ISO 17208-1:2016
(Main)Underwater acoustics — Quantities and procedures for description and measurement of underwater sound from ships — Part 1: Requirements for precision measurements in deep water used for comparison purposes
Underwater acoustics — Quantities and procedures for description and measurement of underwater sound from ships — Part 1: Requirements for precision measurements in deep water used for comparison purposes
ISO 17208-1:2016 specifies the general measurement system, procedure, and methodology used for the measurement of underwater sound from ships under a prescribed operating condition. It does not specify or provide guidance on underwater noise criteria or address the potential effects of noise on marine organisms. The resulting quantities are based on the root-mean-square sound pressure levels (SPL), herein used synonymously with sound pressure level or SPL measured in the far field of the ship and normalized to a distance of 1 m and reported in one-third octave bands (see 4.3). In this part of ISO 17208, the result of these measurements is called "radiated noise level". The underwater sound pressure level measurement is performed in the geometric far field and then adjusted to the 1 m normalized distance for use in comparison with appropriate underwater noise criteria. ISO 17208-1:2016 is applicable to any and all underway surface vessels, either manned or unmanned. It is not applicable to submerged vessels or to aircraft. The method has no inherent limitation on minimum or maximum ship size. It is limited to ships transiting at speeds no greater than 50 kn (25,7 m/s). The measurement method smooths the variability caused by Lloyd's mirror surface image coherence effects, but does not exclude a possible influence of propagation effects like bottom reflections, refraction and absorption. No specific computational adjustments for these effects are provided in this part of ISO 17208. A specific ocean location is not required to use this part of ISO 17208, but the requirements for an ocean test site are provided. The intended uses of the method described in this part of ISO 17208 are: to show compliance with contract requirements or criteria, for comparison of one ship to another ship, to enable periodic signature assessments, and for research and development. The intended users include government agencies, research vessel operators, and commercial ship owners. Additional post-processing would be required to use the data obtained from this measurement method for determination of the ship source levels to perform far field noise predictions such as needed for most environmental impact studies or for creating underwater noise contour maps.
Acoustique sous-marine — Grandeurs et modes de description et de mesurage de l'acoustique sous-marine des navires — Partie 1: Exigences pour les mesurages en eau profonde utilisées pour des besoins de comparaison
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INTERNATIONAL ISO
STANDARD 17208-1
First edition
2016-03-15
Underwater acoustics — Quantities
and procedures for description and
measurement of underwater sound
from ships —
Part 1:
Requirements for precision
measurements in deep water used for
comparison purposes
Acoustique sous-marine — Grandeurs et modes de description et de
mesurage de l’acoustique sous-marine des navires —
Partie 1: Exigences pour les mesurages en eau profonde utilisées pour
des besoins de comparaison
Reference number
ISO 17208-1:2016(E)
©
ISO 2016
---------------------- Page: 1 ----------------------
ISO 17208-1:2016(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2016, Published in Switzerland
All rights reserved. Unless otherwise specified, 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
Ch. de Blandonnet 8 • CP 401
CH-1214 Vernier, Geneva, Switzerland
Tel. +41 22 749 01 11
Fax +41 22 749 09 47
copyright@iso.org
www.iso.org
ii © ISO 2016 – All rights reserved
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ISO 17208-1:2016(E)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 2
4 Instrumentation . 6
4.1 General . 6
4.2 Hydrophone and signal conditioning . 7
4.3 Data acquisition, recording, processing and display . 7
4.4 Distance measurement . 7
5 Measurement requirements and procedure . 8
5.1 General . 8
5.2 Test site requirements . 8
5.3 Sea surface conditions . 8
5.4 Hydrophone deployment . 9
5.5 Test course and ship operation .10
5.6 Test sequence .11
6 Post-processing .12
6.1 General .12
6.2 Background noise adjustments .13
6.3 Sensitivity adjustments .14
6.4 Distance normalization . .14
6.5 Hydrophone and run combination post-processing .15
7 Measurement uncertainty .16
8 Reporting example .17
Bibliography .20
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ISO 17208-1:2016(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 WTO principles in the Technical
Barriers to Trade (TBT) see the following URL: Foreword - Supplementary information
The committee responsible for this document is ISO/TC 43, Acoustics, Subcommittee SC 3, Underwater
acoustics.
This first edition cancels and replaces ISO/PAS 17208-1:2012, which has been technically revised.
ISO 17208 consists of the following parts, under the general title Underwater acoustics — Quantities and
procedures for description and measurement of underwater sound from ships:
— Part 1: Requirements for precision measurements in deep water used for comparison purposes
The following part is under preparation:
— Part 2: Determination of source levels
A third part on measurement of radiated noise levels in shallow water is planned.
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ISO 17208-1:2016(E)
Introduction
This part of ISO 17208 was developed to provide a standardized measurement method for the
quantification and qualification of a ship’s underwater radiated noise level. This procedure measures a
sector average for a certain beam aspect. It promotes the consistency of reported sound measurements
from shipping sources. This part of ISO 17208 provides users with the necessary procedure to compare
a ship’s radiated noise level to criteria established by others or to contract specifications.
Reduction of all types of ship emissions, most notably ballast water and engine emissions, became an
issue in the decade prior to publication of ISO/PAS 17208-1:2012. ISO/PAS 17208-1:2012 was developed
in response to growing international concerns about underwater noise and its impact on marine
animals.
