For NGTL to file calculation of operating condition on pull back stress analysis.

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1 NOVA Gas Transmission Ltd. Exhibit No. B85 National Energy Board Hearing Order GH Undertaking U-10 Submitted November 25, 2014 Response to Undertaking given by Mr. Trout to Chairman Vergette at Transcript Reference Vol. 15, Paragraph 19046, with respect to calculations of operating conditions on pull back stress analysis. Undertaking: For NGTL to file calculation of operating condition on pull back stress analysis. Response: NGTL provides in the stress analysis for the Peace River horizontal directional drill. November 25, 2014 Page 1 of 1

3 North Montney Mainline Aitken Creek Section Document No _HMM_334888_Peace River HDD Installation Loads and Operating Stress _REP_0109 Peace River HDD Installation Loads and Operating Stress Issue and Revision Record Rev Date Originator Checker Approver Description A 11/24/14 S. Crouse G. Duyvestyn R. Delmar Issued for NEB Submission This document has been prepared for the titled project or named part thereof and should not be relied upon or used for any other project without an independent check being carried out as to its suitability and prior written authorization of Hatch Mott MacDonald being obtained. Hatch Mott MacDonald accepts no responsibility or liability for the consequence of this document being used for a purpose other than the purposes for which it was commissioned. Any person using or relying on the document for such other purpose agrees, and will by such use or reliance be taken to confirm their agreement to indemnify Hatch Mott MacDonald for all loss or damage resulting therefrom. Hatch Mott MacDonald accepts no responsibility or liability for this document to any party other than the person by whom it was commissioned. To the extent that this report is based on information supplied by other parties, Hatch Mott MacDonald accepts no liability for any loss or damage suffered by the client, whether through contract or tort, stemming from any conclusions based on data supplied by parties other than Hatch Mott MacDonald and used by Hatch Mott MacDonald in preparing this report.

4 Peace River HDD Installation Loads and Operating Stress TABLE OF CONTENTS 1 INTRODUCTION HDD CALCULATIONS... 3 LIST OF TABLES: TABLE 2.1 PIPELINE PROPERTIES AND INPUT PARAMETERS FOR THE HDD INSTALLATION LOAD AND STRESS EVALUATIONS TABLE 2.2 SUMMARY OF HDD OPERATING STRESS EVALUATION TABLE 2.3 SUMMARY OF ANTICIPATED HDD PULLBACK LOADS TABLE 2.4 SUMMARY OF HDD INSTALLATION STRESS EVALUATION AT THE DESIGN BENDING RADIUS OF 1,280 METRES TABLE SUMMARY OF HDD INSTALLATION STRESS EVALUATION AT THE DESIGN BENDING RADIUS OF 1,050 METRES TABLE 2.6 SUMMARY OF BREAK-OVER STRESS EVALUATION TABLE 2.7 SUMMARY OF SUPPORT LOAD EVALUATION TABLE SUMMARY OF OVER-BEND DETAILS TABLE SUMMARY OF OVER-BEND STRESS EVALUATION (HDD ENTRY POINT SOUTH AT STA ) TABLE SUMMARY OF OVER-BEND STRESS EVALUATION (HDD ENTRY POINT NORTH AT STA )

5 Peace River HDD Installation Loads and Operating Stress 1 INTRODUCTION Hatch Mott MacDonald (HMM) has prepared this Horizontal Directional Drilling (HDD) design report at the request of NOVA Gas Transmission Ltd. (NGTL) for their proposed crossing of the Peace River, as part of the Aitken Creek Section of the larger North Montney Mainline Project. The current diameter for the proposed pipeline is NPS 42 (1067 mm). Specifically, this report summarizes HMM s evaluation of the installation loads and operating stresses for an HDD crossing of the Peace River _HMM_334888_ REP_0109 2

