(A42081)               June 8, 2012 E-FILE National Energy Board 444 Seventh Avenue SW Calgary, AB T2P 0X8 Attention: Ms. Sheri Young Secretary to the Joint Review Panel Enbridge Northern Gateway Project Dear Ms. Young: Re: Northern Gateway Pipelines Application to the National Energy Board Enbridge Northern Gateway Project OH-4-2011 NEB File No: OF-Fac-Oil-N304-2010-01 01 Exhibit B69-6 – Revised Semi-Quantitative Risk Assessment It has come to our attention that Figure 1, Components of the semi-quantitative risk assessment and Figure 2, Overview of methodology were not included in the Semi-Quantitative Risk Assessment that was filed on May 10, 2012 under filing ID A41386. Northern Gateway Pipelines files herewith a revised Semi-Quantitative Risk Assessment that replaces the version originally filed as exhibit B69-6. If the Board requires additional information, please contact the undersigned at 403-718-3444. Yours truly, Ken MacDonald Vice President, Law and Regulatory Northern Gateway Pipelines Limited Partnership Enclosure: ENB LL 26345725 (A42081) Northern Gateway Pipelines Limited Partnership Semi-Quantitative Risk Assessment Submitted in Response to Joint Review Panel Information Request Number 8.1(b) Enbridge Northern Gateway Project WorleyParsons Canada Services Ltd. – Calgary Operations 400, 10201 Southport Road SW Calgary, Alberta T2W 4X9 Canada Telephone: +1 403 258 8000 Facsimile: +1 403 258 5893 www.worleyparsons.com Copyright 2012 WorleyParsons (A42081) NORTHERN GATEWAY PIPELINES LIMITED PARTNERSHIP ENBRIDGE NORTHERN GATEWAY PROJECT Semi-Quantitative Risk Assessment SUBMITTED IN RESPONSE TO JOINT REVIEW PANEL INFORMATION REQUEST NUMBER 8.1(B) EXECUTIVE SUMMARY This Semi-Quantitative Risk Assessment (SQRA) was prepared by WorleyParsons Canada Services Ltd. (WorleyParsons) for Northern Gateway Pipelines Limited Partnership (Northern Gateway) under the Enbridge Northern Gateway Project (the Project). The SQRA is submitted in response to the Joint Review Panel (JRP) Information Request (IR) Number 8.1(b), and in support of a risk-based design process. Risk-based design is an iterative approach that evaluates and prioritizes risks associated with a preliminary design (termed ‘unmitigated risks’ in this report), and their associated risk-drivers, and then establishes mitigation measures to be incorporated into the design to address the principal unmitigated risks. The SQRA provides a risk assessment of a spill from the Northern Gateway oil line for the risk associated with a full-bore rupture and release of diluted bitumen (dilbit). The assessment methodology follows the definitions and guidelines provided in Canadian Standards Association (CSA) CSA Z662-11, Guidelines for Risk Assessment of Pipelines. The magnitude of risk as defined by this standard is the combination of the frequency or likelihood of an event and the consequence of the event if it happens. A semi-quantitative risk assessment is a combination of probabilistic modelling along with semi-quantitative scoring methods. The risk severity is based on a risk matrix of likelihood or frequency and consequence specific to this Project. The SQRA process steps are described in the following paragraphs. The first step in the SQRA was to identify hazard and threat events, including: internal and external corrosion; manufacturing and construction defects; incorrect operations and equipment failure; third-party damage; and geotechnical and hydrological threats. The next step was to determine the failure frequency based on reliability methods and expert judgement. Northern Gateway engaged Dynamic Risk Assessment Systems Inc. (Dynamic) to develop a quantitative failure frequency model. Using reliability methods addressed the primary challenge associated with deriving quantitative risk values for new pipelines. AMEC Environment & Infrastructure (AMEC), a division of AMEC Americas Limited, was engaged to provide a semi-quantitative assessment of failure frequency of geohazards building on AMEC’s original work identifying geohazards for the application. Page ii (A42081) NORTHERN GATEWAY PIPELINES LIMITED PARTNERSHIP ENBRIDGE NORTHERN GATEWAY PROJECT Semi-Quantitative Risk Assessment SUBMITTED IN RESPONSE TO JOINT REVIEW PANEL INFORMATION REQUEST NUMBER 8.1(B) The third step was to evaluate consequences, beginning with spill trajectory modelling to determine whether a product release will affect a consequence area. The magnitude of the effect is a function of spill volume, accessibility, and inherent sensitivity of the particular consequence area. The final step was to evaluate unmitigated risk severity. Risk severity was evaluated through the risk matrix developed for the project as a combination of the frequency of rupture and the consequence, given a rupture. While most of the pipeline route has a low-risk rating, the assessment confirmed a number of higher risk areas, primarily associated with high-value watercourses such as the Kitimat River. A summary of the SQRA results based on the current Route Revision U is shown in