BS ISO 4126-10:2010

1   Scope This part of ISO 4126 specifies the sizing of safety valves for gas/liquid two-phase flow in pressurized systems such as reactors, storage tanks, columns, heat exchangers, piping systems or transportation tanks/containers. The possible fluid states at the safety valve inlet that can result in two-phase flow are given in Table 1.

    NOTE  The expression “safety valve” is a synonym for valves as described in [ISO 4126‑1](/search?q=ISO%C2%A04126%E2%80%911), [ISO 4126‑4](/search?q=ISO%C2%A04126%E2%80%914) and [ISO 4126‑5](/search?q=ISO%C2%A04126%E2%80%915). 

Table 1 — Possible fluid state at the inlet of the safety valve that can result in two-phase flow

            Fluid state at valve inlet 
            Cases 
            Examples 
         
      
      
         
            liquid 
            subcooled (possibly flashing in the safety valve...