Excessive underwater noise has the potential to interfere with a marine animal’s ability to perform a
variety of critical life functions, including navigation, communication and finding food. Because of this,
the environmental impact statements of underwater projects such as pile driving, pipe laying and oil
exploration now include assessments of underwater noise impact.
This part of ISO 17208 converts the PAS to an International Standard and limits its focus to a precision
grade of measurement.
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INTERNATIONAL STANDARD ISO 17208-1:2016(E)
Underwater acoustics — Quantities and procedures for
description and measurement of underwater sound
from ships —
Part 1:
Requirements for precision measurements in deep water
used for comparison purposes
1 Scope
This part of ISO 17208 specifies the general measurement system, procedure, and methodology used
for the measurement of underwater sound from ships under a prescribed operating condition. It does
not specify or provide guidance on underwater noise criteria or address the potential effects of noise
on marine organisms.
The resulting quantities are based on the root-mean-square sound pressure levels (SPL), herein used
synonymously with sound pressure level or SPL measured in the far field of the ship and normalized
to a distance of 1 m and reported in one-third octave bands (see 4.3). In this part of ISO 17208, the
result of these measurements is called “radiated noise level”. The underwater sound pressure level
measurement is performed in the geometric far field and then adjusted to the 1 m normalized distance
for use in comparison with appropriate underwater noise criteria.
This part of ISO 17208 is applicable to any and all underway surface vessels, either manned or
unmanned. It is not applicable to submerged vessels or to aircraft. The method has no inherent
limitation on minimum or maximum ship size. It is limited to ships transiting at speeds no greater than
50 kn (25,7 m/s).
The measurement method smooths the variability caused by Lloyd’s mirror surface image coherence
effects, but does not exclude a possible influence of propagation effects like bottom reflections,
refraction and absorption. No specific computational adjustments for these effects are provided in
this part of ISO 17208. A specific ocean location is not required to use this part of ISO 17208, but the
requirements for an ocean test site are provided.
The intended uses of the method described in this part of ISO 17208 are: to show compliance with
contract requirements or criteria, for comparison of one ship to another ship, to enable periodic
signature assessments, and for research and development. The intended users include government
agencies, research vessel operators, and commercial ship owners.
Additional post-processing would be required to use the data obtained from this measurement method
for determination of the ship source levels to perform far field noise predictions such as needed for
most environmental impact studies or for creating underwater noise contour maps.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are
indispensable for its application. For dated references, only the edition cited applies. For undated
references, the latest edition of the referenced document (including any amendments) applies.
1)
ISO 18405:— , Underwater acoustics — Terminology
1) To be published.
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ISO 17208-1:2016(E)
IEC 60565, Underwater acoustics — Hydrophones — Calibration in the frequency range 0,01 Hz to 1 MHz
IEC 61260, Electroacoustics — Octave-band and fractional-octave-band filters
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 18405 and the following apply.
3.1
background noise
noise from all sources (biotic and abiotic) other than the ship being measured, including self noise
Note 1 to entry: See 6.2 for background noise adjustments.
[SOURCE: ISO 11202:2010, 3.17, modified – in the definition, added “(biotic and abiotic)” and changed
“source under test” to “ship being measured”.]
3.2
beam aspect
direction to either side of the ship under test perpendicular to the vertical plane through the middle of
the ship from front to back
Note 1 to entry: Beam aspect refers to the location of the hydrophone(s) with respect to the ship under test
and is typically referred to as port or starboard directions. Another approach for hydrophone measurement (not
applied here) is keel aspect where the hydrophone(s) are below the keel of the ship under test.
3.3
closest point of approach
CPA
point where the horizontal distance (during a test run) from the ship reference point of the ship under
test to the hydrophone(s) is the smallest
Note 1 to entry: The distance to the hydrophone at the closest point of approach is defined by the symbol d as
CPA
used in Formula (1).
3.4
commence exercise
COMEX
start test range location
position of the ship reference point of the ship under test at least twice (2x) the distance of the “start
data” location ahead of the closest point of approach
Note 1 to entry: See Figure 3.
3.5
data window angle
angle subtended at the hydrophone, between the start data location and the end data location
Note 1 to entry: The data window angle is expressed as a value in degrees as shown in Figure 3.
Note 2 to entry: The data window angle is ±30°.
3.6
data window length
DWL
l
DW
distance between the start data location and end data location
Note 1 to entry: The DWL is defined by the distance at closest point of approach and the data window angle of
±30° as given in Formula (1) and shown in Figure 3.
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ISO 17208-1:2016(E)
3.7
data window period
DWP
t
DWP
time it takes the ship under test to travel the data window length at a certain speed
Note 1 to entry: See Formula (2) and Figure 3.
3.8
end data location
position of the ship reference point of the ship under test where data recording is ended
Note 1 to entry: End data location is one data window length after the start data location. See Figure 3.
3.9
field calibration
method of using known inputs, possibly using physical stimuli (such as a known, calibrated and
traceable acoustic or vibration source) or electrical input (charge or voltage signal injection) at the input
(or other stage) of a measurement system in order to ascertain that the system is, in fact, responding
properly (i.e. within the system’s stated uncertainty) to the known stimulus
3.10
finish exercise
FINEX
end test range location
position of the ship reference point of the ship under test twice (2x) the distance to the “start data”
location past the closest point of approach
Note 1 to entry: See Figure 3.
