ISO/DTS 16943

Thermoplastic pipes for the conveyance of fluids — Inspection of polyethylene electrofusion socket joints using phased array ultrasonic testing

This document describes the phased array ultrasonic testing (PAUT) of polyethylene electrofusion (EF) socket joints used for the conveyance of fluids. This document provides a test whereby the presence of imperfections such as voids, wire dislocation, misalignment, pipe under-penetration, particulate contamination, cold fusion and lack of fusion in electrofusion socket joints can be detected. The technique is only applicable to polyethylene electrofusion socket fittings without a barrier to ultrasonic waves. This document also provides requirements for procedure qualification and guidance for personnel qualifications, which are essential for the application of this test method NOTE 1 At the time of publication, experience only exists on the use of PAUT for polyethylene (PE80 and PE100) electrofusion socket joint sizes between 90 mm and 710 mm (SDR 11 and 17)[7][8][9][10][11][12][13]. NOTE 2 Round robin testing has shown that PAUT is a viable method for enhancing the integrity assessment of electrofusion joints[16]. NOTE 3 This document does not apply to the detection of unscraped pipe. Such detection can be achieved by a simple visual inspection, provided mechanical scraping tools are employed.

Tubes en matières thermoplastiques pour le transport des fluides — Contrôle des assemblages par emboîtures électrosoudables en polyéthylène au moyen de la technique par ultrasons multi-éléments

General Information

• Status: Not Published
• ICS: 23.040.20 - Plastics pipes
• Technical Committee: ISO/TC 138/SC 5 - General properties of pipes, fittings and valves of plastic materials and their accessories -- Test methods and basic specifications
• Drafting Committee: ISO/TC 138/SC 5 - General properties of pipes, fittings and valves of plastic materials and their accessories -- Test methods and basic specifications

Relations

• Revises: ISO/TS 16943:2019 - Thermoplastic pipes for the conveyance of fluids — Inspection of polyethylene electrofusion socket joints using phased array ultrasonic testing
• Effective Date: 06-Jun-2022

Standards Content (Sample)

FINAL
TECHNICAL ISO/DTS
DRAFT
SPECIFICATION 16943
ISO/TC 138/SC 5
Thermoplastic pipes for the
Secretariat: NEN
conveyance of fluids — Inspection
Voting begins on:
2022-10-25 of polyethylene electrofusion socket
joints using phased array ultrasonic
Voting terminates on:
2022-12-20
testing
Tubes en matières thermoplastiques pour le transport des fluides —
Contrôle des assemblages par emboîtures électrosoudables en
polyéthylène au moyen de la technique par ultrasons multi-éléments
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/DTS 16943:2022(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 2022
---------------------- Page: 1 ----------------------
ISO/DTS 16943:2022(E)
FINAL
TECHNICAL ISO/DTS
DRAFT
SPECIFICATION 16943
ISO/TC 138/SC 5
Thermoplastic pipes for the
Secretariat: NEN
conveyance of fluids — Inspection
Voting begins on:
of polyethylene electrofusion socket
joints using phased array ultrasonic
Voting terminates on:
testing
Tubes en matières thermoplastiques pour le transport des fluides —
Contrôle des assemblages par emboîtures électrosoudables en
polyéthylène au moyen de la technique par ultrasons multi-éléments
COPYRIGHT PROTECTED DOCUMENT
© ISO 2022

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.
RECIPIENTS OF THIS DRAFT ARE INVITED TO
ISO copyright office
SUBMIT, WITH THEIR COMMENTS, NOTIFICATION
OF ANY RELEVANT PATENT RIGHTS OF WHICH
CP 401 • Ch. de Blandonnet 8
THEY ARE AWARE AND TO PROVIDE SUPPOR TING
CH-1214 Vernier, Geneva
DOCUMENTATION.
Phone: [phone]
IN ADDITION TO THEIR EVALUATION AS
Reference number
Email: [e-mail]
BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO­
ISO/DTS 16943:2022(E)
Website: www.iso.org
LOGICAL, COMMERCIAL AND USER PURPOSES,
DRAFT INTERNATIONAL STANDARDS MAY ON
Published in Switzerland
OCCASION HAVE TO BE CONSIDERED IN THE
LIGHT OF THEIR POTENTIAL TO BECOME STAN­
DARDS TO WHICH REFERENCE MAY BE MADE IN
© ISO 2022 – All rights reserved
NATIONAL REGULATIONS. © ISO 2022
---------------------- Page: 2 ----------------------
ISO/DTS 16943:2022(E)
Contents Page

