EN ISO 17201-2:2025

SLOVENSKI STANDARD
01-september-2025
Nadomešča:
SIST EN ISO 17201-2:2006
Akustika - Hrup s strelišč - 2. del: Izračun poka potisnih plinov iz ustja strelnih
orožij (ISO 17201-2:2025)
Acoustics - Noise from shooting ranges - Part 2: Calculation of muzzle blast (ISO 17201-
2:2025)
Akustik - Geräusche von Schießplätzen - Teil 2: Berechnung des Mündungsknalls (ISO
17201-2:2025)
Acoustique - Bruit des stands de tir - Partie 2: Calcul de la détonation à la bouche (ISO
17201-2:2025)
Ta slovenski standard je istoveten z: EN ISO 17201-2:2025
ICS:
17.140.20 Emisija hrupa naprav in Noise emitted by machines
opreme and equipment
95.020 Vojaštvo na splošno Military in general
97.220.10 Športni objekti Sports facilities
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN ISO 17201-2
EUROPEAN STANDARD
NORME EUROPÉENNE
July 2025
EUROPÄISCHE NORM
ICS 17.140.20; 97.220.10 Supersedes EN ISO 17201-2:2006
English Version
Acoustics - Noise from shooting ranges - Part 2:
Calculation of muzzle blast (ISO 17201-2:2025)
Acoustique - Bruit des stands de tir - Partie 2: Calcul de Akustik - Geräusche von Schießplätzen - Teil 2:
la détonation à la bouche (ISO 17201-2:2025) Berechnung des Mündungsknalls (ISO 17201-2:2025)
This European Standard was approved by CEN on 7 July 2025.

CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this
European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references
concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN
member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by
translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management
Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and
United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2025 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 17201-2:2025 E
worldwide for CEN national Members.

Contents Page
European foreword . 3

European foreword
This document (EN ISO 17201-2:2025) has been prepared by Technical Committee ISO/TC 43
"Acoustics " in collaboration with Technical Committee CEN/TC 211 “Acoustics” the secretariat of
which is held by DIN.
This European Standard shall be given the status of a national standard, either by publication of an
identical text or by endorsement, at the latest by January 2026, and conflicting national standards shall
be withdrawn at the latest by January 2026.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
This document supersedes EN ISO 17201-2:2006.
Any feedback and questions on this document should be directed to the users’ national standards
body/national committee. A complete listing of these bodies can be found on the CEN website.
According to the CEN-CENELEC Internal Regulations, the national standards organizations of the
following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria,
Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland,
Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of
North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and the
United Kingdom.
Endorsement notice
The text of ISO 17201-2:2025 has been approved by CEN as EN ISO 17201-2:2025 without any
modification.
International
Standard
ISO 17201-2
Second edition
Acoustics — Noise from shooting
2025-07
ranges —
Part 2:
Calculation of muzzle blast
Acoustique — Bruit des stands de tir —
Partie 2: Calcul de la détonation à la bouche
Reference number
ISO 17201-2:2025(en) © ISO 2025

ISO 17201-2:2025(en)
© ISO 2025
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii
ISO 17201-2:2025(en)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
3.1 General .1
3.2 Directivity . .3
3.3 Energy .3
3.4 Fraction .4
3.5 Projectile .5
4 Estimation model for source data of the muzzle blast . 5
4.1 General .5
4.2 Estimation of chemical energy .5
4.3 Estimation of acoustic energy . .6
4.4 Estimation of the Weber energy .6
4.5 Estimation of directivity .6
4.6 Estimation of the spectrum .6
5 Uncertainty of estimation . 7
6 Report . 8
Annex A (informative) Simple blast model for estimation of sound energy and its spectrum . 9
Annex B (informative) Quality of input data.11
Annex C (informative) Comparison between measurements and prediction of muzzle blast . 14
Bibliography .21

iii
ISO 17201-2:2025(en)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out through
ISO technical committees. Each member body interested in a subject for which a technical committee
has been established has the right to be represented on that committee. International organizations,
governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely
with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are described
in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the different types
of ISO document should be noted. This document was drafted in accordance with the editorial rules of the
ISO/IEC Directives, Part 2 (see www.iso.org/directives).
ISO draws attention to the possibility that the implementation of this document may involve the use of (a)
patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed patent
rights in respect thereof. As of the date of publication of this document, ISO had not received notice of (a)
patent(s) which may be required to implement this document. However, implementers are cautioned that
this may not represent the latest information, which may be obtained from the patent database available at
www.iso.org/patents. ISO shall not be held responsible for identifying any or all such patent rights.
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and expressions
related to conformity assessment, as well as information about ISO's adherence to the World Trade
Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 43, Acoustics, Subcommittee SC 1, Noise, in
collaboration with the European Committee for Standardization (CEN) Technical Committee CEN/TC 211,
Acoustics, in accordance with the Agreement on technical cooperation between ISO and CEN (Vienna
Agreement).
This second edition cancels and replaces the first edition (ISO 17201-2:2006), which has been technically
revised.
The main changes are as follows:
— deletion of former Clauses 5 and 6, and Annex D which were moved to ISO 17201-4;
— revision of former Clause 7 (now Clause 5) and Annex C;
— addition of a new Clause 6;
— editorial revision of the document.
A list of all parts in the ISO 17201 series can be found on the ISO website.
The initiative to prepare a standard on impulse noise from shooting ranges was taken by AFEMS, the
Association of European Manufacturers of Sporting Ammunition, in April 1996, by the submission of a
formal proposal to CEN. After consultation in CEN in 1998, CEN/TC 211, Acoustics, asked ISO/TC 43/SC 1,
Noise, to prepare the ISO 17201 series.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.

