Ships and marine technology — Marine environment protection — Continuous on-board pH monitoring method

This document specifies the performance requirements and the test procedures for a pH meter used for continuous on-board monitoring using combination electrodes. The pH meter applies to measuring the pH of the following water for on-board consumption and research purposes: a) natural seawater and freshwater, b) freshwater produced from freshwater generators, c) the used process water for running machinery on-board ships. This document also specifies the method for evaluating performance, calibration, and maintenance of a pH meter used for continuous on-board monitoring.

Navires et technologie maritime — Protection de l'environnement marin — Méthode de surveillance continue du pH à bord

General Information

Status
Published
Publication Date
08-Nov-2022
Current Stage
6060 - International Standard published
Due Date
20-Aug-2022
Completion Date
09-Nov-2022
Ref Project

Buy Standard

Standard
ISO 23668:2022 - Ships and marine technology — Marine environment protection — Continuous on-board pH monitoring method Released:9. 11. 2022
English language
10 pages
sale 15% off
Preview
sale 15% off
Preview

Standards Content (sample)

INTERNATIONAL ISO
STANDARD 23668
First edition
2022-11
Ships and marine technology —
Marine environment protection —
Continuous on-board pH monitoring
method
Navires et technologie maritime — Protection de l'environnement
marin — Méthode de surveillance continue du pH à bord
Reference number
ISO 23668:2022(E)
© ISO 2022
---------------------- Page: 1 ----------------------
ISO 23668:2022(E)
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.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
© ISO 2022 – All rights reserved
---------------------- Page: 2 ----------------------
ISO 23668:2022(E)
Contents Page

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

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

1 S c op e ................................................................................................................................................................................................................................. 1

2 Nor m at i ve r ef er enc e s ..................................................................................................................................................................................... 1

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

4 pH buffer solution ............................................................................................................................................................................................... 2

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

4.2 C ertified pH buffer solution ........................................................................................................................................................ 3

4.3 P ractical-use pH buffer solution ............................................................................................................................................. 3

5 P erformance requirements for the combination electrode .................................................................................. 3

5.1 G eneral ........................................................................................................................................................................................................... 3

5 . 2 S lop e f or c e .................................................................................................................................................................................................. 3

5.2.1 R equirement ........................................................................................................................................................................... 3

5.2.2 Verification .............................................................................................................................................................................. 3

5.3 R epeatability ............................................................................................................................................................................................ 3

5.3.1 Requirement ........................................................................................................................................................................... 3

5.3.2 Verification .............................................................................................................................................................................. 3

5.4 L inearity ....................................................................................................................................................................................................... 3

5.4.1 R equirement ........................................................................................................................................................................... 3

5.4.2 Verification .............................................................................................................................................................................. 4

6 I nt er f er enc e s ............................................................................................................................................................................................................ 4

6.1 General ........................................................................................................................................................................................................... 4

6.2 S ample conductivity .......................................................................................................................................................................... 4

6 . 3 E le c t r o de f ou l i n g .................................................................................................................................................................................. 4

6.4 E lectrical noise ....................................................................................................................................................................................... 4

6 . 5 A i r bubble s ................................................................................................................................................................................................. 4

7 Re quirements for pH meters for continuous on-board monitoring ..............................................................5

7.1 G eneral ........................................................................................................................................................................................................... 5

7.2 A pparatus .................................................................................................................................................................................................... 5

7.2.1 G eneral ........................................................................................................................................................................................ 5

7.2.2 p H combination electrode .......................................................................................................................................... 5

7.2.3 Transmitter ............................................................................................................................................................................. 6

7.2.4 Electrode mounting ......................................................................................................................................................... 7

7.2.5 C leaning device .................................................................................................................................................................... 7

7.3 Pl acement .................................................................................................................................................................................................... 7

7.4 Report ............................................................................................................................................................................................................. 7

Calibration .................................................................................................................................................................................................................. 7

9 Ma i nt en a nce ............................................................................................................................................................................................................. 8

9.1 G eneral ........................................................................................................................................................................................................... 8

9.2 M anual cleaning ........................................................................................................................................... .......................................... 8

9.3 A utomatic cleaning ............................................................................................................................................................................. 9

9.3.1 General ........................................................................................................................................................................................ 9

9.3.2 U ltrasonic cleaning ................................... ........................................................................................................ ................ 9

9.3.3 Mechanical cleaning ........................................................................................................................................................ 9

9.3.4 Air/water cleaning ............................................................................................................................................................ 9

9.4 S torage of the pH combination electrode ....................................................................................................................... 9

Bibliography .............................................................................................................................................................................................................................10

iii
© ISO 2022 – All rights reserved
---------------------- Page: 3 ----------------------
ISO 23668:2022(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/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 8, Ships and marine technology,

Subcommittee SC 2, Marine environment protection.

