Airbags - How to cushion their impact
Testing and Characterisation of Automotive Pyrotechnic (Airbag) Emissions
Since their first development in the 1950s, airbags have played a key part in reducing injury risk in collisions for vehicle occupants. Many of these systems operate by utilising a rapid burning propellant to generate gas, which inflates the airbag within milliseconds. This allows vehicle occupants to 'ride down' the airbag and protects them from interaction with the vehicle's interior during a collision. These rapid burning propellants are now used alongside compressed gases to 'operate' many safety systems. In Europe in the last 15-20 years, their development and uptake has been swift, resulting in contemporary vehicles now being equipped with up to twenty of these systems. They now not only provide passive safety for vehicle occupants but form part of active safety and are beginning to be used to protect pedestrians.
With such high fitment rates and the potentially hazardous nature of these systems and components, European Union legislation now mandates the neutralisation of these devices at the end of a vehicles life, mainly to minimise their environmental impact. In the UK in 2012 the estimated number of devices requiring treatment has risen to 6.5 million, an increase of nearly 45% since 2008; a trend likely to continue for the foreseeable future. The neutralisation of these devices at the end of a vehicles life presents a technical challenge to those involved and a potential risk to health from repeated exposure to post-deployment atmospheres. Previous testing concentrated on single time exposures to these emissions after a collision; this research is characterising repeated exposures with the following objectives:
- To assess existing testing procedures, methods and equipment for neutralisation exposures
- To develop a standard and best practice for sampling particulate matter from post-deployment vehicle atmospheres
- To identify the concentration, size distribution and behaviour of sub-micron solid particulates, to assist in defining the hazards to human health
- To develop safety protocols for the dismantling industry, to allow safe recycling of pyrotechnic devices and end of life vehicles
- Development of pyrotechnic testing facility, verified to represent vehicle interiors for end of life and post-crash exposure assessment-only one of its kind in UK
- Provision of technical support to Society of Automotive Engineers (SAE) Inflatable Restraints Standards Committee.