detect the sudden deceleration. When the sensor(s) close, electricity flows to the inflator and causes ignition of the gas generant.
(ii) The gas generant then rapidly burns in the metal chamber. The rapid burning produces inert gases and small amounts of dust. The inert gases and dust are cooled and filtered, during inflation of the airbag.
(iii) The inflating airbag splits open the trim cover. The airbag then rapidly unfolds and inflates in front of the occupant.
NOTE: Steps 1-3 take place in a fraction of a second.
(iv) After inflation, the gas is vented through openings or open weave areas in the airbag. Airbags deflate at once and may be pushed aside for occupant removal.
NOTE: some recent passenger airbag systems use a compressed inert gas for inflation. The same precautions should be applied as with conventional airbag systems.
Airbags SRS chemicals
Rescuers should not be overtly concerned about the possibility of contact with any airbag SRS chemicals. The two generants in common use are sodium azide and nitrocellulose. Prior to deployment of the airbag SRS, these generants are extremely well sealed within a strong metal container.
Sodium azide in its solid state is toxic. However due to the strong metal container, contact with it is extremely unlikely for rescue workers. In 1984 the National Highway Traffic Safety Administration (NHTSA), part of the US Department of Transportation, reported that both industry and the Federal Government had investigated and resolved health concerns relating to the use of sodium azide in airbag SRSs.
However, as in all other rescue operations, rescuers should wear gloves and eye protection. In the unlikely event that the container has ruptured, the generant will be found in pressed tablet form. Do not touch, ingest or expose the generant to an ignition source.
Nitrocellulose is not considered toxic and has no known irritating effects. A form of it is used mainly in the Eurobag Airbag SRS. In the unlikely event that the container has ruptured, the generant will be found in powder form. Do not expose the generant to an ignition source. Mix water with the powder to prevent ignition.
Once the airbag SRS has deployed, the vehicle interior may briefly appear to contain 'smoke'. This 'smoke' is actually a powdery residue that will settle on the surface of deployed airbag(s) and the vehicle interior. The powdery residue is corn starch or talcum powder, which is used to lubricate the airbag as it deploys. The residue may also contain sodium compounds, mostly sodium carbonates (e.g. baking soda), and the interior air may contain small amounts of carbon monoxide. All of these are by-products of the general combustion. There might also be a very small amount of sodium hydroxide that may be irritating to the skin and eyes.
NOTE: sodium hydroxide powder is slightly alkaline but is not considered toxic.
Engineers and technicians regularly involved in airbag SRS crash tests have reported no ill-effects from the products of airbag SRS deployment In other tests on volunteers, the atmosphere produced by deployed SRS airbags, was found to pose no respiratory system hazard to chronic asthmatics.
The same gloves and eye protections rescuers wear normally, will prevent irritation due to sodium hydroxide. After handling a deployed airbag, rescuers should avoid rubbing their eyes, eating or smoking until they wash their hands with mild soap and water.
How to identify a vehicle fitted with an airbag SRS
To identify a vehicle fitted with an airbag SRS, begin by checking for a 'SRS' or 'Airbag' moulded on the trim cover of the steering wheel hub and on the dashboard on the passenger's side. Side airbags are not always visually identifiable. There may also be a label or placard fitted to the following:
underside of the bonnet
sun visor(s)
inside of the glovebox
driver-side windscreen pillar
driver-side or passenger-side 'B' pillar
driver-side door
lower corner of the windscreen
You can also check for a larger and more rectangular steering wheel hub (about 150 mm by 250 mm) which may indicate the presence of a driver-side airbag SRS. However, Eurobag or Facebag systems (e.g. BMW) are usually housed in normal sized steering wheel hubs.
In many cases vehicles fitted with an airbag SRS can be identified by comparing the Vehicle Identification Number (VIN) with manufacturer's data. Side airbags can be identified in this manner.
How to de-active an airbag SRS
Different types and models of airbag SRS have different methods of de-activation. For electrically activated systems which have a back-up power supply, disconnecting the car battery (in accordance with the manufacturer's instructions) will begin the de-activation period for the back-up power supply. De-activation time for the back-up power supply may take a period of time ranging from seconds to minutes, depending on the system.
Simply turning the ignition switch to 'OFF' may not de-activate the airbag SRS. The airbag SRS deployment mechanism may operate independently of the ignition switch. However, most systems will have a 'safing' sensor which offers additional security against inadvertent deployment of the airbag.
Mechanically activated systems can sometimes be de-activated in the field.
Vehicle fire
When dealing with a vehicle fire, use standard fire extinguishing procedures first. Use any type of fire-fighting agent, including water. The gas generant is sealed in a watertight container. However, perform fire extinguishing procedures from the side of the vehicle and away from the potential deployment path of the airbag.
In the rare case of an interior occupant compartment fire, the airbag SRS module is designed to self-deploy if its internal temperature reaches approximately 175°C. The inflator will remain intact and operate normally.
