×
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

Natural gas pipe sizing upstream of a pressure regulator

Natural gas pipe sizing upstream of a pressure regulator

Natural gas pipe sizing upstream of a pressure regulator

(OP)
I'm looking for some advice on sizing natural gas piping for some boilers. I'm wondering if the method I have been using for years is too conservative.

I have 2 psig gas available and will be running 100 TEL feet through the building to a boiler room. The boilers only need 15"WC of pressure, so I will have a regulator to step it down. My gas tables for 2 psig gas are based on a 10% pressure drop. Using those tables with my 100' and total load of 6,600 CFH, I need a 3" pipe.

It occurred to me however, that I might not have to limit my pressure drop to only 10%. Since I'm reducing the pressure anyway, why not allow a much larger pressure drop in the line before it hits the pressure regulator? Am I missing something obvious here? Are there velocity or noise concerns? Or will the gas regulator not respond well if it sees varying inlet pressures as boilers cycle? If none of these are a concern, I'm sure I could drop my pipe to 2-1/2" or maybe even 2".

Any thoughts?

RE: Natural gas pipe sizing upstream of a pressure regulator

For liquids, we have to worry about "errosional velocity", but there is no gas velocity that trips that particular trigger. As long as you have more than 15 inWC at your regulator you are fine.

David Simpson, PE
MuleShoe Engineering

"Belief" is the acceptance of an hypotheses in the absence of data.
"Prejudice" is having an opinion not supported by the preponderance of the data.
"Knowledge" is only found through the accumulation and analysis of data.

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