3.11
frequency response
frequency range a system is able to measure, for a given uncertainty and repeatability, from the lowest
frequency to the highest stated frequency
3.12
geometric far field
horizontal distance from the ship under test at which the assumption of source co-location causes less
than 1 dB difference between the actual measurement and the hypothetical result when adjusting to
the reference far field distance
Note 1 to entry: The definition for acoustic far field in ISO 18405 also applies.
3.13
hydrophone cable drift angle
angle between the vertical axis and the line created between the fixed support of the hydrophone cable
and the hydrophone
3.14
insert voltage calibration
known, calibrated and traceable input stimulus in the form of an electrical input injected at the input
(or other stage) of a measurement system in order to ascertain that the system is, in fact, responding
properly (i.e. within the system’s stated uncertainty and repeatability) to a known stimulus
3.15
Lloyd’s mirror surface image coherence effects
alteration of radiated noise levels caused by the presence of a free (pressure release) surface
Note 1 to entry: Radiation from the surface image constructively and destructively influences the source’s direct
radiation. For this part of ISO 17208, these effects are considered as part of the source’s radiation, causing it to
exhibit a vertical directivity and necessitating the acquisition angle(s) is defined.
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ISO 17208-1:2016(E)
Note 2 to entry: Lloyd’s mirror effects are reduced but not removed from the final radiated noise level
determined herein.
3.16
measurement repeatability
expected dispersion of radiated noise levels resulting from successive measurements on the same ship
at the same operating condition, carried out under the same conditions of measurement with the same
equipment at the same location
Note 1 to entry: Measurement repeatability is stated in decibels and in one-third octave bands.
3.17
measurement system
data acquisition system consisting of, but not limited to, one or more transducer(s), conditioning
amplifier(s), analogue-to-digital converter(s), digital signal processing computer and ancillary
peripherals
3.18
measurement uncertainty
expected dispersion of the measured radiated noise level values
Note 1 to entry: Measurement uncertainty is stated in decibels for one-third octave bands using a given
measurement method (averaging time, bandwidth-time product, etc.).
Note 2 to entry: See Clause 7.
3.19
omni-directional hydrophone
underwater sound pressure transducer that responds nearly equally to sound from all directions with
a variation in sensitivity with horizontal direction not exceeding ±2 dB within the frequency range of
the measurements.
3.20
overall ship length
longitudinal distance between the forward-most and aft-most part of a ship
3.21
radiated noise level
RNL
L
RN
level of the product of the distance from a ship reference point of a sound source, d, and the far field
root-mean-square sound pressure, p (d), at that distance for a specified reference value
rms
Note 1 to entry: LRN = 20 log (p /p ) dB + 20 log (d/d ) dB.
10 rms 0 10 0
Note 2 to entry: Radiated noise level is expressed in decibels (dB).
Note 3 to entry: The reference value for sound pressure (p ) is 1 µPa. The reference value for distance (d ) is 1 m.
0 0
The combined RNL reference value is p d is 1 μPa·m.
0 0
Note 4 to entry: The resulting level is denoted “LRN, dB re 1 µPa·m”. This designation replaces the past use of
“Lp, dB re 1 µPa @ 1 m”.
Note 5 to entry: RNL varies in both horizontal and vertical aspect in the far field. This procedure determines an
azimuthal sector averaged about the hydrophone position; and vertical-elevation averaged quantity in the beam
aspect about the ship reference point.
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ISO 17208-1:2016(E)
3.22
root-mean-square sound pressure level
sound pressure level
SPL
L
p
for a specified reference value, p , the level of the root-mean-square sound pressure, p
0 rms
Note 1 to entry: In formula form, L = 20 log (p /p ) dB, where p is the root-mean-square sound pressure.
p 10 rms 0 rms
Note 2 to entry: Root-mean-square sound pressure level is expressed in decibels (dB).
Note 3 to entry: In underwater acoustics, the reference value of root-mean-square sound pressure, p , is 1 μPa.
0
Note 4 to entry: Frequency weighting and time weighting, as applicable, shall be specified.
Note 5 to entry: Root-mean-square sound pressure is a field quantity (see ISO 80000-3:2006, Clause 3 and
ISO 80000-1:2009, Annex C).
Note 6 to entry: The abbreviations “RMS SPL” and “root-mean-square SPL” are deprecated because in normal use
of English, these would mean “root-mean-square value of SPL”, which means something different from “level of
the root-mean-square sound pressure”.
3.23
ship reference point
point on the ship from which the distances are defined
Note 1 to entry: For the purpose of this part of ISO 17208, the ship reference point is located transversely at the
ship centreline, longitudinally a quarter-length forward of the stern and vertically at the height of the sea surface.
Note 2 to entry: The location for the ship reference point applies for all frequencies.
Note 3 to entry: The ship reference point may also serve as an approximate location for the ship’s acoustic centre.
3.24
slant range
distance from the ship reference point of the ship under test to each hydrophone
3.25
sound speed profile
measure of the speed of sound in seawater as a function of depth, measured vertically through the
water column
3.26
start data location
position of the ship reference point of the ship under test where data recording is started
Note 1 to entry: See Figure 3.
