BS ISO 9613-2:2024
Acoustics. Attenuation of sound during propagation outdoors - Engineering method for the prediction of sound pressure levels outdoors

Standard No.

BS ISO 9613-2:2024

Release Date

2024

Published By

British Standards Institution (BSI)

Latest

BS ISO 9613-2:2024

Scope

This document specifies an engineering method for calculating the attenuation of sound during outdoor propagation to predict ambient noise levels at a given distance from a variety of sound sources. The method predicts the equivalent continuous A-weighted sound pressure level (as described in the ISO 1996 series) from a known sound emission source under meteorological conditions that are favorable for propagation. These conditions apply to propagation downwind or equivalent to propagation under a fully developed moderate ground temperature inversion, such as typically occurs on a clear, windless night. The method is not applicable to inversion conditions over large areas of water, which may result in sound pressure levels higher than those predicted by this document. The method also predicts the long-term average A-weighted sound pressure level specified in ISO 1996-1 and ISO 1996-2. The long-term average A-weighted sound pressure level covers levels under a wide range of meteorological conditions. Guidance is provided for the derivation of meteorological corrections based on angular wind distributions associated with a reference or long-term time interval. Examples of reference time intervals include daytime, nighttime, or nighttime hours when the sound pressure level is maximum. A long-term time interval is a period of time over which the sound is averaged or evaluated for a series of reference time intervals, representing a significant portion of a year (e.g., 3 months, 6 months, or 1 year). The method specified in this document specifically includes an octave band algorithm (nominal centre frequencies from 63 Hz to 8 kHz) for calculating the attenuation of sound from a point source or combination of point sources. The sound source may be mobile or stationary. Specific terms for the following physical effects are provided in the algorithm: 　——geometric divergence; 　——atmospheric absorption; 　——ground effect; 　——surface reflection; 　——shielding by obstacles. Annex A provides additional information on propagation through foliage, industrial sites and residential buildings. Annex B includes the directivity of chimneys to support sound predictions for industrial sites. Annex C provides an example of how to determine the long-range meteorological correction C0 from the local wind climatology. Annex D summarizes the experience gained in recent decades in predicting the sound pressure level caused by wind turbines. The method is applicable in practice to a wide range of noise sources and environments. It is directly or indirectly applicable to most situations involving road or rail traffic, industrial noise sources, construction activities and other ground noise sources. It is not applicable to the sound of aircraft in flight or blast waves from mining, military or similar operations. To apply the method of this document, it is necessary to know several parameters about the source and the geometry of the environment, the characteristics of the ground surface, and the intensity of the source (expressed as octave-band sound power levels in directions relevant to propagation). If only the A-weighted sound power level of the source is known, the 500 Hz attenuation term can be used to estimate the resulting attenuation. The accuracy of the method and its limitations in practical use are described in clause 9.

BS ISO 9613-2:2024 Referenced Document

• IEC 61260-1 IEC 61260-1: Electroacoustics - Octave-band and fractional-octave-band filters - Part 1: Specifications
• IEC 61672-1 Electroacoustics - Sound level meters - Part 1: Specifications
• ISO 1996-1 Acoustics - Description, measurement and assessment of environmental noise - Part 1: Basic quantities and assessment procedures
• ISO 1996-2 Acoustics - Description, measurement and assessment of environmental noise - Part 2: Determination of sound pressure levels
• ISO 8297 Acoustics — Determination of sound power levels of multisource industrial plants for evaluation of sound pressure levels in the environment — Engineering method — Amendment 1
• ISO 9613-1:1993 Acoustics; attenuation of sound during propagation outdoors; part 1: calculation of the absorption of sound by the atmosphere

BS ISO 9613-2:2024 history

• 2024 BS ISO 9613-2:2024 Acoustics. Attenuation of sound during propagation outdoors - Engineering method for the prediction of sound pressure levels outdoors

Standard and Specification