Pipe Requirements for Pressure

[BChemE]

Hi all,

I am a new engineer working in the vacuum industry. The company I work for has only manufactured crosses, tees, flanges for the vacuum side but we are thinking about crossing over to the pressure side. I have come to realize that there are certain types of piping/tubing required to be used (extruded seamless) and some that are not allowed (structural, porthole, bridged).....is there a list available that shows the pressure-allowable type of piping/tubing?

Furthermore....any tips on where to start on the quest of becoming ASME certified? I've already gotten some info from asme.org but want to present as much info to those in charge about what it'll take.

THANKS!

 

[arto]

For Vacuum design, look in the ASMS B&PV Code, Sec. VIII, Div 1, par. UG-28. Materials are in Sec. IID. Your local engrg college should have a set of codebooks in the reference section.

Contact the National Board

http://www.nationalboard.org/

or your industrial insurance company to find out about getting a code stamp.
also try: Factory Mutual:

http://www.fmglobal.com/irt/BnM.html

or Hartford Steam Boiler:

http://www.hsb.com/contact.asp?id=110

 

[MJCronin]

Bcheme,

It sounds like the answers to the questions that you are asking are contained in the ASME piping codes....B31.1 and B31.3

Within these codes are listings of ANSI and other "dimensional standards" that define acceptable shapes, sizes and piping fittings. Also contained within these codes are methods to calculate acceptable wall thickness of piping for a given pressure and temperature. Your comments about extruded and seamless materials are also addressed there.

If you produce components for vacuum serice and are now thinking of pressure components, I do not understand the thought process and the commercial motivation. Many, many companies produce piping and piping fittings for pressurized service. What unique product or service will you be offering ?

Hope that this helps....

MJC

 

[BChemE]

MJC,

Thanks for the reply. I'm slowly learning about the ASME code and where to find various information for my project. I've recommended to the powers-that-be to purchase the ASME code volumes.

I'm not too sure about my company's commercial motivation but I do know that we are constantly asked by customers whether our fittings are designed for pressure applications. Up until now we've not guaranteed that they are pressure-capable (as we're not ASME certified). However, if a customer is building a system and using our products on the vacuum side of their pump, it might make their lives easier if they can also purchase parts for the pressure side of their pump direct from us too.

Thanks-

 

[zdas04]

BChemE,
I've frequently been in the other side of the situation you describe, I need piping to test to over 600 psig, but there are phases where it will see a significant vacuum (usually for a short period). I have had a hard time getting any pressure-fitting manufacturer's to discuss their fitting's rating under vacuum. I think you may be on to something to approach it from the vacuum side.

David Simpson, PE
MuleShoe Engineering

http://www.muleshoe-eng.com