Understanding of API598-related content
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Section 4.4.3 of the standard states that \"for valves with a preferred flow direction, the sealing test in the non-preferred direction shall be conducted at a reduced pressure rating.\" So how should the specific value of this \"reduced pressure rating\" be determined? ? ?
The valve should be selected based on its design pressure difference. For example, in the case of two-way metal-sealed butterfly valves, it is possible to specify the pressure difference
Based on the meaning of \"standard surface,\" it can be understood that during reverse pressure testing, the test pressure can be less than the pressure-temperature rating value, let alone 1.1 times that rating value. For example, a PN16 double-sealed butterfly valve can be tested at a pressure of less than 16 bar during a reverse pressure testing. I have been studying this standard recently; is it possible to use a low-pressure sealing test pressure of 4–7 bar? ? ?