Foreword ..........................................................................................................................................................................................................................................v

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

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

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

4 General ........................................................................................................................................................................................................................... 3

5 Information required prior to testing .......................................................................................................................................... 3

5.1 Items required for test procedure development ...................................................................................................... 3

5.2 Specific information required by the operator before testing .................................................................... 4

5.3 Written test procedure ................................................................................................................................................................... 4

6 Personnel qualifications ........................................................................................................................................... ...................................4

7 Equipment ................................................................................................................................................................................................................... 4

7.1 General ........................................................................................................................................................................................................... 4

7.2 Ultrasonic instrument and display ....................................................................................................................................... 5

7.3 Ultrasonic probes ................................................................................................................................................................................. 5

7.4 Scanning mechanisms ..................................................................................................................................................................... 5

7.5 Couplant ........................................................................................................................................................................................................ 5

8 Range and sensitivity settings .............................................................................................................................................................. 5

8.1 Settings ......... ............................................................. .................................................................................................................................... 5

8.1.1 General ........................................................................................................................................................................................ 5

8.1.2 Range setting — test volume .................................................................................................................................. 6

8.1.3 Sensitivity setting ............................................................................................................................................................. 7

8.2 Reference sample.................................................................................................................................................................................. 7

8.2.1 General ........................................................................................................................................................................................ 7

8.2.2 Reference block ........................................................................................................................................... ......................... 8

8.2.3 Electrofusion socket fitting ...................................................................................................................................... 8

8.3 Checking of the settings ................................................................................................................................................................. 8

9 Equipment checks ............................................................................................................................................................................................... 8

10 Test procedure .......................................................................................................................................................................................................8

10.1 Procedure qualification .................................................................................................................................................................. 8

10.2 Scan increment ....................................................................................................................................................................................... 9

10.3 Component geometry .................................................................................................................................................................... 10

10.4 Preparation of scanning surfaces ....................................................................................................................................... 10

10.5 Component temperature ............................................................................................................................................................ 10

10.6 Testing ......................................................................................................................................................................................................... 10

10.7 Data storage ........................................................................................................................................................................................... 10

11 Evaluation and analysis of test data.............................................................................................................................................10

11.1 General ........................................................................................................................................................................................................ 10

11.2 Assessing the quality of the test data ............................................................................................................................. 11

11.3 Identification of relevant indications .............................................................................................................................. 11

11.4 Classification of relevant indications .............................................................................................................................. 11

11.5 Determination of location and size of indications ............................................................................................... 11

11.6 Assessment of indications ......................................................................................................................................................... 11

12 Test report ...............................................................................................................................................................................................................12

Annex A (informative) Examples of phased array images .........................................................................................................14

Annex B (informative) Example of a reference block .....................................................................................................................16

Annex C (informative) Example procedures for producing imperfections in electrofusion

socket joints ...........................................................................................................................................................................................................17

Annex D (informative) Detection of melt fusion zone (MFZ) boundary indication ........................................21

iii
© ISO 2022 – All rights reserved
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ISO/DTS 16943:2022(E)

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

© ISO 2022 – All rights reserved
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ISO/DTS 16943:2022(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 non­governmental, 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 of the voluntary nature of standards, the meaning of ISO specific terms and

expressions related to conformity assessment, as well as information about ISO's adherence to

the World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see

www.iso.org/iso/foreword.html.

This document was prepared by Technical Committee ISO/TC 138, Plastics pipes, fittings and valves

for the transport of fluids, Subcommittee SC 5, General properties of pipes, fittings and valves of plastic

materials and their accessories — Test methods and basic specifications.

This second edition cancels and replaces the first edition (ISO/TS 16943:2019), which has been

technically revised.
The main changes are as follows:
— the definitions of "cold fusions" and "lack of fusion" have been clarified;
— procedure qualification (Clause 10) has been revised.

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.
© ISO 2022 – All rights reserved
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TECHNICAL SPECIFICATION ISO/DTS 16943:2022(E)
Thermoplastic pipes for the conveyance of fluids —
Inspection of polyethylene electrofusion socket joints
using phased array ultrasonic testing
1 Scope

This document describes the phased array ultrasonic testing (PAUT) of polyethylene electrofusion (EF)

socket joints used for the conveyance of fluids. This document provides a test whereby the presence

of imperfections such as voids, wire dislocation, misalignment, pipe under­penetration, particulate

contamination and lack of fusion in electrofusion socket joints can be detected. The technique is only

applicable to polyethylene electrofusion socket fittings without a barrier to ultrasonic waves.

