Answer / sam

I cannot remember to much about this but I remember that the
leakage rate is dependent on the valve classification. a
Class 6 valve is a tight shutoff valve with not leakage
tolerance at all. a Class 5 is classified as a modulating
valve and have a tolerances of a small amount of droplets
per minute and so on. The lower the class valve the higher
the acceptable leakage rate. This leakage rate is tested in
a valve shop either by the manufacturer or on your own site
if you have the right equipment to do it with.
We normally had it done by our valve shop after we send a
valve to them for a complete overhaul. Once the control
valve have repaired and overhauled the valve, we had to do
the final testing and acceptance with them. They would
supply us with the specs on the valve so that we can see
what class valve it was and what the acceptable leakage
tolerance was. After this we would witness the testing of
the valve and sign a acceptance certificate.
I suggest you get hold of your valve shop or the original
manufacturer to supply you with a list of the
classifications of the valves you are currently using or
want to use as well as the various acceptable leakage rate
for each class.
Good luck

Answer / trupti

Class VI for Gas service as gas requires tight shutoff &
class I , II, III, IV, V for liquid service as per process
requirement shutoff

Answer / anzal

CLASS 2............ 0.5 % OF CV..........MEDIA AIR
CLASS 3............ 0.1 % OF CV..........MEDIA AIR
CLASS 4............ 0.01 % OF CV..........MEDIA AIR
CLASS 5............ 0.0005 ML/MIN.........MEDIA WATER
CLASS 6............ 1 BUBBLE/MINIT.......MEDIA WATER

IN CLASS 6 IT WILL CHANGE DEPENDING ON THE SIZE

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