ISO/DIS 17201-6

Acoustics -- Noise from shooting ranges

Acoustique -- Bruit des stands de tir

Standards Content (sample)

DRAFT INTERNATIONAL STANDARD
ISO/DIS 17201-6
ISO/TC 43/SC 1 Secretariat: DIN
Voting begins on: Voting terminates on:
2019-12-31 2020-03-24
Acoustics — Noise from shooting ranges —
Part 6:
Sound exposure at close range of the sound source
Acoustique — Bruit des stands de tir —
Partie 6: L´exposition au bruit à proximité de la source sonore
ICS: 13.140; 17.140.20; 95.020; 97.220.10
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ISO/DIS 17201-6:2019(E)
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ISO/DIS 17201-6:2019(E)
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ISO/DIS 17201-6:2019(E)
Contents Page

Foreword ........................................................................................................................................................................................................................................iv

Introduction ..................................................................................................................................................................................................................................v

1 Scope ................................................................................................................................................................................................................................. 1

2 Normative references ...................................................................................................................................................................................... 1

3 Terms and definitions ..................................................................................................................................................................................... 1

4 Measurement system requirements ................................................................................................................................................ 2

4.1 General ........................................................................................................................................................................................................... 2

4.2 Ranges of sound pressure levels .............................................................................................................................................. 2

4.3 Overall system description ........................................................................................................................................................... 2

4.4 Microphone and preamplifier requirements ................................................................................................................ 3

4.5 Fixture ............................................................................................................................................................................................................ 3

4.6 Cable length ............................................................................................................................................................................................... 3

4.7 Data acquisition system .................................................................................................................................................................. 4

4.8 Data storage ............................................................................................................................................................................................... 4

4.9 Frequency-weighting ......................................................................................................................................................................... 4

4.10 Calibration .................................................................................................................................................................................................. 4

5 Measurement setup ........................................................................................................................................................................................... 5

5.1 General considerations .................................................................................................................................................................... 5

5.2 Measurement location ...................................................................................................................................................................... 5

5.2.1 General...................................................................................................................................................................................... 5

5.2.2 Special case: Shooter firing a gun ...................................................................................................................... 5

5.3 Microphone orientation .................................................................................................................................................................. 5

5.4 Weather and ambient conditions ............................................................................................................................................ 6

6 Documentation ....................................................................................................................................................................................................... 6

6.1 General ........................................................................................................................................................................................................... 6

6.2 Shooting range ........................................................................................................................................................................................ 6

6.3 Absorbing and reflecting elements........................................................................................................................................ 6

6.4 Weapon documentation .................................................................................................................................................................. 6

6.5 Location of the primary source of the sound ................................................................................................................ 6

6.6 Shooter ........................................................................................................................................................................................................... 6

6.7 Measurement location ...................................................................................................................................................................... 6

6.8 Weather and ambient conditions ............................................................................................................................................ 7

7 Data evaluation and uncertainties ..................................................................................................................................................... 7

7.1 General ........................................................................................................................................................................................................... 7

7.2 Evaluating discrete time data ..................................................................................................................................................... 7

7.3 Frequency-weighting ......................................................................................................................................................................... 7

7.4 Measurement uncertainties ......................................................................................................................................................... 7

Annex A (informative) Slew rate limitations for impulse sound measurements ...................................................9

Annex B (informative) Calculations with discrete-time data ...................................................................................................15

Annex C (informative) Calculating C-weighted time series using a digital filter .................................................17

Bibliography .............................................................................................................................................................................................................................23

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ISO/DIS 17201-6:2019(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

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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

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URL: www .iso .org/ iso/ foreword .html.

This document was prepared by Technical Committee ISO/TC 43, Acoustics, Subcommittee SC 1, Noise.

A list of all parts in the ISO 17201 series can be found on the ISO website.
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ISO/DIS 17201-6:2019(E)
Introduction

Parts 1 to 5 of the Standard series ISO 17201 ([2] to [5]) relate to the determination or prediction of

environmentally relevant exposure to sound at receiving points outside shooting ranges.

In several countries however also the need exists for knowledge about exposure to sound within a

shooting range at short distance from the sound source, for instance for prediction, evaluation, control

or comparison purposes.

