Air Leakage "Standard" in Piping Connections and Gaskets

[video3d]

Hello, this is my first question here, a very nice site. Anyways, I was looking to see if there were any "Industry Standards" for expected leakage for something like a 3/4 inch piping connection or from different size gasket or o-ring connections. Such as a 3/4 NPT connection may leak .05 SCFM, a 1 inch o-ring may leak .1 SCFM, a 3 inch rubber gasket would leak .01 SCFM etc. I would not expect it to be much as long as the connections were made properly, but I would guess there would be some leakage if there were a number of valves connected together. Thanks for the Info.

 

[svanels]

I do not think that it is that simple, first what is the liquid or gas in the piping? Are the seals or o-rings compatable with the material?

Compare a the service of a line full of compressed air with a line full of propane or worse a line full of H₂S Steven van Els
SAvanEls@cq-link.sr

 

[sirelkhatim]

I have an irrigation system supplied from sewage effluent, by time our gardeners complain that no enough water reaches some remote areas, our system is made of 110 and 75 mm. dia. piping and extends for more than 2 km long. can I make some calculations to check my pump performance or the piping as well.

 

[video3d]

The fluid is compressed air at 100 psig. The piping is 3/4 inch NPT, used with a loctite thread sealant. The piping is regular carbon steel. The O-ring is something like a buna rubber. The size of the O-ring is approximately 1/8 to 1/4 inches thick and 7 1/2 inches in diameter. The O-ring will be used with a carbon or stainless steel.
Thanks again!!

 

[quark]

Video3d!

I cannot give you individual allowable leak rates but as far as energy wastage is concerned, a general standard is 7 to 10%. (A web search about leakage of compressed air gives you this data anyhow)

The procedure for checking leakage rate is, check the loading time and unloading times keeping all terminal valves and drain valves closed.

%leak = unload time*100/(load time+unload time)

Regards,

 

[quark]

Try this link

http://www.escenter.org/Learn/PDFs/AirLeaks.pdf

Regards,

 

[saxon]

I'm glad to hear that it's only air that's leaking and not something hazardous like phosgene or ethylene or any of the other hazardous substances used by industry. I'm assuming that this refers to external leakage (leakage to atmosphere). The only proper theoretical industry standard for this type of leakage is zero, but since we live in real world, here are a few things to check on to try and acheive the theoretical tolerance:
1. human error, got the right components and good mech's.
2. lack of quality control, in component man'f. and fit-up
3. poor protection of components in handling & storage
4. difficult to access fitting connections
5. lack of education in doing proper fit-up
6. poor eng. specs.
7. improper design of piping or routing.

Close attention to all of the above will help you acheive a zero tolerance standard to leakage.