1993 Pontiac Firebird Owner's Manual - Page 28

I When is an air bag expectedto inflate? The airbag is designedto inflate in moderate to severe frontal or near-frontal crashes. The air bag will only inflate if the velocity of the impact is above the designed threshold level. When impacting straight intoa wall that does not move or deform, the threshold level for most GM vehicles is between 9 and 14 mph (14 and 23 km/h). However, this velocity threshold depends on the vehicle design and may be several miles-per-hourfaster or slower. In addition, this threshold velocity will be considerably higherif the vehicle strikes an object such as parked a car which will move and deform on impact. Theair bag is also not designed to inflate in rollovers, side impacts, or rear impacts where the inflation would provide no occupant protection benefit. In any particular crash, the determination of whether the air bag should have inflated cannot be based solely on the level of damage on the vehicle(s). Inflation is determined by the angle of the impact and the vehicle's deceleration, of which vehicle damage is only one indication. Repair cost is not a good indicator of whether an air bag should have deployed. What makes an air baginflate? In a frontal or near-frontal impact of sufficient severity, sensors strategically located on the vehicle detect that the vehicle is suddenly stopping as a result of a crash. These sensors complete an electrical circuit, triggering a chemical reaction of the sodium azide sealed in the inflator. The reaction produces nitrogen gas, which inflates a cloth bag. The inflator, cloth bag, and related hardware are all part of the air bag inflator modules packed inside the steering wheel and in the instrument panel in front of the passenger.