SIST-TS CEN ISO/TS 16901:2025

SLOVENSKI STANDARD
01-julij-2025
Navodilo za oceno tveganja pri načrtovanju napeljav za utekočinjeni zemeljski plin
na kopnem, vključno s povezavo med ladjo in kopnim (ISO/TS 16901:2022)
Guidance on performing risk assessment in the design of onshore LNG installations
including the ship/shore interface (ISO/TS 16901:2022)
Leitfaden zur Durchführung von Risikobewertungen bei der Planung von LNG-Anlagen
an Land, einschließlich der Schnittstelle zwischen Schiff und Land (ISO/TS 16901:2022)
Recommandations sur l'appréciation du risque dans la conception d'installations
terrestres pour le GNL en incluant l'interface terre/navire (ISO/TS 16901:2022)
Ta slovenski standard je istoveten z: CEN ISO/TS 16901:2025
ICS:
75.180.01 Oprema za industrijo nafte in Equipment for petroleum and
zemeljskega plina na splošno natural gas industries in
general
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

CEN ISO/TS 16901
TECHNICAL SPECIFICATION
SPÉCIFICATION TECHNIQUE
May 2025
TECHNISCHE SPEZIFIKATION
ICS 75.180.01
English Version
Guidance on performing risk assessment in the design of
onshore LNG installations including the ship/shore
interface (ISO/TS 16901:2022)
Recommandations sur l'appréciation du risque dans la Leitfaden zur Durchführung von Risikobewertungen
conception d'installations terrestres pour le GNL en bei der Planung von LNG-Anlagen an Land,
incluant l'interface terre/navire (ISO/TS 16901:2022) einschließlich der Schnittstelle zwischen Schiff und
Land (ISO/TS 16901:2022)
This Technical Specification (CEN/TS) was approved by CEN on 11 May 2025 for provisional application.

The period of validity of this CEN/TS is limited initially to three years. After two years the members of CEN will be requested to
submit their comments, particularly on the question whether the CEN/TS can be converted into a European Standard.

CEN members are required to announce the existence of this CEN/TS in the same way as for an EN and to make the CEN/TS
available promptly at national level in an appropriate form. It is permissible to keep conflicting national standards in force (in
parallel to the CEN/TS) until the final decision about the possible conversion of the CEN/TS into an EN is reached.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and
United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2025 CEN All rights of exploitation in any form and by any means reserved Ref. No. CEN ISO/TS 16901:2025 E
worldwide for CEN national Members.

Contents Page
European foreword . 3

European foreword
The text of ISO/TS 16901:2022 has been prepared by Technical Committee ISO/TC 67 "Oil and gas
industries including lower carbon energy” of the International Organization for Standardization (ISO)
and has been taken over as CEN ISO/TS 16901:2025 by Technical Committee CEN/TC 282 “Installation
and equipment for LNG” the secretariat of which is held by AFNOR.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
Any feedback and questions on this document should be directed to the users’ national standards body.
A complete listing of these bodies can be found on the CEN website.
According to the CEN-CENELEC Internal Regulations, the national standards organizations of the
following countries are bound to announce this Technical Specification: Austria, Belgium, Bulgaria,
Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland,
Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of
North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and the
United Kingdom.
Endorsement notice
The text of ISO/TS 16901:2022 has been approved by CEN as CEN ISO/TS 16901:2025 without any
modification.
