---
title: "What is an Airbag made of?"
description: "A coated nylon bag inflated by a small solid-propellant gas generator in about thirty milliseconds. Every component, the material it uses, and the constraint that ma"
url: https://atoneplace.net/made-of/airbag/
site: "At One Place"
---

# What is an Airbag made of?

**What is an Airbag made of?: A coated nylon bag inflated by a small solid-propellant gas generator in about thirty milliseconds.**

The timeline is the whole design. From the crash sensor firing, the propellant burns and fills a 60-litre bag in roughly 30 milliseconds, with the fabric front travelling at up to about 300 km/h — which is why sitting close to the wheel or resting an arm over it is dangerous, and why the bag has already begun deflating by the time an occupant reaches it. Older inflators used sodium azide, which is acutely toxic and made scrapping and disposal a controlled process. The Takata recall, the largest in automotive history, came from inflators using ammonium nitrate propellant that degraded with heat and humidity over years, burnt too fast and burst the metal housing, firing fragments into the cabin.

## Component by component

*Every material is a choice, and the third column is the constraint that drove it.*

| Part | Material | Why that material |
| --- | --- | --- |
| bag | woven nylon 6,6 fabric, silicone-coated | Nylon has the highest energy absorption per gram of the cheap fibres and survives the hot gas; the coating stops the fabric burning and controls porosity. |
| propellant | guanidine nitrate or similar in modern units; sodium azide in units built before the late 1990s | A solid that decomposes to a large volume of nitrogen gas in milliseconds is the only practical way to fill 60 litres that fast. |
| inflator | steel or aluminium housing with filter screens and an igniter | The filter cools the gas and catches solid residue so what enters the bag is not hot particulate. |
| sensing | MEMS accelerometers feeding an airbag control unit | The unit has to distinguish a kerb strike from a crash in a few milliseconds, because firing is irreversible and costs thousands. |
| vents | holes in the rear of the bag | The bag is meant to deflate as you hit it; a sealed bag would bounce the occupant back into the seat. |

## Other cars and driving objects

- [Car tire](https://atoneplace.net/made-of/tire/) — Several different rubber compounds reinforced with steel and textile cord — closer to a composite than to rubber.
- [Car battery](https://atoneplace.net/made-of/car-battery/) — Lead and lead dioxide plates in dilute sulfuric acid, in a polypropylene case — mostly lead, by weight.
- [Brake pad](https://atoneplace.net/made-of/brake-pad/) — A friction compound of fibres, fillers and resin, moulded and bonded onto a steel backing plate.
- [Windshield (windscreen)](https://atoneplace.net/made-of/windshield/) — Two sheets of ordinary glass laminated to a tough plastic interlayer, which is what stops it falling out.
- [Spark plug](https://atoneplace.net/made-of/spark-plug/) — A ceramic insulator carrying a centre electrode of nickel, platinum or iridium inside a steel shell.
- [Seatbelt](https://atoneplace.net/made-of/seatbelt/) — Woven polyester webbing designed to stretch a controlled amount, plus a locking retractor and a pyrotechnic pretensioner.

## Common questions

### What is an Airbag made of?

A coated nylon bag inflated by a small solid-propellant gas generator in about thirty milliseconds.

### What is the bag of an Airbag made of?

Woven nylon 6,6 fabric, silicone-coated. Nylon has the highest energy absorption per gram of the cheap fibres and survives the hot gas; the coating stops the fabric burning and controls porosity.

### What is the propellant of an Airbag made of?

Guanidine nitrate or similar in modern units; sodium azide in units built before the late 1990s. A solid that decomposes to a large volume of nitrogen gas in milliseconds is the only practical way to fill 60 litres that fast.

## Related pages

- [Car tire](https://atoneplace.net/made-of/tire/)
- [Car battery](https://atoneplace.net/made-of/car-battery/)
- [Brake pad](https://atoneplace.net/made-of/brake-pad/)
- [Windshield (windscreen)](https://atoneplace.net/made-of/windshield/)
- [Spark plug](https://atoneplace.net/made-of/spark-plug/)
- [Seatbelt](https://atoneplace.net/made-of/seatbelt/)
- [Pencil](https://atoneplace.net/made-of/pencil/)
- [Tennis ball](https://atoneplace.net/made-of/tennis-ball/)
- [Banknote](https://atoneplace.net/made-of/banknote/)
- [Golf ball](https://atoneplace.net/made-of/golf-ball/)
- [Paper](https://atoneplace.net/made-of/paper/)
- [Glass](https://atoneplace.net/made-of/glass/)

## Sources

- Typical range compiled from manufacturer specifications — At One Place (/about/)