Penstock leaking 2

[ikarga]

Have leaking in pump basin wall penstocks.
Is there any standard or information about permissible leaking l/s/m?

Thank you

 

[MikeHalloran]

Leakage is not a normal condition for a pipe of any kind. I'm not aware of a standard for it, and can't conjecture a reason why there would be one.

Probably, neither can you. I'm guessing an MBA asked you to find a standard, to justify deferred maintenance and avoided costs that make him/her look good. Chances are, said MBA will be long gone when catastrophic failure results or extensive collateral damage is discovered.

Who will get yelled at/ fired/ sued/ prosecuted?



Mike Halloran
Pembroke Pines, FL, USA

 

[quark]

Do you mean from the external periphery of the pipe? Somebody might have forgotten to put puddle flanges there. In any case Mike is right.

 

[MintJulep]

Piping standard may be found here:

http://cfcl.com/vlb/Cuute/f/pipe_notes.txt

 

[gerhardl]

Brief comment:

You do not give any particulars or technical details, but correctly designed,installed and maintained there should be 'dropthight closure'.

As known there exists a number of standards for how valves shall be tested on leakage and thightness, and standards to be reached on leakage. I do not believe similar standards exists for penstocks. An end user will of course require and expect thight closure if not otherwise specified.

'Penstock' covers a great many types, constructions, dimensions and applications vary in a wide range.

Most common you will find leakage in wall penstocks if not mounted correctly (not in plane, skew, frame bolted skew and unproperly to 'buckling - not plane' concrete walls etc.

Another group of faults giving leakage is unproper actuating devices, mounted to give skew or too weak force.

The third group of leaking centers around sealing problems due to faults on sealing material(weak, wrong type, not properly fastened to penstock, seal construction itself) or the penstock itself generally unsuitable - for instance parallell closing rail when a more costly wedge closing rail construction would be far better.

 

[ikarga]

Thank you guys for your effort. I am talking about slide gate 1200x 800 mmm on basin wall and in open channel with 3.7 m of water on wet side. Is there standard (DIN or some) for this type of gate (penstock) - permissible leaking. What I have is about 0.2 l/s/m, but this is empirical data...

Thanks for help!

 

[MintJulep]

There cannot be a standard for such a thing because no standards development organization can know what your application is.

A pipe can carry water, or gas, or other chemical.

If a pipe is carrying some sort of toxic gas, then permissible leakage had better be zero hadn't it?

If a pipe is carrying petroleum, leakage had better be zero, or the environmental people will be on top of you.

If your pipe is carrying water through a phosphorus silo (although I don't recommend this), your leakage had better be zero.

If you are carrying water across a farm field, then some leakage might be tolerable.

Standards are developed for things that are non-application specific.

As Mike said, pipes are not supposed to leak.