TECHNICAL ISO/TS
SPECIFICATION 16901
Second edition
2022-12
Guidance on performing risk
assessment in the design of onshore
LNG installations including the ship/
shore interface
Recommandations sur l’évaluation des risques dans la conception
d’installations terrestres pour le GNL en incluant l’interface terre/
navire
Reference number
ISO/TS 16901:2022(E)
ISO/TS 16901:2022(E)
© 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
ii
ISO/TS 16901:2022(E)
Contents Page
Foreword .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Abbreviated terms . 6
5 Safety risk management . 8
5.1 Decision support framework for risk management . 8
5.2 Prescriptive safety or risk performance . 8
5.3 Risk assessment in relation to project development . 9
6 Risk .11
6.1 What is risk . 11
6.2 Safety philosophy and risk criteria .12
6.3 Risk control strategy . .12
6.4 ALARP .12
6.5 Ways to express risk to people . 13
6.5.1 General .13
6.5.2 Risk contours (RC) . 14
6.5.3 Risk transects (RT) . 14
6.5.4 Individual risk (IR) . 14
6.5.5 Potential loss of life (PLL). 15
6.5.6 Fatal accident rate (FAR) . 15
6.5.7 Cost to avert a fatality (CAF) . 15
6.5.8 F/N curves (FN) . .15
6.5.9 Uncertainties in QRA .15
7 Methodologies.16
7.1 Main steps of risk assessment . . 16
7.2 Qualitative risk analysis . 16
7.2.1 HAZID . 16
7.2.2 Failure mode and effect analysis (FMEA) . 18
7.2.3 Risk matrix . 18
7.2.4 Bow-tie . 18
7.2.5 HAZOP . 20
7.2.6 SIL analysis . 21
7.3 Quantitative analysis: consequence and impact assessment . 21
7.3.1 General . 21
7.3.2 Consequence assessment . 22
7.3.3 Impact assessment. 24
7.4 Quantitative analysis: frequency assessment . 25
7.4.1 General . 25
7.4.2 Failure data . 25
7.4.3 Consensus data . 25
7.4.4 FAULT tree . 26
7.4.5 Event tree analysis (ETA) . 26
7.4.6 Exceedance curves based on probabilistic simulations .26
7.5 Risk assessments (consequence*frequency) . 27
7.5.1 Risk assessment tools . 27
7.5.2 Ad hoc developed risk assessment tools . 27
7.5.3 Proprietary risk assessment tools .28
8 Accident scenarios .29
8.1 Overview accident scenarios .29
8.2 LNG import facilities including SIMOPS .29
8.3 LNG export facilities . 31
iii
ISO/TS 16901:2022(E)
9 Standard presentation of risk.33
Annex A (informative) Impact criteria .34
Annex B (informative) Chain of events following release scenarios .53
Bibliography .57
iv
ISO/TS 16901:2022(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 67, Oil and gas industries including lower
carbon energy, Subcommittee SC 9, Production, transport and storage facilities for cryogenic liquefied
gases.
This second edition cancels and replaces the first edition (ISO/TS 16901:2015), which has been
technically revised.
The main changes are as follows:
— reference to IGF code added to the scope;
— references updated in Clause 2 and the bibliography;
— definitions added for HSE critical activity and HSE critical element.
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.
v
TECHNICAL SPECIFICATION ISO/TS 16901:2022(E)
Guidance on performing risk assessment in the design
of onshore LNG installations including the ship/shore
interface
1 Scope
This document provides a common approach and guidance to those undertaking assessment of the
major safety hazards as part of the planning, design, and operation of LNG facilities onshore and at
shoreline using risk-based methods and standards, to enable a safe design and operation of LNG
facilities. The environmental risks associated with an LNG release are not addressed in this document.
This document is applicable both to export and import terminals but can be applicable to other facilities
such as satellite and peak shaving plants.
This document is applicable to all facilities inside the perimeter of the terminal and all hazardous
materials including LNG and associated products: LPG, pressurized natural gas, odorizers, and other
flammable or hazardous products handled within the terminal.
The navigation risks and LNG tanker intrinsic operation risks are recognised, but they are not in
the scope of this document. Hazards arising from interfaces between port and facility and ship are
addressed and requirements are normally given by port authorities. It is assumed that LNG carriers
are designed according to the IGC code, and that LNG fuelled vessels receiving bunker fuel are designed
according to IGF code.
Border between port operation and LNG facility is when the ship/shore link (SSL) is established.
This document is not intended to specify acceptable levels of risk; however, examples of tolerable levels
of risk are referenced.
See IEC 31010 and ISO 17776 with regard to general risk assessment methods, while this document
focuses on the specific needs scenarios and practices within the LNG industry.
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 Guide 73, Risk management — Vocabulary
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO Guide 73 and the following
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/
ISO/TS 16901:2022(E)
3.1
as low as reasonably practicable
ALARP
reducing a risk (3.28) to a level that represents the point, objectively assessed, at which the time,
trouble, difficulty, and cost of further reduction measures become unreasonably disproportionate to
the additional risk reduction obtained
3.2
boiling liquid expanding vapour explosion
BLEVE
sudden release of the content of a vessel containing a pressurized flammable liquid followed by a fireball
Note 1 to entry: This hazard is not applicable to atmospheric LNG tanks, but to pressurized forms of hydrocarbon
storage.
