> >Is it true that vent and drain are needed at every high and low point of
> >piping if water is used for hydrotest?
> Without the vent you leave air in the system; without the drain you leave
> water in. Not many people use steam for a hydrotest, but if you perform a
> pneumatic test (rather dangerous) there's no water to deal with, so you
> don't need vents or drains.
For pneumatic testing you would need a way to inject and evacuate the pressurizing gas, however (obviously). If both ends of the spool(s) is (are) flanged, it's easier, just a bolt-up.
For hydrotesting (and I admit that I do not have direct field experience with this), I would think that multiple low point drains would be required to dribble out any remaining pockets of liquid - that is if the piping configuration contains more than one low point. I suppose any remaining liquid could be blown out with air pressure, but that wouldn't necessarily make the system liquid-free.
The website seems to be broken at the moment, my apologies and I'm working on fixing it.
Paul Received on Thu Nov 14 00:58:00 2002
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