This document also provides requirements for procedure qualification and guidance for personnel

qualifications, which are essential for the application of this test method.

This document also covers the equipment, the preparation and performance of the test, as well as the

indication assessment and the reporting for polyethylene BF joints. The acceptance criteria are not

covered in this document.

NOTE 1 At the time of publication, experience only exists on the use of PAUT for polyethylene (PE80 and

[1][2][3][4][5][6][7]

PE100) electrofusion socket joint sizes between 90 mm and 710 mm (SDR 11 and 17).

NOTE 2 Interlaboratory testing has shown that PAUT is a viable method for enhancing the integrity assessment

[8][15][16]
of electrofusion joints.

NOTE 3 This document does not apply to the detection of unscraped pipe. Such detection can be achieved by a

simple visual inspection, provided mechanical scraping tools are employed.

NOTE 4 PAUT techniques for cold fusion detection are known to be available. However, further research,

verification and experience are needed to transfer the technique into an ISO International Standard. This

document does not provide any information regarding the detection of cold fusions.

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 5577, Non-destructive testing — Ultrasonic testing — Vocabulary

ISO 9712, Non-destructive testing — Qualification and certification of NDT personnel

ISO 13954, Plastics pipes and fittings — Peel decohesion test for polyethylene (PE) electrofusion assemblies

of nominal outside diameter greater than or equal to 90 mm

ISO 13955, Plastics pipes and fittings — Crushing decohesion test for polyethylene (PE) electrofusion

assemblies
ISO 23243, Non-destructive testing — Ultrasonic testing with arrays — Vocabulary
3 Terms and definitions

For the purposes of this document, the terms and definitions given in ISO 5577, ISO 23243 and the

following apply.
© ISO 2022 – All rights reserved
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ISO/DTS 16943:2022(E)

ISO and IEC maintain terminology databases for use in standardization at the following addresses:

— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
3.1
cold fusion

incomplete intermolecular diffusion of polymer chains for proper molecular entanglement at the joint

interface due to reasons other than contamination

Note 1 to entry: Cold fusion results in insufficient joint integrity, including significant reduction of joint ductility.

3.2
inclusion
foreign material trapped in the fusion joint
3.3
lack of fusion

absence of intermolecular diffusion of polymer chains for molecular entanglement at the interface

Note 1 to entry: A lack of fusion flaw results in complete separation at the flaw location.

3.4
pipe under-penetration
incomplete penetration of the pipe into the electrofusion socket
3.5
melt fusion zone
MFZ

zone containing the fusion interface and having boundaries on either side of the interface which reflect

the limits of crystalline melting during the electrofusion socket jointing process

Note 1 to entry: Note1 to entry: The MFZ is shown in Figure 1.
3.6
misalignment

angular offset between the axis of the electrofusion socket fitting (3.15) and the axis of the pipe

3.7
particulate contamination

fine particles (e.g. airborne dust) or coarse particles (e.g. sand and grit) that are present at the fusion

interface
3.8
void
empty space (or air pocket) in an electrofusion socket joint (3.16)
3.9
wire dislocation
displacement of heating wires from their original position in the fitting
3.10
phased array image
one-, two-, or three-dimensional display, constructed from the phased array data
3.11
phased array set-up

probe arrangement defined by probe characteristics (e.g. frequency, probe element size, beam angle,

wave mode), probe position (3.12) and the number of probes
© ISO 2022 – All rights reserved
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ISO/DTS 16943:2022(E)
3.12
probe position

axial and radial position of the probe with respect to the heating wire coil in the electrofusion socket

joint (3.16)
3.13
scan increment
distance between successive data collection points in the direction of scanning
3.14
false call
reporting an imperfection when none exists
3.15
electrofusion socket fitting

part containing one or more integral heating elements that are capable of converting electrical energy

to heat to make a joint between pipes
3.16
electrofusion socket joint

fused combination of one or more pipe components using an electrofusion socket fitting (3.15)

3.17
fusion zone
one side of an electrofusion socket joint (3.16)
Note 1 to entry: There are two fusion zones in a straight joint.
4 General

This document covers the PAUT equipment, the preparation and performance of the test and the

reporting for polyethylene electrofusion socket joints.

