FE Class A and Class B Production Testing on Valves

[priya17385]

As per Shell requirement what is the main difference between FE class A and Class B production testing.Is there any difference in the testing procedure or only in the leakage rates.
Can anybody help me out?

 

[NGiLuzzu]

priya17385,
you probably refer to Shell document MESC SPE 77/312 about "INDUSTRIAL VALVES – MEASUREMENT TEST AND QUALIFICATION PROCEDURES FOR FUGITIVE EMISSIONS (FE)".

About that specification, first of all, I'd suggest you to read Thread408-64093 within this Forum.

As far I know, in previous editions, the Leakage Class (A, B or C) also affected the number of thermal cycles to be performed in both production and prototype testing: see for example Table 4 of the 18-06-2004 edition.

In the most recent revisions (the latest edition should be still the one dated 28-05-2005), instead, Temperature Classes (T1, T2, T3, etc.) have been deleted and the thermal cycles depend on the valve design temperature range, while the Leakage Class affects the maximum allowable leak rates only.



Hope this helps, 'NGL