6 2 HDD CALCULATIONS PIPE PROPERTIES Peace River HDD Installation Loads and Operating Stress The pipeline properties used for the evaluation of the Peace River HDD crossing are summarized in Table 2-1 below. Table 2-1: Pipeline properties and input parameters for the HDD installation load and stress evaluations. Evaluation Parameter Value Pipe Size NPS 42 Outer Diameter 1067 mm Wall Thickness 22.2 mm Pipe Grade 483 MPa Maximum Allowable Operating Pressure 9930 kpa Minimum Operating Temperature -5 C Maximum Operating Temperature 49 C Poisson s Ratio 0.30 Elastic Modulus 207,000 MPa Coefficient of Thermal Expansion 1.2 x / o C Design Factor 0.8 Location Factor Temperature Derating Factor 1.0 Joint Factor HDD DESIGN PROCEDURE INSTALLATION LOAD AND STRESS EVALUATIONS The installation load and stress analysis process for horizontal directional drill (HDD) installations consists of the following steps: 1. Evaluate minimum allowable bending radius and confirm wall thickness and grade. 2. Evaluate operating stresses based on the identified minimum bending radii. 3. Evaluate product pipe HDD installation loads. 4. Evaluate product pipe HDD installation stresses. 5. Evaluate product pipe HDD break-over stresses. 6. Evaluate product pipe HDD over-bend stresses ULTIMATE, ALLOWABLE AND DESIGN BEND RADII Vertical curvature is inherent to all HDD installations. The need for horizontal curvature however, is dependent on the restrictions specific to a single crossing. While horizontal curvature is feasible, the scope of design and construction greatly increases in complexity when horizontal curves are required. The addition of horizontal curvature also increases the stress, and therefore the risk to the product pipe _HMM_334888_ REP_0109 3

7 Peace River HDD Installation Loads and Operating Stress Steering in both planes is not a standard industry practice and can lead to complex radii and a reduction in the overall bending radius that the product pipe will be subjected to, increasing risk to the product pipe and the overall installation. For this reason, a straight alignment has been selected for the Peace River crossing eliminating risks associated with drilling a horizontal curve. The minimum ultimate bend radius is a function of the maximum allowable operating pressures, pipe diameter, wall thickness, design factor, location factor, and specified minimum yield strength. The calculation is based on determining the calculated hoop and longitudinal stresses and then determining the available magnitude of stress that the product pipe can accommodate in an alignment curve. The minimum ultimate bending radius evaluation is completed in accordance with: CSA Z Oil and Gas Pipeline Systems ASCE Manual of Practice No. 108 Pipeline Design for Installation by Horizontal Directional Drilling. 49 CFR 192 Transportation of Natural and Other Gas by Pipeline: Minimum Federal Safety Standards. ASME B31.8 Gas Transmission Distribution and Piping Systems ASME B31.4 Pipeline Transportation Systems for Liquid Hydrocarbons and Other Liquids Using the pipe properties presented in Table 2-1, the ultimate minimum bending radius is calculated for the pipe and pressure conditions. This radius represents the lowest radius that could be drilled without overstressing the product pipe for the identified pipe properties and in-service loading. Based on the pipe properties provided in Table 2-1, the ultimate minimum bending radius is approximately 905 metres, based on a design factor of 0.8 and a location factor of 0.625, yielding a combined design factor of 0.5 (0.8 multiplied by equaling 0.5) per CSA Z The minimum allowable bending radius is the minimum radius that the HDD contractor can drill during their pilot bore to maintain the design alignment and profile. This radius is established above the calculated ultimate minimum bending radius to ensure that the product pipe is not overstressed during the HDD installation process. Based on an ultimate minimum bending radius of 905 metres, the minimum allowable bending radius has been established at 1,050 metres. The design radius is the radius selected to develop the HDD plan and profile. This radius is greater than the minimum allowable bending radius given to the HDD contractor to complete the construction of the crossing. The design bending radius for developing the Peace River HDD profile has been established at 1,280 metres, consistent with the HDD industry standard of 1,200 times the outer diameter of the project pipe OPERATING STRESS EVALUATION Evaluation of operating loads for pipelines installed by HDD methods is generally similar to the evaluation for pipelines installed by open-cut construction methods. The main difference between the two scenarios is that the condition of elastic bending (as a result of the curved HDD alignment profile) has to be considered for the HDD installation. Elastic bending stresses occur as the product pipe takes on the final shape of the HDD bore. As a rule, the bending stresses induced are not a critical stress condition on their own, but must be considered in a combined loading condition with other stress conditions such as hoop stress and longitudinal stress _HMM_334888_ REP_0109 4