This document may be used to draft a detailed procedure for phased array ultrasonic testing of

polyethylene electrofusion socket joints.
5 Information required prior to testing
5.1 Items required for test procedure development
Information on the following items is required:
a) purpose and extent of testing;
b) reference sample;

c) requirements for getting access to the electrofusion socket joints, the surface condition of the pipe

and the temperature range;
d) personnel qualifications;
e) reporting requirements;

f) manufacturing or operation stage of electrofusion socket joints at which the testing is to be carried

out.
© ISO 2022 – All rights reserved
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ISO/DTS 16943:2022(E)
5.2 Specific information required by the operator before testing

Before any testing of an electrofusion socket joint begins, the operator shall have access to all the

information as specified in 5.1 together with the following additional information:

a) written test procedure, qualified in accordance with Clause 10;
b) all relevant pipe and fitting dimensions.
5.3 Written test procedure

For all testing a written test procedure is required. This test procedure shall include at least the

following information:
a) purpose and extent of testing;
b) reference sample;

c) requirements for access to the electrofusion socket joints, surface conditions and temperature;

d) personnel qualifications;
e) reporting requirements;

f) equipment requirements and settings (including but not limited to frequency, sampling rate, pitch

between elements and elements size);
g) evaluation of indications;
h) environmental and safety issues;
i) documented testing strategy or scan plan.

NOTE The testing strategy gives information on the probe placement, movement and component coverage

that provides a standardized and repeatable methodology for fusion joint testing. The scan plan gives information

on the volume tested for each electrofusion socket joint.
6 Personnel qualifications

Personnel performing testing in accordance with this document shall be qualified to an appropriate

level in accordance with ISO 9712 or an equivalent standard in the relevant industrial sector.

In addition to a general knowledge of ultrasonic testing, the operators shall be familiar with and have

practical experience in the use of phased array systems. Specific theoretical and practical training

and examination of personnel shall be performed on representative polyethylene electrofusion socket

joints containing natural or artificial reflectors similar to those expected in the field. These training

and examination results shall be documented.
7 Equipment
7.1 General

The complete equipment (i.e. ultrasonic instrument, probe, cables and display monitor) shall be capable

of the repetition of test results.

NOTE 1 For selecting the system components (hardware and software), ISO 13588 and ISO/TS 16829 provide

useful information.

NOTE 2 Ultrasonic equipment used for phased array testing is described in ISO 18563-1, ISO 18563-2 and

ISO 18563­3.
© ISO 2022 – All rights reserved
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ISO/DTS 16943:2022(E)
7.2 Ultrasonic instrument and display

The instrument shall be capable of selecting an appropriate portion of the time base within which

A-scans are digitized. It is recommended that the sampling rate of the A-scan should be at least six

times the nominal probe frequency. The instrument and display shall achieve a resolution capable of

identifying each heating wire individually.
7.3 Ultrasonic probes
Only longitudinal wave modes are feasible for polyethylene.

Any type of phased array probe can be used if it satisfies the requirements of Clause 8 with the phased

array equipment.

The most suitable ultrasonic probe frequency should be selected in accordance with the thickness of

the electrofusion socket fitting. Table 1 shows recommended frequencies for each thickness range of

the electrofusion socket fitting. However, the optimal frequency can be shifted up or down depending

on the attenuation and thickness of the sample to be tested.
Table 1 — Selection of probe frequency
Recommended frequency Fitting wall thickness, t
MHz mm
3,5 30 ≤ t ≤ 50
5,0 10 ≤ t ≤ 50
7,5 10 ≤ t ≤ 30

NOTE In general, higher frequencies provide better resolution and lower frequencies provide better

penetration.
7.4 Scanning mechanisms

To achieve consistency of the images (collected data), guiding mechanisms and scan encoder(s) shall be

used.

NOTE Space and accessibility conditions can require specialty encoded scanners to facilitate the inspection.

7.5 Couplant

In order to generate proper images, a couplant should be used which provides a constant transmission

of ultrasound between the probe and the material. The same couplant used for calibration shall be used

for the testing.
Any couplant used needs to be cleaned off after testing.
8 Range and sensitivity settings
8.1 Settings
8.1.1 General

Setting of range and sensitivity shall be carried out prior to each testing period in accordance with this

document. Any change of the phased array set-up (e.g. probe position and steering parameters) will

require a new setting. The set-up should be optimized on the reference reflectors to give a minimum

signal­to­noise ratio minimum of 6 dB.
© ISO 2022 – All rights reserved
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ISO/DTS 16943:2022(E)
8.1.2 Range setting — test volume

The range in the depth direction shall cover at least the melt fusion zone above the plane of the heating

wires and the same distance below. If the position of the melt fusion zone is unknown, at least half of

the thickness of the electrofusion socket fitting above and below the plane of the heating wires shall

be used (see Figure 2). When feasible, the range monitored may be extended from the probe-fitting

interface and may include the inside surface of the pipe.