3.27
test site
location where the underwater noise measurements are performed
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ISO 17208-1:2016(E)
4 Instrumentation
4.1 General
In order to quantify the underwater sound from a ship, three main instrumentation components
are required: (1) hydrophone and signal conditioning, (2) data acquisition, recording, processing
and display system, and (3) distance measurement system. Detailed specifications of each of the
measurement systems are given below. A summary of the parameters is given in Table 1.
Table 1 — Summary of measurement parameters
Measurement parameter Value/Quantity
Achievable expanded measurement uncertainty 5 dB (10 Hz to 100 Hz one-third octave bands)
(expressed as the typical value for applicable one-
3 dB (125 Hz to 16 000 Hz one-third octave bands)
third octave bands)
4 dB (≥20 000 Hz one-third octave bands)
Measurement repeatability (expressed as the typical 3 dB (10 Hz to 100 Hz one-third octave bands)
value for applicable one-third octave bands)
1 dB (125 Hz to 16 000 Hz one-third octave bands)
1 dB (≥20 000 Hz one-third octave bands)
Bandwidth One-third octave band
Frequency range, lower one-third octave band 10 Hz
Frequency range, upper one-third octave band 20 000 Hz (minimum) but up to 50 000 Hz as may be
required by the criteria (see 4.3)
Number of hydrophones Three
Hydrophone geometry See Figure 1
Nominal hydrophone angles 15°, 30°, 45° angle
Minimum water depth Greater of 150 m or 1,5× overall ship length
Nominal distance at closest point of approach (CPA) Greater of 100 m or 1× overall ship length
Tolerance of the actual distance at CPA -10 % to +25 %
Distance ranging measurement uncertainty (at CPA) ≤10 %
Data window angle (±CPA) ±30°
Data window length, metres Determined using Formula (1)
Shown in Figure 3
Data window time, seconds Determined Using Formula (2)
Shown in Figure 3
Data window averaging time One overall sample equal to DWP
Minimum number of runs per ship condition 4 Total
2 Port
2 Starboard
Recommended weather/sea conditions Wind speed ≤20 kn (see 5.3)
Portable hydrophone calibration Laboratory calibration every 12 months
Field calibration, as below, daily during measurements
Fixed hydrophone calibration Laboratory calibration prior to installation
Confirmation using calibrated sound source or
reference hydrophone every 12 months
Field calibration, as below, daily during measurements
System field calibration Insert voltage calibration
Auxiliary measurements Shaft speed, wind speed and direction (see Clause 8 for
other measurements)
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ISO 17208-1:2016(E)
4.2 Hydrophone and signal conditioning
For the purposes of this part of ISO 17208, the terms hydrophone, underwater electro-acoustic
transducer, or underwater microphone may be used synonymously. Here, the term hydrophone is
used and includes any signal conditioning electronics either within or exterior to the hydrophone. The
hydrophone(s) shall have the sensitivity, bandwidth and dynamic range necessary to measure the ship
under test and meet the performance parameters given in Table 1.
This part of ISO 17208 requires three hydrophones that should be omni-directional across the required
frequency range of 10 Hz to 20 000 Hz, or higher if required, see Table 1. Directional hydrophones may
be used, as long as the directional characteristics are accounted for in the post-processing (see 6.3). The
hydrophones may or may not have integral cable. However, the required performance shall be obtained
with the full cable length to be used during the test.
When portable hydrophones are used, they shall be laboratory calibrated every 12 months in
accordance with IEC 60565 for all required one-third octave bands. When fixed (i.e. permanently
installed underwater) hydrophones are used, they shall be laboratory calibrated before installation in
accordance with IEC 60565 for all required one-third octave bands. The fixed hydrophone calibration
shall be confirmed by a comparative measurement utilizing a calibrated underwater sound source
every 12 months. Alternatively, the fixed hydrophones and associated cabling may be lifted from the
water every 12 months for maintenance and the hydrophones laboratory calibrated.
The sensitivity and directivity of the hydrophones shall be determined to within ±2 dB.
4.3 Data acquisition, recording, processing and display
The data acquisition, recording, processing and display system shall be capable of accurately acquiring,
recording, processing and displaying data from the hydrophones. Such systems may comprise tape
recorders, computer-based data acquisition systems or hardware-specific devices (such as spectrum
analysers) or combinations of these. The data acquisition system should have an appropriate sampling
rate and anti-aliasing filters following Nyquist requirements and appropriate dynamic range for either
analogue or digital systems. All frequency-domain averaging shall be linear with sampling consistent
with the data window period (DWP), see 6.1.
The time domain signal from each hydrophone shall be acquired and recorded simultaneously and
be sample-accurate for all three channels. Tracking and time stamp data (see 4.4) shall be recorded
synchronously with the acoustic data to enable reconstruction of the track and data processing.
The broadband processing shall cover the one-third octave bands from 10 Hz to 20 000 Hz in accordance
with IEC 61260, Base 2 (true one-third octaves) or Base 10 (as also called decidecade in ISO 18405),
Class 1. Throughout this International Standard, the use of the term one-third octave can be considered
equivalent to the term decidecade. If required by a ship’s noise criteria specification (i.e. ICES CRR-209),
one-third octave band processing up to 50 000 Hz may be necessary.
