×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Are you an
Engineering professional?
Join Eng-Tips Forums!
• Talk With Other Members
• Be Notified Of Responses
• Keyword Search
Favorite Forums
• Automated Signatures
• Best Of All, It's Free!

*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.

# Gas Pipe Sizing

## Gas Pipe Sizing

(OP)
Good Morning,
Could anyone help me to find the formula to design the pipe diameter and thickness if I know the pressure, temperature, CFM, type of gas and length of pipe?

### RE: Gas Pipe Sizing

What do you require for fluid velocity? Once you determine that, use volumetric flow rate and velocity to get required cross sectional area (which will give diameter).

Are you moving the fluid a long distance (and worried about pressure drop)? Otherwise velocity and CFM will drive line size.

### RE: Gas Pipe Sizing

Note that many online calculators etc are only valid for low pressure systems where Pin and P out only change by 10% or less

Thickness is from the relevant design code or material spec.

High pressure, long pipelines, large differences in Pin to P out are more complex, but often a rough approximation can be made or you divide your pipe into segments and iterate between them.

see https://www.lmnoeng.com/Flow/weymouth.php for a bit of an explanation

Did you do any research into this?

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

### RE: Gas Pipe Sizing

Generally, the local AHJ has a code requirement, whether IFGC or the NFGC for sizing natural gas piping within a building.

Start there.

### RE: Gas Pipe Sizing

(OP)
Thank you.
I don't have the velocity. Following are rest of my parameters:
Pressure = 450 PSI
Pipe Capacity = 100 CFM
Pipe Length = 300 ft
Gas = Nitrogen

Yes, I did some research, but couldn't find out an appropriate answer.

### RE: Gas Pipe Sizing

Look at the Darcy equation for compressible flow.

That is the best bet.

### RE: Gas Pipe Sizing

To the pipe sizing, you still need either the desired gas velocity or pressure drop allowed for the 300ft pipe.

### RE: Gas Pipe Sizing

(OP)
If I have the velocity what equation I can use?

### RE: Gas Pipe Sizing

The Crane tech paper #410 "Flow of Fluids" is good to have for the engineering reference.

### RE: Gas Pipe Sizing

At that pressure your 100 cfm is about 3 cfm in the pipe. That's about 7.5 cu inches per second. So work out internal area of your pipe sizes and then velocity to see which pipe size works.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

#### 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.

Close Box

# Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

• Talk To Other Members
• Notification Of Responses To Questions
• Favorite Forums One Click Access
• Keyword Search Of All Posts, And More...

Register now while it's still free!