The range in the axial direction shall cover the nominal length of the fusion zone, which is the expected

fusion length indicated by the aligned heating wires.

The range in the circumferential direction shall include the full circumference. Areas not tested due to

obstacles (e.g. fusion indicators and connectors) shall be reported.
Key
1 electrofusion socket fitting
2 MFZ boundary
3 heating wire
4 pipe

NOTE Annex D provides information regarding the measurement of MFZ thickness using PAUT.

SOURCE Reference [13], reproduce with the permission of the author
Figure 1 — Photograph of MFZ
© ISO 2022 – All rights reserved
---------------------- Page: 11 ----------------------
ISO/DTS 16943:2022(E)
Key
1 electrofusion socket fitting
2 MFZ boundary
3 heating wire
4 test area
5 pipe
Figure 2 — Test area with known MFZ (top) and unknown MFZ (bottom)
8.1.3 Sensitivity setting

After selection of the scanning technique, the following steps shall be taken using the same focusing,

coupling and wedge or delay-line conditions for calibrating reference sensitivity as used for

electrofusion socket joint testing.

a) Equalize the response for each delay law on a side-drilled hole (SDH) at the depth of interest.

Ensure that the difference between each delay law shall not deviate by more than ±3 dB from the

average amplitude response.

b) Set the response from the SDH to an amplitude between 40 % and 80 % screen height. This shall be

considered the reference sensitivity.

c) Evaluate the scan surface interface ring time to ensure sufficient resolution exists to discern the

MFZ.

d) Evaluate the resolution of adjacent turns of wire in the fitting to ensure that there is more than a

12 dB drop between the peak amplitudes from adjacent turns of wire.
8.2 Reference sample
8.2.1 General

A reference sample shall be used to determine the adequacy of the setting (e.g. coverage, sensitivity).

The temperature of the reference sample shall be the same as the temperature ±5 °C of the test object

at the time of testing and shall be kept in the same environment as the test object throughout the test. A

reference block with SDHs satisfying the conditions in 8.2.2 or an electrofusion socket fitting satisfying

the conditions in 8.2.3 shall be used as the reference sample.
© ISO 2022 – All rights reserved
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ISO/DTS 16943:2022(E)
8.2.2 Reference block

The reference block used shall be of the same material classification as the electrofusion socket

fitting being tested. The thickness of the reference block shall be at least equal to the thickness of the

electrofusion socket fitting to be tested. The length and width of the reference block shall be chosen

such that all relevant reflectors can be properl
...

ISO/TC 138/SC 5 N
Date: 2022-06-2710
ISO /DTS 16943:20192022(E)
Revision: Second Edition
Secretariat: NEN
Thermoplastic pipes for the conveyance of fluids — Inspection of polyethylene
electrofusion socket joints using phased array ultrasonic testing
Tubes en matières thermoplastiques pour le transport des fluides — Contrôle des

assemblages par emboîtures électrosoudables en polyéthylène au moyen de la technique pas

ultrasons multi-éléments
DTS stage
Warning for WDs and CDs

This document is not an ISO International Standard. It is distributed for review and comment. It is subject to change

without notice and may not be referred to as an International Standard.

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 supporting documentation.
---------------------- Page: 1 ----------------------
© ISO ####
---------------------- Page: 2 ----------------------
© ISO 2022

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: [phone]
Email: [e-mail]
Website: www.iso.org
Website: www.iso.org
Published in Switzerland
iii © ISO 2019 – All rights reserved
---------------------- Page: 3 ----------------------

Contents Page

Foreword .......................................................................................................................................................................... 5

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

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

3 Terms and definitions ................................................................................................................................... 2

4 General ................................................................................................................................................................ 3

5 Information required prior to testing ..................................................................................................... 3

5.1 Items required for test procedure development ................................................................................. 3

5.2 Specific information required by the operator before testing ....................................................... 4

5.3 Written test procedure ................................................................................................................................. 4

6 Personnel qualifications ............................................................................................................................... 4

7 Equipment ......................................................................................................................................................... 5

