EN ISO 11691:1995

Acoustics - Measurement of insertion loss of ducted silencers without flow - Laboratory survey method (ISO 11691:1995)

Publication date:   Sep 1, 2002

General information

99.60 Withdrawal effective   Aug 19, 2009

CEN

CEN/TC 211 Acoustics

European Norm

17.140.99   Other standards related to acoustics

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Scope

This International Standard specifies a laboratory substitution method to determine the insertion loss without flow of ducted, mainly absorbent, circular and rectangular silencers as well as other duct elements for use in ventilating and air-conditioning systems. Note 1: Laboratory measurement procedures for ducted silencers with superimposed flow are described in ISO 7235. This International Standard is applicable to silencers where the design velocity does not exceed 15 m/s. As the method does not include self-generated flow noise, this International Standard is not suitable for tests on silencers where this type of noise is of great importance for the evaluation of the silencer performance. The insertion loss determined according to this International Standard in a laboratory will not necessarily be the same as the insertion loss that will be obtained in an installation in the field. Different sound and flow fields in the duct will yield different results. As this International Standard requires regular test ducts, the results may include some flanking transmission via structural vibrations in the duct walls, that sets an upper limit to the insertion loss that can be determined. Note 2: ISO 7235 gives methods for determining this limit. This International Standard is intended to be used for circular silencers with diameters of 80 mm to 2 000 mm or rectangular silencers with cross-sectional areas within the same range.

Related legislation

Legislation related to this standard

98/37/EC

Machinery

Harmonized/Supporting
89/392/EEC

Machinery - Safety of machinery: general essential health and safety requirements

Harmonized/Supporting

Life cycle

NOW

WITHDRAWN
EN ISO 11691:1995
99.60 Withdrawal effective
Aug 19, 2009

REVISED BY

WITHDRAWN
EN ISO 11691:2009