Safety around airbags and other explosive parts

Most modern vehicles have airbags and seat belt pre-tensioners which may need to be repaired or replaced over time.

Many such devices incorporate a small explosive charge/pyrotechnic ignition device and should be treated with the appropriate level of care. If you store or work on such devices, you need to be aware of the risks involved and the precautions to take.

There is specific legislation covering the manufacture, sale/supply and storage of explosives (The Explosives Regulations 2014 and The Pyrotechnic Articles (Safety) Regulations 2010) which will apply in addition to other general health and safety legislation.

The amount of explosive that can be stored and where it must be kept depends on the type of explosive and the quantity. The Net Explosive Content (NEC) is an important detail you need to consider, since it will tell you the actual amount of explosive, ignoring the weight of other components and packaging which make up the article.

Within the Explosives Regulations 2014 four hazard types (HT) for explosives are described (type 1 being the most hazardous and type 4 being the least hazardous). The explosive element of vehicle airbags and seat belt pre-tensioners is normally classed as HT 3 or 4 (these classifications mirror UN hazard divisions (HD) 1.3 and 1.4 respectively; this may be displayed on boxes or packaging in an orange box).

What about UN hazard classes 2 and 9?

Airbags and pre-tensioners with a UN hazard class 2 (gas) or 9 (miscellaneous) are not classified as explosive, so the Explosives Regulations 2014 won’t apply. However, such devices should still be kept in similar conditions due to their potentially hazardous nature. Information relating to the UN hazard class/type and the NEC should be visible on the packaging or available via the supplier or the device safety data sheet.

Key actions to work safely around explosive vehicle parts

Ensure that you are aware of and comply with your obligations under the Explosives Regulations 2014.

There are 10 general principles of safety which should form part of the arrangements and working practices of anyone working with or storing explosive material.
The following is quoted from Health and Safety Executive (HSE) publication L150 which provides guidance on the Explosives Regulations 2014:

    - 1. People undertaking explosives operations should be competent to carry out their particular roles.

    - 2. The particular hazards associated with the explosives should be understood.

    - 3. The sources of energy that could cause the explosives to initiate should be identified.

    - 4. Appropriate safety measures should be part of a planned and proportionate system of work to control all sources of energy that could cause an initiation.

    - 5. Particular care should be taken where an activity involves the application of energy to an explosive to ensure that this is controlled.

    - 6. So far as reasonably practicable, the quantity of explosives, extent and duration of exposure to the hazard should be minimised.

    - 7. The number of people exposed to the hazard should be limited to the minimum necessary for the activity in hand.

    - 8. Precautions should be in place to prevent an explosives event from escalating if an initiation does take place.

    - 9. Precautions should be in place to protect people if an initiation does occur.

    - 10. Robust systems should be in place to make sure that the necessary precautions are in place and remain effective.

Take simple precautions to avoid triggering an explosion while handling items classed as HT 3 or 4, such as keeping the items away from stocks of flammable substances and sources of ignition, ensuring that the building can be effectively evacuated in an emergency and providing information on the building’s contents to the emergency services.

These measures may be deemed to be adequate to control the risks they pose.