For such assessment various measures are in use, which all can be derived from the time history

of sound pressure at the locations of interest. Close to the muzzle blast or blast of an explosion the

measurement of sound pressure has particular features to be dealt with.

This Part 6 of the Standard series ISO 17201 therefore defines how the time histories of the sound

pressure at locations of interest within a shooting range can be reliably obtained.

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DRAFT INTERNATIONAL STANDARD ISO/DIS 17201-6:2019(E)
Acoustics — Noise from shooting ranges —
Part 6:
Sound exposure at close range of the sound source
1 Scope

This document specifies methods for recording the time history of the sound pressure produced by

shooting with calibres of less than 20 mm or by detonation of explosive charges of less than 50 g TNT

equivalent in locations within the shooting range. The location of the measurement can be the position

of the shooter or any person in the shooting range. The time history of the sound pressure can be the

basis for further analyses of exposure of persons to these kinds of sounds.
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.

IEC 60942, Electroacoustics — Sound calibrators

IEC 61094-6:2004, Measurement microphones — Part 6: Electrostatic actuators for determination of

frequency response
IEC 61672-1:2013, Electroacoustics — Sound level meters — Part 1: Specifications

ISO 17201-1:2018, Acoustics — Noise from shooting ranges — Part 1: Determination of muzzle blast by

measurement
ISO 80000-8, Quantities and units — Part 8: Acoustics
3 Terms and definitions

For the purposes of this document, the terms and definitions given in ISO 80000-8 and the following 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
discrete-time sound pressure series
sound pressure history with values given for discrete times

Note 1 to entry: In general, this time-series is the result of sampling the recorded sound pressure time-history.

Note 2 to entry: In all applications in this document, equal time spacing is assumed.

3.2
sampling
reduction of a continuous-time signal to a discrete-time signal series
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3.3
sample
value at a point in time in a discrete-time signal series

Note 1 to entry: Samples can be in various number formats, typically Integer or Real.

Note 2 to entry: Calibration information is needed to convert from a sample value to a sound pressure.

3.4
sampling interval
time between two adjacent values in a discrete-time signal series
Note 1 to entry: The sampling interval T is expressed in seconds.
Note 2 to entry: f = .
3.5
sampling rate
number of samples per second
Note 1 to entry: The sampling rate f is expressed in hertz.
4 Measurement system requirements
4.1 General

This clause specifies instrumentation for measuring impulsive sounds in the audible frequency range

from 20 Hz to 20 kHz. The purpose is to enable the reliable and accurate measurement of sound pressure

histories which can be used as input to various methods for describing impulsive sound characteristics

such as sound exposure level, peak sound pressure level, A-duration etc. as for example defined in

[1]
ISO 10843 .

Impulsive sound signals may contain significant contributions in the frequency range outside the

audible range from 20 Hz to 20 kHz, and impulsive sound quantifiers will therefore depend on the

frequency range of the instrumentation used for the measurements, and can therefore not be directly

compared for measurements where these parameters are not the same. As this clause specifies the

frequency range and other system requirements, data obtained within the given specifications can be

compared to other measurements obtained using this method.
4.2 Ranges of sound pressure levels

The peak sound pressure level depends – among other things – on the source energy of the blast and the

distance to it. At close distances, the peak sound pressure may be above 1 kPa, corresponding to a level

above 154 dB. The other parts of the standard series ISO 17201 limit its use for measurements with

peak sound pressure levels below 154 dB, since these parts are concerned with sound propagation.

This document is focused on the measurement of the time history of the sound pressure, therefore no

limit on the peak sound pressure level is set.
4.3 Overall system description

The measurements system shall consist of at least a microphone with a preamplifier and a digital data

acquisition system capable of storing digital signals for later retrieval and processing.

The measurement system shall be class 1 according to IEC 61672-1 using Z-weighting.

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4.4 Microphone and preamplifier requirements

The measurements shall be performed with a pressure type microphone meeting the requirements for

a WS3-P or WS2-P microphone as defined in IEC 61094-4. The use of a WS3-P microphone is preferred,

since the influence of the angle of incidence within the frequency range of interest is smaller compared

to a WS2-P microphone.

