gerhardl
Mechanical
- Feb 25, 2007
- 2,025
A couple of years ago a customer of ours was involved in a case where a new installation of a larger water main (800mm) with different dismantling joints at different pressure classes, was trial tested with water.
Several of the dismantling joints, in this case lockable pipe connections, where found leaking at the joints during the test. The joint tightening flanges for the joint sealings had to be (re)thightened to obtain proper sealing. (End flanges to the pipeline where OK)
A discussion started, as the end user meant this leakage to be 'out of norm'.
The nature of lockable dismantling joints, even if they require 'straight pipe' is in practice often that smaller excentricities or angles are compensated by the joints. Accordingly one side of the thightening flange may have to be thightened more than the opposite.
Now the question: does there exists any procedure or torque description or requirement trying to ensure that all is 'thight sealed' before water test anywhere in the world?
Our own conclusion for this case:
Unable through supplier and search to find anything differing from: 'To be centered, endflanges mounted and thigtened, sealing joint to be thightened 'firm / as necessary - not too thight / thight as normal practice plus a quarter bolt turn etc'. After this water test and rethightening as necessary.'
I would appreciate any comment or experience.