1 Scope
2 Normative references
3 Terms and definitions
4 Specifications, selection and design considerations
    4.1 Requirements to be specified
    4.2 Selection and layout of silencers
    4.3 Design of special silencers
5 Types of silencers, general principles and
    operational considerations
    5.1 Overview
    5.2 Acoustic and aerodynamic performance of silencers
    5.3 Sound propagation paths
    5.4 Acoustic installation effect
    5.5 Abrasion resistance and protection of absorbent
          surfaces
    5.6 Fire hazards and protection against explosion
    5.7 Starting-up and closing-down of plants
    5.8 Corrosion
    5.9 Hygienic requirements and risk of contamination
    5.10 Inspection and cleaning, decontamination
6 Performance characteristics of types of silencers
    6.1 Dissipative silencers
    6.2 Reactive silencers
    6.3 Blow-off silencers
7 Measurement techniques
    7.1 Laboratory measurements
    7.2 Measurements in situ
    7.3 Measurements on vehicles
8 Information on silencers
    8.1 Information to be provided by the user
    8.2 Information to be provided by the manufacturer
Annex A (informative) Applications
Annex B (informative) Effect of spectral distribution of
sound on the declaration of attenuation in one-third-octave
or octave bands
Annex C (informative) Operating temperatures of sound sources
and temperature limits of sound-absorbent materials
Bibliography