4.4 Distance measurement
Distance measurement is required to continuously determine the actual distance between the
hydrophones and the ship reference point of the ship under test.
For measurement with surface-suspended hydrophones, the distance measurement systems shall
determine the horizontal distance from the sea surface position above the hydrophone(s) (i.e. the
device or buoy used to suspend the cable) to the ship reference point of the ship under test. The distance
measurement device may utilize any method (e.g. optical, acoustical, GPS, radar) to achieve the required
accuracy.
For measurement with bottom-suspended hydrophones, the distance measurement systems
shall determine the horizontal distance from the sea surface position above the hydrophone(s)
(corresponding to the point of attachment of the cable on sea bottom) to the ship reference point of the
ship under test.
© ISO 2016 – All rights reserved 7
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ISO 17208-1:2016
...
FINAL
INTERNATIONAL ISO/FDIS
DRAFT
STANDARD 17208-1
ISO/TC 43/SC 3
Underwater acoustics — Quantities
Secretariat: ANSI
and procedures for description and
Voting begins on:
2015-12-14 measurement of underwater sound
from ships —
Voting terminates on:
2016-02-14
Part 1:
Requirements for precision
measurements in deep water used for
comparison purposes
Acoustique sous-marine — Grandeurs et modes de description et de
mesurage de l’acoustique sous-marine des navires —
Partie 1: Exigences pour les mesurages en eau profonde utilisées pour
des besoins de comparaison
RECIPIENTS OF THIS DRAFT ARE INVITED TO
SUBMIT, WITH THEIR COMMENTS, NOTIFICATION
OF ANY RELEVANT PATENT RIGHTS OF WHICH
THEY ARE AWARE AND TO PROVIDE SUPPOR TING
DOCUMENTATION.
IN ADDITION TO THEIR EVALUATION AS
Reference number
BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO-
ISO/FDIS 17208-1:2015(E)
LOGICAL, COMMERCIAL AND USER PURPOSES,
DRAFT INTERNATIONAL STANDARDS MAY ON
OCCASION HAVE TO BE CONSIDERED IN THE
LIGHT OF THEIR POTENTIAL TO BECOME STAN-
DARDS TO WHICH REFERENCE MAY BE MADE IN
©
NATIONAL REGULATIONS. ISO 2015
---------------------- Page: 1 ----------------------
ISO/FDIS 17208-1:2015(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2015, Published in Switzerland
All rights reserved. Unless otherwise specified, 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
Ch. de Blandonnet 8 • CP 401
CH-1214 Vernier, Geneva, Switzerland
Tel. +41 22 749 01 11
Fax +41 22 749 09 47
copyright@iso.org
www.iso.org
ii © ISO 2015 – All rights reserved
---------------------- Page: 2 ----------------------
ISO/FDIS 17208-1:2015(E)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 2
4 Instrumentation . 5
4.1 General . 5
4.2 Hydrophone and signal conditioning . 7
4.3 Data acquisition, recording, processing and display . 7
4.4 Distance measurement . 7
5 Measurement requirements and procedure . 8
5.1 General . 8
5.2 Test site requirements . 8
5.3 Sea surface conditions . 8
5.4 Hydrophone deployment . 9
5.5 Test course and ship operation .10
5.6 Test sequence .12
6 Post-processing .12
6.1 General .12
6.2 Background noise adjustments .13
6.3 Sensitivity adjustments .14
6.4 Distance normalization . .14
6.5 Hydrophone and run combination post-processing .15
7 Measurement uncertainty .16
8 Reporting example .17
Bibliography .20
© ISO 2015 – All rights reserved iii
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ISO/FDIS 17208-1:2015(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 WTO principles in the Technical
Barriers to Trade (TBT) see the following URL: Foreword - Supplementary information
The committee responsible for this document is ISO/TC 43, Acoustics, Subcommittee SC 3,
Underwater acoustics.
This first edition cancels and replaces ISO/PAS 17208-1:2012, which has been technically revised.
ISO 17208 consists of the following parts, under the general title Underwater acoustics — Quantities and
procedures for description and measurement of underwater sound from ships:
— Part 1: Requirements for precision measurements in deep water used for comparison purposes
The following part is under preparation:
— Part 2: Determination of source levels
A third part on measurement of radiated noise levels in shallow water is planned.
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ISO/FDIS 17208-1:2015(E)
Introduction
This part of ISO 17208 was developed to provide a standardized measurement method for the
quantification and qualification of a ship’s underwater radiated noise level. This procedure measures a
sector average for a certain beam aspect. It promotes the consistency of reported sound measurements
from shipping sources. This part of ISO 17208 provides users with the necessary procedure to compare
a ship’s radiated noise level to criteria established by others or to contract specifications.
Reduction of all types of ship emissions, most notably ballast water and engine emissions, became an
issue in the decade prior to publication of ISO/PAS 17208-1:2012. ISO/PAS 17208-1:2012 was developed
in response to growing international concerns about underwater noise and its impact on marine animals.
Excessive underwater noise has the potential to interfere with a marine animal’s ability to perform a
variety of critical life functions, including navigation, communication and finding food. Because of this,
the environmental impact statements of underwater projects such as pile driving, pipe laying and oil
exploration now include assessments of underwater noise impact.