[SOURCE: ISO/TS 18683, 3.1.2, modified — Note to entry added.]
3.3
bow-tie
pictorial representation of how a hazard can be hypothetically released and further developed into a
number of consequences (3.6)
Note 1 to entry: The left-hand side of the diagram is constructed from the fault tree (causal) analysis and involves
those threats associated with the hazard, the controls associated with each threat, and any factors that escalate
likelihood. The right-hand side of the diagram is constructed from the hazard event tree (consequence) analysis
and involves escalation factors and recovery preparedness measures. The centre of the bow-tie is commonly
referred to as the “top event”.
3.4
cost to avert a fatality
CAF
value calculated by dividing the costs to install and operate the protection/mitigation (3.20) by the
reduction in potential loss (3.22) of life (PLL)
Note 1 to entry: It is a measure of effectiveness of the protection/mitigation.
3.5
computational fluid dynamics
CFD
numerical methods and algorithms to solve and analyse problems that involve fluid flows
3.6
consequence
outcome of an event
3.7
cost benefit analysis
CBA
means used to assess the relative cost and benefit of a number of risk (3.28) reduction alternatives
Note 1 to entry: The ranking of the risk reduction alternatives evaluated is usually shown graphically.
3.8
design accidental load
DAL
most severe accidental load that the function or system is able to withstand during a required period of
time, in order to meet the defined risk (3.28) acceptance criteria
ISO/TS 16901:2022(E)
3.9
explosion barrier
structural barrier installed to prevent explosion damage in adjacent areas
EXAMPLE A wall.
3.10
F/N curve
FN
plot of cumulative frequency versus N or more persons that sustain a given level of harm from defined
sources of hazards
3.11
failure mode and effect analysis
FMEA
analytically derived identification of the conceivable equipment failure modes and the potential adverse
effects of those modes on the system and mission
Note 1 to entry: It is primarily used as a design tool for review of critical components.
3.12
fatal accident rate
FAR
number of fatalities per 100 million hours exposure for a certain activity
3.13
harm
physical injury or damage to the health of people or damage to property or the environment
3.14
hazard
potential source of harm (3.13)
3.15
hazard identification
HAZID
brainstorming exercise using checklists the hazards in a project are identified and gathered in a risk
register (3.39) for follow up in the project
3.16
hazard and operability study
HAZOP
systematic approach by an interdisciplinary team to identify hazards and operability problems
occurring as a result of deviations from the intended range of process conditions
Note 1 to entry: It consists of four steps: definition, preparation, documentation/follow up and examination to
manage a hazard completely.
3.17
health, safety and environmental critical activity
HSE critical activity
activity or task that provides or maintains barriers
3.18
health, safety and environmental critical element
HSE critical element
component or system whose failure could cause or substantially contribute to the loss of integrity and
safety of a system and whose purpose is to prevent or mitigate from the effects of hazards
ISO/TS 16901:2022(E)
3.19
impact assessment
assessment of how consequences (3.6) (fires, explosions, etc.) do affect people, structures the
environment, etc.
3.20
mitigation
limitation of any negative consequence (3.6) of a particular event
3.21
Monte Carlo simulation
simulation having many repeats, each time with a different starting value, to obtain distribution
function
3.22
potential loss
product of frequency and harm (3.13) summed over all the outcomes of a number of top events
3.23
probability
extent to which an event is likely to occur
3.24
probit
inverse cumulative distribution function associated with the standard normal distribution
Note 1 to entry: Probit is used in QRA to describe the relation between exposure, e.g. to radiation or toxics, and
fraction fatalities.
3.25
protective measure
means used to reduce risk
3.26
quantitative risk assessment
QRA
techniques that allow the risk (3.28) associated with a particular activity to be estimated in absolute
quantitative terms rather than in relative terms such as high or low
Note 1 to entry: QRA may be used to determine all risk dimensions, including risk to personnel, risk to the
environment, risk to the installation, and/or the assets and financial interests of the company. See ISO 17776:2016,
B.12.
