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  • BS EN ISO 7235:2009

    Current The latest, up-to-date edition.

    Acoustics. Laboratory measurement procedures for ducted silencers and air-terminal units. Insertion loss, flow noise and total pressure loss

    Available format(s):  Hardcopy, PDF

    Language(s):  English

    Published date:  30-04-2010

    Publisher:  British Standards Institution

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    Table of Contents - (Show below) - (Hide below)

    Foreword
    Introduction
    1 Scope
    2 Normative references
    3 Terms and definitions
    4 Symbols
    5 Test facilities and requirements for instrumentation
    6 Test procedures
    7 Information to be recorded
    8 Information to be reported
    Annex A (normative) - Design of the sound field excitation
            equipment and qualification tests
    Annex B (normative) - Transmission element
    Annex C (normative) - Duct walls and limiting insertion loss
    Annex D (normative) - Conversion of one-third-octave-band
            attenuation values to octave-band attenuation values
    Annex E (normative) - Measurements on large parallel-baffle
            silencers
    Annex F (normative) - Test of longitudinal attenuation
    Annex G (informative) - Anechoic terminations
    Annex H (informative) - Examples of measurement arrangements
    Bibliography
    Annex ZA (informative) - Relationship between this European
             Standard and the Essential Requirements of EU
             Directive 98/37/EC
    Annex ZB (informative) - Relationship between this European
             Standard and the Essential Requirements of EU
             Directive 2006/42/EC

    Abstract - (Show below) - (Hide below)

    Describes the methods for determining: - the insertion loss, in frequency bands, of ducted silencers with and without airflow; - the sound power level, in frequency bands, of the flow noise (or regenerated sound) generated by ducted silencers; - the total pressure loss of silencers with airflow; and - the transmission loss, in frequency bands, of air-terminal units.

    Scope - (Show below) - (Hide below)

    This International Standard specifies methods for determining

    • the insertion loss, in frequency bands, of ducted silencers with and without airflow,

    • the sound power level, in frequency bands, of the flow noise (or regenerated sound) generated by ducted silencers,

    • the total pressure loss of silencers with airflow, and

    • the transmission loss, in frequency bands, of air-terminal units.

    The measurement procedures are intended for laboratory measurements at ambient temperature. Measurements on silencers in situ are specified in ISO 11820.

    It is to be noted that the results determined in a laboratory according to this International Standard will not necessarily be the same as those obtained in situ (installation), as different sound and flow fields will yield different results. For example, the pressure loss will be lower under laboratory conditions than in situ, but will be comparable between different laboratories.

    This International Standard is applicable to all types of silencer including silencers for ventilating and airconditioning systems, air intake and exhaust of flue gases, and similar applications. Other passive air-handling devices, such as bends, air-terminal units or T-connectors, can also be tested using this International Standard.

    This International Standard is not applicable to reactive silencers used for motor vehicles.

    NOTE 1 Annex A specifies the sound field excitation equipment. Annex B gives requirements for the transition element. Annex C gives details of duct walls and limiting insertion loss. Annex D specifies how to convert one-third-octave band attentuation values to octave band values. Annex E gives requirements for measurements on large parallel-baffle silencers. Annex F specifies a test of longitudinal attenuation. Annex G gives guidelines on anechoic terminations and Annex H shows examples of measurement arrangements.

    NOTE 2 Acoustic testing of air-terminal devices and fan-coil units is to be carried out as described for air-terminal units.

    NOTE 3 Sound power measurements on air-terminal units are specified in ISO 5135. Measurements of the pressure loss of air-terminal units are described in EN 12238, EN 12239 and EN 12589.

    General Product Information - (Show below) - (Hide below)

    Committee EH/1/4
    Development Note Supersedes BS 4718(1971) and 01/562316 DC. (09/2003)
    Document Type Standard
    Publisher British Standards Institution
    Status Current
    Supersedes

    Standards Referencing This Book - (Show below) - (Hide below)

    ISO 5725-1:1994 Accuracy (trueness and precision) of measurement methods and results — Part 1: General principles and definitions
    ISO 11200:2014 Acoustics Noise emitted by machinery and equipment Guidelines for the use of basic standards for the determination of emission sound pressure levels at a work station and at other specified positions
    EN 12238:2001 Ventilation for buildings - Air terminal devices - Aerodynamic testing and rating for mixed flow application
    IEC 60942:2003 Electroacoustics - Sound calibrators
    ISO 5725-3:1994 Accuracy (trueness and precision) of measurement methods and results — Part 3: Intermediate measures of the precision of a standard measurement method
    ISO 5725-6:1994 Accuracy (trueness and precision) of measurement methods and results — Part 6: Use in practice of accuracy values
    ISO 5725-4:1994 Accuracy (trueness and precision) of measurement methods and results Part 4: Basic methods for the determination of the trueness of a standard measurement method
    ISO 11820:1996 Acoustics — Measurements on silencers in situ
    ISO 3746:2010 Acoustics Determination of sound power levels and sound energy levels of noise sources using sound pressure Survey method using an enveloping measurement surface over a reflecting plane
    ISO 5135:1997 Acoustics Determination of sound power levels of noise from air-terminal devices, air-terminal units, dampers and valves by measurement in a reverberation room
    ISO 5167-1:2003 Measurement of fluid flow by means of pressure differential devices inserted in circular cross-section conduits running full Part 1: General principles and requirements
    ISO 9614-3:2002 Acoustics — Determination of sound power levels of noise sources using sound intensity — Part 3: Precision method for measurement by scanning
    EN 12239:2001 Ventilation for buildings - Air terminal devices - Aerodynamic testing and rating for displacement flow applications
    ISO 5725-2:1994 Accuracy (trueness and precision) of measurement methods and results Part 2: Basic method for the determination of repeatability and reproducibility of a standard measurement method
    ISO 14163:1998 Acoustics — Guidelines for noise control by silencers
    ISO 3741:2010 Acoustics Determination of sound power levels and sound energy levels of noise sources using sound pressure Precision methods for reverberation test rooms
    ISO 5221:1984 Air distribution and air diffusion Rules to methods of measuring air flow rate in an air handling duct
    1998/37/EC : 1998 DIRECTIVE 98/37/EC OF THE EUROPEAN PARLIAMENT AND OF THE COUNCIL OF 22 JUNE 1998 ON THE APPROXIMATION OF THE LAWS OF THE MEMBER STATES RELATING TO MACHINERY
    IEC 61260:1995 Electroacoustics - Octave-band and fractional-octave-band filters
    EN 12589:2001 Ventilation for buildings - Air terminal units - Aerodynamic testing and rating of constant and variable rate terminal units
    ISO 3966:2008 Measurement of fluid flow in closed conduits Velocity area method using Pitot static tubes
    ISO 5136:2003 Acoustics — Determination of sound power radiated into a duct by fans and other air-moving devices — In-duct method
    ISO 5725-5:1998 Accuracy (trueness and precision) of measurement methods and results — Part 5: Alternative methods for the determination of the precision of a standard measurement method
    IEC 60651:1979+AMD1:1993+AMD2:2000 CSV Sound level meters
    IEC 60804:2000 Integrating-averaging sound level meters
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