the following chart. Overall distribution of unmitigated risk severity by one-kilometre segments The terrain and geotechnical conditions that this pipeline traverses are similar to those of other liquid transmission pipelines in Canada and throughout the world. The products carried by this pipeline are also carried by other existing pipelines in Canada and the United States. This SQRA was based on assessing risk from a full-bore rupture on the proposed oil pipeline. Northern Gateway recognizes that a release of any magnitude from the pipeline is unacceptable and will undertake additional work during the detailed design phase to identify and apply mitigation to minimize risk of a release. The Project is undertaking a more detailed evaluation of higher risk sections of the Coast Mountain portion of the Route Revision U. This evaluation will focus on risk reduction for threats identified, as well as Page iii (A42081) NORTHERN GATEWAY PIPELINES LIMITED PARTNERSHIP ENBRIDGE NORTHERN GATEWAY PROJECT Semi-Quantitative Risk Assessment SUBMITTED IN RESPONSE TO JOINT REVIEW PANEL INFORMATION REQUEST NUMBER 8.1(B) reducing the overall risk along the Kitimat River. It will be a demonstration of the approach that will be taken for other higher risk areas and will inform detailed engineering design in subsequent project phases. Further work will be undertaken by Northern Gateway in detailed design, construction and operations using the liquid pipeline risk assessment and management tools being developed by Enbridge. Page iv (A42081) NORTHERN GATEWAY PIPELINES LIMITED PARTNERSHIP ENBRIDGE NORTHERN GATEWAY PROJECT Semi-Quantitative Risk Assessment SUBMITTED IN RESPONSE TO JOINT REVIEW PANEL INFORMATION REQUEST NUMBER 8.1(B) TABLE OF CONTENTS EXECUTIVE SUMMARY ........................................................................................................................... II TABLE OF CONTENTS ............................................................................................................................ V LIST OF FIGURES ................................................................................................................................. VII LIST OF TABLES.................................................................................................................................... VII 1. INTRODUCTION ....................................................................................................................... 1 1.1 Purpose of the Semi-Quantitative Risk Assessment ................................................................. 1 1.2 Background ................................................................................................................................ 3 1.2.1 Project description ...................................................................................................... 3 1.3 Terminology ............................................................................................................................... 4 2. OVERVIEW ............................................................................................................................... 5 2.1 Semi-Quantitative Risk Assessment ......................................................................................... 5 2.2 Northern Gateway Oil-Spill Risk Assessment Timeline ............................................................. 6 2.3 Assessment Methodology Overview ......................................................................................... 6 3. HAZARDS, THREATS AND EVENT IDENTIFICATION ........................................................... 8 3.1 Pipeline System Threats ............................................................................................................ 8 3.2 Geotechnical Hazards and Threats ........................................................................................... 8 4. FULL-BORE RUPTURE FAILURE FREQUENCY ASSESSMENTS ......................................10 4.1 Pipeline System Failure Frequency .........................................................................................10 4.1.1 External corrosion .....................................................................................................10 4.1.2 Internal corrosion ......................................................................................................11 4.1.3 Materials and manufacturing defects ........................................................................11 4.1.4 Construction – (welding and installation) defects .....................................................13 4.1.5 Third-party damage ...................................................................................................14 4.1.6 Incorrect operations ..................................................................................................16 4.1.7 Equipment failure ......................................................................................................17 4.2 Geohazards and Hydrological Threats ....................................................................................18 4.2.1 Summary of methods ................................................................................................18 4.3 Summary of Results for Full-Bore Rupture Failure Frequencies ............................................21 4.3.1 Combined unmitigated full-bore rupture frequencies ................................................22 Page v (A42081) NORTHERN GATEWAY PIPELINES LIMITED PARTNERSHIP ENBRIDGE NORTHERN GATEWAY PROJECT Semi-Quantitative Risk Assessment SUBMITTED IN RESPONSE TO JOINT REVIEW PANEL INFORMATION REQUEST NUMBER 8.1(B) 5. ASSESSING CONSEQUENCES ............................................................................................23 5.1 Full-Bore Rupture Volumes and Spill Extents .........................................................................23 5.1.1 Calculations ...............................................................................................................23 5.1.2 Full-bore rupture spill extents ....................................................................................23 5.2 High Consequence Areas ........................................................................................................25 5.2.1 Definitions .................................................................................................................25 5.2.2 Consequence scoring factors ...................................................................................25 5.3 Consequence Scoring .............................................................................................................26 5.4 Consequence Scoring by Pipeline Segment ...........................................................................28 5.5 High Consequence Area Impacts ............................................................................................28 5.6 Translation of Consequence Scoring into Consequence Ranking ..........................................30 6. RISK ASSESSMENT ...............................................................................................................31 6.1 Methodology ............................................................................................................................31 6.2 Results – Risk by Pipe Segment .............................................................................................32 7. DISCUSSION OF RESULTS...................................................................................................34 7.1 Conclusions .............................................................................................................................34 7.2 Risk-Based Design and Mitigation ...........................................................................................35 7.2.1 Kitimat Valley risk reduction planning .......................................................................35 REFERENCES ........................................................................................................................................36 APPENDIX A: ABBREVIATIONS .....................................................................................................38 APPENDIX B: CONSEQUENCE AREA DEFINITIONS ...................................................................39 APPENDIX C: LIST OF ATTACHMENTS ........................................................................................42 ATTACHMENT 1: THREAT ASSESSMENT ........................................................................................43 ATTACHMENT 2: FAILURE LIKELIHOOD ASSESSMENT.................................................................44 ATTACHMENT 3: SIMULATIONS OF HYPOTHETICAL OIL SPILLS FROM THE NORTHERN GATEWAY PIPELINE CENTERLINE REV-U ...................................................45 ATTACHMENT 4: REPORT ON QUANTITATIVE GEOHAZARD ASSESSMENT ..............................46 Page vi (A42081) NORTHERN GATEWAY PIPELINES LIMITED PARTNERSHIP ENBRIDGE NORTHERN GATEWAY PROJECT Semi-Quantitative Risk Assessment SUBMITTED IN RESPONSE TO JOINT REVIEW PANEL INFORMATION REQUEST NUMBER 8.1(B) LIST OF FIGURES Figure 1: Components of the semi-quantitative risk assessment .......................................................... 5 Figure 2: Overview of methodology ....................................................................................................... 7 Figure 3: Land use distribution ............................................................................................................15 Figure 4: Frequency of third-party damage creating a full-bore rupture .............................................16 Figure 5: Full-bore rupture unmitigated failure frequency along Route Revision U ............................22 Figure 6: Consequence scoring...........................................................................................................27 Figure 7: Risk matrix ............................................................................................................................31 Figure 8: Overall distribution of unmitigated risk severity by kilometre segments ..............................32 Figure 9: Unmitigated risk classification by physiographic region .......................................................33 LIST OF TABLES Table 1: Terms and definitions used in this report ............................................................................... 