3.27
residual risk
risk (3.28) remaining after protective measures (3.25) have been taken
3.28
risk
combination of the probability (3.23) of occurrence of harm (3.13) and the severity of that harm
3.29
risk analysis
systematic use of information to identify sources and to estimate the risk (3.28)
3.30
risk assessment
overall process of risk analysis (3.29) and risk evaluation (3.33)
ISO/TS 16901:2022(E)
3.31
risk contour
RC
two-dimensional representation of risk (3.28) on a map
Note 1 to entry: Also called individual risk contours (IRC) or location-specific risk (LSR).
3.32
risk criteria
terms of reference by which the significance of risk (3.28) is assessed
3.33
risk evaluation
procedure based on the risk analysis (3.29) to determine whether the tolerable risk (3.47) has been
achieved
3.34
risk management
coordinated activities to direct and control an organization with regard to risk (3.28)
3.35
risk management system
set of elements of an organization’s management system concerned with managing risk (3.28)
3.36
risk matrix
matrix portraying risk (3.28) as the product of probability (3.23) and consequence (3.6), used as the
basis for risk determination
Note 1 to entry: Considerations for the assessment of probability are shown on the horizontal axis. Considerations
for the assessment of consequence are shown on the vertical axis. Multiple consequence categories are included:
impact on people, environment, assets, and reputation. Plotting the intersection of the two considerations on the
matrix provides an estimate of the risk.
3.37
risk perception
way in which a stakeholder (3.46) views a risk (3.28) based on a set of values or concerns
3.38
risk ranking
outcome of a qualitative risk analysis (3.29) with a numerical annotation of risk (3.28)
Note 1 to entry: It allows accident scenarios and their risk to be ranked numerically so that the most severe risks
are evident and can be addressed.
3.39
risk register
hazard management communication document that demonstrates that hazards have been identified,
assessed, are being properly controlled, and that recovery preparedness measures are in place in the
event control is ever lost
3.40
risk transect
RT
representation of risk (3.28) as a function of distance from the hazard
3.41
rollover
sudden mixing of two layers in a tank resulting to a massive vapour generation
ISO/TS 16901:2022(E)
3.42
rapid phase transition
RPT
explosive change from liquid into vapour phase
Note 1 to entry: When two liquids at two different temperatures come into contact, explosive forces can occur,
given certain circumstances. This phenomenon, called rapid phase transition (RPT), can occur when LNG and
water come into contact. Although no combustion occurs, this phenomenon has all the other characteristics
of an explosion. RPTs resulting from an LNG spill on water have been both rare and with relatively limited
consequences (3.6).
3.43
safety
freedom from unacceptable risk (3.28)
3.44
SIMOPS
concatenation of simultaneous operations
Note 1 to entry: SIMOPS often refers to events such as maintenance or construction work in an existing plant
when there are more personnel near a live operating plant and who are exposed to a higher level of risk (3.28)
than normal.
3.45
showstopper
event or consequence (3.6) that produces an unacceptable level of risk (3.28) such that the project cannot
proceed and where the level of risk cannot be mitigated to an acceptable level
3.46
stakeholder
individual, group, or organization that can affect, be affected by, or perceive itself to be affected by a
risk (3.28)
3.47
tolerable risk
risk (3.28) that is accepted in a given context based on the current values of society
3.48
individual risk
probability of being killed (or harmed at certain level) on an annual basis from all hazards (3.13)
3.49
potential loss of life
expected value of the number of fatalities per year (or over the life time of a project)
4 Abbreviated terms
ALARP as low as reasonably practicable
BLEVE boiling liquid expanding vapour explosion
CAF cost to avert a fatality
CFD computational fluid dynamics
CBA cost benefit analysis
DAL design accidental load
EDP emergency depressuring
ISO/TS 16901:2022(E)
ERC emergency release coupling
ESD emergency shutdown
ETA event tree analysis
FAR fatal accident rate
FEED front-end engineering design
FEM finite element method
FN frequency vs number (of affected individuals)
FMEA failure mode and effect analysis
FMECA failure, modes, effects, and criticality analysis
HAZID hazard identification
HAZOP hazard and operability study
HEMP hazards and effects management process
HSE health, safety and environmental
IR individual risk contour
LSR location-specific risk
LOPA layers of protection analysis
MTTF mean time to failure
MTTR mean time to repair
OBE operating basis earthquake
PERC power emergency release coupler
P&IDs process and instrument diagrams
PIMS pipeline integrity management system
PLL potential loss of life
QRA quantitative risk assessment
RC risk contour
RPT rapid phase transition
RT risk transect
SIL safety integrity level
SMS safety management system
SSE safe shutdown earthquake
SSL ship/shore link
ISO/TS 16901:2022(E)
5 Safety risk management
5.1 Decision support framework for risk management
Safety risk management is integrated in the project development and decision-making processes and
need as consistent support for decisions in all phases of an LNG development but does not include the
full operational lifecycle.
