ISO/DIS 23314-2

Ships and marine technology -- Ballast water management systems (BWMS)

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DRAFT INTERNATIONAL STANDARD
ISO/DIS 23314-2
ISO/TC 8 Secretariat: SAC
Voting begins on: Voting terminates on:
2021-01-11 2021-04-05
Ships and marine technology — Ballast water management
systems (BWMS) —
Part 2:
Risk assessment and risk reduction of BWMS using
electrolytic methods
ICS: 47.020.99; 13.110
THIS DOCUMENT IS A DRAFT CIRCULATED
FOR COMMENT AND APPROVAL. IT IS
THEREFORE SUBJECT TO CHANGE AND MAY
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STANDARD UNTIL PUBLISHED AS SUCH.
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BEING ACCEPTABLE FOR INDUSTRIAL,
This document is circulated as received from the committee secretariat.
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ISO/DIS 23314-2:2021(E)
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PROVIDE SUPPORTING DOCUMENTATION. ISO 2021
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ISO/DIS 23314-2:2021(E)
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ISO/DIS 23314-2:2021(E)
Contents Page

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

Introduction ................................................................................................................................................................................................................................vi

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

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

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

4 Strategy for risk assessment and risk reduction ................................................................................................................ 3

5 Risk assessment process .............................................................................................................................................................................. 4

5.1 General ........................................................................................................................................................................................................... 4

5.2 Information for risk assessment .............................................................................................................................................. 4

5.2.1 System description ......................................................................................................................................................... 4

5.2.2 Regulations, standards and other applicable documents ............................................................ 5

5.2.3 Related to experience of use .................................................................................................................................. 5

5.3 Determination of the limits .......................................................................................................................................................... 5

5.3.1 General...................................................................................................................................................................................... 5

5.3.2 Use limits ................................................................................................................................................................................ 5

5.3.3 Space limits ........................................................................................................................................................................... 5

5.3.4 Time limits ............................................................................................................................................................................ 6

5.3.5 Environmental limits.................................................................................................................................................... 6

5.4 Hazard identification ......................................................................................................................................................................... 7

5.4.1 Human interaction with the equipment over the entire life cycle of

a BWMS using the electrolytic method ......................................................................................................... 7

5.4.2 Possible states of BWMS using the electrolytic method ................................................................ 8

5.4.3 Unintended behaviour of the operator or reasonably foreseeable misuse ................... 9

5.5 Risk estimation ....................................................................................................................................................................................... 9

5.5.1 General...................................................................................................................................................................................... 9

5.5.2 Elements of risk .............................................................................................................................................................10

5.5.3 Aspects to be considered during risk estimation .............................................................................10

5.6 Risk estimation ....................................................................................................................................................................................12

6 Risk reduction ......................................................................................................................................................................................................12

6.1 Inherently safe design ....................................................................................................................................................................12

6.1.1 Considerations during the initial design ..................................................................................................12

6.1.2 Choice of appropriate technology ..................................................................................................................13

6.1.3 Applying inherently safe design measures to control systems .............................................13

6.2 Safeguarding and/or complementary protective measures .........................................................................14

6.2.1 Safeguarding measures ...........................................................................................................................................14

6.2.2 Complementary protective measures ........................................................................................................14

6.3 Information for use ..........................................................................................................................................................................16

6.3.1 Installation guide ..........................................................................................................................................................16

6.3.2 Commissioning procedure ...................................................................................................................................16

6.3.3 OMSM ......................................................................................................................................................................................17

6.3.4 Maintenance scheme .................................................................................................................................................17

6.3.5 Calibration manual ........................................................................................................................................... ...........17

6.3.6 Warning indication .....................................................................................................................................................18

6.3.7 Training plan and documentation .................................................................................................................18

7 Documentation of risk assessment ................................................................................................................................................18

Annex A (informative) Example of a risk estimation matrix table in accordance with

ISO/TR 14121-2 ..................................................................................................................................................................................................19

Annex B (informative) Example of a risk assessment and risk reduction worksheet –

filtration unit .........................................................................................................................................................................................................20

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ISO/DIS 23314-2:2021(E)

Annex C (informative) Example of a risk assessment and risk reduction worksheet –

electrolysis unit ..................................................................................................................................................................................................22

Annex D (informative) Example of a risk assessment and risk reduction worksheet –

neutralization unit ..........................................................................................................................................................................................26

Annex E (informative) Example of a training plan for BWMS using the electrolytic method .................27

Bibliography .............................................................................................................................................................................................................................28

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ISO/DIS 23314-2:2021(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.

