SIST EN ISO 17201-3:2019

SLOVENSKI STANDARD
01-maj-2019
1DGRPHãþD
SIST EN ISO 17201-3:2010
$NXVWLND+UXSVVWUHOLãþGHO,]UDþXQãLUMHQMD]YRND,62
Acoustics - Noise from shooting ranges - Part 3: Sound propagation calculations (ISO
17201-3:2019)
Akustik - Geräusche von Schießplätzen - Teil 3: Berechnung der Schallausbreitung (ISO
17201-3:2019)
Acoustique - Bruit des stands de tir - Partie 3: Calcul de la propagation du son (ISO
17201-3:2019)
Ta slovenski standard je istoveten z: EN ISO 17201-3:2019
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 17201-3
EUROPEAN STANDARD
NORME EUROPÉENNE
February 2019
EUROPÄISCHE NORM
ICS 17.140.20; 95.020; 97.220.10 Supersedes EN ISO 17201-3:2010
English Version
Acoustics - Noise from shooting ranges - Part 3: Sound
propagation calculations (ISO 17201-3:2019)
Acoustique - Bruit des stands de tir - Partie 3: Calcul de Akustik - Geräusche von Schießplätzen - Teil 3:
la propagation du son (ISO 17201-3:2019) Berechnung der Schallausbreitung (ISO 17201-3:2019)
This European Standard was approved by CEN on 19 January 2019.

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, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,
Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Turkey 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
© 2019 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 17201-3:2019 E
worldwide for CEN national Members.

Contents Page
European foreword . 3

European foreword
This document (EN ISO 17201-3:2019) 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 August 2019, and conflicting national standards shall
be withdrawn at the latest by August 2019.
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 17201-3:2010.
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, Former Yugoslav Republic of Macedonia,
France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta,
Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland,
Turkey and the United Kingdom.
Endorsement notice
The text of ISO 17201-3:2019 has been approved by CEN as EN ISO 17201-3:2019 without any
modification.
INTERNATIONAL ISO
STANDARD 17201-3
Second edition
2019-01
Acoustics — Noise from shooting
ranges —
Part 3:
Sound propagation calculations
Acoustique — Bruit des stands de tir —
Partie 3: Calcul de la propagation du son
Reference number
ISO 17201-3:2019(E)
©
ISO 2019
ISO 17201-3:2019(E)
© ISO 2019
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
Fax: +41 22 749 09 47
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2019 – All rights reserved

ISO 17201-3:2019(E)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Source modelling. 2
4.1 General . 2
4.2 Muzzle blast . 2
4.2.1 Background. 2
4.2.2 Free-field situation . 3
4.2.3 Non-free-field situation . 3
4.3 Projectile sound . 6
5 Propagation calculation . 6
5.1 General . 6
5.2 Application of ISO 9613-2 for free-field situations . 6
5.3 Application of ISO 9613-2 for non-free-field situations . 8
5.4 Sophisticated models. 8
6 Conversion of sound exposure levels . 9
7 Uncertainties .10
Annex A (normative) Benchmark cases for shooting sheds with baffles .11
Annex B (informative) Sophisticated modelling approaches .27
Annex C (informative) Modelling of shooting scenarios — Examples of shooting ranges .36
Annex D (informative) Uncertainty .54
Bibliography .58
ISO 17201-3:2019(E)
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 documents 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).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www .iso .org/patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation on 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 the following URL: www .iso .org/iso/foreword .html.
This document was prepared by ISO/TC 43, Acoustics, Subcommittee SC 1, Noise.
This second edition cancels and replaces the first edition (ISO 17201-3:2010), of which it constitutes a
minor revision. The changes compared to the previous edition are as follows:
— Formulae (B.1) and (B.3) have been corrected by insertion of F .
— Minor corrections have been made in Annex C.
A list of all parts in the ISO 17201 series can be found on the ISO website.
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 2019 – All rights reserved