8 Peace River HDD Installation Loads and Operating Stress An operating stress evaluation has been completed in compliance with the American Society of Mechanical Engineers B31.4 and B31.8 and CSA Z (Revised August 2013). The input parameters for this analysis are provided Table 2-1. The results of the evaluation are provided below in Table 2-2 and are based on the minimum allowable bending radius of 1,050 metres (based on the allowable bend radius provided to the HDD contractor). This is to account for the minimum allowable bending radius established for the HDD contractor, as noted on the HDD drawings. As observed in Table 2-2, the operating stresses are below the maximum allowable limits. Hence, the pipe properties (wall thickness and grade) are sufficient to meet the operating stresses within the HDD alignment. Table 2-2: Summary of HDD operating stress evaluation. Percent of SMYS 1 (%) Maximum Allowable Percent of SMYS 1 (%) Estimated Stress Stress Condition (MPa) Longitudinal Bending Stress Hoop Stress (2) Longitudinal Tensile Stress from Hoop Stress Longitudinal Stress from Thermal Expansion (3) Net Longitudinal Stress (Compression Side of the Curve) (4) Net Longitudinal Stress (Tension Side of the Curve) (4) Maximum Shear Stress Combined Biaxial Stress (4) Notes: 1 Specified Minimum Yield Stress 2 Limited by design factor multiplied by location factor (0.8 x = 0.5) per CSA Z Limited by ASME B Limited by ASME B HDD PULLBACK LOADS A total of six (6) pull load evaluations were completed for the HDD bore profile. These calculations are based on a modified version of the installation load calculation method provided in American Society of Civil Engineer MREP 108 (2005) and the Pipeline Research Committee at the American Gas Association publication entitled Installation of Pipelines by Horizontal Directional Drilling, an Engineering Guide. The modification includes inclusion of an updated fluidic drag calculation based on observed drilling fluid properties and the anticipated bore diameter. The pull load evaluation includes assumptions for final bore diameter, soil and pipe roller friction coefficients, drilling fluid yield point and plastic viscosity, drilling fluid pumping rate, and other installation parameters such as buoyancy control measures (i.e., whether or not the pipe will be filled with water during pullback operations). In addition, the evaluation accounts for the capstan effect induced by curves in the alignment, fluidic drag, buoyancy of the pipe string within the bore, and the weight of the tail string at startup and throughout the installation process _HMM_334888_ REP_0109 5

9 Peace River HDD Installation Loads and Operating Stress Six (6) installation evaluations have been completed to investigate the effects of varying mud weights and buoyancy control measures during the installation of the product pipe. The six (6) scenarios evaluated include: Case 1: Drilling Fluid Weight 10 ppg (Specific Gravity of 1.20) No buoyancy control (pipe empty of water) Case 2: Drilling Fluid Weight 10 ppg (Specific Gravity of 1.20) Full buoyancy control measures (pipe full of water) Case 3: Drilling Fluid Weight 11 ppg (Specific Gravity of 1.32) No buoyancy control (pipe empty of water) Case 4: Drilling Fluid Weight 11 ppg (Specific Gravity of 1.32) Full buoyancy control measures (pipe full of water) Case 5: Drilling Fluid Weight 12.0 ppg (Specific Gravity of 1.44) No buoyancy control (pipe empty of water) Case 6: Drilling Fluid Weight 12.0 ppg (Specific Gravity of 1.44) Full buoyancy control measures (pipe full of water) A summary of the pull load evaluation for each pull load scenario is provided in Table 2-3. The anticipated installation loads as shown in Table 2-3 are well below the ultimate allowable load of the steel product pipe of approximately 28,129 kn (6,323,621 lb), based on a tensile stress equivalent to 80 percent of the yield stress for the given wall thickness and pipe grade provided in Table 2-1. It is important to note the difference in pull loads when buoyancy control measures are implemented and water is added to the product pipe during pullback, as the estimated installation loads are much lower when buoyancy control measures are used. A start-up factor of 1.5 has been applied to the estimated pullback forces to replicate the higher installation loads observed during stoppages and recommencing of pullback operations. Table 2-3: Summary of anticipated HDD pullback loads. Buoyancy Condition Estimated Pullback Force (kn) Initial Start-Up Force (kn) Drilling Fluid Specific Gravity 1.2 (Case 1) Empty 4,217 6, (Case 2) Full 2,418 3, (Case 3) Empty 4,791 7, (Case 4) Full 2,220 3, (Case 5) Empty 5,708 8, (Case 6) Full 2,281 3, HDD PULLBACK INDUCED STRESSES Results of the corresponding HDD installation stresses (based on the design bending radius of 1,280 metres) are summarized in Table _HMM_334888_ REP_0109 6

