Guidance on performing risk assessment in the design of onshore LNG installations including the ship/shore interface

ISO/TS 16901:2015 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 Technical Specification.

Guide pour l’évaluation des risques dans la conception d’installations terrestres pour le GNL en incluant l’interface terre/navire

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Status
Published
Publication Date
01-Mar-2015
Current Stage
6060 - International Standard published
Start Date
10-Feb-2015
Completion Date
02-Mar-2015
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TECHNICAL ISO/TS
SPECIFICATION 16901
First edition
2015-03-01
Guidance on performing risk
assessment in the design of onshore
LNG installations including the ship/
shore interface
Guide pour l’évaluation des risques dans la conception d’installations
terrestres pour le GNL en incluant l’interface terre/navire
Reference number
ISO/TS 16901:2015(E)
ISO 2015
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ISO/TS 16901:2015(E)
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© ISO 2015

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Published in Switzerland
ii © ISO 2015 – All rights reserved
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ISO/TS 16901:2015(E)
Contents Page

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

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

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

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

4 Abbreviations........................................................................................................................................................................................................... 6

5 Safety Risk Management .............................................................................................................................................................................. 7

5.1 Decision support framework for risk management ................................................................................................ 7

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 .....................................................................................................................................11

6.3 Risk control strategy .......................................................................................................................................................................11

6.4 ALARP ..........................................................................................................................................................................................................12

6.5 Ways to express risk to people ...............................................................................................................................................13

6.5.1 General...................................................................................................................................................................................13

6.5.2 Risk contours (RC) ......................................................................................................................................................13

6.5.3 Risk transects (RT) ........................................................................................................................................... ...........14

6.5.4 Individual risk (IR) ......................................................................................................................................................14

6.5.5 Potential loss of life (PLL) .....................................................................................................................................14

6.5.6 Fatal accident rate (FAR)........................................................................................................................................14

6.5.7 Cost to avert a fatality (CAF) ...............................................................................................................................14

6.5.8 F/N curves (FN) .............................................................................................................................................................14

6.6 Uncertainties in QRA.......................................................................................................................................................................15

7 Methodologies ......................................................................................................................................................................................................15

7.1 Main steps of risk assessment ................................................................................................................................................15

7.2 Qualitative risk analysis ...............................................................................................................................................................15

7.2.1 HAZID .....................................................................................................................................................................................15

7.2.2 Failure mode and effect analysis (FMEA) ................................................................................................17

7.2.3 Risk matrix .........................................................................................................................................................................17

7.2.4 Bow-tie ..................................................................................................................................................................................18

7.2.5 HAZOP ....................................................................................................................................................................................19

7.2.6 SIL analysis ........................................................................................................................................................................21

7.3 Quantitative analysis: consequence and impact assessment .......................................................................21

7.3.1 Consequence assessment ......................................................................................................................................21

7.3.2 Impact assessment ......................................................................................................................................................23

7.4 Quantitative analysis: frequency assessment ............................................................................................................24

7.4.1 General...................................................................................................................................................................................24

7.4.2 Failure data ........................................................................................................................................................................24

7.4.3 Consensus data ...............................................................................................................................................................25

7.4.4 FAULT tree ..........................................................................................................................................................................25

7.4.5 Event tree analysis (ETA) ......................................................................................................................................25

7.4.6 Exceedance curves based on probabilistic simulations ..............................................................25

7.5 Risk assessments (consequence*frequency) .............................................................................................................26

7.5.1 Risk assessment tools ...............................................................................................................................................26

7.5.2 Ad hoc developed risk assessment tools ..................................................................................................27

7.5.3 Proprietary risk assessment tools .................................................................................................................27

8 Accident scenarios ...........................................................................................................................................................................................28

8.1 Overview accident scenarios ...................................................................................................................................................28

8.2 LNG import facilities including SIMOPS .........................................................................................................................28

8.3 LNG export facilities ........................................................................................................................................................................31

8.4 Chain of events following release scenarios ...............................................................................................................32

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ISO/TS 16901:2015(E)

9 Standard presentation of risk ..............................................................................................................................................................34

Annex A (informative) Impact criteria ............................................................................................................................................................36

Bibliography .............................................................................................................................................................................................................................57

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ISO/TS 16901:2015(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 on the meaning of ISO specific terms and expressions related to conformity

assessment, as well as information about ISO’s adherence to the WTO principles in the Technical Barriers

to Trade (TBT) see the following URL: Foreword - Supplementary information.

The committee responsible for this document is ISO/TC 67, Materials, equipment and offshore structures

for petroleum, petrochemical and natural gas industries.
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TECHNICAL SPECIFICATION ISO/TS 16901:2015(E)
Guidance on performing risk assessment in the design of
onshore LNG installations including the ship/shore interface
1 Scope

This Technical Specification 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 Technical

Specification.

This Technical Specification is aimed to be applied both to export and import terminals, but can be

applicable to other facilities such as satellite and peak shaving plants.

It applies to all facilities inside the perimeter of the terminal and all hazardous materials including LNG

and associated products: LPG, pressurised 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 Technical Specification. 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 LNG fuelled vessels receiving bunker is designed according

to IMO’s regulations.

Border between port operation and LNG facility is when the ship/shore link (SSL) is established.

It is not intended to specify acceptable levels of risk; however, examples of tolerable levels of risk

are referenced.
This Technical Specification is not intended to be used retrospectively.

It is recognised that national and/or local laws, regulations, and guidelines take precedence where they

are in conflict with this Technical Specification.