This part of ISO 17208 converts the PAS to an International Standard and limits its focus to a precision
grade of measurement.
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FINAL DRAFT INTERNATIONAL STANDARD ISO/FDIS 17208-1:2015(E)
Underwater acoustics — Quantities and procedures for
description and measurement of underwater sound from
ships —
Part 1:
Requirements for precision measurements in deep water
used for comparison purposes
1 Scope
This part of ISO 17208 specifies the general measurement system, procedure, and methodology used
for the measurement of underwater sound from ships under a prescribed operating condition. It does
not specify or provide guidance on underwater noise criteria or address the potential effects of noise
on marine organisms.
The resulting quantities are based on the root-mean-square sound pressure levels (SPL), herein used
synonymously with sound pressure level or SPL measured in the far-field of the ship and normalized
to a distance of 1 m and reported in one-third octave bands (see 4.3). In this part of ISO 17208, the
result of these measurements is called “radiated noise level.” The underwater sound pressure level
measurement is performed in the geometric far field and then adjusted to the 1 m normalized distance
for use in comparison with appropriate underwater noise criteria.
This part of ISO 17208 is applicable to any and all underway surface vessels, either manned or
unmanned. It is not applicable to submerged vessels or to aircraft. The method has no inherent
limitation on minimum or maximum ship size. It is limited to ships transiting at speeds no greater than
50 kn (25,7 m/s).
The measurement method mitigates the variability caused by Lloyd’s mirror surface image coherence
effects, but does not exclude a possible influence of propagation effects like bottom reflections,
refraction and absorption. No specific computational adjustments for these effects are provided in
this part of ISO 17208. A specific ocean location is not required to use this part of ISO 17208, but the
requirements for an ocean test site are provided.
The intended uses of the method described in this part of ISO 17208 are: to show compliance with
contract requirements or criteria, for comparison of one ship to another ship, to enable periodic
signature assessments, and for research and development. The intended users include government
agencies, research vessel operators, and commercial ship owners.
Additional post-processing would be required to use the data obtained from this measurement method
for determination of the ship source levels to perform far-field noise predictions such as needed for
most environmental impact studies or for creating underwater noise contour maps.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are
indispensable for its application. For dated references, only the edition cited applies. For undated
references, the latest edition of the referenced document (including any amendments) applies.
1)
ISO 18405:— , Underwater acoustics — Terminology
1) To be published.
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ISO/FDIS 17208-1:2015(E)
IEC 60565, Underwater acoustics — Hydrophones — Calibration in the frequency range 0,01 Hz to 1 MHz
IEC 61260, Electroacoustics — Octave-band and fractional-octave-band filters
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 18405 and the following apply.
3.1
background noise
noise from all sources (biotic and abiotic) other than the ship being measured, including self noise
Note 1 to entry: See 6.2 for background noise adjustments.
[SOURCE: ISO 11202:2010, 3.17, modified – in the definition, added “(biotic and abiotic)” and changed
“source under test” to “ship being measured”.]
3.2
beam aspect
direction to either side of the ship under test perpendicular to the vertical plane through the middle of
the ship from front to back
Note 1 to entry: Beam aspect refers to the location of the hydrophone(s) with respect to the ship under test
and is typically referred to as port or starboard directions. Another approach for hydrophone measurement (not
applied here) is keel aspect where the hydrophone(s) are mounted at or near the sea floor.
3.3
closest point of approach
CPA
point where the horizontal distance (during a test run) from the ship reference point of the ship under
test to the hydrophone(s) is the smallest
Note 1 to entry: The distance to the hydrophone at the closest point of approach is defined by the symbol d as
CPA
used in Formula (1).
3.4
commence exercise
COMEX
start test range location
position of the ship reference point of the ship under test at least twice (2x) the distance of the “start
data” location ahead of the closest point of approach
Note 1 to entry: See Figure 3.
3.5
data window angle
angle subtended at the hydrophone, between the start data location and the end data location
Note 1 to entry: The data window angle is expressed as a value in degrees as shown in Figure 3.
Note 2 to entry: The data window angle is ±30°.
3.6
data window length
DWL
l
DW
distance between the start data location and end data location
Note 1 to entry: The DWL is defined by the distance at closest point of approach and the data window angle of
±30° as given in Formula (1) and shown in Figure 3.
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3.7
data window period
DWP
t
DWP
time it takes the ship under test to travel the data window length at a certain speed
Note 1 to entry: See Formula (2) and Figure 3.
3.8
end data location
position of the ship reference point of the ship under test where data recording is ended
Note 1 to entry: End data location is one data window length after the start data location. See Figure 3.
3.9
field calibration
method of using known inputs, possibly using physical stimuli (such as a known, calibrated and
traceable acoustic or vibration source) or electrical input (charge or voltage signal injection) at the input
(or other stage) of a measurement system in order to ascertain that the system is, in fact, responding
properly (i.e. within the system’s stated uncertainty) to the known stimulus
3.10
finish exercise
FINEX
end test range location
position of the ship reference point of the ship under test twice (2x) the distance to the “start data”
location past the closest point of approach
Note 1 to entry: See Figure 3.
