When should an air bag go off?

[sandrajo]

Do you have to be going at a certain speed for an air bag to go off in your car or does it go by what speed you were going when you crashed?

[Cakeboy]

You've asked the same thing twice there.

An airbag will go off when a certain amount of force is applied to its sensors

[sandrajo]

so I did sorry!



My sister drives a clio and was hit by a car doing around 40 mph and the airbag didn't go off, she thought it would have!

[Loosehead]

I think It's about deceleration so if someone hits you up the rear they won't go off but if you hit something with the fron't of the car they will. I think they also go off if someone reverses into you whilst stationary.

[sandrajo]

they hit her head on, just find it strange at that speed and the airbag not going off?!

[gouldc]

It's complicated - different manufacturers set the airbag sensors at differing levels, so each car is different.

I've recently dealt with a case where a car (Golf) went off at under 10mph.

It's all dependent on where the car is struck, speeds, etc.

Cakeboy has actually summed it up in his response - there is no overall answer unfortunately.

I've seen one case where a car hit a tree at nearly sixty, the car is mangled, yet the bags didn't go off

[sandrajo]

whats the point in having them then?? if the airbag had went off she wouldn't of sustained any injuries as it is she can hardly move her chest is that sore.

[Loosehead]

well in this case they probably should have gone off so it seems the airbag is faulty.

[Cakeboy]

A 40mph head on collision would set the airbags off, there is no doubt about that. From what you're saying, it sounds very much like the airbag or the sensor is faulty, which is an MOT fail at the best, death at the worst.

If it's an older car, it's entirely possible the CO2 canister that inflates the airbag has leaked or gone wrong in some way, the material for the airbag has degraded to the point where it no longer works or, and most probably, the sensor in the front of the car has gone to Silicon Heaven

[Cakeboy]

Further to my previous, she still would've sustained injuries even if the airbag had gone off. It goes off with enough force to break an arm if you catch it wrong, which is why you have to disable them when you have a rear-facing baby seat in the passenger seat.

The reason her chest is sore is because the seat belt restrained her, it leaves some hideous bruising.

[david1702198]

airbags are not tested in the mot i think you will find cakeboy as not every car has them

[david1702198]

the car wouldnt even fail the mot should the airbag or srs warning light be illuiminated

[Cakeboy]

If the airbag is there it has to be working, same as a rear windscreen wiper. If you have not got one, it doesn't have to work - if it's fallen off then your car will fail.

If the car doesn't have an airbag, then it won't be tested.

[Twinkle17]

Hi Sandrajo
I work for a large car manufacturer and I can tell you that and airbag will not definately go off if you are travelling over 40mph, it depends on the angle of the impact and lots of other technical factors. There are ways of finding out if it should of gone off but as I say it depends on a lot of things. I completely agree that it should go off regardless of speed, angles etc but thats the position all manufacturers will probably state if you ask them.
x

[vivandorron]

How does one test an airbag to ensure that it will activate?

Sorry if I've raised another question but it is relevent if there is a suggestion that a faulty airbag would be a reason for an MOT failure......Ron.

[david1702198]

cakeboy i can confirm that you are talking S H I T E i was an mot tester for 6 years and ia can GUARANTEE that the airbags OR rear wiper are not tested during the mot so i suggest you maybe check up on these things before you go advising folk with your B O L L O C K S

[tufty7]

The road outside my unit has not been adopted as yet by the council due to it being an unfinished trading estate, there is a manhole cover that sticks up just off the ramp from the old road to the new , there has been two incidents with this , the first being an audi tt that had the sump ripped off and also the airbag went off, the most recent one being a fiat punto which did the same and that air bag went off as well, the driver came in a little shocked with powder all over ther face , he asked to borrow some scissors to cut the air bag off his steering wheel, So I would say that if the chassis end where the sensor is recieves a knock they will go off..........

[blackcat77]

This is what airbags are for....!

[blackcat77]

This is the link to the above answer....let's hope that it works this time!