The microphone shall be connected to a cylindrical preamplifier with a diameter not larger than that

of the microphone. The microphone and preamplifier combination shall have the capability to measure

peak sound pressure levels in the appropriate range, with
LL≤−5dB (1)
pp,,maxOL
where
L is the peak sound pressure level to be measured; expressed in decibel;
p,max

L is the maximum peak sound pressure level at which the microphone and preamplifier com-

p,OL
bination is not overloaded; expressed in decibel.
LL≤−60dB (2)
pp,,nf max
where
L is the peak sound pressure level to be measured; expressed in decibel;
p,max

L is the A-weighted noise floor of the microphone and preamplifier combination; expressed

p,nf
in decibel.

NOTE 1 The A-weighted noise floor is used because this value is typically specified in microphone and

preamplifier data sheets.

A microphone and preamplifier combination capable of measuring peak sound pressure levels of at

least 165 dB is recommended.

The dynamic range of the microphone and preamplifier combination shall be at least 100 dB. The

dynamic range is the range from the highest peak sound pressure level capacity of the microphone to

the A-weighted noise floor level of the microphone and preamplifier combination.

The frequency response of the microphone and preamplifier shall be calibrated with an electrostatic

actuator according to IEC 61094-6 in the frequency range from 250 Hz to 20 kHz. This calibration shall

be performed less than 365 days before the measurements.

NOTE 2 The calibration according to IEC 61094-6 is usually performed by the microphone manufacturer or a

calibration laboratory.
4.5 Fixture

A fixture shall be used for the preamplifier and microphone that reduces influences of the fixture on

the measured sound field.
4.6 Cable length

The microphone and preamplifier shall be capable of handling the occurring signal rise times. The

signal rise time handling capacity is often determined by the preamplifier and the capacity of the

cable between the preamplifier and data acquisition system. If the cable length is increased, the cable

capacity will increase and the signal rise time handling capacity of the system will decrease. It is

therefore important to ensure that the signal rise time handling capacity is determined for the actual

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cable length used in the setup. For more information about slew rate limitations and signal rise time

handling capacity see Annex A.

NOTE In many microphone and preamplifier combinations, the limiting factor for the high peak sound

pressure handling capacity will be the preamplifier rather than the microphone.
4.7 Data acquisition system

The data acquisition system shall have a sample rate of at least 96 000 samples per second and shall be

able to store at least 10 s of continuous data. The resolution of the data acquisition system shall be at

least 24 bit.

The data acquisition system shall be equipped with an anti-aliasing filter attenuating all signal

component above the frequency f , with
f f
s s
≤≤f (3)
25, 2
where
f is the cut-off frequency of the anti-aliasing filter; expressed in hertz;
f is the sampling rate, expressed in hertz.
NOTE 1 f /2 is the Nyquist-frequency.

NOTE 2 For a sampling rate of 96 000 samples per second, the cut-off of the anti-aliasing filter should therefore

be between 38,4 kHz and 48,0 kHz.

The anti-aliasing filter shall have a roll-off rate of not less than 36 dB/octave.

4.8 Data storage

The recorded sound pressure time-series shall be stored in a digital uncompressed file format. It can

be stored directly as a sound pressure time-series, or as a sampled data time-series. In the latter case

calibration and offset information shall be provided additionally. In both cases, timing information

shall be provided to link each sample or data point to time.
If sampled data time-series are stored, the WAV-Format may be used for example.

Timing information shall be provided either by giving the time for each data point or by giving the

sampling rate and the starting time of the recording.
4.9 Frequency-weighting

All data shall be recorded within the range of the Z-weighting given in IEC 61672-1.

4.10 Calibration

The system calibration shall include the response of the microphone, preamplifier, all cables and data

acquisition system. The calibration shall be performed at either 250 Hz or 1 kHz, at a minimum sound

pressure level of 114 dB, using a sound calibrator Class 1 as defined in IEC 60942. The calibration shall

be performed on the same day before the measurements, and again after the measurements on the

same day.

The calibration shall be documented, and this documentation shall be included with the measurement

documentation.
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5 Measurement setup
5.1 General considerations

The measured time history of the sound pressure from a specific weapon or explosive charge is

influenced by the acoustical environment within the specific shooting range. Any reflections from the

ground, walls or other obstacles will be included in the measurement. Also, the result will depend on

the directivity of the sound radiation from the weapon and the location and posture of the shooter and

bystanders.

As the result may be different for different shooter locations and postures as well as bystander

positions, the measurements should either be performed in designated typical locations or in all

individual shooting and bystander positions and postures of interest.

