×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

Sizing the vents off the pressure regulator

Sizing the vents off the pressure regulator

Sizing the vents off the pressure regulator

(OP)
I am trying to size the vent off of a pressure regulator from a medical oxygen manifold.  Pressure is ~350 psig.  The vent is about 150 feet in length to get to the exterior of the building.

The manifold manufacturer recommends 1/2" pipe for the first 50 feet and 3/4" for the remaining.  That just seems too small.  

I have also seen a rule of thumb that say you increase your pipe one size for every twenty feet.  That would put me at 2.5" by the time I get outside.  That seems excessive, but I do not have any justification against it.

If anybody has any suggestions, I would appreciate it.

Thanks

RE: Sizing the vents off the pressure regulator

A pressure regulator has a high pressure inlet and a low pressure outlet.  Most have a vent connection that puts atmospheric pressure on the non-process side of the diaphragm.

Are you piping the vent connection outside in the event of diaphragm failure?

Good luck,
Latexman

RE: Sizing the vents off the pressure regulator

(OP)
Yes I am.  

Typically the rooms with the manifolds are very close to an outside wall or to the roof.  

This project is a remodel and the room is in the basement.  The only route to the outside is in a storage room and through three floors to the roof.

RE: Sizing the vents off the pressure regulator

On the regulators I am familiar with, if they have a diaphragm failure, the high pressure gas flows through the regulator orifice to the outlet side, a tube that connects the outlet side of the regulator to the underside of the diaphragm (assumes no leakage through the valve stem and it's bushing, the hole in the diaphragm, the vent connection, and finally through the piping you are going to install.  If we assume the hole in the diaphragm is large, i.e. offers little resistance, you have 4 resistances in series:

350 psig ---> regulator orifice ---> equalizer tube ---> vent connection ---> vent piping ---> 0 psig

Now you just need the details from the regulator and a good compressible flow reference, or textbook, and work it out.  By hand, it's a two martini problem, but with the right software, it's a 5 minute job.

Good luck,
Latexman

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources