Adv Antic a Presentation on Draft Report

8/8/2019 Adv Antic a Presentation on Draft Report

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Safety Review of the Proposed Onshore

Section of the Corrib Gas Pipeline- Draft Report

Dr. Mike Acton and Dr. Bob Andrews (Consultants)

Mr. Arwel Griffiths (Executive Director)

Copyright 2005 Advantica, Inc. (USA Only) and Advantica Ltd. (Outside USA). All rights reserved by the respective owner.


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Overview

Introduction to Advantica Company Overview Key Personnel

Safety Review of the Corrib Gas Pipeline Background Scope of Safety Review

Safety Review Process Draft Report

Summary of Recommendations and Closing Remarks


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What Does Advantica Do?

Provide engineering, consultancy andsoftware services to customers acrossthe hydrocarbon chain

throughout the project lifecycle, frominfrastructure development through toasset management.

Approximately 500 highly qualifiedscientific and engineering staff, including

internationally renowned experts. Complete gas chain coverage.


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We are a Global Business

Advantica Clients found in these locations


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Award Winning Technology


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Key Personnel

Dr. Mike Acton (Hazard & Risk Management) 17 years oil & gas experience at Advantica (formerly British Gas R&T) Involved in many large and full scale pipeline tests

Chairman of PIPESAFE Group of companies Extensive experience in the application of pipeline risk assessment Experienced incident investigator, including transmission pipeline failures

Active member of IGEM Committees, and contributed to several IGEMCodes of Practice and Safety Recommendations

Dr. Bob Andrews (Integrity Management) 20 years experience at The Welding Institute and then Advantica

Extensive experience of structural integrity issues in components andstructures, particularly pipelines

Specialist in pipeline integrity and fracture control

Active member of IGEM and BSI Committees, and contributed to IGEM and

BSI Codes of Practice and Standards


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Safety Review of the Corrib Gas Pipeline


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Background

The pipeline industry has a good safetyrecord, but incidents have occasionally

occurred

The Corrib onshore pipeline is plannedto operate at high pressure, carrying

untreated gas

Serious concerns expressed by local

residents over the safety of the pipeline,especially the consequences of failure

Safety review commissioned inresponse to those concerns


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Scope of Safety Review

Included: Review of the health and safety aspects of the proposed pipeline in terms of

engineering design and risk to public safety

Review of the available documentation for completeness and suitability NOT included

Assessment of environmental impact

Assessment of the risk to workers during construction

Review of the onshore terminal, offshore pipeline or subsea equipment


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Safety Review Process

Evaluate initial set of documents supplied by TAG

Identify and request additional information from Shell

Meeting with Shell for points of clarification and discussion of projectdesign selection process

Documents classified as: Technical documents requiring detailed technical review by specialists

Documents providing background information including project history Documents outside the scope of the review

Site visit to confirm understanding of pipeline route and local conditions

2 day oral hearing and opportunity for written submissions to raiseissues of concern and points to be taken into account in the review

Draft report issued for comment

Final report


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Draft Report


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Report Structure

Executive Summary Main Report

1. Introduction

2. The Safety Review Process3. Overall Project Development Plan

4. Review of Pipeline Design

5. Quantified Risk Assessment

6. Discussion7. Final Remarks and Recommendations

AppendicesA. Advantica Personnel

B. Summary of Oral and Written SubmissionsC. Geotechnical Analysis

D. Societal Risk Analysis

E. Geotechnical Investigations on Corrib Pipeline Route

F. Comments on Rossport Pipeline Hazard Calculations by DJ Aldridge PhD


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Overall Project Development Plan

High level review of constraints relevant to the onshore pipeline

Assessment of consideration given to safety issues in the design optionselection process for:

Sub-sea tie-back option Landfall and terminal locations

Proposed onshore pipeline route

This section considers the process followed Not a detailed technical review

Consideration of alternative design options, terminal locations orpipeline routes was outside the scope of our work


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Terminal location, 9km inland, drives requirement for an onshorepipeline

High pressure onshore pipeline required whether gas processed

onshore or offshore Onshore processing introduces additional threats that must be

managed

Public safety was one of many factors in selection process, which alsoincluded: Visual impact

Economic

Environmental Technical


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QRA informed design and route selection

Risk levels within recognised international criteria

Ireland has no formal risk-based framework in place

Consideration should be given by the Irish Government to establishinga risk-based framework for decisions on proposed and existing major

hazard pipelines and related infrastructure


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Four route options considered: Pollatomish via Dooncarton landfall Brandy Point via Brandy Point landfall

Via Struwaddacon Bay Rossport via Dooncarton landfall (preferred)


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Initial design based on pressure of 150 bar

Subsequently adopted more cautious approach Wall thickness increased

Withstand 345 bar theoretical worst case

Most cautious approach to routing based on consequence distances,but in practice, rarely practical to avoid all population

Design codes have more onerous requirements for Higher population density Proximity to housing (in some cases)


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Route through Rossport determined by Ground stability

Avoidance of possible future land development

Maximising distance from housing Nearest building 70m from pipeline

Justified by QRA


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Review of Pipeline Design


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Integrity - fatigue

Failure due to variations in pressure

Several predictions from flowsimulations

Stresses around cut-off in codes Recommend:

Monitoring of pressure variations

Check small attachments

1000 10000 100000 10000002 3 4 5 6 7 2 3 4 5 6 2 3 4 5 6

Cycles

100

30

40

50

60

70

80

90

200

Stressrang

e(Nmm-2)

165Nmm-2

35Nmm-2

Edition 4

Edition 3

I i i i


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Integrity impact protection

Protection at road crossings using concrete slabs is accepted practice

Concerns with the data supplied: Design left to contractor and not location specific

Slabbing should extend the full width of the route already addressed Distance between slab and pipe may be too shallow Support slab from subsoil in peat areas

Formal safety analysis for 72% SMYS operation at crossings notdocumented

These issues should be addressed to provide best practice impactprotection


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I t it d t


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Integrity ground movement

We also checked other failure modes such as buckling

We considerother analyses are required to demonstrate integrity: Movement parallel to the pipe

Effect of bends Increased depth of cover

We recommend monitoring of stresses in critical areas

Gro nd Mo ement


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Ground Movement

Effects of pipeline on ground stability have been considered

Dooncarton type slide on steep slopes will not affect the route as theslopes are too shallow

Shallow slope slide has been addressed by Shells consultants All recommendations by these consultants should be implemented in

full

Materials


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Materials

Pipe material to DNV OS-F101 Grade 485

This grade (or equivalent) has been widely used for onshore andoffshore projects

Plate produced by German and Japanese mills and pipe produced inUK

Mill certificates examined requirements satisfied

Formal fracture control plan not produced, but we have checked therequirements for the gas composition and consider material issatisfactory


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External Corrosion


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External Corrosion

Mainline coating specificationgenerally satisfactory

We recommend testing to assess

possible long term UV degradationduring storage

We are concerned with the quality offield joint coating and recommend a

robust inspection regime during

construction

Cathodic protection system requiresan insulation jointat the beach to

achieve separation from offshore

system

Construction


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Construction

Welding to British Standards

Toughness requirements exceed BS

Actual levels above requirements

Welds meet best practice

Pressure Testing


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Pressure Testing

We recommend: A high level pressure test to 105% SMYS should be carried out The test pressure should be calculated on nominal wall thickness not

design We support the recommendation for a fingerprinting ILI run during

commissioning

Operations & Maintenance


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Procedures were requested from Shell but we were advised that thesehad not yet been written and would be prepared prior to operation in

accordance with BS 8010

An Integrity Management System (IMS) is required and should include Inspections

Management systems and management of change

Audit and corrective actions

IMS should be in place from the start of the project

Frequency of inspections should be updated based on results

We consider a leak detection system is not sufficient as an integrity

management system A formal integrity management system should be established for the

pipeline before construction is allowed to commence



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We recommend: Defect assessment and procedures should be defined in advance so that

anomalies can be sentenced quickly

Repair procedures should be developed for non-leaking damage Procedures are required for safe working in proximity to the pipeline

Future Operation


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Future Operation

We have not considered tie-ins of other fields to this pipeline

We note the system is designed for sweet gas, ie no H2S

Monitoring is required to check that H2S is not introduced into the

system In the event that additional fields were proposed to be tied in to the

pipeline at any future date, a full review would be required to consider

issues such as extension of the life beyond the initial design life,

changes in the fluids in the pipeline or changes in the operating

pressures


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Risk Assessment

HAZard IDentification (HAZID)