3.11
frequency response
frequency range a system is able to measure, for a given uncertainty and repeatability, from the lowest
frequency to the highest stated frequency
3.12
geometric far field
horizontal distance from the ship under test at which the assumption of source co-location causes less
than 1 dB difference between the actual measurement and the hypothetical result when adjusting to
the reference far-field distance
Note 1 to entry: The definition for acoustic far field in ISO 18405 also applies.
3.13
hydrophone cable drift angle
angle between the vertical axis and the line created between the fixed support of the hydrophone cable
and the hydrophone
3.14
insert voltage calibration
known, calibrated and traceable input stimulus in the form of an electrical input injected at the input
(or other stage) of a measurement system in order to ascertain that the system is, in fact, responding
properly (i.e. within the system’s stated uncertainty and repeatability) to a known stimulus
3.15
Lloyd’s mirror surface image coherence effects
alteration of radiated noise levels caused by the presence of a free (pressure release) surface
Note 1 to entry: Radiation from the surface image constructively and destructively influences the source’s direct
radiation. For this part of ISO 17208, these effects are considered as part of the source’s radiation, causing it to
exhibit a vertical directivity and necessitating the acquisition angle(s) is defined.
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Note 2 to entry: Lloyd’s mirror effects are reduced but not removed from the final radiated noise level
determined herein.
3.16
measurement repeatability
expected dispersion of radiated noise levels resulting from successive measurements on the same ship
at the same operating condition, carried out under the same conditions of measurement with the same
equipment at the same location
Note 1 to entry: Measurement repeatability is stated in decibels and in one-third-octave bands.
3.17
measurement system
data acquisition system consisting of, but not limited to, one or more transducer(s), conditioning
amplifier(s), analogue-to-digital converter(s), digital signal processing computer and ancillary peripherals
3.18
measurement uncertainty
expected dispersion of the measured radiated noise level values
Note 1 to entry: Measurement uncertainty is stated in decibels for one-third-octave bands using a given
measurement method (averaging time, bandwidth-time product, etc.).
Note 2 to entry: See Clause 7.
3.19
omni-directional hydrophone
underwater sound pressure transducer that responds nearly equally to sound from all directions with
a variation in sensitivity with horizontal direction not exceeding ±2 dB within the frequency range of
the measurements.
3.20
overall ship length
longitudinal distance between the forward-most and aft-most part of a ship
3.21
radiated noise level
RNL
L
RN
level of the product of the distance from a ship reference point of a sound source, d, and the far-field
root-mean-square sound pressure, p (d), at that distance for a specified reference value
RMS
Note 1 to entry: LRN = 20 log10 (p /p ) dB + 20 log10 (d/d ) dB.
RMS 0 0
Note 2 to entry: Radiated noise level is expressed in decibels (dB).
Note 3 to entry: The reference value for pressure (p ) is 1 µPa. The reference value for distance (d ) is 1 m. The
0 0
combined RNL reference value is p d is 1 μPa·m.
0 0
Note 4 to entry: The resulting level is denoted “LRN, dB re 1 µPa·m”. This designation replaces the past use of
“Lp, dB re 1 µPa @ 1 m”.
Note 5 to entry: RNL varies in both horizontal and vertical aspect in the far-field. This procedure determines an
azimuthal sector averaged about the hydrophone position; and vertical-elevation averaged quantity in the beam
aspect about the ship reference point.
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3.22
root-mean-square sound pressure level
sound pressure level
SPL
L
p
for a specified reference value, p , the level of the root-mean-square sound pressure, p
0 RMS
Note 1 to entry: In formula form, L = 20 log (p /p ) dB, where p is the root-mean-square sound pressure.
p 10 RMS 0 RMS
Note 2 to entry: Root-mean-square sound pressure level is expressed in decibels (dB).
Note 3 to entry: In underwater acoustics, the reference value of root-mean-square sound pressure, p , is 1 μPa.
0
Note 4 to entry: Frequency weighting and time weighting, as applicable, shall be specified.
Note 5 to entry: Root-mean-square sound pressure is a field quantity (see ISO 80000-3:2006, Clause 3 and
ISO 80000-1:2009, Annex C).
Note 6 to entry: The abbreviations “RMS SPL” and “root-mean-square SPL” are deprecated because in normal use
of English, these would mean “root-mean-square value of SPL”, which means something different from “level of
the root-mean-square sound pressure”.
[SOURCE: ISO 18405:—, 2.2.2.1]
3.23
ship reference point
point on the ship from which the distances are defined
Note 1 to entry: For the purpose of this part of ISO 17208, the ship reference point is located transversely at the
ship centreline, longitudinally a quarter-length forward of the stern and vertically at the height of the sea surface.
Note 2 to entry: The location for the ship reference point applies for all frequencies.
Note 3 to entry: The ship reference point may also serve as an approximate location for the ship’s acoustic centre.
3.24
slant range
distance from the ship reference point of the ship under test to each hydrophone
3.25
sound speed profile
measure of the speed of sound in seawater as a function of depth, measured vertically through the
water column
3.26
start data location
position of the ship reference point of the ship under test where data recording is started
Note 1 to entry: See Figure 3.
3.27
test site
location where the underwater noise measurements are performed
4 Instrumentation
4.1 General
In order to quantify the underwater sound from a ship, three main instrumentation components
are required: (1) hydrophone and signal conditioning, (2) data acquisition, recording, processing
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and display system, and (3) distance measurement system. Detailed specifications of each of the
measurement systems are given below. A summary of the parameters is given in Table 1.
