Plan 76 Orifice Sizing 1

[RS82]

We are being asked to size of the orifice for API Plan 76 where the vapour is being directed to either flare or a vapour recovery system.

1. Whose responsiblity is it to supply orifice size, seal vendor, pump vendor, or end user?

2. What factors are considered when calculating orifice size for this plan?

 

[Airsporter1st]

1. Generally this information is provided by the seal vendor - because they know the expected leakage rates.

2. Flare pressure, normal leakage rate, properties of leakage, desired alarm/trip levels, characteristics of pressure transducer, process criticality of equipment versus hazard posed by external leakage.