ISO 17201-3:2019(E)
Introduction
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,
Acoustics, Subcommittee SC 1, Noise to prepare ISO 17201 (all parts).
This document provides guidance for sound propagation calculation of shooting sound from shooting
ranges. If calculation procedures are not implied or specified by local or national guidelines, rules and
regulations, and if a more sophisticated propagation model is not available, then ISO 9613-2 may be
applied, provided that the recommendations in this document are observed.
The source energy of muzzle blast is typically measured or calculated for free-field conditions and
often exhibits strong directivity. In many cases, firearms are fired within a shooting range which has
structures such as firing sheds, walls or safety barriers. Guns, particularly shotguns, are sometimes
fired in many directions, e.g. in trap and skeet where the shooting direction is dictated by the flight
path of the clay target. This document recommends ways in which source data can be adapted for
use with ISO 9613-2 to obtain a general survey for the sound exposure levels to be expected in the
neighbourhood around shooting ranges.
INTERNATIONAL STANDARD ISO 17201-3:2019(E)
Acoustics — Noise from shooting ranges —
Part 3:
Sound propagation calculations
1 Scope
This document specifies methods of predicting the sound exposure level of shooting sound for a single
shot at a given reception point. Guidelines are given to calculate other acoustic indices from the sound
exposure level. The prediction is based on the angular source energy distribution of the muzzle blast as
defined in ISO 17201-1 or calculated using values from ISO 17201-2.
This document applies to weapons with calibres of less than 20 mm or explosive charges of less than
50 g TNT equivalent, at distances where peak pressures, including the contribution from projectile
sound, are less than 1 kPa (154 dB).
NOTE National or other regulations, which could be more stringent, can 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 9613-2:1996, Acoustics — Attenuation of sound during propagation outdoors — Part 2: General
method of calculation
ISO 17201-1:2018, Acoustics — Noise from shooting ranges — Part 1: Determination of muzzle blast by
measurement
1)
ISO/IEC Guide 98-3 , Uncertainty of measurement — Part 3: Guide to the expression of uncertainty in
me a s ur ement (GUM: 1995)
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https: //www .iso .org/obp
— IEC Electropedia: available at http: //www .electropedia .org/
3.1
substitute source
substitute for a sound source and its firing shed (3.4) by a model source without a firing shed positioned in
the centre of the opening of the firing shed to represent the emission in the direction of a reception point
3.2
safety barrier
barrier that is intended to stop projectiles leaving the range
1) ISO/IEC Guide 98-3 is published as a reissue of the Guide to the expression of uncertainty in measurement
(GUM), 1995.
ISO 17201-3:2019(E)
3.3
safety baffle
overhead barrier that is intended to stop projectiles leaving the range
3.4
firing shed
structure constructed to protect the shooters and their equipment from precipitation and wind, having
an opening that allows shooting at a target located on open ground
3.5
shooting range
enclosed arrangement of firing positions (3.7) and matching targets which, depending on the design,
may include such features as a firing shed (3.4), safety barriers (3.2), safety baffles (3.3), and unsafe areas
3.6
shooting facility
organizational entity consisting of one or more shooting ranges (3.5), and associated buildings and
infrastructure
3.7
firing position
position of the shooter within a shooting range (3.5)
3.8
impact sound
sound produced by the projectile hitting the target
3.9
diffraction point
point on top of a barrier which provides the shortest path length for the sound travelling over the
barrier to the reception point
4 Source modelling
4.1 General
The basic quantities to be used are the angular source energy distribution, S (α), and angular source
q
energy distribution level, L (α), as defined in ISO 17201-1. The angle between the line of fire and the
q
line from the muzzle to the reception point is designated by α. If the gun is fired in a free-field situation,
S (α) can be used to describe the muzzle blast. For rifle shots, projectile sound has to be included (see
q
4.3). Substitute sources can be used for shed situations and for the incorporation of reflection and
diffraction to calculate the reception levels as if it was a free-field situation. Impact sound caused by
the projectile hitting the target can usually be neglected. This document does not apply to projectiles
containing a charge which is detonated at the target.
4.2 Muzzle blast
4.2.1 Background
For the non-free-field situation (such as a shed with one opening), the propagation model of ISO 9613-2
is insufficient, and more complex propagation models and calculation procedures are needed.
Annex A provides a benchmark case and a demonstration of how sophisticated sound propagation
approximations (see Annex B) may be used to describe the sound emitted from such a range, based
on the free-field data of the angular source energy distribution levels. The sound emission is then
expressed by the angular source energy distribution level of a substitute source positioned at a
representative position in front or above the firing shed. All further calculations of the sound pressure
level are carried out as specified in Clause 5 by a point source with directivity independent from the
range, which may be formed by a shed, baffles and side walls, etc.
2 © ISO 2019 – All rights reserved

