Bursting discs with long relief lines of uniform diameter

2 Bursting discs with long relief lines of uniform diameter 

It is usual for a disc to be specified to be the same diameter as the piping. When a bursting disc opens as intended, the flow area is close to the pipe cross-sectional area, and choking at the disc itself is not therefore expected. (An exception may be if a permanent vacuum support reduces the flow area through the disc assembly, in which case the method given in 9.6.3 below should be used). The flow capacity of a bursting disc system is determined by the piping system, rather than by the disc itself. 

The flow capacity of any particular diameter line can then be evaluated using the HEM. Simplified methods such as the ERM (see 9.4.2) or Tangren et al s method (see 9.4.3) are not appropriate for long or complex relief lines because they assume 

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