Rupture Disc Reliefs in Vapor or Gas Service

Flow of vapor through rupture discs is described using an orifice equation similar to Equation 9-9 but without the additional correction factors. The result is 

If appreciable backpressures exist from downstream relief systems, a procedure similar to the procedure used for liquid reliefs through rupture discs is required. The procedure is iterative. 

5Marx Isaacs, Pressure Relief Systems, Chemical Engineering (Feb. 22,1971), p. 113. 

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