Determination of acoustic characteristics of pneumatic exhaust silencers: Proposal for a new standard.

This paper describes the development of a standard test procedure for assessing the acoustical efficiency of pneumatic exhaust silencers. Manufacturers wish to take profit of existing ISO 6358 test benches to characterize also the acoustical behavior of the silencers. Tests were carried out on 40 silencers to assess the different parameters required by acoustic measurements.
Two test procedures have been established, one with stabilized pressure, the other one using discharge. A relationship between the pneumatic pressure decay and the noise decay was established, allowing the determination of the radiated noise as a function of the pressure. Thus, the new test procedures will provide the end-user with the parameters to evaluate the mean acoustic level at 1 m. These procedures will be proposed for standardization.