A list of all parts in the ISO 23314 series can be found on the ISO website.

Any feedback or questions on this document should be directed to the user’s national standards body. A

complete listing of these bodies can be found at www .iso .org/ members .html.
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ISO/DIS 23314-2:2021(E)
Introduction

A ballast water management system (BWMS) using the electrolytic method applies a combination of

filtration (if applicable), electrolysis, and a neutralization process to treat ballast water to meet Regulation

D-2 of the International Maritime Organization (IMO) BWM Convention or the ballast water discharge

standard (BWDS) requirements of port state administrations, e.g., the U.S. Coast Guard (USCG).

At the uptake of ballast water, the BWMS utilizes filtration (if applicable) and injection of active

substances (e.g., sodium hypochlorite) generated by an electrolysis process. The active substance may

be generated within the full flow of the ballast pipe (full stream) or generated from a smaller side

stream (either extracted from the ballast pipe or sourced from a brine tank) and then mixed with the

full ballast flow. The active substance in the ballast pipe is measured as total residual oxidants (TRO)

and the BWMS regulates the TRO level to ensure ballast water is treated to the threshold level. During

discharge, the residual TRO is monitored and neutralized prior to discharge overboard to ensure

that the amount of residual active substance entering the receiving environment is acceptable. The

treatment process is shown in Figure 1.
Figure 1 — Overview of BWMS using the electrolytic method
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DRAFT INTERNATIONAL STANDARD ISO/DIS 23314-2:2021(E)
Ships and marine technology — Ballast water management
systems (BWMS) —
Part 2:
Risk assessment and risk reduction of BWMS using
electrolytic methods
1 Scope

This document provides guidance for designers of BWMS using electrolytic methods to document

the risk assessment and risk reduction process over the lifecycle of the equipment, and to support its

approval for use on ships by Administrations and classification societies. Specifically, this document

provides basic terminology, principles, and a methodology to identify and subsequently minimize the

risk of hazards in the design of BWMS using electrolytic methods. It specifies the procedures for risk

assessment and risk reduction following the guidance of ISO 12100. Risks considered include: human

health and safety; marine environment related to conditions on board; ship installation, operation,

maintenance, and structural integrity.

This document does not address the methodology for the risk assessment of corrosion effects, toxicity

and ecotoxicity of active substances, relevant chemicals, and/or other chemicals generated or used

by BWMS using electrolytic methods, which is evaluated by the IMO GESAMP-Ballast Water Working

Group as prescribed in the document IMO, Methodology for the Evaluation of Ballast Water Management

Systems using Active Substances.

This document does not address risks associated with the end of life disposition of the BWMS.

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 12100:2010, Safety of machinery — General principles for design — Risk assessment and risk reduction

IEC 31010, Risk management — Risk assessment techniques

IMO, International Convention for the Control and Management of Ships' Ballast Water and

Sediments, 2004

IMO, Code for Approval of Ballast Water Management Systems (BWMS Code), MEPC.300 (72), as may

be amended

IMO, Procedure for Approval of Ballast Water Management Systems that Make Use of Active Substances

(G9), MEPC.169(57)
3 Terms and definitions

For the purposes of this document, the terms and definitions given in ISO 12100 and the following apply.

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

— ISO Online browsing platform: available at https:// www .iso .org/ obp
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ISO/DIS 23314-2:2021(E)
— IEC Electropedia: available at http:// www .electropedia .org/
3.1
active substance

substance or organism, including a virus or fungus that has a general or specific action on or against

harmful organisms and pathogens

Note 1 to entry: For BWMS using electrolytic methods, it means reaction products that are generated by the

electrolytic method for the ballast water treatment.
[SOURCE: IMO G9]
3.2
ballast water

water with its suspended matter taken on board a ship to control trim, list, draught, stability or stresses

of the ship
3.3
ballast water management system
BWMS

any system which processes ballast water (3.2) such that it meets or exceeds the ballast water discharge

performance standard in Regulation D-2 of the BWM Convention

Note 1 to entry: A BWMS includes ballast water treatment equipment, all associated control equipment, piping

arrangements within the BWMS as specified by the manufacturer, control and monitoring equipment, and

sampling devices.

Note 2 to entry: A BWMS does not include the ship's ballast water fittings, which may include piping, valves,

pumps, etc. that would be required if the BWMS was not fitted.