The approach to risk management should address the project-specific requirements as agreed between
the different parties and stakeholders and also establish an agreed format to communicate risk and
ensure that decisions are made in a consistent and agreed format through the life of the project.
The acceptance criteria including the format should be defined in conformity with company standards.
The format of the acceptance criteria prescribes thereby the approach as discussed below.
There is a wide range of tools and approaches that can be used to support decisions related to risk
management. UK Offshore Operators Association (UKOOA) presented a framework for decision
support reflecting the significance of the decision as well decision context. The framework as shown
for information in Figure 1 illustrates the balancing between use of codes and standards, QRA, and
decision processes reflecting company and societal values.
Figure 1 — Decision support framework for risk management
5.2 Prescriptive safety or risk performance
Both prescriptive and risk-based approaches are used in the planning, design, and operation of LNG
facilities.
Prescriptive approaches represent industry experience and practices.
The main advantages with prescriptive approaches are predictability and effective decision processes
in the design.
The main objections to the use of prescriptive approaches are that they do not accommodate new
solutions and thereby can limit novel development and improvement. Further, when the requirements
are met, the prescriptive approaches do not encourage a continued effort for further improvements.
ISO/TS 16901:2022(E)
Risk-based approaches have developed in the nuclear and offshore industries. Risk-based approaches
are used in many parts of the world and are gaining a wider usage.
In essence, risk-based approaches start from first principles aiming at demonstration that the risk
acceptance criteria are met with a proper selection of design and operational measures. In principle,
no “prescribed solutions” should be given as a starting point (but in reality, good industry experience,
practices and standards are adopted as the starting point).
The main advantage of a risk-based approach is that it stimulates new and improved solutions; it
encourages continuous focus on improved safety, and it focuses efforts on the key areas as formulated
in the risk acceptance criteria.
Normally, a risk-based approach starts early and focuses the attention on the key issues that should be
addressed in the different project phases. In most cases, a risk-based approach ensures that the correct
decisions are made at the right time and thereby avoids costly revisions and adjustments. Further, the
site-specific conditions and particular stakeholder views are better reflected.
The main criticism to risk-based approaches focuses on the complexity of the process, and the line
of responsibility can become unclear. It is essential that risk acceptance criteria are established and
derived from owner’s requirements. National and international regulations can apply.
It is often found that a risk-based design does not enable all engineering design disciplines to proceed
on a firm design basis until the results from the risk analysis is available. This can have a schedule
impact.
Further, the uncertainty involved due to, e.g. lack of relevant failure data, model assumptions can make
it difficult to relate to the results. A situation where detailed results from sophisticated computational
models can generate false confidence in the results can lead to the wrong conclusion. The uncertainty is
a particular concern when a risk-based approach is used to demonstrate that sensible safety measures
are not needed.
Risk analyses shall not be used to deviate from good engineering practice.
Finally, it is often claimed that the lack of predictability leads to increased cost. But the savings earned
by adopting novel solutions can be significant but difficult to quantify.
Successful use of a risk-based approach normally requires an iterative process where the first layouts
and decision are based on experience and industry practice (i.e. prescriptive guidelines, standards for
process design, etc.) and that this first estimate is qualified and improved using risk-based techniques.
Risk analyses also enable areas and causes of higher risk to be identified so that mitigation measures
can be applied in a cost-effective manner.
5.3 Risk assessment in relation to project development
Risk assessment is used for decision support.
The decisions being made in the different phases of a project development vary, and the need for
decision support accordingly.
The available information and level of detail as input to any risk assessment increase as the planning
progresses. As a result, the requirements to risk assessment techniques and results vary over the
project phases, and this can represent a challenge in the communication of the results.
