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  • BS 4718(1971) : 1971

    Superseded A superseded Standard is one, which is fully replaced by another Standard, which is a new edition of the same Standard.
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    METHODS OF TEST FOR SILENCERS FOR AIR DISTRIBUTION SYSTEMS

    Available format(s):  Hardcopy, PDF

    Superseded date:  08-09-2003

    Language(s):  English

    Published date:  01-01-1971

    Publisher:  British Standards Institution

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

    Co-operating organizations
    Foreword
    Methods of test
    1 General
    1.1 Scope
    1.2 General
    1.3 Definitions
    1.4 Symbols
    1.5 Instrumentation
    1.6 Installation
    1.7 Quantities to be measured
    1.8 Methods of measurement
    1.9 Thermal environment
    1.10 Accuracy of measurements
    2 Measurement of static insertion loss
    2.1 General requirements
    2.2 The in-duct method
    2.3 The diffuse field method
    3 Measurement of generated noise loss
    3.1 General requirements
    3.2 Diffuse field: direct method
    3.3 Diffuse field: substitution method
    4 Measurement of pressure loss
    4.1 Test methods
    4.2 Presentation of results
    Appendices
    A Calculation of mean band sound pressure level
    B End reflection
    C Typical coupler and anechoic termination
    D Illustration of reference sound source
    E Extrapolation from results of individual tests
    F Measurement of casing radiation
    Figures
    1 Substitution duct arrangements
    2 Arrangement of test installation for in-duct tests
    3 Microphone positions at in-duct measuring plane
    4 Arrangement of test installation: diffuse field
          method
    5 Typical arrangement of installation for generated
          noise level measurement
    6 Positioning of reference sound source, diffuse
          field substitution method
    7 Installation for pressure loss measurements

    Abstract - (Show below) - (Hide below)

    Describes the measurement and performance of silencers and silencing elements for ducted ventilating and air conditioning systems. It considers three aspects, the attenuation of broad band airborne sound, the generation of aerodynamic noise by air flowing through the silencer and the change in pressure or air flowing through the silencer. Not to be used to determine the performance of silencers providing selective attenuation over narrow frequency bands or to silencers which are designed for direct coupling to a fan, or to silencers designed to be installed to increase the sound insulation of a partition having a ventilation opening.

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

    Committee RHE/3
    Document Type Standard
    Publisher British Standards Institution
    Status Superseded
    Superseded By

    Standards Referenced By This Book - (Show below) - (Hide below)

    UNE-EN ISO 7235:2010 Acoustics - Laboratory measurement procedures for ducted silencers and air-terminal units - Insertion loss, flow noise and total pressure loss (ISO 7235:2003)
    ISO 7235:2003 Acoustics Laboratory measurement procedures for ducted silencers and air-terminal units Insertion loss, flow noise and total pressure loss
    I.S. EN ISO 7235:2009 ACOUSTICS - LABORATORY MEASUREMENT PROCEDURES FOR DUCTED SILENCERS AND AIR-TERMINAL UNITS - INSERTION LOSS, FLOW NOISE AND TOTAL PRESSURE LOSS
    DIN EN ISO 7235:2010-01 Acoustics - Laboratory measurement procedures for ducted silencers and air-terminal units - Insertion loss, flow noise and total pressure loss (ISO 7235:2003)
    EN ISO 7235:2009 ACOUSTICS - LABORATORY MEASUREMENT PROCEDURES FOR DUCTED SILENCERS AND AIR-TERMINAL UNITS - INSERTION LOSS, FLOW NOISE AND TOTAL PRESSURE LOSS
    UNI EN ISO 7235 : 2009 ACOUSTICS - LABORATORY MEASUREMENT PROCEDURES FOR DUCTED SILENCERS AND AIR- TERMINAL UNITS - INSERTION LOSS, FLOW NOISE AND TOTAL PRESSURE LOSS

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

    BS 848-1(1980) : 1980 FANS FOR GENERAL PURPOSES - METHODS OF TESTING PERFORMANCE
    BS 848-2(1985) : 1985 FANS FOR GENERAL PURPOSES - METHODS OF NOISE TESTING
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