leak on commercial pipework

[billybob150811]

have a u65 meter unknown volume of pipework say.25 m\3 and a leak of 1mbar in 2min at 20mbar pressure the MPLR is .0014m\3 per hour i have the leak rate as a pressure but i need it as a volume to calc if this is an acceptable leak theres no smell of gas the leak is too big but i need to prove it mathmatically to make some one other than me go and look for it i would guess its the bolts on the flanges but finding this leak on a small system like this should be easy but its not i might be a lazy so and so but this has just been strength tightness tested and purged so i dont see this as my problem so if anyone knows how to do this calc i,d be grateful

 

[SimonJohns]

I'll be back home tomor. But until then hopefully someone else will help


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[SimonJohns]

Just had a quick thought. I'm pretty sure on igeup1a you have to apply a min of 15min tt. And without a calculation you can't do a correct tt. Doesn't a u65 have quite a large capacity too.

Do you have a tightness testing and purging ticket?


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[billybob150811]

yeah origanally i was asked to test and purge but it had no handle on the ecv so i didnt do it They got a handle and a test and purge was done its all been signed off and i dont know any of the figures but i,m the bad guy cause i wouldn,t do the test and i was asked "as your passing" to have a look at this In the intervening few weeks a floor standing 160kw boiler developed a fault and has been replaced now they say there,s a leak and i get a lot of pressure there,s a feeling i,ve ducked this one which im going to keep on doing but i like to give a reason for not touching it of course it will fail a tt the next step is to find and fix it which i want the person who fitted it to do i didnt do a tightness test as to me this is an existing install and i was just asked to look at it "it probably his hoses it tested ok" was the story i was given my own cynical view is it was never ok and im being given a load of rubbish to fix and no time to do it so were playing a game with reasons i cant touch it if i can come up with the leak exceeds the MPLR i dont have to say what i really think

 

[SimonJohns]

You'll need to get ur self a copy of IGE up 1A

I have a copy of up1 and the only reference I have for 1a is my books from Coll. But off top of my head I beleave it's all done on tables.

Send me your iV MIP MOP and il do my best to reply by monday morn


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[tamz]

have a u65 meter unknown volume of pipework say.25 m\3 and a leak of 1mbar in 2min at 20mbar pressure the MPLR is .0014m\3 per hour i have the leak rate as a pressure but i need it as a volume to calc if this is an acceptable leak theres no smell of gas the leak is too big but i need to prove it mathmatically to make some one other than me go and look for it i would guess its the bolts on the flanges but finding this leak on a small system like this should be easy but its not i might be a lazy so and so but this has just been strength tightness tested and purged so i dont see this as my problem so if anyone knows how to do this calc i,d be grateful

I can't work it out to up1a without looking it up as i don't use it but to up1 your results would have to be obtained using an electronic guage to 2dp's so i'll show you how it is worked out.

I'll show you the way i do it

Pipework vol approx 0.25 + U65 vol 0.1 = 0.35
I don't know where your pipe is running so i'll assume type a (the worst, unventilated space)
TTD(test duration) = grm (0.1 for elec 2dp's) x 0.35 x 42 = 1.47mins = 2 mins..........(if it was a water guage it is 0.5 x 0.35 x 42 = 7.35mins = 8 mins test)
MPLR = 0.0014
LR= F3(0.059) x GM(1mb) x Iv(0.35)/TTD = 0.010325m³ so it has failed (7 and a bit times more than allowed).

UP1 is a bit stricter than 1a. Give me some more info on where the pipe passes through and i'll work it out for you. (any vented spaces below 60m³ i'll need the approx area)

 

[billybob150811]

thanks guys i will copy that leak rate calc and pass it along i dont have the iv and i have good reason not to find out its not my job the person responsable is off for two weeks doing his commercial re-assesment lol ! the op is 21mbar and the mip is 75mbar but he has all the details and i,m not falling for that "you should give him a hand" its got a few welded flange joints which could be the weak link i dont weld so i bow to his greater know how in this area i know he fits flanges dry does anyone have a view dry verses pasted gaskets

 

[tamz]

The recommended way these days is dry which works fine. Pasted is frowned upon.

 

[Ryster]

Never paste a flange on commercial pipework was what I was always taught.
I have commercial folders here, would you like a copy of TTD, Vent tables and any others I have?

 

[billybob150811]

thanks very much for the offer if you dont mind i,ll take you up on that offer the only stuff i,ve got is from the training and assesment

 

[Pssst]

If anyonw wants a copy of up1a see me... £

 

[bristolflier]

i need a copy of ige/up1a...have up 1 but not 1a...help