ISO 23314-2:2021

FINAL
INTERNATIONAL ISO/FDIS
DRAFT
STANDARD 23314-2
ISO/TC 8
Ships and marine technology —
Secretariat: SAC
Ballast water management systems
Voting begins on:
2021-08-17 (BWMS) —
Voting terminates on:
Part 2:
2021-10-12
Risk assessment and risk reduction of
BWMS using electrolytic methods
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Reference number
BEING ACCEPTABLE FOR INDUSTRIAL, TECHNO-
ISO/FDIS 23314-2:2021(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 2021

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ISO/FDIS 23314-2:2021(E)

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© ISO 2021
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
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ISO/FDIS 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
5.3 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 General. 7
5.4.2 Human interaction with the equipment over the entire life cycle of
a BWMS using the electrolytic method . 7
5.4.3 Possible states of BWMS using the electrolytic method . 8
5.4.4 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 . 9
5.5.3 Aspects to be considered during risk estimation .10
5.6 Risk evaluation .11
6 Risk reduction .12
6.1 General .12
6.2 Inherently safe design .12
6.2.1 General.12
6.2.2 Considerations during the initial design .12
6.2.3 Choice of appropriate technology .13
6.2.4 Applying inherently safe design measures to control systems .13
6.3 Safeguarding and/or complementary protective measures .14
6.3.1 General.14
6.3.2 Safeguarding measures .14
6.3.3 Complementary protective measures .14
6.4 Information for use .16
6.4.1 General.16
6.4.2 Installation guide .16
6.4.3 Commissioning procedure .16
6.4.4 Operation, maintenance and safety manual (OMSM) .17
6.4.5 Maintenance scheme .17
6.4.6 Calibration manual . .17
6.4.7 Warning indication .18
6.4.8 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/FDIS 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/FDIS 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/FDIS 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
[19]
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
[31]
(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 can
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.
Key
or treatment flow
feedback signal
Figure 1 — Overview of BWMS using the electrolytic method
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FINAL DRAFT INTERNATIONAL STANDARD ISO/FDIS 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 requirements and recommendations 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 in ISO 12100.
Risks considered include: human health and safety; marine environment related to conditions on
board; and 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 GESAMP, Methodology for the Evaluation of Ballast Water
[26]
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
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
— IEC Electropedia: available at https:// 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 (3.3) using electrolytic methods (3.8), it means reaction products that are generated by
the electrolytic method for the ballast water treatment.
[SOURCE: IMO G9]
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ISO/FDIS 23314-2:2021(E)

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
system that 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 can 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
gas that can develop an explosive and/or toxic atmosphere hazardous to the crew and/or the ship
EXAMPLE Hydrogen (H ), hydrocarbon gas, ozone (O ), chlorine (Cl ), chlorine dioxide (ClO ).
2 3 2 2
3.5
electrical distribution conductor
conductor intended for distributing the electricity, such as bus bars or conductors of insulated cables
3.6
electrolysis unit
unit that mainly consists of one or several chambers making use of an electrolytic method (3.8) to
produce active substances (3.1) for the treatment of ballast water (3.2), including ventilation components
for the safe handling of dangerous gases (3.4) if applicable, as well as relevant piping, valves, electrical
and electronic components
3.7
electrolytic chamber
chamber that contains one or several sets of electrodes and associated power connections, and that
makes use of the electrolytic method (3.8) for the production of active substances (3.1) when water flows
through it
3.8
electrolytic method
treatment process in which water flows through a set of special electrodes, producing active substances
(3.1) when an electric current is applied
3.9
flammable liquid
liquid having a flash point not exceeding 60 °C (closed cup test)
3.10
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 (3.2)
and other shipping-related information
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ISO/FDIS 23314-2:2021(E)

3.11
life cycle
entire lifespan from the design, manufacturing, storage, installation, to operation and disposal of a
BWMS (3.3)
3.12
maximum allowable discharge concentration
MADC
maximum allowable concentration of active substances (3.1) during discharge of ballast water (3.2) as
defined by port state control or local regulation
3.13
neutralization unit
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 (3.14) concentration to achieve compliance with the MADC (3.12)
3.14
total residual oxidant
TRO
sum of the effect of oxidizing chemicals, such as hypochlorous acid (HClO), hypochlorite (ClO), chlorine
(Cl ), hypobromous acid (HBrO), hypobromite (BrO), bromine (Br ), chloramine compounds, bromine
2 2
compound
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/FDIS 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 the information required
for the risk evaluation (see 5.6), which in turn allows judgment to be made about whether or not risk
reduction (see Clause 6) 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 list.
a)  System description
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Documents related to installation guidance; the operation, maintenance and safety manual (OMSM);
schematic diagrams; process flow diagrams; and applicable test reports.
b)  Regulations, standards and other applicable documents
— ISO and 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.
c)  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. 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 carry out installation,
commissioning, operation, and maintenance of the BWMS, e.g. unexpected system shutdown can 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;
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— operation and maintenance space;
— 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 can 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 (TRC);
— 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 can 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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5.4 Hazard identification
5.4.1 General
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 hazards associated with 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 designer of the BWMS shall identify
hazards specific to the electrolytic method while considering the items in 5.4.2 to 5.4.4.
5.4.2 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
can be exposed to a number of hazards. These can be a result of normal
...