×
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

Gasket type and material in natural gas piping systems

Gasket type and material in natural gas piping systems

Gasket type and material in natural gas piping systems

(OP)
In a natural gas medium pressure aboveground piping system, what type and material of gaskets have others used between a 125# cast iron valve flange and 150# steel pipe flange with the raised portion machined down?

Has anyone successfully used a spiral wound metal gasket?

RE: Gasket type and material in natural gas piping systems

I would get with your gasket supplier and see what in has for natural gas lines with Cast Iron Valves. There are quite a few materials for your application.
 
I would not try to use a spiral wound gasket in your situation.  

Do you think there is some need for the spiral wound, ie fire?

RE: Gasket type and material in natural gas piping systems

Historically, I've used a 1/16" thk. nitrile ring full face gasket on 125# gas, and a 1/8 thk. Flexitallic type "CG" for the 150# gas service. The Flexitallic gasket is a spiral wound S.S. gasket. Good Luck!  ...Mark

RE: Gasket type and material in natural gas piping systems

(OP)
11echo:
Thanks for your response.

Have you ever used the Flexitallic type CG when connecting the 150# steel pipe flange to the 125# cast iron valve flange?
If you have did you have any problem with stressing the cast iron?

RE: Gasket type and material in natural gas piping systems

It's not a fuel code, but the ASME B31.1 Power Piping Code requires that the when flanging 125# cast iron to 150# steel, the raised face on the steel be removed (as you have done), and a full face gasket be used so you're not springing the relatively thin & bittle cast iron flange into a gap when tightening the bolts. By the time you get done taking the raised face off the 150 flange, and playing with gaskets, I'll bet it's not much more money to just go with 150 cast steel valves right from the start.

RE: Gasket type and material in natural gas piping systems

cluelessinohio   ...NO! The Flexitallic type "CG" is for a raised face application. IF you are going to mate up a 125# FF flange to a 150# flange you need to verify two things: 1st that the raise face on the 150# has been machine off so what you have is a flat face flange, and 2nd you need to use a flat face gasket! This type of connection is fairly common on cast iron pumps, so it's not "odd" as you might think. GOOD LUCK!  ...Mark

RE: Gasket type and material in natural gas piping systems

Style CG or RW spiral wound gaskets are typically used on raised face flanges.  In order to use this gasket style on flat face flanges- especially cast iron, you'll need to specify a full-face outer guide ring.  

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