ISO 17201-3:2019(E)
4.2.2 Free-field situation
If the weapon under consideration is used outside a firing shed or similar structure, use the angular
source energy distribution level, L (α), of the specific weapon/ammunition combination directly. If a
q
shot is fired with a reflecting surface near the shooter, take the reflection into account. The directivity
has to be adjusted accordingly. If the gun can be fired in varying horizontal and vertical directions,
account for these directions separately. Examples of free-field situations are described in Annex C.
4.2.3 Non-free-field situation
4.2.3.1 Shooting shed
In this case, the shot is fired in a shed (see for example Annex B). Part of the energy radiated due to the
muzzle blast is absorbed by the walls and the ground. If baffles and side walls are present, take the
reflections from the ground, side walls and baffles into account (see Annex A). An absorbing ceiling within
the shed can be considered to be state of the art. The remaining energy is emitted through the opening of
the shed. Therefore, free-field data shall not be used directly. If no absorption occurs within the shed and
at the baffles, the benchmark case is not a suitable model to describe the emitted sound energy.
Figure 1 depicts a shed with the side walls and safety overhead baffles.
ISO 17201-3:2019(E)
a) Top view
4 © ISO 2019 – All rights reserved

ISO 17201-3:2019(E)
b) View in shooting direction
c) Side view
Key
1 gun/rifle 7 reception point
a
2 side berm Shooting direction.
b
3 roof Diffracted sound.
c
4 safety baffle Shielded sound.
5 barrier
6 ground
Figure 1 — Shooting shed situation and illustration of diffraction effects on the propagation path
4.2.3.2 More complex situations
For more complex situations consisting of different shooting facilities, such as a trap and skeet range
together with rifle ranges for large and small calibres, a larger number of sources and substitute
sources sometimes have to be included to adequately model the situation. These sources are considered
incoherent. However, reflections are considered to be coherent, when at the reception point the time
delay between the muzzle blast and its reflections is less than 3 ms. Then, they shall be modelled as one
ISO 17201-3:2019(E)
substitute source. If the prediction focuses on F-time-weighted levels, substitute sources can combine
multiple sound paths that have time delays within a time span less than (125/2) ms.
NOTE 62,5 ms is half the exponential time constant for time-weighting F (125 ms) as specified in IEC 61672-
1:2013, 5.8.1.
4.3 Projectile sound
Modelling of projectile sound is described in ISO 17201-2 and ISO 17201-4. ISO 17201-4 also gives
guidelines for the calculation of the propagation of projectile sound, as far as it deviates from the
propagation of other sound. This means that for the attenuation for projectile sound, A , ISO 9613-2
excess
can also be used. The other attenuation parameters such as geometrical divergence, air absorption
and non-linear attenuation are specified in ISO 17201-4. In free-field situations, especially in front
of the weapon when the distance to the trajectory is short, projectile sound can be a relevant source
for the sound exposure level of shooting sound. If a shot is fired in a shooting range, projectile sound
is in general of minor importance in the estimation of the sound exposure level at a reception point.
However, if measures are taken to reduce the sound emission of the muzzle blast, projectile sound can
then become a dominant factor.
5 Propagation calculation
5.1 General
The propagation calculation may be performed using ray-tracing or more sophisticated models, which
take specific weather conditions into account. To calculate a long-term L , the results are weighted
eq
with respect to the frequency of occurrence of weather conditions pertinent to the time periods of
interest during which the shooting range is operated.
5.2 Application of ISO 9613-2 for free-field situations
ISO 9613-2 neither applies to shooting sound nor accounts for changes in sound pressure time history
during propagation. It therefore cannot yield results for time-weighted metrics such as L (see
Fmax
Clause 6). ISO 9613-2 does not adequately account for meteorological effects on sound propagation over
distances greater than 1 km. Furthermore, the use of ISO 9613-2 is not recommended if the spectrum at
the reception point is dominated by frequencies below 100 Hz.
However, ISO 9613-2 may be applied to model propagation of shooting sound if modifications are
introduced.
The sound power level and the directivity have to be substituted by the angular source energy
distribution level and the ambient level by the resulting sound exposure level, L ( f ), at the reception
E
point of one specific shot under favourable sound propagation conditions.
The sound exposure level for one shot fired is obtained by:
Lf =Lfα,,−+Ar() 11dB−Ar fA− rf,,−Ar fA− rrf,,−Ar f (1)
() () () () () () ()
Eq divatm bargrz misc
where
L (α, f ) is the angular source energy distribution level, in decibels, of the weapon ammunition
q
combination under consideration;
r is the distance, in metres, from the source or substitute source P(x , y , z ) to the reception
0 0 0
point P(x, y, z);
α is the angle between the line of fire and the line from the source to the reception point
P(x, y, z), provided that the latter line does not interfere with a barrier;
6 © ISO 2019 – All rights reserved

