Help regarding fugitive emission type testing 2

[Ryguy1988]

Hi all.

I really hope someone has more knowledge about fugitive emission testing than I do. I work for a South African based ball valve manufacturer. Im a year out of university and the company has asked me to take charge of there fugitive emission 'program'. All that the 'program' is, is a few discussions and the fact we would be testing to the ISO 15848-1. Ive got a good understanding of what the standard is asking for, the equipment needed, test procedure and so on. I have a few concerns when it comes to the leak detector. 1) Im thinking of using the Pfeiffer vacuum A560 SmartTest helium leak detector. We are aiming for a tightness class A so will use the vacuum method to measure stem leakage. This leads to problem 2. The valve needs to be heated and the leak detector can only suck in helium at a certain temp (way below valve temp), im assuming the leak detector will pull helium at a temperature higher than what it can handle. What can i do about this that still conforms to the standard?

If there are any other pointers and tips one can give regarding the ISO 15848-1 testing, it would be greatly appreciated.

 

[Compositepro]

The helium will cool long before it reaches the detector. I hope you realize just how sensitive this method is.

 

[NGiLuzzu]

I agree with Compositepro.
Moreover, I’d suggest to compare the ISO 15848-1 Tightness Class A maximum allowable helium leak rate limit for your valves (in mbar*l/s or equivalent units) with the accuracy of your measurement system (unluckily, the ones who write ISO standards about valves do not read ISO standards about metrology…!)

I would also suggest to have NDE Operators qualified for Leak Testing (LT or MSLT) according to ASNT SNT-TC-1A , ISO 9712 and/or EN 473 (even if this is not explicitly required by the reference ISO 15848-1 standard): a level 2 could be enough to carry out the tests, but a level 3 could for sure help with your doubts and prepare a reasonable testing procedure.


Hope this helps,
‘NGL

 

[Ryguy1988]

Thanks for the replies. I do realise that Class A is really tight and hence why most valve manufacturers achieve a class B. So for us that is more realistic. Also we dont use bellow seals which would make a Class A rating near impossible. Im from South Africa so finding qualified operators will be like trying to achieve a class A rating. If anything we will send a valve to a company the specialises in type testing.

We would still want to do the production testing however. Its been suggested that hand held leak detectors would be sufficient. I feel they would be sensitive enough but no accurate enough. I think the ISO standard calls for about 2.5% accuracy. Do you think a hand held unit leak detector would be sufficient or would it be better to get a portable bench top leak detector? (I also need to keep price in mind)

 

[NGiLuzzu]

Ryguy1988,
for some type testing Companies’ address, see thread408-114236 within this Forum.

Before choosing your mass spectrometer helium leak detector, I’d suggest to take a look at the various Project and/or Customer specifications: sometimes they include a positive list of the approved equipment (see, for example: Shell MESC SPE 77/312…).
Even if you probably know it already, another basic reference worth mentioning are the various APPENDIXES of the ASME B&PV Code, Sect. V, Article 10, of course.

Ciao and… good luck! ;-)
‘NGL

 

[reverman]

In the US. The two independent companies doing the most valve fugitive emission testing are Yarmouth research up in Maine and United Valve in Houston You can try getting in contact with them to discuss. VMA is having a fugitive emission conference in Vegas mid March also could be a good thing to attend to learn more about what is going on in the industry.