4 Table 2: Threats with full-bore rupture failure frequencies that do not vary along the route .....................................................................................................................................21 Table 3: Threats with frequencies that vary along the route for a full-bore rupture ...........................21 Table 4: Full-bore rupture extent without mitigation or emergency response ....................................24 Table 5: Unmitigated probability of full-bore rupture for higher consequence watercourses ........................................................................................................................29 Table 6: Consequence matrix ............................................................................................................30 Page vii (A42081) NORTHERN GATEWAY PIPELINES LIMITED PARTNERSHIP ENBRIDGE NORTHERN GATEWAY PROJECT Semi-Quantitative Risk Assessment SUBMITTED IN RESPONSE TO JOINT REVIEW PANEL INFORMATION REQUEST NUMBER 8.1(B) 1. INTRODUCTION This Semi-Quantitative Risk Assessment (SQRA) was prepared by WorleyParsons Canada Services Ltd. (WorleyParsons) for Northern Gateway Pipelines Limited Partnership. (Northern Gateway) under the Enbridge Northern Gateway Pipeline (the Project). Northern Gateway recognizes and shares the public’s concern about the consequences of oil spills. The pipeline industry is very much aligned with its regulators and the public in wanting to avoid spills of any size. Northern Gateway’s objective of pipeline design, engineering, construction and operations is to mitigate and manage the level of risk over the life of the pipeline with the goal of avoiding spills of any size. Risk-based design is especially critical for those areas identified as higher risk. This report will serve as part of the basis for subsequent design decisions. Enbridge is the operator of the longest liquids pipeline system in the world. As part of Enbridge’s commitment to continuous improvement, a suite of risk assessment tools are under development for use in operational settings. This includes development of a quantitative risk assessment model and risk assessment matrix applicable to mainline operations. When completed, these will assist Enbridge Operations in evaluating and prioritizing operational safety initiatives and programs, and will provide an important supplement to ongoing pipeline integrity management programs. These risk management tools and innovations will be available to Northern Gateway as it proceeds into detailed design, construction, and operations. 1.1 Purpose of the Semi-Quantitative Risk Assessment This SQRA report is supported by the Quantitative Failure Likelihood Assessment report contained in Attachment 2, and the Report on Quantitative Geohazard Assessment contained in Attachment 4. These reports were prepared in keeping with Northern Gateway’s commitment to a risk-based design. The risk- based design process is an iterative approach that evaluates and prioritizes risks, and their associated risk- drivers, and then establishes mitigation measures to be incorporated into the design to address the principal risks. Because risk-based design is a process that focuses on identifying and pre-empting risk, it is a more rigorous approach than more traditional design approaches that don’t incorporate specific risk assessment to identify and pre-empt risks. Consistent with the guidance that was given during the JRP IR process to characterize full-bore rupture effects, (March 2011), the SQRA report focuses exclusively on ruptures. Nevertheless, because Attachment 2 evaluates and characterizes all failure modes (leaks and ruptures), guidance from that reference document will be used in the risk-based design process for mitigating failure likelihood. From the Page 1 (A42081) NORTHERN GATEWAY PIPELINES LIMITED PARTNERSHIP ENBRIDGE NORTHERN GATEWAY PROJECT Semi-Quantitative Risk Assessment SUBMITTED IN RESPONSE TO JOINT REVIEW PANEL INFORMATION REQUEST NUMBER 8.1(B) perspective of consequence mitigation, the focus of the SQRA is on ruptures because ruptures have the most extreme consequence and are of the greatest interest in completing risk-based design. This is because any consequence mitigation measures that are developed and incorporated into the design for mitigating ruptures will also be effective in mitigating less significant releases. This document describes ● the components and methodology of the risk assessment, including the threat evaluation, the frequency assessment and the risk evaluation; ● the results of the risk assessment; and ● a discussion of these results and next steps. Page 2