Table 1 — Summary of measurement parameters
Measurement parameter Value/Quantity
Achievable expanded measurement uncertainty 5 dB (10 Hz to 100 Hz one-third octave bands)
(expressed as the typical value for applicable
3 dB (125 Hz to 16 000 Hz one-third octave bands)
one-third octave bands)
4 dB (>20 000 Hz one-third octave bands)
Measurement repeatability (expressed as the 3 dB (10 Hz to 100 Hz one-third octave bands)
typical value for applicable one-third octave
1 dB (125 Hz to 16 000 Hz one-third octave bands)
bands)
1 dB (>20 000 Hz one-third octave bands)
Bandwidth One-third-octave band
Frequency range, lower one-third-octave band 10 Hz
Frequency range, upper one-third-octave band 20 000 Hz (minimum) but up to 50 000 Hz as may be re-
quired by the criteria (see 4.3)
Number of hydrophones Three
Hydrophone geometry See Figure 1
Nominal hydrophone angles 15°, 30°, 45° angle
Minimum water depth Greater of 150 m or 1,5× overall ship length
Nominal distance at closest point of approach Greater of 100 m or 1× overall ship length
(CPA)
Tolerance of the actual distance at CPA -10 % to +25 %
Distance ranging measurement uncertainty (at ≤10 %
CPA)
Data window angle (±CPA) ±30°
Data window length, metres Determined using Formula (1)
Shown in Figure 3
Data window time, seconds Determined Using Formula (2)
Shown in Figure 3
Data window averaging time One overall sample equal to DWP
Minimum number of runs per ship condition 4 Total
2 Port
2 Starboard
Recommended weather/sea conditions Wind speed ≤20 kn (see 5.3)
Portable hydrophone calibration Laboratory calibration every 12 months
Field calibration, as below, daily during measurements
Fixed hydrophone calibration Laboratory calibration prior to installation
Confirmation using calibrated sound source or reference
hydrophone every 12 months
Field calibration, as below, daily during measurements
System field calibration Insert voltage calibration
Auxiliary measurements Engine shaft speed, wind speed and direction (see Clause 8
for other measurements)
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4.2 Hydrophone and signal conditioning
For the purposes of this part of ISO 17208, the terms hydrophone, underwater electro-acoustic
transducer, or underwater microphone may be used synonymously. Here, the term hydrophone is
used and includes any signal conditioning electronics either within or exterior to the hydrophone. The
hydrophone(s) shall have the sensitivity, bandwidth and dynamic range necessary to measure the ship
under test and meet the performance parameters given in Table 1.
This part of ISO 17208 requires three hydrophones that should be omni-directional across the required
frequency range of 10 Hz to 20 000 Hz, or higher if required, see Table 1. Directional hydrophones may
be used, as long as the directional characteristics are accounted for in the post-processing (see 6.3). The
hydrophones may or may not have integral cable. However, the required performance shall be obtained
with the full cable length to be used during the test.
When portable hydrophones are used, they shall be laboratory calibrated every 12 months in
accordance with IEC 60565 for all required one-third-octave bands. When fixed (i.e. permanently
installed underwater) hydrophones are used, they shall be laboratory calibrated before installation in
accordance with IEC 60565 for all required one-third-octave bands. The fixed hydrophone calibration
shall be confirmed by a comparative measurement utilizing a calibrated underwater sound source
every 12 months. Alternatively, the fixed hydrophones and associated cabling may be lifted from the
water every 12 months for maintenance and the hydrophones laboratory calibrated.
The sensitivity and directivity of the hydrophones shall be determined to within ±2 dB.
4.3 Data acquisition, recording, processing and display
The data acquisition, recording, processing and display system shall be capable of accurately acquiring,
recording, processing and displaying data from the hydrophones. Such systems may comprise tape
recorders, computer-based data acquisition systems or hardware-specific devices (such as spectrum
analysers) or combinations of these. The data acquisition system should have an appropriate sampling
rate and anti-aliasing filters following Nyquist requirements and appropriate dynamic range for either
analogue or digital systems. All frequency-domain averaging shall be linear with sampling consistent
with the data window period (DWP), see 6.1.
The time domain signal from each hydrophone shall be acquired and recorded simultaneously and
be sample-accurate for all three channels. Tracking and time stamp data (see 4.4) shall be recorded
synchronously with the acoustic data to enable reconstruction of the track and data processing.
The broadband processing shall cover the one-third-octave bands from 10 Hz to 20 000 Hz in accordance
with IEC 61260, Base 2 (true one-third octaves) or Base 10 (as also called decidecade in ISO 18405),
Class 1. Throughout this International Standard, the use of the term one-third octave can be considered
equivalent to the term decidecade. If required by a ship’s noise criteria specification (i.e. ICES CRR-209),
one-third-octave band processing up to 50 000 Hz may be necessary.
4.4 Distance measurement
Distance measurement is required to continuously determine the actual distance between the
hydrophones and the ship reference point of the ship under test.
For measurement with surface-suspended hydrophones, the distance measurement systems shall
determine the horizontal distance from the sea surface position above t
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