Investigation Into the Noise Associated With Air Bag Deployment: Part I - Measurement Technique and Parameter Study

High-amplitude, short-duration noise is called impulse noise. A large body of literature on impulse noise has been developed primarily by military researchers for multiple exposures such as those caused by weapons firing. Some research into the impulse noise associated with air bag deployments was performed in the late 1960's and early 1970's to ascertain the risk of hearing loss. Several criteria for risk of noise-induced hearing loss were proposed and much was learned about the sources of the noise. Unfortunately, the instrumentation used to measure the noise in many of those studies lacked adequate low frequency response characteristics. Perhaps more importantly, results from experiments with human volunteers do not seem to agree with the proposed criteria.

For this study, a new system consisting of commercially available pressure transducers and microphones was assembled and a new software package was developed. This system allows analysis of the pressure-time data using two analysis methods and criteria proposed in the early 1970's. A series of experiments using this system was run over a four year period to investigate the parameters that affect the impulse noise associated with a deploying air bag. Some observations are presented and conclusions drawn from the data.