7.1. General………………………………………………………………………………………………………………………………...5

7.2 Ultrasonic instrument and display ........................................................................................................... 5

7.3 Ultrasonic probes ............................................................................................................................................ 5

7.4 Scanning mechanisms ................................................................................................................................... 5

7.5 Couplant.............................................................................................................................................................. 6

8 Range and sensitivity settings .................................................................................................................... 6

8.1 Settings ................................................................................................................................................................ 6

8.1.1 General…………………………………………………………………………………………………………………………………6

8.1.2 Range setting — Test volume...................................................................................................................... 6

8.1.3 Sensitivity setting ............................................................................................................................................ 7

8.2 Reference sample ............................................................................................................................................ 7

8.2.1 General…………………………………………………………………………………………………………………………………7

8.2.1 Reference block ............................................................................................................................................... 8

8.2.3 Electrofusion socket fitting.......................................................................................................................... 8

8.3 Checking of the settings ................................................................................................................................ 8

9 Equipment checks ........................................................................................................................................... 8

10 Test procedure ................................................................................................................................................. 8

10.1 Procedure qualification ................................................................................................................................ 8

10.2 Scan increment .............................................................................................................................................. 10

10.3 Component geometry ................................................................................................................................. 10

10.4 Preparation of scanning surfaces ........................................................................................................... 10

10.5 Component temperature ........................................................................................................................... 10

10.6 Testing .............................................................................................................................................................. 10

10.7 Data storage ................................................................................................................................................... 11

11 Evaluation and analysis of test data ...................................................................................................... 11

11.1 General……………………………………………………………………………………………………………………………….10

11.1 Assessing the quality of the test data .................................................................................................... 11

11.2 Identification of relevant indications ................................................................................................... 11

11.3 Classification of relevant indications .................................................................................................... 11

11.4 Determination of location and size of indications ........................................................................... 12

11.5 Assessment of indications ......................................................................................................................... 12

12 Test report ...................................................................................................................................................... 12

ii © ISO 2019 – All rights reserved
---------------------- Page: 4 ----------------------
ISO/DTS 16943:2022(E)

Annex A (informative) Examples of phased array images .......................................................................... 14

Annex B (informative) Example of a reference block .................................................................................. 16

Annex C (informative) Example procedures for producing imperfections in electrofusion

socket joints ................................................................................................................................................... 17

C.1 Planar lack of fusion .................................................................................................................................... 17

C.2 Fine particulates ........................................................................................................................................... 18

Annex D (informative) Detection of melt fusion zone boundary indication ........................................ 21

D.1 General ............................................................................................................................................................. 21

D.2 Detection of the MFZ boundary ............................................................................................................... 21

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

iii © ISO 2019 – All rights reserved
© ISO 2022 – All rights reserved iii
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ISO/DTS 16943:2022(E)
Contents Page

Foreword ......................................................................................................................................................................... vi

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

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

3 Terms and definitions ................................................................................................................................... 2

4 General ................................................................................................................................................................ 4

5 Information required prior to testing ..................................................................................................... 4

5.1 Items required for test procedure development ................................................................................. 4

5.2 Specific information required by the operator before testing ....................................................... 4

5.3 Written test procedure ................................................................................................................................. 4

6 Personnel qualifications ............................................................................................................................... 5

7 Equipment ......................................................................................................................................................... 5

7.1 General ................................................................................................................................................................ 5

7.2 Ultrasonic instrument and display ........................................................................................................... 5

7.3 Ultrasonic probes ............................................................................................................................................ 5

7.4 Scanning mechanisms ................................................................................................................................... 6

7.5 Couplant.............................................................................................................................................................. 6

8 Range and sensitivity settings .................................................................................................................... 6

8.1 Settings ................................................................................................................................................................ 6

8.1.1 General ................................................................................................................................................................ 6

8.1.2 Range setting — test volume ....................................................................................................................... 6

8.1.3 Sensitivity setting ............................................................................................................................................ 8

8.2 Reference sample ............................................................................................................................................ 9

8.2.1 General ................................................................................................................................................................ 9

8.2.2 Reference block ............................................................................................................................................... 9

8.2.3 Electrofusion socket fitting.......................................................................................................................... 9

8.3 Checking of the settings ................................................................................................................................ 9

9 Equipment checks ........................................................................................................................................ 10

10 Test procedure .............................................................................................................................................. 10

10.1 Procedure qualification ............................................................................................................................. 10

10.2 Scan increment .............................................................................................................................................. 11