10 Peace River HDD Installation Loads and Operating Stress Table 2-4: Summary of HDD installation stress evaluation at the design bending radius of 1,280 metres. Stress Condition Case 1 Case 2 Case 3 Case 4 Case 5 Case 6 Maximum Tensile Stress (Percent of Allowable) 57.9 MPa (12.0%) 33.2 MPa (6.9%) 65.8 MPa (13.6%) 30.5 MPa (6.3%) 78.4 MPa (16.2%) 31.3 MPa (6.5%) Maximum Bending Stress (Percent of Allowable) 86.3 MPa (17.9%) 86.3 MPa (17.9%) 86.3 MPa (17.9%) 86.3 MPa (17.9%) 86.3 MPa (17.9%) 86.3 MPa (17.9%) Maximum Hoop Stress (Percent of Allowable) 26.8 MPa (5.6%) 26.8 MPa (5.6%) 29.4 MPa (6.1%) 29.4 MPa (6.1%) 32.1 MPa (6.7%) 32.1 MPa (6.7%) Maximum Unity Check Tensile and Bending (must be less than 1.0) Maximum Unity Check Tensile, Bending, and Hoop (must be less than 1.0) As observed in Table 2-4, the results of the HDD installation stress evaluation are within the allowable limits for all cases. Results of the corresponding HDD installation stresses (based on the design bending radius of 1,050 metres) are summarized in Table 2-5. These stresses are based on the same HDD alignment and installation loads as observed in Table 2-4, but with the minimum bending radius of 1,050 metres inserted in place of the 1,280 metre design radius for the stress calculations. Similarly, as observed in Table 2-5, the results of the HDD installation stress evaluation are within the allowable limits for all cases. Table 2-5: Summary of HDD installation stress evaluation at the design bending radius of 1,050 metres. Stress Condition Case 1 Case 2 Case 3 Case 4 Case 5 Case 6 Maximum Tensile Stress (Percent of Allowable) 57.9 MPa (12.0%) 33.2 MPa (6.9%) 65.8 MPa (13.6%) 30.5 MPa (6.3%) 78.4 MPa (16.2%) 31.3 MPa (6.5%) Maximum Bending Stress (Percent of Allowable) 105 MPa (21.8%) 105 MPa (21.8%) 105 MPa (21.8%) 105 MPa (21.8%) 105 MPa (21.8%) 105 MPa (21.8%) Maximum Hoop Stress (Percent of Allowable) 26.8 MPa (5.6%) 26.8 MPa (5.6%) 29.4 MPa (6.1%) 29.4 MPa (6.1%) 32.1 MPa (6.7%) 32.1 MPa (6.7%) Maximum Unity Check Tensile and Bending (must be less than 1.0) Maximum Unity Check Tensile, Bending, and Hoop (must be less than 1.0) BREAK-OVER STRESS EVALUATION Stresses are induced within the product pipe as it transitions from above ground into the completed HDD bore. This stress is commonly referred to as the break-over stress and is temporary. A break-over stress evaluation was completed to evaluate pipe supports, loads and pipe stresses while the product pipe is pulled into the HDD bore. The evaluation was performed utilizing Autopipe Version 9.6 and reflects the stresses and loads induced within the product pipe as it transitions from the staging area on the ground surface, into the air, and into the HDD bore. Input parameters include the pipe properties _HMM_334888_ REP_0109 7