ISO 17201-3:2019(E)
f is the centre frequency, in hertz, of any frequency band;
A is a correction, in decibels, for the geometric spread;
div
A is the air absorption, in decibels, according to ISO 9613-1;
atm
A is the shielding by barrier, in decibels, according to ISO 9613-2;
bar
A is the ground effect, in decibels, according to ISO 9613-2;
gr
[2] [3]
A is a correction for non-standard meteorological conditions [see ISO 3741 , ISO 3745 ,
z
[4]
ISO 9614-3 , and ISO 17201-1:2018, Formula (11)];
A is a correction, in decibels, for miscellaneous other effects according to ISO 9613-2.
misc
Concerning α, if the sound is shielded by a barrier, separate calculations for each point of diffraction are
necessary. The angle, α, used to obtain L (α, f ) is the angle between the line of fire and the line from the
q
source point to the point of diffraction under consideration. This approach deviates from ISO 9613-2.
The insertion loss, A , is related to sound exposure level in the direction of the point of diffraction
bar
(see example in Annex C) for the same distance between the reception point and the source point (see
Reference [11]).
To include the ground effect and determine A , ISO 9613-2:1996, 7.3.1 can be used. ISO 9613-2:1996,
gr
7.3.2 can also be used, in which case an additional term D needs to be added to L (α, f ). D can be
Ω q Ω
determined by using ISO 9613-2:1996, Formula (11), or it can be set to 3 dB.
The calculation of L (x, y, z, f ) for a shed opening is specified in 5.3.
q
The long-term sound exposure level is obtained by:
LL=−C (2)
EE,longtermmet
The way to obtain C depends strongly on the definition of the weather condition for which the sound
met
exposure level, L ( f ), is to be calculated. If the long-term L is needed, take the long-term weather
E eq
conditions at the site into account. If such information is not available, C for the long term L
met A,eq
can be determined according to ISO 9613-2:1996, Formula (22), using C = 5 dB. By application of ray
tracing models and long-term statistics of wind direction, wind speed and atmospheric stability, a more
accurate value for long-term levels can be obtained (see References [12], [13]).
NOTE The value 5 dB for C results from the assumption that favourable sound propagation conditions occur
for one third of the time.
If ISO 9613-2 is applied, the following limitations are observed:
— For longer distances, ISO 9613-2 has the tendency to overestimate the long-term sound exposure
level, L , during daytime (Reference [14]).
E,long term
— For downwind conditions, the effect of screens can be overestimated as a consequence of the
induced air flow at the top of the screen (Reference [15]).
— During daytime, the barrier attenuation tends to be higher compared to the value obtained by
ISO 9613-2 (Reference [16]).
— ISO 9613-2 does not consider diffraction apart from shielding. However, diffracted sound from
safety baffles for example (see Figure 1) can produce a major contribution at the reception point.
Scattering is only approximately taken into account. That effect can be an important contribution to the
overall level at a reception point for situations in which the sound sources are well shielded.
ISO 17201-3:2019(E)
5.3 Application of ISO 9613-2 for non-free-field situations
For calculation of the sound immission in a non-free-field situation, more sophisticated sound
propagation models are needed (see 5.4). These model calculations are usually very time consuming.
Even if the distance between the shooting range and the reception point is not more than a few hundred
metres, the calculation over all frequencies takes too long to be used for noise mapping.
Therefore the concept of the substitute source is introduced to allow the use of generally available
software to calculate noise maps. A sophisticated model is used to calculate the sound exposure level,
L ( f ), at some immission-relevant reception points, P(x, y, z), which are far enough from the shed
E
to allow the substitution of the original source and its direct surroundings by a point source with
directivity characteristics. The distance between the range and such a reception point should at least
be twice the largest dimension of the range. The position of the substitute source with the angular
source energy distribution level, L (x, y, z, f ), for this reception site and other reception sites is chosen
q,S
to be in the middle of the opening through which most of the sound energy travels. For a simple shed
without barriers and baffles, the source point is chosen to be in the middle of the shed opening. For
ranges with a shed and barriers and baffles, the position is chosen in the centre of the first opening (see
Figure B.1, point P).
The calculated levels can also be chosen on a circle and the angular source energy distribution level can
then be calculated according to the procedures specified for measurement in ISO 17201-1.
The angular source energy distribution level of the substitute source, L (α, f ), is calculated from the
q,S
exposure level using Formula (3).
Lfα,,=Lx yz,, fA−+11dB r (3)
() () ()
qE,Sdiv
where
L (x, y, z, f ) is the sound exposure level, expressed in decibels, for frequency f at point P(x, y, z)
E
obtained by boundary element method (BEM) or similar (see Annex B);
A (r) is the correction, expressed in decibels, for geometrical divergence between the as-
div
sumed source position and point P(x, y, z);
r is the distance, in metres, between the chosen substitute source position and P(x, y, z).
In this model, the substitute source replaces the original source and its direct surroundings. If only
the direction of α is of interest, Formula (1) can be applied directly. If the directivity is needed, as for
example in a noise map, use the process specified in ISO 17201-1. A , A , A , A are excluded from
atm bar gr misc
the calculation of L (α). Only take into account barrier effects, etc. for those barriers which are not
q,S
included in the calculation using the sophisticated model.
Figure 1 shows a typical shooting shed with the overhead baffles and side walls. In Annex A, the sound
exposure level for a gun fired in such a shed is given. This has been calculated with the BEM over hard
ground for a number of heights and positions in the surrounding. In the benchmark case, the ground
reflection has been included; A , A and A have been assumed to be zero.
atm bar misc
For existing situations, it is recommended that the chosen sophisticated model be verified by
measurement of the sound exposure level at the reception point, provided that the actual propagation
conditions during the measurements are well defined. For propagation calculation outside the shed, the
ground reflection has been included. Ensure that the same surface type is used for any sophisticated
model as well as for the application of ISO 9613-2.
5.4 Sophisticated models
For the non-free-field situation, more sophisticated calculation models – compared to ISO 9613-2 – are
needed. BEMs, ray-tracing models, wave models or combinations should be used in which reflection,
8 © ISO 2019 – All rights reserved

