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# VALVE LEAKAGE TEST

## VALVE LEAKAGE TEST

(OP)
Class IV 0.01% of rated valve capacity.

Class V 5 5 x 10-4 ml per minute of water per inch of seat diameter per psi differential
5 x 10-12 m3 per second of water per mm of seat diameter per bar differential
4.7 standard ml per minute of air per inch of orifice diameter
11.1 x 10-6 standard m3 per hour of air per mm of orifice diameter

Class VI bubble tight
Hi sir/friends please anyone help to understand these leak class 4 5 6. from basic onwards.
and leak acceptance rate in bar. please

### RE: VALVE LEAKAGE TEST

It is self explanatory

Some may use different approach, depending on the application
This is refer to FCI 70-2, control valve leakage
Control valve always have data sheet which incorporate flow rate (read: rated valve capacity); Delta P (read: psi or bar differential) and eventually lead to (calculated) orifice or seat diameter
And leakage rate with exception of ppm is always volume/time e.g. ml/s; cc/min; bubble/min, etc. never pressure loss. of course you can convert it easily by google with some deviation to be expected. So you cannot say leak acceptance rate in bar only.

Class IV, 0.01% times flow rate would be your leakage rate. Test valve in close position 1.1 x MAWP then the measured leakage rate should be smaller than the leakage rate calculated

Class V, calculate this using orifice diameter and DeltaP from datasheet. your first two line is for water as testing medium (one with metric and one with imperial) and your last two line is for gas.
Put normal actuator thrust to close the valve, pressurized with DeltaP (if given DeltaP is 50 bar, then one side with 50 bar and other side is atm). The atm side leakage rate shall be lower than calculated.

Class VI, simply no leak (measured and visible) 0000000

Don't you have someone to consult with within your company??
Regards,
MR

https://nosuchvalve.com
All valves will last for years, except the ones that were poorly manufactured; are still wrongly operated and or were wrongly selected

http://www.eng-tips.com/faqs.cfm?&rat1=2&f...

### RE: VALVE LEAKAGE TEST

(OP)
Thank you sir.

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