iv
ISO 17201-2:2025(en)
Introduction
There are two basic sources that dominate the shooting sound from firearms: the muzzle blast and the
projectile sound. These two sources are basically different. The explosion blast from devices can be treated
as muzzle blast. This document describes the calculation of muzzle blast. The calculation of projectile sound
is described in ISO 17201-4.
The muzzle blast is caused by the expanding gases of the propellant at the muzzle. The muzzle blast can
be modelled approximately based on a spherical volume of these gases at the moment when the expansion
speed becomes subsonic.
In general, the procedures for estimating the muzzle blast rely on the estimation of energies that are
involved in the related processes. The procedures give estimates for the fraction of these energies that
transforms into acoustic energy. The results of the estimation are acoustical source data with respect to
energy, direction and frequency content.

v
International Standard ISO 17201-2:2025(en)
Acoustics — Noise from shooting ranges —
Part 2:
Calculation of muzzle blast
1 Scope
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 does not apply to the prediction of sound levels for the assessment of hearing damage; nor
can it be used to predict sound pressure levels or sound exposure levels at distances where linear acoustics
do not apply.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content constitutes
requirements of this document. For dated references, only the edition cited applies. For undated references,
the latest edition of the referenced document (including any amendments) applies.
ISO 17201-1, Acoustics — Noise from shooting ranges — Part 1: Determination of muzzle blast by measurement
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 17201-1 and the following apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
3.1 General
3.1.1
air density
ρ
density of air for the estimation conditions
Note 1 to entry: The air density is expressed in kilograms per cubic metre (kg/m ).

ISO 17201-2:2025(en)
3.1.2
angular frequency
ω
frequency multiplied by 2π
Note 1 to entry: The angular frequency is expressed in radians per second (rad/s) in all formulae.
3.1.3
cosine coefficients
c
1,2…N
coefficients of the cosine-transform used to describe the directivity of the angular source energy
3.1.4
specific chemical energy
u
specific chemical energy content of the propellant
Note 1 to entry: The specific chemical energy is usually expressed in joules per kilogram (J/kg).
3.1.5
sound exposure
E
time integral of frequency-weighted squared instantaneous sound pressure over the event duration time
Ep= ()ttd
∫
T
Note 1 to entry: The sound exposure is expressed in pascal-squared seconds (Pa ⋅s).
3.1.6
sound exposure level
L
E
ten times the logarithm to the base 10 of the ratio of the sound exposure, E, to the reference sound exposure
Note 1 to entry: The sound exposure level is expressed in decibels.
[1]
Note 2 to entry: See also ISO 1996-1 .
Note 3 to entry: The sound exposure level of a single burst of sound or transient sound with duration time T is given
by the formula
 
pt()
L =10lg dt  dB
E
∫
 pT 
0 0
 
T
where
p(t) is the instantaneous sound pressure as a function of time;
2 2
p T is the reference value [(20 µPa) × 1 s].
0 0
3.1.7
speed of sound
c
speed of sound for the estimation condition
Note 1 to entry: The speed of sound in air is expressed in metres per second (m/s).

ISO 17201-2:2025(en)
3.1.8
Weber radius
R
W
radius of an equivalent radiating sphere of the “simple blast model”
Note 1 to entry: The Weber radius is expressed in metres (m).
3.1.9
Weber pressure
p
W
sound pressure at the surface of the Weber sphere
Note 1 to entry: The Weber pressure is expressed in pascals (Pa).
3.2 Directivity
3.2.1
correction factor due to source directivity
c
s
correction taking into account that different orders of Fourier functions contribute differently to the energy
3.2.2
directivity factor
Y(α)
factor that specifies how many times higher the source energy is in direction α, compared with
omnidirectional radiation and the same source energy
3.3 Energy
3.3.1
effective angular source energy
Q
Y
energy of an equivalent Weber source with a uniform energy density having the same energy density at
direction α of the muzzle blast under consideration
Note 1 to entry: The effective angular source energy is expressed in joules (J).
3.3.2
total acoustic source energy
Q
e
total acoustic energy after integration of Q over the whole sphere
Y
Note 1 to entry: The total acoustic energy is expressed in joules (J).
3.3.3
energy in the propellant gas
Q
g
energy in the gaseous efflux of the propellant at the muzzle
Note 1 to entry: The energy in the propellant gas is expressed in joules (J).
3.3.4
muzzle source energy
Q
m
total acoustic energy of the muzzle blast
Note 1 to entry: The muzzle source energy is expressed in joules (J).