ISO 17201-3:2019(E)
diffraction and scattering can be taken into account in more detail (see Annex A, Annex B and
References [17], [18], [19], [20]).
A benchmark case is given in Annex A for a shed as depicted in Figure A.1. This case has been calculated
using BEM.
If other models or approximations are used such as
— Kirchhoff-approximation (see B.2),
— ray tracing models (see B.3),
ensure that the sound exposure levels of the benchmark case according to Annex A at 100 Hz and 200 Hz
are reproduced by the levels of the sophisticated model without significant deviations. For distances
twice as large, the model levels should not be greater than +5 dB and not less than −1 dB compared to
the benchmark case:
L + 5 dB > L > L − 1 dB (4)
benchmark model benchmark
with a probability of less than 5 %.
6 Conversion of sound exposure levels
Sound exposure level, L , is a widely used metric for sound from small arms. However, a number of
E
metrics in legal codes or regulations generally used to describe small arms noise are based on the
maximum level for a specific time weighting. An estimate of these metrics can be obtained from the
relationships:
L ≈ L (5)
Smax E
L ≤ L + 9,0 dB (6)
Fmax E
L ≤ L + 14,6 dB (7)
Imax E
L ≤ L + 5,6 dB (8)
Imax Fmax
where
L is the highest S-time-weighted sound pressure level within a stated time interval, expressed
Smax
in decibels;
L is the highest F-time-weighted sound pressure level within a stated time interval, expressed
Fmax
in decibels;
L is the highest I-time-weighted sound pressure level within a stated time interval, expressed
Imax
in decibels.
The equal sign is valid if the event duration is less than 10 % of the time constant of exponential time
weighting, τ (S: τ =1 s, F: τ =0,125 s, I: the onset time constant τ =0,035 s differs from the decay time
constant τ = 1,5 s), which is the case close to the source and if no reflections occur.
For increasing distances, the duration of the time signal increases, e.g. as a consequence of ground
reflections. The sound pressure time history of the signal including its reflections needs to be calculated
ISO 17201-3:2019(E)
to ensure the proper evaluation of the above metrics. If sufficient information is not available, L
Imax
may, according to Reference [21], be approximated by:
Lr+−14,,60dB 003 /R dB
 formr<2000
 E 0
L = (9)