10.3 Component geometry ................................................................................................................................. 12

10.4 Preparation of scanning surfaces ........................................................................................................... 12

10.5 Component temperature ........................................................................................................................... 12

10.6 Testing .............................................................................................................................................................. 12

10.7 Data storage ................................................................................................................................................... 12

11 Evaluation and analysis of test data ...................................................................................................... 12

11.1 General ............................................................................................................................................................. 12

11.2 Assessing the quality of the test data .................................................................................................... 13

11.3 Identification of relevant indications ................................................................................................... 13

11.4 Classification of relevant indications .................................................................................................... 13

11.5 Determination of location and size of indications ........................................................................... 13

11.6 Assessment of indications ......................................................................................................................... 14

12 Test report ...................................................................................................................................................... 14

Annex A (informative) Examples of phased array images ......................................................................... 16

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Annex B (informative) Example of a reference block .................................................................................. 20

Annex C (informative) Example procedures for producing imperfections in electrofusion

socket joints ................................................................................................................................................... 22

Annex D (informative) Detection of melt fusion zone (MFZ) boundary indication ........................... 28

Bibliography ................................................................................................................................................................. 30

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ISO/DTS 16943:2022(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/patentswww.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 onof the voluntary nature of standards, the meaning of ISO specific terms and expressions

related to conformity assessment, as well as information about ISO's adherence to the World Trade

Organization (WTO) principles in the Technical Barriers to Trade (TBT) see the following URL:

www.iso.org/iso/foreword.html), see www.iso.org/iso/foreword.html.

This document was prepared by Technical Committee ISO/TC 138, Plastics pipes, fittings and valves for the

transport of fluids, Subcommittee SC 5, General properties of pipes, fittings and valves of plastic materials and

their accessories — Test methods and basic specifications.

This second edition cancels and replaces the first edition (ISO /TS 16943:2019), which has been technically

revised.
The main changes compared to the previous edition are as follows:

— Clarified definition— the definitions of "cold fusionfusions" and "lack of fusion." have been clarified;

— Revision of procedure qualification (Clause 10) has been revised.

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.
vi © ISO 2022 – All rights reserved
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TECHNICAL SPECIFICATION ISO/DTS 16943:2022(E)
Thermoplastic pipes for the conveyance of fluids — Inspection
of polyethylene electrofusion socket joints using phased array
ultrasonic testing
1 Scope

This document describes the phased array ultrasonic testing (PAUT) of polyethylene electrofusion (EF)

socket joints used for the conveyance of fluids. This document provides a test whereby the presence of

imperfections such as voids, wire dislocation, misalignment, pipe under-penetration, particulate

contamination and lack of fusion in electrofusion socket joints can be detected. The technique is only

applicable to polyethylene electrofusion socket fittings without a barrier to ultrasonic waves.

This document also provides requirements for procedure qualification and guidance for personnel

qualifications, which are essential for the application of this test method.

This document also covers the equipment, the preparation and performance of the test, as well as the

indication assessment and the reporting for polyethylene BF joints. The acceptance criteria are not

covered in this document.

NOTE 1 At the time of publication, experience only exists on the use of PAUT for polyethylene (PE80 and PE100)

[ [1][2][3][4][5][6][7] ]
electrofusion socket joint sizes between 90 mm and 710 mm (SDR 11 and 17) ). .

NOTE 2 Round robinInterlaboratory testing has shown that PAUT is a viable method for enhancing the integrity

[ [8] [][15] [][16] ]
assessment of electrofusion joints . .

NOTE 3 This document does not apply to the detection of unscraped pipe. Such detection can be achieved by a

simple visual inspection, provided mechanical scraping tools are employed.

NOTE 4 PAUT techniques for cold fusion detection are known to be available. However, further research,

verification and experience are needed to transfer the technique into an ISO International Standard. This document

does not provide any information regarding the detection of cold fusions.
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 5577, Non-destructive testing — Ultrasonic testing — Vocabulary

ISO 9712, Non-destructive testing — Qualification and certification of NDT personnel

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ISO/DTS 16943:2022(E)

ISO 13954, Plastics pipes and fittings — Peel decohesion test for polyethylene (PE) electrofusion assemblies

of nominal outside diameter greater than or equal to 90 mm

ISO 13955, Plastics pipes and fittings — Crushing decohesion test for polyethylene (PE) electrofusion

assemblies

ISO 23243, Non-destructive testing — Terminology — Terms used in ultrasonic — Ultrasonic testing with

phased arrays — Vocabulary
3 Terms and definitions

For the purposes of this document, the terms and definitions given in ISO 5577, ISO 23243 and the

following apply.