In the early phase of the planning where the key issue is to select business model and technical concept,
the main risk activities are to establish risk criteria and safety targets, as well as to demonstrate
absence of showstoppers. This requires qualitative approaches.
At this stage of project development, quantitative risk analyses have limited value as no detailed
information to describe the facilities are available as input.
ISO/TS 16901:2022(E)
In the next phase, the risk assessment should provide quantitative risk information related to the land
planning in support of the permitting process.
In later project phases where key issues are the design of mitigation measures, more detailed analyses
are appropriate to provide a proper basis for project decisions.
In some jurisdictions, the planning process makes it difficult to modify proposals once they have been
submitted to the planning authorities. This makes it difficult to modify the design to reduce risk as
detailed engineering develops. This aspect should be considered in project planning.
The requirements, recommendations, and advice given in this document reflect this need. Risk
assessment and risk results shall always reflect the following:
a) the type of decision that shall be made;
b) effective utilization of available information.
Actions arising from reviews such as HAZID, risk matrix, HAZOP, etc., which are not closed out after
the review, should be recorded in a tracking system (for example, a risk register). This should answer
that items requiring action at later project stages (i.e. items for operating manuals, etc.) should not be
overlooked or forgotten.
This varying level of details in the risk assessment process is illustrated in Table 1 which also is relevant
to a wide range of different types of industrial risk assessment.
Table 1 should be used instead of IEC 31010:2019, Table A.1 to identify risk assessment methods.
Further description is given in Clause 7.
Table 1 — Typical requirements to risk-related information in different project phases
Project phase Needed risk related Key decisions based on Method of risk assessment
information risk assessment within this guideline
Pre-FEED — Identify stakeholders — Select site — HAZID
(i.e. Concept
— Input to the permitting — Select concept — Consequence analyses of
selection and
process (demonstrate major accident scenarios
business case
— Identify and decide risk
absence of showstoppers)
development)
criteria — Prepare risk criteria
— Risk criteria
— Select design criteria — Risk communication to
— First estimate of the risk legislation and
— Select design options
level (when required by stakeholders
regulators)
— Approve continued
development
— Basic design options
— Go-ahead for the
development
ISO/TS 16901:2022(E)
TTabablele 1 1 ((ccoonnttiinnueuedd))
Project phase Needed risk related Key decisions based on Method of risk assessment
information risk assessment within this guideline
FEED — Focus areas for the — Optimisation of the — Qualitative analysis (risk
Development of design process, i.e. results design in terms of safety by matrix)
basic design from HAZID and comparison of options
— HAZOPs and
Consequence analysis
— Select main technologies determination of SIL
— Estimate of the risk level requirements
— Performance standards
of design options
for safety system — QRA
— Basis for selection of an
— Confirm concept — Determine DALs
optimized basic design
selection
— Detailed consequence
— Authority permit assessment
— Decide to start detail — Fire/explosion analysis
design
— Risk communication to
legislation and
stakeholders
Detail design — Performance standards — Selection of equipment, — Detailed QRA
for components and solutions and operational
— Detailed HAZOPs
systems procedures
— SIL assessment
— Issues to be addressed — Detailed design
in the design identified in
— Vendor HAZOPs
HAZOP findings incl. SIL
requirements
— Evacuation analysis
— Specifications for
buildings and equipment
Commissioning — Final results from risk — Approve the design — Completion of risk
and start-up assessment studies and verification
— Approve decision to
schemes
— Confirmation of start up
acceptance according to — Commissioning of safety
regulations systems
— Risk communication to
legislation and
stakeholders
6 Risk
6.1 What is risk
To be able to express the risk, the consequences shall be defined and the associated probability
determined.
Risk is also often referred to as potential loss. The loss or consequence can be loss of life, damage to the
environment, assets, or reputation. The probability term is usually expressed as a frequency. In QRAs,
the potential loss in general is not calculated from the product of one event and one consequence, but
the sum of a large number of frequency and consequence probability combinations.
Risk or potential loss, combination of the probability of an event, and the consequences of the event
cannot be readily used as an indicator to decide the tolerability of the risk. It can be used to compare
options when all things different between the two options have been evaluated in terms of probability
and consequence and included in the assessment.
IS
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