I,max
L +86, dB for r≥20000m

 E
where
r is the distance, in metres, between the substitute source and the reception point P(x, y, z);
R is 1 m.
The relations are valid for single shots when the time lapse between successive shots is greater than
the time constant.
7 Uncertainties
The uncertainty of the one-third-octave-band spectrum of the sound exposure level of the muzzle blast
determined in accordance with this document shall be evaluated, preferably in conformity with ISO/
IEC Guide 98-3.
The uncertainties arise from a number of causes:
— the angular source energy distribution level (see ISO 17201-1 for situations in which that level is
determined by measurements or ISO 17201-2 when that level is estimated based on the chemical
energy of the propellant);
— the modelling of an actual complex source situation into a substitute source or a number of substitute
sources;
— the modelling of the actual situation by simplification of the propagation-influencing objects
(complex structures modelled by cubes, uneven terrain modelled by flat terrain, etc.);
— the position of the sound source with respect to the propagation influencing objects and the actual
shooting direction;
— the sound propagation model used.
If, instead of the sound exposure level, another metric is used for the evaluation of shooting sound,
additional uncertainties arise from the estimation of these metrics from the sound exposure level.
If the prognosis is done on the basis of the acoustical energy of all shots over a certain time period,
uncertainties also arise with respect to the actual number of shots fired and the actual weapon and
ammunition combinations.
The expanded uncertainty together with the corresponding coverage factor shall be stated for a
coverage probability of 95 % as defined in ISO/IEC Guide 98-3.
Guidance on how to evaluate and express the uncertainty is given in Annex D.
10 © ISO 2019 – All rights reserved