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
---------------------- Page: 4 ----------------------
ISO 23668:2022(E)
Introduction

The pH of water is an important indicator of water quality. Continuous pH monitoring of water served

in marine equipment/systems installed on-board ships for various applications, such as exhaust gas

cleaning systems (scrubbers) and boilers, is essential. “Continuous” describes a monitoring situation.

The pH meter for continuous monitoring is situated in a fixed position on-board to monitor a stream,

as opposed to batched-based deployment in a laboratory. This situation imparts some challenges that

should be addressed. For installation of systems such as scrubbers to remove sulfur oxide from the

exhaust gas by using seawater or freshwater, pH monitoring of the processed water is important not

only for the process control of the systems but also for ensuring compliance with regulations when

discharging the processed water [see IMO Resolution MEPC. 340(77)]. It is expected that reliable pH

meters are robust over time, and suitable for processed water that can contain sea salts and/or oily

substances or can exhibit a wide range of pH.
© ISO 2022 – All rights reserved
---------------------- Page: 5 ----------------------
INTERNATIONAL STANDARD ISO 23668:2022(E)
Ships and marine technology — Marine environment
protection — Continuous on-board pH monitoring method
1 S cope

This document specifies the performance requirements and the test procedures for a pH meter used for

continuous on-board monitoring using combination electrodes. The pH meter applies to measuring the

pH of the following water for on-board consumption and research purposes:
a) natural seawater and freshwater,
b) freshwater produced from freshwater generators,
c) the used process water for running machinery on-board ships.

This document also specifies the method for evaluating performance, calibration, and maintenance of a

pH meter used for continuous on-board monitoring.
2 Normat ive 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.

ASTM D6569-14, Standard Test Method for On-Line Measurement of pH

IEC 60746-2:2003, Expression of Performance of Electrochemical Analyzers — Part 2 — pH value

3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.

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

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

value derived from the potential difference between the glass electrode (3.5) and the reference electrode

(3.6) and compensated using temperature measured with the temperature sensor (3.7)

Note 1 to entry: This is based on a measure of the relative hydrogen ion activity in an aqueous solution given in

IEC 60746-2:2003, 3.1
3.2
continuous monitoring

measurement using fixed equipment that continually and automatically takes a reading at a

predetermined interval and then returns a result
© ISO 2022 – All rights reserved
---------------------- Page: 6 ----------------------
ISO 23668:2022(E)
3.3
pH meter for continuous on-board monitoring

on-board equipment composed of a pH combination electrode (3.4), a transmitter (3.9), and an electrode

mounting (3.10), which automatically and continuously measures pH and contains a cleaning device

(3.11), if needed
3.4
pH combination electrode

electrode holding a glass electrode (3.5) and a reference electrode (3.6) in a single unit

3.5
glass electrode

electrode measuring the electromotive force that corresponds to hydrogen ion concentration

3.6
reference electrode

electrode measuring reference potential to determine the electromotive force of the glass electrode

(3.5)
3.7
temperature sensor

sensor that measures the actual temperature of a sample solution to compensate for changes in the

slope force (3.8) of the glass electrode (3.5) due to temperature variations
3.8
slope force
electromotive force per a unit pH of the glass electrode (3.5)

Note 1 to entry: Theoretical Nernstian slope, which is temperature dependent, is 59,16 mV at 25 °C. The

temperature dependency of theoretical Nernstian slope is specified in IEC 60746-2:2003, Table A.1.

3.9
transmitter

device capable of outputting the potential difference as pH value (3.1), temperature, and state signal

3.10
electrode mounting

equipment to hold in place the pH combination electrode (3.4) when used for continuous monitoring (3.2),

which may contain a cleaning device (3.11), if needed
3.11
...

Questions, Comments and Discussion

Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.