ISO 17201-2:2025(en)
3.3.5
kinetic energy of the projectile
Q
p0
translational kinetic energy of the projectile at the muzzle
Note 1 to entry: The projectile muzzle translational kinetic energy is expressed in joules (J).
3.3.6
propellant energy
Q
c
total chemical energy of the propellant
Note 1 to entry: The propellant energy is expressed in joules (J).
3.3.7
reference length
r
r = 1 m
3.3.8
reference Weber energy
Q
W,1
Weber energy for a mass of propellant having a Weber radius of r = 1 m
Note 1 to entry: The reference Weber energy is expressed in joules (J).
3.3.9
angular source energy distribution
S (α)
q
acoustic energy radiated from the source into the far field per unit solid angle
Note 1 to entry: The acoustic energy radiated by the source within a narrow cone centred around the direction α is
dQ
S ()α =
q
dΩ
where Ω is the solid angle in steradian (sr).
Note 2 to entry: The angular source energy distribution is expressed in joules per steradian (J/sr).
3.4 Fraction
3.4.1
projectile kinetic fraction
σ
cp
fraction of the projectile kinetic energy, Q , relative to chemical energy, Q
p c
Note 1 to entry: The efficiency is the kinetic fraction, expressed as percentage.
3.4.2
gas kinetic fraction
σ
cg
fraction of the chemical energy, Q , relative to propellant gas energy, Q
c g
3.4.3
acoustical efficiency
σ
ac
fraction of an energy that converts into acoustic energy

ISO 17201-2:2025(en)
3.5 Projectile
3.5.1
projectile launch speed
v
p0
speed of the projectile at the muzzle
Note 1 to entry: The projectile launch speed is expressed in metres per second (m/s).
3.5.2
projectile mass
m
p
mass of the projectile, for shotguns the total mass of the pellets
Note 1 to entry: The projectile mass is expressed in kilograms (kg).
4 Estimation model for source data of the muzzle blast
4.1 General
If possible, the muzzle blast source data should be determined according to ISO 17201-1.
This clause specifies a method for the estimation of acoustic source data of muzzle blast and explosions.
Firearm muzzle blast is highly directional. Both angular source energy distribution and spectrum vary with
angle from the line of fire.
For the propagation calculations, frequency and angle-dependent source data are required as input data.
Such detailed emission data, measured according to ISO 17201-1, are not readily available for a large variety
of weapons and ammunition and there is a need to estimate the data from other technical information. This
method may also be applied for explosives. For muzzle blasts, linear acoustics applies if the peak pressure is
below 1 kPa.
NOTE This method might not be suitable for firearms fitted with muzzle devices that influence the blast field, for
example, a muzzle brake that reduces recoil by deflecting propellant gas flow as it exists from muzzle.
The method is separated in two parts: firstly, the acoustic energy of the shot shall be estimated; secondly,
the directional pattern of the source is to be applied and the spectrum calculated. The procedure allows
the use of very general data or, if available, specific data to provide a more accurate result. Therefore, the
procedure allows the use of alternatives such as default values or specific values for certain parameters.
Due to this flexibility a flow chart is used to describe the way through the procedure. The flow chart provides
all steps including the formulae. In Figure 1 the left part of the flow chart shows the way to estimate the
muzzle blast source energy that is to be used in the right part of the flow chart to determine the acoustical
source data. Branches in the flow chart that are alternatives are depicted by a logical sign “or”, ⊕. The logical
sign for “and”, ⊗, means that both sets of information are needed to continue. The symbol xˆ denotes a
default input value for the parameter x. If the parameter x is not known the default value may be used.
Numbers at the top of boxes are the formulae reference numbers.
4.2 Estimation of chemical energy
The key quantity for estimating the acoustic energy is the propellant energy involved, Q . If Q is not known,
c c
there are two alternatives given here for determining Q . The left-hand branch uses the kinetic energy of the
c
projectile, Q , either known directly or alternatively calculated from the projectile mass, m , and projectile
p0 p
launch speed, v , of the projectile [see Formula (1), in Figure 1]. The projectile energy is a fraction of the
p0
total energy. If the projectile kinetic fraction, σ , is not known, 35 % should be used as default. Formula (2)
cp
in Figure 1 then determines Q . The right-hand branch uses the mass of propellant or explosives. The impetus
c
(conversion factor), u, depends on the type of propellant (e.g. 4,31 MJ/kg for TNT, or 5,86 MJ/kg for PETN). If
the specific chemical energy, u, is not known a value of u = 4,5 MJ/kg should be used.

ISO 17201-2:2025(en)
4.3 Estimation of acoustic energy
The total chemical energy (Q ) is partially converted into heat and into the kinetic en
...