WHY VENTS AND DRAINS REQUIRED
WHY VENTS AND DRAINS REQUIRED
(OP)
Please can someone explain to me in laymans terms in general when would you implement the use of drains and vents on a piping system.I am told at all high points for vents and all low point for drains.But why? please help





RE: WHY VENTS AND DRAINS REQUIRED
RE: WHY VENTS AND DRAINS REQUIRED
Best Regards
Morten
RE: WHY VENTS AND DRAINS REQUIRED
RE: WHY VENTS AND DRAINS REQUIRED
RE: WHY VENTS AND DRAINS REQUIRED
Low point drains are also useful for blowdown of accumulated sediment where needed.
The price of a few 3/4" weld-o-lets and ball valves is negligible in comparison with the benefit of having a system with adequate vent and drain connections.
RE: WHY VENTS AND DRAINS REQUIRED
If you are designing a piping system for a compressed gas you will have to expect condensing of liquid from the gas stream as pressures / temperatures change. Low point drains, either automatic or manual, can get rid of this liquid load and reduce carryover.
As for high point vents, any liquid system that is filled and emptied on a regular basis has a need for venting to displace the air in the system as the liquid enters.
RE: WHY VENTS AND DRAINS REQUIRED
Obviously when you want to shut a system down for repairs that require opening the system, you need to drain the low points. This is almost always done with the vents open to faciliate (or even allow) draining.
Another reason for a solid system is mentioned above, i.e., to ensure that the hydro test is, in fact, just a hydro test and not a pneumatic test which as mentioned above can be very dangerous due to the explosive effect of air when released rapidly when the test fails.
Yet another reason for a solid system is for proper system lay-up, that is to put it in standby when not needed. Removing all the air, i.e., the oxygen, is needed to ensure corrosion is minimized. Sometimes O2 scavengers are used, e.g., hydrazine, to facillitate the process.
RE: WHY VENTS AND DRAINS REQUIRED
It has been my experience that we let the contractors locate and install vents/drain as required for hydro testing. They can determine where they would like to see and readily use these connections. Then after testing, these connections are normally "seal welded" shut, with the exception of vents and drains needed for system operation. My 2 cents. Good Luck! ...Mark
RE: WHY VENTS AND DRAINS REQUIRED
Hi stuarte,
The purpose of giving drain in lower points is to take out the drain where all liquid matter will be deposited. This will lead to disturb your flow rate and affect your system
efficiency.
The same way, the purpose of giving vent in upper points in pipeline is to takeout all gases( including vapour, air)
which will try to stay in the top of the pipe. This also will create so many problems like corrosion in pipes, non-
uniform flow.
The above said reasons are the purposes to give drain & vent in the pipelines.
I hope this will be a answer for you.
thanks,
uthaya.
RE: WHY VENTS AND DRAINS REQUIRED
I dont think it very common to use low point drain for your purpose. That would require something like a steam trap and a return line - not the way a low point drain usually is hokked up.
If you expect large quantities of condensate your piping should be designed with a slop towards a KO drum - no low-points!
Best Regards
Morten