This International Standard deals with the practical selection of silencers for noise control in gaseous media. It specifies the acoustical and operational requirements which are to be agreed upon between the supplier or manufacturer and the user of a silencer. The basic principles of operation are described in this International Standard, but it is not a silencer design guide.

The silencers described are suitable, among others,

• for attenuating system noise and preventing crosstalk in heating, ventilation and air-conditioning (HVAC) equipment;
• for preventing or reducing sound transmission through ventilation openings from rooms with high inside sound levels;
• for attenuating blow-off noise generated by high-pressure lines;
• for attenuating intake and exhaust noise generated by internal combustion engines; and
• for attenuating intake and outlet noise from fans, compressors and turbines.

They are classified according to their types, performance characteristics and applications. Active and adaptive passive noise-control systems are not covered in detail in this International Standard.