ISO and IEC maintain terminologicalterminology 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/https://www.electropedia.org/

3.1
cold fusion

incomplete intermolecular diffusion of polymer chains for proper molecular entanglement at the joint

interface due to reasons other than contamination.

Note 1 to entry: Cold fusion results in insufficient joint integrity, including significant reduction of joint ductility.

3.2
inclusion
foreign material trapped in the fusion joint
3.3
lack of fusion

absence of intermolecular diffusion of polymer chains for molecular entanglement at the interface.

Note 1 to entry: A lack of fusion flaw results in complete separation at the flaw location.

3.4
pipe under-penetration
incomplete penetration of the pipe into the electrofusion socket
3.5
melt fusion zone
MFZ

zone containing the fusion interface and having boundaries on either side of the interface which reflect

the limits of crystalline melting during the electrofusion socket jointing process

Note1 to entry: The melt fusion zoneMFZ is shown in Figure 1.
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ISO/DTS 16943:2022(E)
3.6
misalignment

angular offset between the axis of the electrofusion socket fitting (3.15) and the axis of the pipe

3.7
particulate contamination

fine particles (e.g. airborne dust) or coarse particles (e.g. sand and grit) that are present at the fusion

interface
3.8
void
empty space (or air pocket) in an electrofusion socket joint (3.16)
3.9
wire dislocation
displacement of heating wires from their original position in the fitting
3.10
phased array image
one-, two-, or three-dimensional display, constructed from the phased array data
3.11
phased array set-up

probe arrangement defined by probe characteristics (e.g. frequency, probe element size, beam angle,

wave mode), probe position (3.12) and the number of probes
3.12
probe position

axial and radial position of the probe with respect to the heating wire coil in the electrofusion socket joint

(3.16)
3.13
scan increment
distance between successive data collection points in the direction of scanning
3.14
false call
reporting an imperfection when none exists
3.15
electrofusion socket fitting

part containing one or more integral heating elements that are capable of converting electrical energy to

heat to make a joint between pipes
3.16
electrofusion socket joint

fused combination of one or more pipe components using an electrofusion socket fitting (3.15)

3.17
fusion zone
one side of an electrofusion socket joint (3.16)
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ISO/DTS 16943:2022(E)
Note 1 to entry: There are two fusion zones in a straight joint.
4 General

This document covers the PAUT equipment, the preparation and performance of the test and the

reporting for polyethylene electrofusion socket joints.

This document canmay be used to draft a detailed procedure for phased array ultrasonic testing of

polyethylene electrofusion socket joints.
5 Information required prior to testing
5.1 Items required for test procedure development
Information on the following items is required:
a) purpose and extent of testing;
b) reference sample;

c) requirements for getting access to the electrofusion socket joints, the surface condition of the pipe

and the temperature range;
d) personnel qualifications;
e) reporting requirements;

f) manufacturing or operation stage of electrofusion socket joints at which the testing is to be carried

out.
5.2 Specific information required by the operator before testing

Before any testing of an electrofusion socket joint begins, the operator shall have access to all the

information as specified in 5.1 together with the following additional information:

a) written test procedure, qualified in accordance with clause Clause 10;
b) all relevant pipe and fitting dimensions.
5.3 Written test procedure

For all testing a written test procedure is required. This test procedure shall include at least the following

information:
a) purpose and extent of testing;
b) reference sample;

c) requirements for access to the electrofusion socket joints, surface conditions and temperature;

d) personnel qualifications;
e) reporting requirements;
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ISO/DTS 16943:2022(E)

f) equipment requirements and settings (including but not limited to frequency, sampling rate, pitch

between elements and elements size);
g) evaluation of indications;
h) environmental and safety issues;
i) documented testing strategy or scan plan.

NOTE The testing strategy gives information on the probe placement, movement and component coverage that

provides a standardized and repeatable methodology for fusion joint testing. The scan plan gives information on

the volume tested for each electrofusion socket joint.
6 Personnel qualifications

Personnel performing testing in accordance with this document shall be qualified to an appropriate level

in accordance with ISO 9712 or an equivalent standard in the relevant industrial sector.

In addition to a general knowledge of ultrasonic testing, the operators shall be familiar with and have

practical experience in the use of phased array systems. Specific theoretical and practical training and

examination of personnel shall be performed on representative polyet
...