ISO 17201-3:2019(E)
Annex A
(normative)
Benchmark cases for shooting sheds with baffles
A.1 General
The benchmark case is based on the numerical solution of the Helmholtz-Kirchhoff wave equation using
BEM (see Reference [22]). For simplicity, a small shooting shed with three overhead safety baffles is
used, projectile sound is neglected and the directivity is assumed to be uniform.
A.2 Benchmark case
A.2.1 Model shed
Figure A.1 shows the geometry of the shed modelled. This consists of a rectangular box, with a semi-
open ceiling with baffles. The geometry is approximately that of a typical 25 m long shooting shed used
in the Netherlands; however, in the benchmark case, the length has been reduced to test for the proper
function of the solution for longer wavelengths. A xyz-co-ordinate system is used, with the x-axis along
the shooting direction. Dimensions are indicated in Figure A.1. The baffles are 2 m high, so the space
between the ground and the baffles is also 2 m high.
All walls and the ceiling have a finite thickness of about one-sixth of a wavelength (for computational
reasons). For a frequency of 100 Hz, the thickness is 0,5 m; for a frequency of 200 Hz, the thickness
is 0,25 m. The source is a monopole source located on the ground, at position P(−3 m, 0 m, 0 m). All
inner surfaces are acoustically absorbing (shown in Figure A.1), except for the ground surface and the
baffles, which are acoustically rigid (shown in Figure A.1). Outer surfaces are all rigid. For the absorbing
surfaces, a normalized impedance of unity was assumed (normalized to the impedance of air).
ISO 17201-3:2019(E)
Dimensions in metres
Key
1 roof 3 side wall
a
2 overhead safety barrier Shooting direction.
Figure A.1 — Geometry of the benchmark model shooting range
A.2.2 Computational method
The BEM in acoustics (see Reference [22]) is a numerical technique for solving the Kirchhoff-Helmholtz
integral equation. The basic idea of the method is that the Kirchhoff-Helmholtz integral is approximated
numerically by representing all solid boundaries in the system by a finite number of surface elements.
The elements have linear dimensions of the order of one sixth of a wavelength or smaller. The
calculations are performed with an implementation of BEM which neglects the variation of the acoustic
pressure within a single surface element. The rigid ground surface is treated as a plane of symmetry in
this case, by including an image system below the ground surface.
A.3 Results
Figure A.2 and Figure A.3 show BEM results at two frequencies (100 Hz and 200 Hz, respectively) and
three reception heights (2 m, 5 m and 8 m), in a rectangular area of 160 m × 160 m around the shooting
range. The colour represents the relative sound pressure level, i.e. the level with the shooting range
minus level without the shooting range. In other words, the relative sound pressure level is equal to
minus the insertion loss of the shooting range. Thus, the relative sound pressure level is low and the
insertion loss is high in shadow regions.
Values of the insertion loss at a grid with spacing 10 m are given in Tables A.1 to A.6.
12 © ISO 2019 – All rights reserved

ISO 17201-3:2019(E)
Figure A.2 — Relative sound pressure level, in dB, at frequency 100 Hz, for three reception
heights (2 m, 5 m and 8 m)
ISO 17201-3:2019(E)
Figure A.3 — Relative sound pressure level, in dB, at frequency 200 Hz, for three reception
heights (2 m, 5 m and 8 m)
14 © ISO 2019 – All rights reserved