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HAZard IDentification (HAZID)

Original HAZID covered main onshore pipeline hazards

Some additional hazards identified

Project Hazard Register prepared to track HAZID actions

Some actions to be addressed in operations and maintenanceprocedures (not yet prepared)

Action to address H2S threat needs to be more robust

The Project Hazard Register should be maintained and updated and allHAZID actions addressed

Population Density Analysis


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Population Density Analysis

Area classification in accordance with BS8010, based on 345 bar Minimum proximity distance of 170m by extrapolation

Population density found to be low (Class 1 or Rural)

Ribbon development parallel to pipeline Anomaly of increasing population density with reducing pressure Not enough for Class 2 (Suburban) classification

Consideration should be given to the nature of ribbon developmentsparallel to the pipeline in calculating population density in any future

reassessment of the pipeline classification

Quantified Risk Assessment (QRA)


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Quantified Risk Assessment (QRA)

Pipeline risk assessment: Failure cause Failure mode

Gas outflow Ignition Thermal radiation Thermal effects

Risk calculations

Risk reduction measures

Input

Parameters

Failure cause?

Failure mode?

Calculation of

Failure Frequency

Outflow Dispersion IgnitionThermal

radiation

Radiation

effects

Consequence calculations

Rupture or Puncture?

Fatigue

External

interferenceGround

movementCorrosion

Causes

Risk Calculations

Risk Transect

FN curve (PLL, EV)

Societal

Individual

Review of JP Kenny QRA


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Failure frequencies included for: Third party interference Ground movement

Inherent and construction defects Assumes measures against other threats effective and no H2S

Inclusion of ground movement inconsistent

Concluded that Individual Risk levels acceptable at all distances The measures to protect the pipeline integrity assumed in the QRAmust be established for the Corrib pipeline, and maintained throughout

its life

A procedure should be established for monitoring of the gas for H2S,specifying the actions to be taken and the threshold concentrations

above which action would be required



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Consequence modelling simplistic

No recognition of uncertainty at very high pressures

Low value for ignition probability assumed for rupture case

Consideration of Individual Risk only Risk unexpectedly insensitive to pipeline pressure

Advantica Risk Assessment


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Advantica Risk Assessment

Independent check on QRA results PIPESAFE package Validated at pressures up to 120 bar

Assumes proposed measures AND those recommended in this report Range of hazard distances given

Increasing uncertainty with higher pressures recognised

Individual Risk levels lower than JP Kenny results Included Societal Risk analysis

Individual Risk Analysis


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Individual Risk Analysis

1.00E-11

1.00E-10

1.00E-09

1.00E-08

1.00E-07

1.00E-06

0 50 100 150 200 250 300

Distance from Pipeline (m)

Individua

lRisk(peryear)

144barg 240barg 345barg

Societal Risk Analysis


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Societal Risk Analysis

1 . 0 0 E - 1 3

1 . 0 0 E - 1 2

1 . 0 0 E - 1 1

1 . 0 0 E - 1 0

1 . 0 0 E - 0 9

1 . 0 0 E - 0 8

1 . 0 0 E - 0 7

1 . 0 0 E - 0 6

1 . 0 0 E - 0 5

1 . 0 0 E - 0 4

1 1 0 1 0 0 1 0 0 0

N u m b e r o f C a s u a l t ie s (N )

FrequencyofNo

rMoreCasualtiesperYear(F)

I G E / T D / 1 S o c ie t a l R is k C r ite r io n E n v e l o p e

1 4 4 b a r g

2 4 0 b a r g

3 4 5 b a r g

Risk Reduction Measures


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Risk levels within recognised limits

Other possible risk reduction options considered

Third party damage dominates residual risk

Pipeline wall thickness main defence against failure The proposed arrangements for surveillance and landowner liaison

should be specified in the operations and maintenance procedures



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Uncertainty increases with increasing pressure

