1 Scope
This document specifies an engineering method for calculating the attenuation of sound
during propagation outdoors in order to predict the levels of environmental noise
at a distance from a variety of sources. The method predicts the equivalent continuous
A-weighted sound pressure level (as described in ISO 1996‑series) under meteorological conditions favourable to propagation from sources of known
sound emission.
These conditions are for downwind propagation or, equivalently, propagation under
a well-developed moderate ground‑based temperature inversion, such as commonly occurs
in clear, calm nights. Inversion conditions over extended water surfaces are not covered
and may result in higher sound pressure levels than predicted from this document (see
e.g. References [11] and [12]).
The method also predicts a long-term average A‑weighted sound pressure level as specified
in ISO 1996‑1 and ISO 1996‑2. The long-term average A‑weighted sound pressure level encompasses levels for a wide
variety of meteorological conditions.
Guidance has been provided to derive a meteorological correction based on the angular
wind distribution relevant for the reference or long-term time interval as specified
in ISO 1996‑1:2016, 3.2.1 and 3.2.2. Examples for reference time intervals are day, night, or the hour of the night with
the largest value of the sound pressure level. Long-term time intervals over which
the sound of a series of reference time intervals is averaged or assessed representing
a significant fraction of a year (e.g. 3 months, 6 months or 1 year).
The method specified in this document consists specifically of...
Open preview (PDF)Acoustics. Attenuation of sound during propagation outdoors - Engineering method for the prediction of sound pressure levels outdoors