ISO 7235:1991

Acoustics — Measurement procedures for ducted silencers — Insertion loss, flow noise and total pressure loss

Specifies the substitution method for determining the insertion loss. The measurement procedures are intended for laboratory measurements on silencers but may also be used for in situ measurements on silencers if the requirements of ISO 7235 can be met. Applies to silencers for ventilating and air-conditioning systems. Does not apply to reactive silencers used for motor vehicles.