Air Bag-Equipped Car Emergency Rescue Questions And Answers
Most air bag-equipped cars on the road today have a driver-side air bag. A
few makes, Lincoln, Mercedes, and Porsche, have both driver- and
passenger-side air bags as standard or optional equipment. The air bag is
designed to supplement the protection offered by safety belts. In a frontal
impact of sufficient severity ....
Bookmark this Article
Most air bag-equipped cars on the road today have a driver-side air bag. A
few makes, Lincoln, Mercedes, and Porsche, have both driver- and
passenger-side air bags as standard or optional equipment. The air bag is
designed to supplement the protection offered by safety belts. In a frontal
impact of sufficient severity (comparable to a collision into a solid wall at
10-14 MPH or above), sensors in the vehicle detect the sudden deceleration and
trigger the inflator module. This causes the solid chemical propellant sealed
inside the inflator, principally sodium azide, to undergo a rapid chemical
reaction. This reaction produces primarily nitrogen gas, the same gas that
makes up 80 percent of the air we breathe. The gas inflates a woven nylon bag
packed inside the steering wheel hub or the instrument panel for the front seat
passenger. The bag inflates in less than one-twentieth of a second, splitting
open its protective cover, and inflating in front of the occupant. As the
occupant contacts the bag, the nitrogen gas is vented through openings in the
back of the bag, which helps to cushion forward movement.
Because air bags are designed to deploy only in frontal or near-frontal
crashes--not in side, rear, or rollover crashes--it is possible that you will
be involved in rescuing someone from a car with an air bag that did not deploy.
Q2. How do I identify a car equipped with an air bag?
If the bag has deployed, you will be able to see it dropping from the steering
wheel hub or the instrument panel om the passenger side.
If the bag did not deploy, several methods can be used. The steering wheel hub
is large and rectangular, (about 6" X 9"). The large hub usually will be
covered with a scored, soft plastic material. The words, "Supplemental
Inflatable Restraint," "Air Bag," or initials such as "S.I.R.," or "SRS," may
be embossed somewhere on the surface. In most cases, the Vehicle
Identification Number (VIN) can be used to determine the presence of an air
bag. Exhibit 1 shows the codes used by the auto manufacturers. Some
manufacturers indicate the presence of an air bag system by placing placards
under the hood and on the driver side windshield pillar.
If you cannot determine whether the car is equipped with an air bag, you
should assume that it has one, particularly if it's a late model car, and
follow the guidelines for air bag cars.
Q3. Is smoke produced during deployment?
There are three kinds of "smoke." First, many people mistake the corn starch
or talcum powder used to lubricate the bag as smoke. These substances should
not be a problem for rescue workers or accidents victims. Second, a sealant
which is used to prolong the life of the air bag system can smoke when the air
bag is deployed. This smoke dissipates rapidly and should not be cause for
concern. Lastly, during deployment, small particles from inside some bag
systems are vented into the passenger compartment. These airborne particles
look like some, and some are deposited as a powdery residue on and around the
bag.
Q4. Is the air bag hot?
The bag itself will not be hot. Some components within the air bag module will
be hot for a short time, but they are relatively in accessible and should pose
no threat to rescue personnel or crash victims. However personal contact with
the steering wheel hub should be avoided for at least 15 minutes after
deployment.
Q5. What about the powdery residue on and around the air bag?
The residue is primarily corn starch or talcum powder, which is used to
lubricate the bag as it deploys, and by-products of the chemical reaction that
produces the nitrogen gas to inflate the air bag. This residue may contain a
small amount of a potential skin irritant, sodium hydroxide.
The same gloves and eye protection that rescuers would normally wear to protect
themselves (from sharp metal edges, glass, or from bodily fluids) also will
prevent any irritation to the skin or eyes resulting from the residue release
during deployment. Thus, the potential for this type of exposure is not severe
enough to warrant delaying rescue operations. Hands should be washed with mild
soap and water after handeling a deployed bag. Also avoid rubbing your eyes,
eating, or smoking after handeling the bag until you have removed the gloves
and washed your hands. Rescuers also should take care to avoid introducing the
residue into the eyes or any wounds of the patient. If the residue gets into
the eyes, they should be flushed with water.
Q6. Is there any sodium azide in the residue? Is it harmful?
There is no detectable amount of sodium azide residue present in the passenger
compartment after an air bag deployment. Sodium azide, a component of the air
bag inflator propellent, converts to the nitrogen gas used to inflate the air
bag. Sodium azide in it's solid state is toxic, but since it is hermetically
sealed in a very strong metal container, which itself is located inside a
protective housing within the steering hub, it is unlikely that rescue workers
will be exposed.
Q7. If a undeployed air bag module is somehow ruptured, what precautions
should be taken?
In the unlikely event that the canister containing the sodium azide-based
propellent is ruptured, any unburned propellent will be found in a variety of
pressed tablet forms. Do not touch or ingest any exposed propellent or expose
it to an ignition source. As in all other rescue operations, rescuers should
wear gloves and eye protection.
Q8. Is the sodium azide canister likely to explode during a car fire?
No. The air bag is designed to inflate normally in the event that a vehicle
fire causes the canister to be heated above 300 Degrees F. Consequently it is
possible that the air bag will deploy in a car fire, but there should be no
fragmentation of the inflator.
Q9. If there is a fire in an air bag car, can water be used to extinguish it?
Yes. Any effective firefighting medium, including water, may be used to
extinguish a fire in an air bag-equipped car.
Q10. Is it all right to breathe the passenger compartment air after an air bag
has deployed?
Chemical analyses of deployment by-products show no reason for concern. Also
tests have been conducted with volunteers, chronic asthmatics known to be
highly susceptible to airborne particles. These tests showed that the
atmosphere produced by an air bag inflation posed no respiratory system hazard
to the asthmatics studied.
Q11. What has been the experience of crash test personnel in dealing with air
bag-equipped cars?
NHTSA has crash tested more than 70 with air bags. The test engineers and
technicians who regularly handle deployed air bags and test dummies have
reported no ill effects from their repeated exposure to the products of air bag
deployments.
Q12. If the air bag did not deploy in the crash, is it likely to deploy after
the crash?
No. The sensor devices used to activate the system are designed to respond
only to the type of violent forces present during a crash. It is unlikely that
the same type of forces will be created during rescue operations.
In most cases, rescue operations can proceed normally and without delay. In
the unlikely event that a driver or passenger is pinned behind an undeployed
air bag, it will be necessary to take special precautions (See Q15).
Q13. If the air bag(s) did not deploy in the crash, can the system be
deactivated?
The electrically activated systems used on most air bag-equipped cars can be
deactivated. First, disconnect or cut both battery cables. This will begin
the deactivation period for the backup power system that it part of most
electrically activated systems. For some vehicle makes, deactivation will
occur in a matter of seconds; others take a few minutes, (See Exhibit 2).
Mechanically activated systems, used only on 1990 Jaguar coupes and
convertibles, cannot be deactivated in the field.