Issues with valve settings in the pipeline downstream of the coal tar hydrogenation feed pump

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As is well known, in coal tar units, the pressure after the hydrogenation feed pump is very high (around 17 MPa). On the process diagrams we received, both the check valve and the isolation valve located after the pump are double-valve types. However, the drain valve between the two valves is a single valve. I just checked section on valve settings in HG 20570.18-95; regarding the settings for dual valves (application temperature and pressure conditions), the standard specifies as follows: for heavy hydrocarbons: T>200℃, P>20 atmospheres. If anyone knows, does this requirement mean that both temperature and pressure must be met in order to use the dual valves, or is it sufficient if just one of these conditions is satisfied? (My understanding is that as long as one of them is met, it’s sufficient.) I hope everyone can give me some guidance; thank you!