CASES OF THE B16 VALVE, FLANGES, FITTINGS AND GASKETS STANDARDS. Approval Date: December 16, 2013

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Maryann Douglas
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1 Approval Date: December 16, 2013 Cases will remain available for use until annulled by the applicable Standards Committee B16 Case 1 High Strength/High Temperature Material ASME B16.34 Group 3 Valves ASME B16.34 Valves Flanged, Threaded, and Welding End Inquiry: Is there an acceptable alternative method for the Pressure-Temperature rating of Standard, Special, Limited and Intermediate Class ASME B16.34 threaded and welding end valves constructed of high strength/high temperature Group 3 forging, casting, plate, rod, seamless pipe or tube materials listed in Table 1 of ASME B16.34? Reply: It is the opinion of the committee that Standard, Special, Limited and Intermediate Class threaded and welded end valves constructed of Group 3 alloys of Table 1 of ASME B16.34 and complying with the rules of ASME B16.34 may be pressure temperature rated to the rules of this Case provided the following rules are met: (a) The Standard Class rules of B-2, Appendix B of ASME B16.34 shall be used to determine the Selected Stress S 1 and pressure-temperature rating but the Ceiling Pressure (p ca ) used in Equation (B-2) shall be in accordance with Table 1 of this Case. (b) The Special Class rules of B-3, Appendix B of ASME B16.34 shall be used to determine the Selected Stress S 2 and pressure-temperature rating but the Ceiling Pressure (p cb ) used in Equation (B-4) shall be in accordance with Table 2 of this Case. (c) The Limited Class rules of Appendix V of B16.34 apply but the Special Class ratings as determined from (b) above shall be used to determine the Limited Class pressure temperature ratings for valves under this Case. (d) For Standard, Special or Limited Intermediate Class Designation valves the rules of B-4, Appendix B of ASME B16.34 shall be used to determine the pressure-temperature ratings based on Standard, Special or Limited Class pressure-temperatures as determined from (a), (b) or (c) above. The Intermediate Class valve wall thickness shall also be determine by the rules of B-4, Appendix B of B (e) Pressure boundary body joint, body-bonnet or cover bolting material from Table 1 of B16.34 shall be selected that supports the full pressuretemperature rating range of the valve. (f) Valves constructed under this B16 Case shall have the Case Number shown on the valve nameplate.

2 Table 1 A Standard Class PRESSURE by CLASS, psig Temperature F 20 to

3 Table 2 B-Special Class PRESSURE by CLASS, psig Temperature F to

4 SUPPORTING INFORMATION 1. Class 150 ceiling pressures have not been increased from inception and are not proposed to be increased by the proposed Case. 2. Material Group 3.19 (typical B564 N06230) has been selected to provide the ceiling pressures at elevated temperatures for both Standard and Special Class. This material can be used for Section I construction to 1650F and Section VIII to 1800F. It has a higher allowable stress and Modulus of Elasticity (E) than Material Group 2.2 (typical A182 F316), which is the material that currently establishes the ceiling pressure for Standard and Special Class valves from 950F to 1500F. 3. For Standard Class the current B ceiling pressures to 500F has been retained. For Standard Class above 500F the current Standard Class ceiling pressures have been increased by multiplying them by the Ratio of Modulus of Elasticity (E) of Material Group 3.19 (N06230) at temperature to that of the Current Ceiling Material E at temperature. 4. For Special Class the current B ceiling pressures to 650F have been retained. For Special Class above 650F the current Special Class ceiling pressures have been increased by multiplying them by the Ratio of Modulus of Elasticity (E) of Material Group 3.19 (N06230) at temperature to that of the Current Ceiling Material E at temperature. For 650F, 700F and 750F a transition pressure has been applied, which is less than the multiple of current pressure x ratio of Es. Reason: The multiple is greater than ceiling pressure at above temperature. The proposed Case does not change the ASME B16.34 Appendix B method for pressure-temperature rating. Only the ceiling pressures (pca and pcb) are proposed to be changed. 5. The proposed Case will maintain the Valve Joint rules of Para. 6.4 of B The bolting stress at 100F will still be in balance with the bolting stress at the valve s primary pressure (Class). Allowing the 100F rating of the valve to exceed 2.5 x Pressure Class can cause the bolting stress at 100F to lose compatibility with the 9000 psi and 7000 psi requirement of and of B16.34, respectively. 6. If the Proposed Case is adopted it will have no impact on pressure-temperature ratings for the Group 1 or Group 2 materials in Table 1 of B It will not impact flanged valves ratings made from Group 1, 2, or 3 materials. 7. Only a few of the pressure-temperature ratings of the Group 3 materials of Table 1 of B16.34 will have a pressure-temperature increase due to the proposed increase in ceiling pressures of this Case. 8. Tables 1A and 1B is the E data and the Ratio (C/A) on which the proposed Ceiling Pressure increases were calculated. The Ratio (B/A) for A182 F91/F92 Modulus of Elasticity (E) versus E for ceiling material is given for information. Even though the F91/F92 are limited to 1200F the C/A ratio indicates these materials could also withstand higher pressures than the current ceiling materials without additional deflection. 4

5 TEMP TEMP MATERIAL GROUP NO. Table #1A ASME B16.34 STANDARD CLASS MODULUS OF ELASTICITY DATA MATERIAL GROUP NO. (TYPICAL ALLOY) A MATERIAL Table #1B ASME B16.34 SPECIAL CLASS MODULUS OF ELASTICITY DATA A MATERIAL B A182 F91/F92 B A182 F91/F92 C ASTM B564 N06230 B/A C/A (A216 WCC) (A182 F11) (A182 F316) E data from ASME Section II, Part D, 2010 Edition thru addenda C ASTM B564 N06230 B/A C/A (A216 WCC) A182 F A182 F E data from ASME Section II, Part D, 2010 Edition thru addenda 5

ASME B31.8 INTERPRETATIONS VOLUME 13

ASME B31.8 INTERPRETATIONS VOLUME 13 Replies to Technical Inquiries July 2001 Through December 2003 Interpretations 13-1 Through 13-8 It has been agreed to publish intepretations issued by the B31 Committee