The International Standards Organization (ISO) developed EN-ISO 15848-1 and 2. This two-part standard used information from a wide range of industry sources. The standard incorporates the testing of commodity valves as well as control valves. Industrial valves—measurement, test and qualification procedures for testing fugitive emissions of industrial valves are described. Part 1 addresses a classification system and qualification procedures for type testing of valves, while part 2 covers production acceptance testing of valves.
a) EN-ISO 15848 - Part 1 (February 2006)
Included in part 1 is the testing of completely assembled valves using vacuum, flushing or sniffing (EPA Method 21), depending on which annex is used and the type and class of the valve. The standard uses helium or methane as the test fluid and only permits one adjustment to the valve packing every performance cycle. Valves are typically tested vertically with horizontal as an option, with cycling rates based on the type of valve: isolating or control. Stem packing leakage is categorized in so called Tightness classes, A, B and C, for both helium and methane.
The difference between the leakage of helium and methane is not correlated. Tightness class A is the most stringent qualification and should not exceed a leakrate of 10-6 mg/(s*m) during the complete test. For Class B the rate is 10-4 mg/(s*m) and for class C 10-2 mg/(s*m). The numbers of mechanical cycles are described as endurances classes.
For isolating valves these are CO1 (500 cycles), CO2 (1500 cycles) and CO3 (2500 cycles).
Endurance classes for control valves are CC1 (20,000 cycles), CC2 (60,000 cycles) and CC3 (100,000 cycles) 4 different temperature classes are included in this standard.
Testing can be performed at -196°C (-320°F), -46°C (-51°F), +200°C (392°F) and 400°C (752°F).
Last but by no means least the total leakage from the body seals may not exceed 50 ppmv. The above all relate to the current issue of the standard, but a revision is currently taking place and it is expected that the revised standard should be released during the first quarter of 2015. The major changes anticipated are the replacement of the flushing method with two alternative bagging methods, and Class A leakage has sensibly been revised to be 10-5 mg/(s*m) When methane is used as a test gas for the testing of the packing limits are specified in ppm (Class A ≤ 50ppm, Class B ≤ 100ppm and Class C ≤ 500ppm).