NOTE: airbag SRS modules will not explode.
Vehicle recover - towing
Towing a vehicle with an undeployed airbag SRS
Standard towing procedures are unlikely to deploy an airbag SRS. However, as a precaution when towing a vehicle with major frontal damage and an undeployed airbag SRS, safely disconnect the battery. Although generally good practice, be aware that this may not de-activate the system immediately, or at all with some types of airbag SRS.
Towing a vehicle with a deployed airbag SRS
When towing a vehicle with a deployed airbag SRS, follow the deployed airbag SRS precautions.
Vehicle scrapping
If a vehicle with an undeployed SRS is designated for scrapping, it is recommended that prior to scrapping, the airbag be safely deployed in accordance with the manufacturer's instructions.
Rescue with undeployed airbag SRS
Remember an airbag SRS will deploy only in moderate to major frontal or near-frontal crashes. An airbag SRS is not designed to deploy in side, rear, rollover, or less severe frontal crashes. For this reason, it is likely that you will be involved in a rescue from a vehicle with an airbag SRS that did not deploy.
An airbag SRS is unlikely to deploy during a rescue. On some vehicles there are two sensors which must close at the same time, therefore it is unlikely that rescue operations will result in a deployment. On many vehicles, the diagnostic module will also disable the airbag SRS if it detects crash sensor circuit 'shorts' that exist for ten seconds while the ignition is 'ON'.
The metal combustion chamber in the airbag SRS module is sealed and protected. It is contained inside a permanently closed metal inflator located under the folded airbag that is behind the airbag SRS module trim cover. It is unlikely that the combustion chamber will rupture during a crash.
Never cut or drill directly into an undeployed airbag SRS module or attempt to take the module apart. This will avoid possible deployment and exposure to toxic chemicals. Do not touch exposed chemicals in the unlikely event the metal inflator canister of an undeployed airbag SRS module is ruptured or cut.
Rescue steps for undeployed airbag SRS
If the vehicle has been identified as having an airbag SRS the rescue steps are as follows:
(i) If possible, de-activate the airbag SRS. When fully de-activated (including waiting for any specified de-activation period), rescue operations can be carried out as normal.
(ii) While the airbag SRS is being de-activated, or if it is unable to be de-activated, the following rescue operations should begin immediately:
(a) DO move the seat of a stabilised occupant back as far as possible or lower the seat back.
(b) DO turn off the ignition
(c) DO safely disconnect the battery. Disconnecting the battery immediately stops all power sources entering the steering column. Although good practice, be aware that this may not de-activate the system immediately, or at all with a mechanical type.
(iii) It is important to appreciate the following during rescue operations with an airbag SRS that has not deployed and has not been de-activated
(a) DO perform rescue efforts from the side of the vehicle and away from the potential deployment path of the airbag.
(b) DO keep your body or objects/tools off the airbag SRS trim cover and away from the front of an undeployed airbag.
(c) DO NOT apply sharp blows to the steering column or dashboard if a vehicle is fitted with internal crash sensors, that is, a self contained system in the steering wheel.
(d) DO NOT cut into the steering column. Only cut the steering wheel rim or spokes. Do not apply heat near the SRS module, as this could cause the inflator to deploy.
(e) If the vehicle is fitted with side airbags, avoid sharp blows to the door, seat or B-pillar areas.
Rescue with deployed airbag SRS
If the airbag SRS has deployed, use normal rescue procedures and equipment. Do not delay rescue. There are no hazardous medical consequences for an occupant or rescue personnel from a deployed airbag SRS.
Wear the same gloves and eye protection that rescuers would normally wear. Protective equipment will guard against possible skin or eye irritation from the powdery airbag residue. Whether gloves are worn or not, wash your hands with mild soap and water after handling a deployed airbag.
Be aware of hot metal parts underneath the deployed airbag fabric. These components are located inside the steering wheel hub or behind the dashboard when there is a deployed passenger-side airbag SRS. These components are somewhat out of the way and should pose no threat.
NOTE: the airbag fabric, steering column, and steering wheel rim and spokes will not be hot.
Never cut or drill directly into an airbag SRS module or attempt to take the module apart. This will avoid exposure to toxic chemicals. Do not touch exposed chemicals in the unlikely event the metal inflator canister of an airbag SRS is ruptured or cut.
Push deflated airbag aside for occupant removal. Airbags deflate at once after a deployment. There is no need to cover, remove, or repack the airbag during rescue operations.
Occupants can sustain minor skin redness or abrasions from contact with a deploying airbag, e.g. on the inside of the forearm or on the chin.
http://www.police.qld.gov.au/rti/published/policies/traffic-manual/05/App_05_02.htm
I really liked that old car and your picture brought back a TON of good childhood memories - thanks a LOT for that!!!!!!!!!!