Akustik och bullermätning

This document specifies a computational method (in line with ISO 17201-4) for estimating the acoustic source data of muzzle blast and explosions on the basis of non-acoustic data for firearms with calibres less than 20 mm and explosions less than 50 g TNT equivalent. This document addresses those cases where no source measurements exist. This document can also be used as an interpolation method between measurements of muzzle blast. Source data are given in terms of spectral angular source energy covering the frequency range from 12,5 Hz to 10 kHz and can be used as data input for sound propagation calculation. This document is not applicable to the prediction of sound levels for the assessment of hearing damage; neither can it be used to predict sound pressure levels nor sound exposure levels at distances where linear acoustics do not apply.

This document provides computational methods for determining the acoustical source level of projectile sound and its one-third octave band spectrum, expressed as the sound exposure level for nominal mid band frequencies from 12,5 Hz to 10 kHz. It also gives a method on how to use this source level to calculate the sound exposure level at a receiver position. Results obtained with the standard can be used as a basis for assessment studies for sound around shooting ranges. Additionally, the data can be used to compare sound emission or immission from different types of ammunition used with the same weapon. The prediction methods apply to outdoor conditions and straight projectile trajectories. Two computational methods are given to determine the acoustical source level: one for streamlined projectile shapes and one for non-streamlined shapes, such as pellets.