Highest pressure should be assumed Dormant defects may fail when pressure rises

Limiting pressure reduces failure frequency and consequences Limiting design factor to 0.3 or less (~144 bar for Corrib pipeline)

recognised as effective measure to allow pipelines to be routed in

higher population density (Suburban) locations

UKOOA Decision Framework


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Significance of Bases to

Decision Making Process

Means of Calibration Decision Context

Codes and Standards

Verification

Peer Review

Benchmarking

Internal Stakeholder

Consultation

External StakeholderConsultation

Codes &

Standards

Goo

dPrac

tice

Engineerin

gJudg

emen

t

QRA

CBA

Company

Values

Societal Values

Nothing new or unusual

Well understood risks

Established practice

No major stakeholder

implications

No significant economic

implications

A

B

C

Business risk or lifecycle

implications

Some risk trade-offs/transfer

Some uncertainty

Some deviation from standard

or best practice

Some significant economic

implication

Very novel or challenging

Strong stakeholder views

and perceptions

Significant risk trade-offs

or risk transfer

Large uncertainties

Perceived lowering of safetystandards

Major economic implications

Significance of Bases to

Decision Making Process

Means of Calibration Decision Context

Codes and Standards

Verification

Peer Review

Benchmarking

Internal Stakeholder

Consultation

External StakeholderConsultation

Codes &

Standards

Goo

dPrac

tice

Engineerin

gJudg

emen

t

QRA

CBA

Company

Values

Societal Values

Nothing new or unusual

Well understood risks

Established practice

No major stakeholder

implications

No significant economic

implications

A

B

C

Business risk or lifecycle

implications

Some risk trade-offs/transfer

Some uncertainty

Some deviation from standard

or best practice

Some significant economic

implication

Very novel or challenging

Strong stakeholder views

and perceptions

Significant risk trade-offs

or risk transfer

Large uncertainties

Perceived lowering of safetystandards

Major economic implications



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Risk assessment powerful tool to inform decisions, but not only factor

Corrib pipeline conventional in that the pipeline wall thickness isincreased to accommodate high design pressure and upstream pipeline

technology is well-established BUT:

It lies outside normal range of application on onshore design codes

There is uncertainty in the risk analysis at such high pressures

It gives rise to significant societal concerns

We therefore recommend that the pressure in the onshore pipelineshould be limited to enable the pipeline to be reclassified as a Class 2

(Suburban) pipeline, with a design factor not exceeding 0.3

Pressure Safety Measures


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y

Reliability assessment of subsea pressure control systems flawed

Does not form a basis for selection of options

A full and technically thorough reliability analysis should be carried out

of the subsea pressure control and isolation systems specified in thefield design

Additional pressure control measures should be implemented and theeffective limitation of the pressure in the onshore pipeline demonstrated


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Discussion

Selection of Design Code


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We consider BS 8010 was an appropriate choice of design code Synthesis of accumulated UK experience IS 328 closely related

Better safety levels than US or ISO codes see later Generally accepted practice to keep the original code on long running

projects unless there are reasons for change

IGE codes allow continued operation to an earlier edition

Should have considered adopting PD 8010 O&M section



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Withdrawal of BS 8010 Some observations have been made that BS 8010 was obsolete This is incorrect, the withdrawal was a consequence of the introduction of

European standards BSi paid for the conversion of the BS into a PD so that the guidance was

still available

UK National Foreword to EN 14161 states:

that a more comprehensive approach to the design of pipelines is possible

through using BS EN 14161 in association with the following Codes of

Practice: PD 8010-1:2004



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Code Comparison BS 8010 calculates design thickness on minimum, not nominal wall BS 8010 allows a higher level hydrotest, giving a more searching test of

integrity BS 8010 has minimum proximity distances based on pressure US andCanadian codes have no restrictions on proximity except for access

If the onshore pipeline is reclassified as a Class 2 (Suburban) pipeline,

the pipeline design should be revised in accordance with PD 8010, toensure that the pipeline is consistent with current best practice, while

minimising the change required to the existing design

Design Pressure


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High design pressure of 345 bar Higher than normal for onshore gas transmission Above range of onshore pipeline codes and standards

Pressures over 100 bar increasingly used for new pipeline designs Cautious approach by Shell resulted in a very thick and strong pipe

Maximum pressure falls steadily as gas extracted

Advantica recognises the concerns and recommends limiting thepressure to ~144 bar, consistent with pipeline design factor used forpipelines in more densely populated suburban areas