Reference is made to ISO 31010 and ISO 17776 with regard to general risk assessment methods, while this

Technical Specification focuses on the specific needs scenarios and practices within the LNG industry.

2 Normative references

The following documents, in whole or in part, are normatively referenced in this document and are

indispensable for its application. For dated references, only the edition cited applies. For undated

references, the latest edition of the referenced document (including any amendments) applies

ISO/IEC Guide 73:2009, Risk management — Vocabulary

ISO 17776:2000, Petroleum and natural gas industries — Offshore production installations — Guidelines on

tools and techniques for hazard identification and risk assessment.
3 Terms and definitions

For the purposes of this document, the terms and definitions given in ISO/IEC Guide 73 and the

following apply.
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ISO/TS 16901:2015(E)
3.1
as low as reasonably practical
ALARP

reducing a risk (3.26) 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 pressurised liquid and for flammables often

followed by a fireball

Note 1 to entry: This hazard is not applicable to atmospheric LNG tanks, but to pressurized forms of

hydrocarbon storage.
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 (3.18) by the

reduction in potential loss (3.20) 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 (3.26) 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 shall be able to withstand during a required

period of time, in order to meet the defined risk (3.26) acceptance criteria
3.9
explosion barrier
structural barrier installed to prevent explosion damage in adjacent areas
Note 1 to entry: A wall is an example of an explosion barrier.
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ISO/TS 16901:2015(E)
3.10
F/N curve

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 (3.37) 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: All four steps are in place and recorded to manage a hazard completely.

3.17
impact assessment

assessment of how consequences (3.6) (fires, explosions, etc.) do affect people, structures the

environment, etc.
3.18
mitigation
limitation of any negative consequence (3.6) of a particular event
3.19
Monte Carlo simulation

simulation having many repeats, each time with a different starting value, to obtain distribution function

3.20
potential loss

product of frequency and harm (3.13) summed over all the outcomes of a number of top events

3.21
probability
extent to which an event is likely to occur
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ISO/TS 16901:2015(E)
3.22
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.
3.23
protective measure
means used to reduce risk
3.24
quantitative risk assessment
QRA

techniques which allow the risk (3.26) 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. Reference is made

to ISO 17776:2000, B.12.
3.25
residual risk
risk (3.26) remaining after protective measures (3.23) have been taken
3.26
risk

combination of the probability (3.21) of occurrence of harm (3.13) and the severity of that harm

3.27
risk analysis

systematic use of information to identify sources and to estimate the risk (3.26)

3.28
risk assessment
overall process of risk analysis (3.27) and risk evaluation (3.31)
3.29
risk contour
two dimensional representation of risk (3.26) on a map

Note 1 to entry: Also called individual risk contours (IRC) or location-specific risk (LSR).

3.30
risk criteria
terms of reference by which the significance of risk (3.26) is assessed
3.31
risk evaluation

procedure based on the risk analysis (3.27) to determine whether the tolerable risk (3.45) has been achieved

3.32
risk management

coordinated activities to direct and control an organization with regard to risk (3.26)

3.33
risk management system

set of elements of an organization’s management system concerned with managing risk (3.26)

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ISO/TS 16901:2015(E)
3.34
risk matrix

matrix portraying risk (3.26) as the product of probability (3.21) 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, assets, environment and reputation. Plotting the intersection of the two considerations on the

matrix provides an estimate of the risk.
3.35
risk perception

way in which a stakeholder (3.44) views a risk (3.26) based on a set of values or concerns

3.36
risk ranking

outcome of a qualitative risk analysis (3.27) with a numerical annotation of risk (3.26)

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.
3.37
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
3.38
risk transect
representation of risk (3.26) as a function of distance from the hazard
3.39
rollover
sudden mixing of two layers in a tank resulting to a massive vapour generation
3.40
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).

3.41
safety
freedom from unacceptable risk (3.26)
3.42
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 (3.26) than normal.

3.43
showstopper

event or consequence (3.6) that produces an unacceptable level of risk (3.26) such that the project cannot

proceed and where the level of risk cannot be mitigated to an acceptable level
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ISO/TS 16901:2015(E)
3.44
stakeholder

any individual, group, or organization that can affect, be affected by, or perceive itself to be affected by

a risk (3.26)
3.45
tolerable risk

risk (3.26) which is accepted in a given context based on the current values of society

4 Abbreviations

For the purposes of this Technical Specification, the following abbreviations apply:

ALARP as low as reasonably practical;
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;
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;
IR individual risk contour;
LSR location-specific risk;
LOPA layers of protection analysis;
MTTF mean time to failure;
MTTR mean time to repair;
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ISO/TS 16901:2015(E)
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.
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 compliance with regulations and 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.
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ISO/TS 16901:2015(E)
Signiicance to Decision
Making Progress
MEANS OF CALIBRATIONDECISION CONTEXT TYPE
Nothing new or unusual
Codes and Standards Well understood risks
Established practice
No major stakeholder implications
Veriication
Lifecycle implications
Peer Review
Some risk trade-offs/transfers
Some uncertainty or deviation from
standard or best practice
Benchmarking
Signiicant economic implications
Internal Stakeholder
Very novel or challenging
Consultation
Strong stakeholder views and perceptions
C Signiicant risk trade-offs or risk transfer
Large uncertainties
External Stakeholder
Perceived lowering of safety standards
Consultation
Figure 1 — Decision support framework for major accident 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.

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,
...

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