Using a valve as limit for a test system
Using a valve as limit for a test system
(OP)
ASME B31.3 para 345.3.4 allows using a valve as a limit for tested piping. "A valve may be used provided the valve (including
its closure mechanism) is suitable for the test pressure."
1. How can it be determined that a valve satisfies this demand?
2. Can we do a pneumatic test on a piping system using a closed valve as a system limit?
its closure mechanism) is suitable for the test pressure."
1. How can it be determined that a valve satisfies this demand?
2. Can we do a pneumatic test on a piping system using a closed valve as a system limit?





RE: Using a valve as limit for a test system
Direct answer is yes, it can and has been done, but bad things can happen if you are not careful.
RE: Using a valve as limit for a test system
I agree with the above comments. You are risking damage to the valve and seats by defining the limits to the hydrotest by shutting a valve.
What is the reson that you would want to do this in lieu of using the more traditional "flange and blind" limits to the hydrotest?
Is this yet another idle question by an inexperienced project manager ?
RE: Using a valve as limit for a test system
MJCronin, I'm just an engineer, more used used with the design phase and amazed by what field engineering will do to get things done(first time on a construction site). To make things worse we're building in the middle of nowhere. So, if you don't have enough blind flanges you have to find other solutions or wait 3-4 month to get the blind flanges. The last solution won't make you very popular with the construction manager. I'm trying to find a solution. I'm sure it's a case by case, i'm sure that testing against valves has been done before.
RE: Using a valve as limit for a test system
Don't worry about calculating the thickness, as the thicknesses you get will be VERY thick. That is due to calc's giving you the "last 100 years w/o deformation" thickness. For a hydro blind, it only has to last once [although more uses are prefferable] and the failure mechanism is benign. The hydro blind 'pancake' will first hydro-form and develop a permanent eliptical shape, but not leak. Bulge makes is a little hard to remove, but not too tough.
If it bulges until it fails, you just get a [high-pressure for 1/2 second] splash of water. Just stay out of the line of the flange pairs while pumping up to full pressure.