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Untreated Gas Composition


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Corrib gas has unusually high natural methane content (~94%) Typical of methane content of treated gas Similar to composition used in validating Advantica models

Other fluids contained in the gas stream present additional threats: Gas is wet - combined with CO2 can cause internal corrosion Hydrates - can cause blockage

H2S - not detected, but can be formed during lifetime of a gas field

Appropriate precautions have been identified to combat these additionalthreats

Must be maintained and effectiveness monitored

A plan should be in place in case H2S is detected

Ground Stability


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Effects of ground movement on the pipeline JP Kenny analysis conservative for straight pipe Expected to withstand ground movement loading

Analysis should be extended to other configurations (e.g. bends) If not acceptable, need to consider additional measures Techniques to stabilize pipelines in muskeg (similar to peat) used in

Canada

Effects of pipeline construction on future ground stability Raised as an issue in oral hearings

Obtained advice on Irish peat issues from GSI

Practical advice from contacts with experience of construction in peat

Additional information supplied by Shell includes reports by AGEC

The recommendations made by AGEC should be followed in full and theproposed construction methods revised accordingly, in order that the

ground stability issues are managed appropriately

Risk Mitigation Options


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Main additional measure identified is pressure limitation for onshoresection

Scope for further risk reduction limited

Very important that measures already identified and recommended inour report are in place not only when pipeline is new but also

throughout the life of the pipeline

Arrangements should be made for an independent audit of construction

work and an inspection regime established to confirm safe operation ofthe pipeline in future


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Summary of Recommendations and

Closing Remarks

Summary of Recommendations (1)


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1. Consideration should be given by the Irish Government to establishing

a risk-based framework for decisions on proposed and existing major

hazard pipelines and related infrastructure, to ensure transparency and

consistency of the decision-making process

2. A formal integrity management plan should be established prior to

construction, including the operational and maintenance philosophy,

and that an independent audit and inspection regime for both the

construction and operation of the pipeline is established3. The pressure in the onshore pipeline should be limited to enable the

pipeline to be reclassified as a Class 2 (Suburban) pipeline, with a

design factor not exceeding 0.3, and the pipeline design revised in

accordance with PD 8010

Summary of Recommendations (2)


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4. A full and technically thorough reliability analysis should be carried out

of the subsea pressure control and isolation systems specified in the

field design to enable appropriate additional pressure control measures

to be implemented and the effective limitation of the pressure in the

onshore pipeline demonstrated

5. The recommendations made by AGEC should be followed in full and

the proposed construction methods revised accordingly, in order that

the ground stability issues are managed appropriately6. In the event that additional fields were proposed to be tied in to the

pipeline at any future date, a full review would be required to consider

issues such as extension of the life beyond the initial design life,

changes in the fluids in the pipeline or changes in the operatingpressures

Closing Remarks (1)


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We recognise the real concerns over the safety of the Corrib pipeline

The review has been undertaken by independent, professional staff withwide-ranging experience of pipeline safety issues including pipeline

incidents We have applied world class risk assessment tools and methodologies

for the assessment of risk from gas pipelines, validated by full scale

experiments and incident data

In making our recommendations, we have taken into account thesocietal concerns and the uncertainty in risk analysis

Our recommendations are in line with the principles embodied in soundengineering design standards for pipelines

Closing Remarks (2)


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The fact that a new design is not fully covered by an existing standarddoes not make it unsafe, but it does make the requirement to

demonstrate that the design is safe more onerous

Based on a rigorous assessment of the detailed engineeringdocumentation, we have identified a number of areas where importanttechnical issues must be addressed

Provided that these detailed recommendations are followed, the

pressure is limited effectively as recommended, and a robust integritymanagement plan is in place to ensure that safety levels are maintained

throughout the life of the pipeline, we believe that there will be a

substantial safety margin in the pipeline design

Closing Remarks (3)


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We recognise that it is the nature of any review of this type that areaswhere problems are identified are given a high profile, whereas much of

the engineering design work is satisfactory and receives little credit

We would like to recognise the co-operation received from Shell andtheir contractors, including responses to requests for information

We would also like to thank those that made submissions as part of theprocess, both written and oral, and in particular the courtesy shown to

us at the oral hearings