Car Airbags: How One-Twenty-Fifth Of A Second Of A Chemical Reaction Saves Your Life

Car Airbags: How One-Twenty-Fifth Of A Second Of A Chemical Reaction Saves Your Life

In 2021, when famous golfer Tiger Woods’s over-speeding 2021 Genesis GV80 SUV rolled over several times off the road, it seemed like a fatal accident. However, Woods “miraculously” came out of it alive. Thanks to the airbags. 

While there is no consensus on who invented the first car airbag, everyone agrees that airbags save lives. According to the US Department of Transportation (USDoT) airbags saved more than 50,000 lives from 1987 to 2017. 

While we all know how they look and why they get deployed, not many know how they work. If you’re curious – this blog is for you. 

How Do Airbags Work?

Modern airbags are controlled by an electronic control unit called Airbag Control Unit (ACU). This unit monitors and processes signals coming from various sensors (brake pressure sensors, wheel speed sensors, impact sensors, accelerometers and gyroscopes, etc). It is ACU which decides whether an airbag should be deployed or not. 

Based on the signals received from these sensors, if the ACU decides that an airbag should be deployed, it sends a signal to the initiator to ignite the chemical present inside the airbag inflator. The chemicals in this case could be silicon dioxide, potassium nitrate and sodium azide. When sodium azide is ignited it decomposes to produce nitrogen gas and sodium metal. These then react with potassium nitrate to release more nitrogen. As a result, large amounts of heat is produced. It is this heat which inflates the airbag. 

And just before you would begin to think this must take a longtime, know this – the entire chemical reaction from ACU telling the initiator to inflate the airbag takes place in less than a second. One-twenty-fifth of a second to be precise. Once the heat dissipates, the airbag starts to deflate. 

You must be wondering why don’t airbags catch fire since large amounts of heat is produced during this chemical reaction? To know the answer you need to know what they are made of.

What Are Airbags Made Of?

Airbags don’t catch fire because they are made of woven nylon fabric which is coated with a heat shield. The coat can be of silicone or urethane. To ensure ready deployment of airbags, airbag fabric is coated with talcum powder or cornstarch.

The inflator is made of cast aluminum or stainless steel. It also contains metal-foiled filters that seal the propellant into the inflator. These metal-foiled filters are made of stainless steel as well in wire mesh form.  

This is how an airbag deploys in a nutshell. We hope you found this blog informative. For other such blogs, read:

What safety features to look for when buying a car

If you are looking for airbags and their accessories, find them on OLX Pakistan. 

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