API 20K Flange Design Task Group API SC6 Task Group Date: June 26, 2008.

Design Analysis Procedure Yes No Design Verification Design meets Static Load requirements Redesign Design Validation Testing Fatigue Analysis Fatigue life Sealability Analysis Design Flange Functional Design Specification Static Loads per Task Group Consensus Dynamic Loads-TBD

Bolt Diameter Estimation Bolt Diameter Based on Internal Pressure + Gasket Load and 20 No. bolts (Estimate purposes only, Bolt Strength > 4” Dia & Temp Derating not included) Bolt Grade B7 L7 B7M L7M A453 Gr.660 120K yield 135K Yield >2.5 Dia, Yield Strength, psi 95000 80000   Test Pressure Condition, Bolt Dia (Bolt Stress at 83% Sy) 4.75 5.25 4.25 4 Observation: Large Bolt Diameter. Concerns/Design Considerations: 1. For High Strength Bolts-Tapped Hole depth need to be adjusted for material yield differences. Availability of bolt material with uniform cross sectional properties. Ability to achieve uniform make-up through applied torque. Larger Flange OD. Increase in equipment weight. Increased cost. Monolithic equipment design: Increased Handling weight & Machining Cost.

Alternate Bolt Materials Higher Strength, >120 to 130 ksi yield may be needed Higher than 120 Yield Strength Inconel 718 not included in API 6A718 --- 130 ksi/150 ksi may be included in next revision. Inconel 925 is being considered by NACE Alloy bolting, hardness 35 Rc/strength is limited due to Hydrogen Embrittlement when connected to C P protection

BX-164 Seal Ring Gasket At Make-up condition entire gasket(316 S.S,) cross section yields Gasket leakage concerns: (a) Cyclic loads, (b) At high temperature New Cross section to be designed. (Reference: R. Eichenberg’s method.) New Cross section is under development. Design guidelines & Test protocol for Gasket needs to be established. Concerns: Cost of testing . Material Selected will verify performance of that material.

BX-164 Seal Ring Gasket Design Parameters Check per Eichenberg Method API 6A Dimensions Ring No. Bore Dia Max Bore Pressure Rating Height Width   B B max P H A BX164 18.75 18.78 10K-15k 1.185 0.968 Eichenberg Design parameters checked   10ksi WP 15ksi WP 20ksi WP Ring No. Bore Dia Ht of Gskt Width of Gskt B BX164 18.75 1.170 0.968 1.185 1.368

Hydril 18-3/4” 20 ksi Flange Design (Preliminary) Stress Calculations Method: ASME Section VIII, Division 2, Appendix 3

Flange Design API 6A Flange Design: Reference: API TR 6AF2 ASME Methodology, ASME Section VIII, Div2, Appendix 4 Design Allowable per API 6A, Based on Tresca Theory (Stress Intensity): For API 75K Material Working Pressure: Sm = (2/ 3)*Sy Test Pressure: ST = (0.83)* Sy Bolt Allowable: API 6A: 83 % of Yield, Max Stress, Make up load 50% of Sy ASME Method, Section VIII, Div2, 2007 Edition: Sm = Lower of (2/ 3)*Sy or ST = TS/2.4 Bolt Allowable @ Hydrostatic Pressure: Sbm = 0.95 Sy Sbm + Sbb = lower of 1.43 SY or 2.43 SY-1.5Sbm

Summary Bolt Size affects flange OD. Need higher strength bolt material Deepwater application requires considerations for affects of CP protection and potential exposure to well bore fluid when insulated, Bolting Allowable being reviewed. Recommendation to follow. BX-164 Gasket is inadequate. New Gasket is needed. Material selection for subsea use may qualify only one gasket material Flange Design Method/Allowable being reviewed. Recommendation to follow. API 6A + ASME Sect VIII (Edition referenced in API 6A) or ASME Sect VIII, 2007 Edition

Mission Statement and Deliverables To design a standardized 18-3/4”-20K Flange for deepwater application and analyze the flange capabilities under combination of internal and external structural loads at exposed temperatures. Deliverables: 1. Integral Flange Dimensions 2. Blind Flange Dimensions 3. Design File Design Method & Acceptance criteria Bolting Design loads, Operating envelope Assumptions Design Calculations Flange Capability, FEA Report 4. Flange Capabilities chart (Similar to API TR 6AF2) 5. Life Cycle Calculations 6. Material Requirements: Refer to API 6A or specify per design 7. Quality Control Requirements