If a person of interest were present, measured values may be influenced by slight variations in head

position. Also, differences between the sound levels at the left and right hand side of the head can be

different for other orientations of the head. To reduce these influences the measurements are therefore

carried out without the presence of the person of interest.
5.2 Measurement location
5.2.1 General
To determine the exposure to sound of a person
— within a specific shooting range;
— in a specific location and in a specific body posture;
— for a specific shooting situation;

measurements are performed with that person being absent, and the microphone placed in the position

where the head of the person would be.

All effects of a specific ground, reflections on walls, and the effects due to the presence of other persons,

are included in the measurement.
5.2.2 Special case: Shooter firing a gun

To determine the exposure to sound at the location of a shooter firing a gun, the person is removed,

and the weapon is placed in a fixture and operated remotely. The microphone is placed in the position

where the head of the shooter would be.

Only in this special case the measurement of shooting sound shall be performed in the absence of the

shooter.

As there is not a universal applicable weapons fixture, it is mandatory that the used fixture is extensively

documented. It should be constructed to minimize reflections.

Since the presence of the shooter can influence the exposure to sound of other persons in the shooting

range, such as for instance an instructor or bystanders, the measurements for the assessment of the

exposure to shooting sound at the location of these persons is to be performed with the shooter present.

The persons of interest shall not be present during the measurements.
5.3 Microphone orientation
The microphone shall be mounted vertically, with the diaphragm facing upwards.
Note 1 to entry In terms of IEC 61672-1, the reference direction is vertical.
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5.4 Weather and ambient conditions

There are no restrictions for weather and ambient conditions. For outdoor shooting ranges, it is

recommended to make measurements not during rain.
6 Documentation
6.1 General

A general description of the situation that concerns the measurements shall be given. Also, a brief

explanation of the purpose of the measurement shall be given.
6.2 Shooting range

A schematic diagram of the shooting range shall be given. This shall include markings that define the

firing locations of the weapon and positions of all persons of interest in a three dimensional space.

6.3 Absorbing and reflecting elements

For elements such as the ground, walls, baffles and barriers which are part of the shooting range, a

description of the materials thereof shall be documented and a statement as to their sound absorbing

and reflecting nature.
6.4 Weapon documentation

Weapon documentation of the weapon and ammunition as specified in ISO 17201-1:2018, Clause 4 shall

be given.
6.5 Location of the primary source of the sound

The location and shooting direction shall be clear from the schematic diagram of the shooting range or

given in the text of the report.

The height of the muzzle shall be stated. If the elevation of the gun is larger than five degrees or smaller

than minus five degrees, this shall also be stated in the report.
6.6 Shooter

It shall be stated whether the weapon is operated by a shooter or remotely operated and in a fixture.

The location and posture of the shooter (standing, kneeling, sitting, prone), and the left or right handed

use of the fired gun shall be documented.
6.7 Measurement location

The measurement location shall be specified. For the microphone, the height of the diaphragm shall be

reported.

If measurements are taken at several locations at the same time, each measurement location shall be

reported.

For each measurement location, the person of interest is removed. As other persons of interest will

influence this measurement result, these persons need to be present.
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6.8 Weather and ambient conditions
The weather and ambient conditions shall be reported. This includes at least:
— temperature;
— barometric pressure;
— humidity.

If the measurement is performed outside or inside a partial enclosure of the shooting range, the

following weather information shall also be reported:
— rain;

— wind speed and direction, including the height at which these values are determined.

7 Data evaluation and uncertainties
7.1 General

The scope of this document is the recording of the time history of the sound pressure that can be

used for further evaluation and assessment. While this standard does not provide an evaluation or

assessment for these time series, guidelines on how to use the sound pressure time series are given in

this clause.
7.2 Evaluating discrete time data

Some evaluation schemes require the calculations of quantities that are given as an integral of a function

of the sound pressure over time. A guideline on how to replace the integral with a sum and work with a

discrete sound pressure time series is given in Annex B.
7.3 Frequency-weighting

All data shall be recorded meeting the requirements for Z-weighting given in IEC 61672-1.

If A- or C-weighting are to be applied to the sound pressure time series for evaluation or assessment of

the data, filters as specified in Annex E of IEC 61672-1:2013
...