RE: Stored energy calculation for Pneumatic pressure testing

From: <Al>
Date: Tue Apr 27 2004 - 13:06:00 EDT

good question, yes, been there. A large reputable OIlsands giant has a set of curves which generates results between the two but closer to the FLUOR Formula.
CAnt post charts here, besides proprietary. Its the same with FLuors buried depth pipeline formulas and others, I've always found them very conservative.
HOwever the important point this shows is that the stored energy in Pneumatic testing is enormous and hence considered an undesirable approach. SHould be avoided where-ever possible. Our local juridictional authority does not allow it except in very exceptional circumstances which have to be extensively justified.
  al

-----Original Message-----
From: umesh k.n. [mailto:umesh_kn@yahoo.com] Sent: Tuesday, April 27, 2004 4:29 AM
To: <a href="/group/PipingDesign/post?postID=4T4Q8_6JvFCEACXJkSEo6KVo3bSUMk8qbdD5AidkwDw14tPsNz6JdU49OdnSCEJ47Ih2LCMUKAZBO5RwY38mQ3X3SWo">PipingDesign@yahoogroups.com</a> Subject: [PipingDesign] Stored energy calculation for Pneumatic pressure testing

Hello members,

     To calculate stored energy for pneuamatic pressure testing there are two formulas. One by Floue Danial... as per this Stored energy=A*ABTP*V*(1-C rise to B)*144 Ft-LBs Where,
C rise to B means C to the power of B
K= Isentropic ratio of specific heat...Generally it is 1.4 A= K/K-1
ABTP = Absolute test pressure in PSI = Test Pressure+14.7

V=Volume of pipeline Cu.Ft.
C=ATTP/ABTP where ATTP is atmospheric test pressure=14.7
B=K-1/K

Fluor limits the maximum energy as 25000000 Ft-lbs

There is another formula by Kellog..as per this formula... Stored energy=144*ABTP*V*log to base e(ABTP/ATTP) Where,
Log to base e means Natural log...
Kellog limits stored energy maximum limit as 200000000 Ft-Lbs Of cource this limit is big...

For a same size pipe if you calculate the maximum length of pipe that can be pneumatic tested at one time...you will get totally different answers...

For example take 56" pipe...In flour formula we get around 91 meters where as in kellog formula we get 586 meters...

I wonder which one is correct...anyone came across the similer problem..or any other trustable formulas....

Thanks in advance,

Umesh K.N.,
Piping Engineer, SKEC, Seoul, Korea

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