Note 3 to entry: A ballast water treatment system (BWTS) defined in Environmental Technology Verification

(ETV) is considered the same as BWMS.
[SOURCE: IMO BWMS Code]
3.4
dangerous gas

any gas which may develop an explosive and/or toxic atmosphere which is hazardous o the crew and/or

the ship, e.g., hydrogen (H ) hydrocarbon gas, ozone (O ), chlorine (Cl ) and chlorine dioxide (ClO ), etc.

2 3 2 2
3.5
electrolytic method

treatment process in which water flows through a set of special electrodes, producing active substances

(3.1) when current is applied
3.6
electrolytic chamber

chamber which contains one or several sets of electrodes and associated power connections and makes

use of the electrolytic method (3.5) for the production of active substances (3.1) when water flows

through it
3.7
electrolysis unit

any unit that mainly consists of one or several chambers making use of electrolytic method (3.5) to

produce active substances (3.1) for the treatment of ballast water (3.2), including ventilation components

for the safe handling of dangerous gas (3.4) if applicable, as well as relevant piping, valves, electrical and

electronic components
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ISO/DIS 23314-2:2021(E)
3.8
global integrated shipping information system
GISIS

public integrated information database developed by the IMO, which is composed of several modules

that deal with ship particulars, maritime safety, chemicals associated with treated ballast water and

other shipping-related information
3.9
life cycle

entire lifespan from the design, manufacturing, storage, installation, to operation and disposal of a BWMS

3.10
maximum allowable discharge concentration
MADC

maximum allowable concentration of active substances during discharge of ballast water as defined by

port state control or local regulation
3.11
neutralization unit

any unit that mainly consists of neutralizing agent preparation and dosing equipment for the purpose of

neutralizing active substances (3.1) by adding neutralizing agent into the de-ballast pipe so as to reduce

TRO concentration to achieve compliance with the MADC (3.10)
3.12
total residual oxidant
TRO

the sum of the effect of hypochlorous acid (HClO), hypochlorite (ClO), chlorine (Cl ), hypobromous acid

(HBrO), hypobromite (BrO), bromine (Br ), chloramine compounds, bromine compound, etc.

4 Strategy for risk assessment and risk reduction

The process for risk assessment and risk reduction is based on guidance from ISO 12100 and is

summarized in Figure 2.
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ISO/DIS 23314-2:2021(E)

Figure 2 — General procedure of risk assessment and risk reduction for BWMS using

the electrolytic method
5 Risk assessment process
5.1 General

The risk assessment for BWMS using the electrolytic method is comprised of risk analysis and risk

evaluation.

Risk analysis consists of determining the limits, identifying the hazards, and estimating risk over the

whole lifespan of a BWMS, as considered in 5.3 to 5.5. Risk analysis provides information required for

the risk evaluation, which in turn allows judgment to be made about whether or not risk reduction is

required.
5.2 Information for risk assessment

The information for the risk assessment of a BWMS using the electrolytic method shall consider the

documentation described in the following sub-clauses.
5.2.1 System description

Documents related to installation guidance; the operation, maintenance, and safety manual (OMSM);

schematic diagrams; process flow diagrams; and applicable test reports
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ISO/DIS 23314-2:2021(E)
5.2.2 Regulations, standards and other applicable documents

• ISO/IEC standards (e.g., IEC 60079), IMO regulations or circulars (e.g., BWM Convention, BWMS

Code, Procedure G9), IACS Unified requirements (e.g., IACS UR M74), port state administration rules

(e.g., USCG 46 CFR 162.060), and classification society rules

• Safety data sheets (SDSs) of the active substance, neutralizing agent, TRO measurement reagent,

and dangerous gas (e.g., hydrogen)

• Database of chemicals commonly associated with treated ballast water in the IMO GISIS

5.2.3 Related to experience of use

• Known accidents, incidents or malfunction history of the actual or similar electrochlorination

systems (from database of marine incidents, e.g., GISIS)

• The potential for adverse effects from human exposure (e.g., to active substances)

• The experience of users of similar system e.g., electrochlorination system in power plant,

waterworks, etc.

The information used in the risk assessment shall be updated throughout the design process or when

modifications to the BWMS are required.
5.3 Determination of the limits
5.3.1 General

Risk assessment begins with the determination of the limits of the BWMS, taking into account all the

phases over the lifespan of the BWMS. This means considering the characteristics and performances of

both subsystems and the overall system as an integrated process. Here, characteristics of the system,

including its relationship with humans, the environment, and other products shall be identified in

terms of the limits of the BWMS as given in 5.3.2 to 5.3.5.