ISO 17201-3:2019(E)
Table A.1 — Insertion loss at a frequency of 100 Hz, for y from 0 m to 80 m and
x from −80 m to 80 m, at a reception height of 8 m
y
m
x
0 10 20 30 40 50 60 70 80
m
Insertion loss
dB
−80 22,8 22,2 20,9 20,0 20,0 21,0 22,9 24,5 24,9
−70 24,7 23,7 21,9 20,9 21,4 23,2 25,2 25,5 24,5
−60 28,0 26,2 23,5 22,7 24,0 26,4 26,5 24,9 23,6
−50 30,5 29,0 26,1 26,2 28,7 28,2 25,6 23,9 23,3
−40 24,3 26,6 31,2 34,9 31,1 26,6 24,6 24,1 24,3
−30 18,7 21,8 28,8 30,5 28,5 26,3 25,8 26,4 27,6
−20 18,8 20,1 23,0 30,9 31,3 30,5 31,7 33,6 35,5
−10 15,0 21,8 28,9 35,3 39,9 49,6 46,5 41,0 38,3
0 10,2 32,1 28,2 31,2 35,3 36,1 35,1 34,1 33,3
10 12,4 25,3 29,6 40,2 44,2 36,9 34,2 32,8 32,0
20 17,8 18,0 25,2 33,5 49,2 41,9 36,4 34,1 32,7
30 16,3 18,8 25,2 34,9 32,1 35,7 39,3 37,3 34,9
40 21,1 24,0 30,1 45,9 30,2 28,5 30,3 33,5 35,6
50 24,4 27,7 46,2 34,9 29,6 26,8 26,4 27,8 30,1
60 23,5 25,2 30,4 30,9 28,1 26,3 25,2 25,3 26,3
70 21,7 22,7 25,5 27,6 26,9 25,7 24,8 24,3 24,5
80 20,5 21,2 23,0 25,1 25,7 25,1 24,4 23,9 23,8
Table A.2 — Insertion loss at a frequency of 100 Hz, for y from 0 m to 80 m and
x from −80 m to 80 m, at a reception height of 5 m
y
m
x
0 10 20 30 40 50 60 70 80
m
Insertion loss
dB
−80 19,8 19,4 18,6 18,1 18,3 19,5 21,4 23,2 23,9
−70 20,6 20,0 19,0 18,5 19,3 21,2 23,3 24,2 23,5
−60 21,7 20,9 19,5 19,4 21,0 23,6 24,6 23,7 22,6
−50 23,8 22,3 20,5 21,2 24,0 25,3 23,9 22,7 22,3
−40 28,3 24,7 22,5 25,1 26,6 24,2 22,9 22,7 23,2
−30 30,7 28,8 28,6 29,5 24,9 23,5 23,8 24,8 26,2
−20 20,5 28,7 32,2 26,8 25,5 26,6 28,6 30,8 32,8
−10 29,8 22,0 38,4 35,0 37,7 39,2 38,1 36,7 35,6
0 8,2 31,7 32,0 36,5 35,0 33,5 32,7 32,1 31,8
10 16,1 26,2 36,5 41,5 34,8 32,5 31,5 30,9 30,6
20 16,3 22,2 35,1 32,8 38,9 36,3 33,6 32,2 31,3
30 23,7 33,9 34,6 27,5 27,6 31,3 34,8 34,7 33,4
40 23,8 27,7 29,3 26,4 24,9 25,5 28,0 31,2 33,6
50 21,2 22,9 25,7 25,3 24,3 23,8 24,5 26,3 28,7
ISO 17201-3:2019(E)
Table A.2 (continued)
y
m
x
0 10 20 30 40 50 60 70 80
m
Insertion loss
dB
60 19,7 20,7 23,2 24,2 23,8 23,4 23,3 23,9 25,2
70 18,9 19,6 21,5 23,1 23,4 23,1 22,9 23,0 23,5
80 18,3 18,9 20,4 22,1 22,9 22,9 22,7 22,6 22,8
Table A.3 — Insertion loss at a frequency of 100 Hz, for y from 0 m to 80 m and
x from −80 m to 80 m, at a reception height of 2 m
y
m
x
0 10 20 30 40 50 60 70 80
m
Insertion loss
dB
−80 18,4 18,1 17,5 17,1 17,5 18,7 20,6 22,5 23,3
−70 18,7 18,3 17,6 17,4 18,2 20,2 22,4 23,4 23,0
−60 19,1 18,6 17,7 17,9 19,6 22,3 23,6 23,0 22,2
−50 19,7 18,9 18,0 19,1 22,1 23,8 23,0 22,1 21,8
...