B16案例8 B16.34《双压带阀阀体设计规则》B16 Case 8_ B16.34 _Body Design Rule for Two-Pressure Zone Valves_

B16 CASE 8 CASE OF ASME B16 VALVE, FLANGES, FITTINGS, AND GASKETS STANDARDS Approval Date August 1, 2017 Cases will remain available for use until annulled by the applicable Standards Committee B16 Case 8 Body Design Rules for Two-Pressure-Zone Valves ASME B16.34 Valves Flanged, Threaded, and Welding End Inquiry Is there an acceptable alternative for the design and construction of ASME B16.34 Standard, Special, Limited, and Intermediate Pressure Class flanged, threaded, welding or combination end two-pressure-zone valve bodies, including pressure relief valve bodies with their primary high pressure inlet side and secondary low pressure outlet side, that may have a different size NPS/DN for inlet and outlet connection Reply Yes, providing the following rules are met for design and construction of the two-pressure-zone valve body 1 The rules for valve bodies of B16.34 1 apply except as modified by the following requirements of this Case. For this Case the primary pressure zone shall be the high-pressure zone of the body and the secondary pressure zone shall be the low- pressure zone of the body. 2 The Pressure Class rating requirements of the valve body may have a different Pressure Class rating for the primary pressure zone and secondary pressure zone of the valve body. 3 The valve body may have a different inlet NPS DN and outlet NPS DN including the inlet and outlet type of joint examples a flanged inlet and welding outlet, welding inlet and flanged outlet, or threaded inlet and flanged outlet. 4 The primary pressure zone pressure class shall be used to satisfy the primary pressure zone construction details. The secondary pressure zone pressure class shall be used to satisfy the secondary pressure zone construction details. 5 The rating temperature of the valve body for the primary pressure zone shall be the service temperature specified or experienced by the primary pressure zone of the valve body. The rating temperature of the secondary pressure zone shall be the temperature specified or experienced by the secondary pressure zone of the valve body. 6 For the valve body the minimum wall thickness t m shall be determined for both the primary and the secondary pressure zones of the valve body. The wall thickness determination of the primary pressure zone side shall be based on the pressure class of the primary side. The wall thickness determination of the secondary pressure zone side shall be based on the pressure class of the secondary side. 7 For the valve body an inside diameter “d” shall be determined per paragraph 6.1.2 for both the primary pressure zone and for the secondary pressure zone. The applicable inside diameter “d” values shall be used to determine the minimum wall thickness t m of the primary pressure zone and the secondary pressure zone of the valve body based on the primary and secondary pressure zone pressure class per the requirements of paragraph 6.1.1. The separation wall thickness between the primary and secondary pressure zones shall be transitioned gradually. 8 The valve body neck shall have a minimum wall thickness t determination per paragraph 6.1.3 corresponding to the applicable pressure zone pressure class and body neck inside diameter d. The Designer shall take into account the primary pressure zone hydrostatic test pressure see 12 when designing the valve closure and metal thickness of the seat and adjacent area that separates the primary pressure zone from the secondary pressure zone. 9 The valve body end joint dimensions shall be applicable to the pressure zone pressure class rating and paragraph 6.2 requirements. Table 4 requirements applies for threaded and socket- welding end wall thickness. 10 The valve body end-to-end or face-to-face dimensions shall be manufacturers standard. 11 Valve body bonnet and body joints shall meet paragraph 6.4 rules applicable to the pressure zone pressure class rating. 12 For the type line valve, the primary pressure zone of the valve body shall be tested to a minimum hydrostatic test pressure of 1.5 x the Pressure Class 100F 38C rating and the secondary pressure zone of the valve body shall be tested to a minimum hydrostatic test pressure of 1.5 x the Pressure Class 100F 38C rating in accordance with requirements of paragraph 7.1. The closure tests shall be at 1.1 x the Pressure Class 100F 38C rating of the primary side in accordance with paragraph 7.2. The secondary pressure zone shall be positively isolated from the hydrostatic test pressure of the primary pressure zone if the pressure class of the primary zone exceeds that of the secondary zone. Test duration for the primary and secondary pressure zone of the valve body shall be per Para. 7.1.2, based on the larger NPS DN of the outlet or inlet. 13 For the type pressure relief valve body, the hydrostatic shell and closure testing shall be in accordance with the requirements of the applicable ASME BPV Section Code. 14 For a pressure relief valve body the body and nameplate markings shall be in accordance with the requirements of the applicable ASME BPV Section Code. 15 For the type line valve, valve marking shall be as follows a Both the primary pressure zone Pressure Class and the secondary pressure zone Pressure Class ratings shall be marked on the valve body example 600 x 300. b The primary/secondary side size NPS DN shall be shown on the valve body. c The primary and secondary pressure zone pressure rating 100F shall be shown on the nameplate. d The nameplate shall include this B16 Case number and conance mark “B16” for Standard Class, “B16 SPL” for Special Class, or “B16 LTD” for Limited Class. NOTE 1 B16.34 paragraph and table reference in this B16 Case is to B16.34-2013 edition. This B16 Case may be used with other B16.34 editions provided the requirements, including the reference paragraphs and table, are reconciled with the B16.34-2013 requirements.