11 Peace River HDD Installation Loads and Operating Stress provided in Table 2-1, site-specific topography, staging area constraints, and the HDD bore geometry. In addition, a support spacing of 30 m, an allowable bending radius of 550 m (based on an non-pressurized pipe configuration), and the weight of a 200-mm diameter high-density polyethylene water line installed within the product pipe for buoyancy control were incorporated into the evaluation. It is assumed that the portion of the product pipe above ground will not be filled with water (for buoyancy control). Break-over stresses are determined by deforming the product pipe into the required break-over geometry. The resultant pipe stresses are provided in Table 2-6. Table 2-6: Summary of break-over stress evaluation. Notes: Lifting Point Induced Pipe Stress (MPa) Percent of SMYS 1 (%) Maximum allowable percent of SMYS is 80 percent per CSA Z Support loads associated with each lifting point, relative to a horizontal plane equal to the elevation of the HDD entry location, are provided in Table 2-7. Table 2-7: Summary of support load evaluation. Lifting Point Lifting Height (mm) Support Load (kn) Support Load (Kg) , , , , , , , , , , _HMM_334888_ REP_0109 8

12 2.1.8 OVER-BEND STRESS EVALUATION Peace River HDD Installation Loads and Operating Stress The connection/transition/tie-in between the mainline pipeline and the HDD installation will experience stresses associated with the operation of the pipeline. Referred to as the over-bend connection, this transition piece must be designed for various operational stresses and thermal effects in accordance with CSA Z The over-bend stress evaluation was completed to evaluate the stresses induced within the transition/connection/tie-in at the start and end locations of the HDD installations. The evaluation was performed utilizing Autopipe Version 9.6. Input parameters include the pipe properties provided in Table 2-1, mainline pipe properties, mainline and HDD pipeline alignments, and soil data provided by BGC (spreadsheet entitled NMML Soil Properties at Horizontal Bend Locations dated 1/27/2014). A summary of the over-bend details used in this evaluation is summarized in Table 2-8. Table 2-8: Summary of over-bend details. Soil Type at Bend Location Bend Angle (degrees) Bend Wall Thickness (mm) Bend Material Grade (MPa) Bend Stationing Bend Radius Bend Orientation D Horizontal Silty Sand D Horizontal Silty Sand D Horizontal Silty Sand D Horizontal Silty Sand Results of the over-bend stress evaluation are provided in Table 2-9 and Table 2-10 for the east and west HDD transition locations, respectively. Table 2-9: Summary of over-bend stress evaluation (HDD Entry Point South at STA ). Estimated Value Percent of SMYS 1 (%) Maximum Allowable 1 Stress Condition Thermal Stresses (Expansion Case) MPa 28.9 % 72 % of SMYS Hoop Stress (Maximum Pressure Drop) MPa 49.4 % 50 % of SMYS Pressure and Gravity Stresses (Sustained Case) MPa 27.4 % 80 % of SMYS Hoop and Longitudinal Stresses (Equivalent Tensile 1 Case MPa 49.4 % 90 % of SMYS Combined Stresses (Tresca / Octahedral Case) MPa 59.6 % 100 % of SMYS Total Stress / Allowable Stress (Stress Ratio) Vertical Deflection mm mm Notes: 1 Allowable values as established per CSA Z _HMM_334888_ REP_0109 9

13 Peace River HDD Installation Loads and Operating Stress Table 2-10: Summary of over-bend stress evaluation (HDD Entry Point North at STA ). Estimated Value Percent of SMYS 1 (%) Maximum Allowable 1 Stress Condition Thermal Stresses (Expansion Case) MPa 35.2 % 72 % of SMYS Hoop Stress (Maximum Pressure Drop) MPa 49.4 % 50 % of SMYS Pressure and Gravity Stresses (Sustained Case) MPa 36.2 % 80 % of SMYS Hoop and Longitudinal Stresses (Equivalent Tensile 1 Case MPa 49.4 % 90 % of SMYS Combined Stresses (Tresca / Octahedral Case) MPa 73.4 % 100 % of SMYS Total Stress / Allowable Stress (Stress Ratio) Vertical Deflection mm mm Notes: 1 Allowable values as established per CSA Z _HMM_334888_ REP_

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