The purpose of this step is to identify all key parameters and their associated performance limits. These

parameters pertain to installation, operation, maintenance, personnel, and the environment.

5.3.2 Use limits

Use limits include the intended use and the reasonably foreseeable misuse of the BWMS. Aspects to

account for include the following:

• The anticipated levels of training, experience or ability of the people who will carry out installation,

commissioning, operation, and maintenance of the BWMS, e.g., unexpected system shutdown may

be activated due to misuse by an operator who is improperly trained or unfamiliar with the BWMS.

• Exposure of other persons to the hazards associated with the system that can be reasonably be

predicted, e.g., crew for other duties, administration officer or service personnel for other equipment

adjacent to the BWMS.
5.3.3 Space limits

Aspects of space limits shall address the requirements for safe installation, operation, and maintenance

of the BWMS. Considerations shall include:
• power supply and cabling
• cooling water or ventilation air
• operation and maintenance space
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ISO/DIS 23314-2:2021(E)
• space for chemical storage (e.g., neutralizing agent, TRO measurement reagent)
• space for dangerous gas exhaust on open deck
• installation location (e.g., hazardous area)
5.3.4 Time limits

Aspects of time limits shall consider specific operating and maintenance factors, including:

• life limit of parts that can wear due to corrosion, or life of critical components where a decline in

efficiency affects performance capabilities (e.g., electrode)
• recommended service and calibration intervals
• holding time (minimum for efficacy and maximum based on regrowth)

NOTE The holding time may be dependent on water salinity, water temperature and TRO concentration.

• TRO measurement reagent service life/neutralizing agent shelf life in both solid (if applicable) and

aqueous forms (stored in ready to use form)
5.3.5 Environmental limits

Environmental limits shall consider the range of uptake water chemistries to be treated, operational

limits of process variables within the BWMS, limitations imposed by the shipboard environment on the

BWMS, hazardous by-products of the electrolytic process, and any environmental constraints on the

storage and use of chemicals associated with the BWMS. At a minimum, the following limits shall be

considered:
• recommended minimum salinity and temperature of the ballast water

• recommended minimum salinity and minimum and maximum temperature of the electrolytic unit

feed water
• recommended minimum inlet pressure of the filtration unit (if applicable)
• treatment rated capacity

• maximum allowable discharge concentration (MADC), related to potential toxicity to the receiving

environment
• lower TRO limit for treatment efficacy
• upper TRO limit for the potential corrosive effects on ballast tanks
• ambient marine environment related to locations on board

• potential flammable and explosive atmospheres that may be created on board the vessel

• potential health risks to personnel due to exposure to dangerous gas, and flammable and explosive

environments
• personnel exposure to active substances or other relevant chemicals
• TRO measurement waste (if applicable)

NOTE The limits including water salinity, water temperature, holding time, and TRO concentration are also

identified as representative system design limitations (SDL) for a BWMS using the electrolytic method as per the

BWMS Code.
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ISO/DIS 23314-2:2021(E)
5.4 Hazard identification

After determination of the limits of the BWMS, the next essential step is to identify the reasonably

foreseeable hazards (permanent hazards), unexpected hazards, hazardous situations, and hazardous

events during all lifecycle phases of the system, including:
• design
• transportation, storage and installation
• commissioning
• operation
• maintenance

Only when hazards have been identified can steps be taken to eliminate them or to reduce risks. Hazard

identification shall identify the operations to be performed by the BWMS and the tasks to be performed

by persons who interact with it while considering the different components, mechanisms or functions

of the system, and the environment in which the system can be operated.

In addition to general mechanical and electrical hazards, the designed of the BWMS shall identify

hazards specific to the electrolytic method while considering the items in the following sub-clauses:

5.4.1 Human interaction with the equipment over the entire life cycle of a BWMS using

the electrolytic method

Over the course of building, installation, operation, maintenance, and removal of a BWMS, personnel

may be exposed to a number of hazards. These may be a result of normal operation, or consequences of

maintenance or repair activities. Hazards shall be considered for the following conditions or activities:

5.4.1.1 Health effects due to contact with active substances or other relevant chemicals

5.4.1.2 Start-up/shutdown of systems (i.e.
...