ASME B31.1 Power Piping Code - Pipe Support Welding 1

[helmley]

ASME B31.1 is silent on the pipe support requirement for frame type support. There is also no guidance on how this support is to be design. Frame type support refers to pipe support composed mainly of structural steel members. Examples are; pipe boxed in structural steel members (guide), a beam between two legs with the pipe installed either on top of the beam or underneath it. These are only two examples where-in structural steel members are used to support a pipe.

It is understood that any welding to the pressure boundary shall be welded to ASME IX requirement. It is also understood that any welding of the frame type pipe support to an existing structural steel member shall be to AWS D1.1

Questions:
1.) What is the design base for these structural steel members? For piping experience high load (main steam, feedwater, aux steam), the support load would be very excessive. ASME B31.1 is silent.
2.) Would ASME IX welding requirement be applicable to these pipe supports? Why? Or rather to what is the applicable welding code for the frame type pipe support structural steel members?
3.) ASME B31.1 mentioned about special support (not define in MSS SP58), what is the definition of special support? Is frame type support equal to guide,i.e., special guide? why and why not?
4.) How do we size the weld for these structural steel members? Where in ASME B31.1 does it lead the reader to a particular code to design the frame type support?

Many thanks .

 

[metengr]

ASME B31.1 provides technical guidance in what to account for and review to assure a safe piping design, and is not intended to be used as a piping design handbook or other all encompassing standard to design power piping. This is all stated in the Forward and Introduction of B31.1 Power Piping Code. Regarding pipe supports, anchors and rods, technical information is mentioned in B31.1 per the following paragraphs – 120, 120.1, 120.2, and sub-paragraphs 120.2.1, 120.2.2,120.2.3, 120.2.4. Again the information in 120 of B31.1 is not for detail design purposes, it is intended to make sure that the design is proper.

With that being said and to answer your questions, you should obtain a Piping or Piping Design Handbook along with MSS (Manufacturers Standardization Society) Standard SP-58-2002 (this standard establishes the material, design, fabrication and inspection criteria to be used in the manufacture of standard types of pipe hanger components), and MSS SP-69-2002 to supplement the requirements in B31.1.

Regarding the design of pipe supporting elements, B31.1 does mention the American Institute of Steel Construction (AISC) to frame structural steel members. The allowable stresses for the material used in the supporting frame members shall be based on 121.2 of B31.1. The welding code typically mentioned by AISC is the AWS D1.1 Structural Steel Welding Code. Attachment of the support to the pipe pressure boundary surface by welding shall be in accordance with ASME Section IX.

 

[MJCronin]

helmley,

I agree with the wise comments about B31.1 of "metengr" as noted above....I feel that many engineering forums owe him a great debt for his learned comments and clear presentation.

It seems that you come from a "non-structural" background and would be well served by having a discussion with a structural steel engineer.

By the way, all of the questions you have asked above are answered in this book:

"Piping and Pipe Support Systems: Design and Engineering"
by Paul R. Smith, Thomas J. Van Laan

http://www.amazon.com/exec/obidos/tg/detail/-/0070589313/102-9151706-6480931?v=glance

It's way, way overpriced on AMAZON.....but I can sell you my copy for considerably less

MJC
MJC

 

[bvi]

There is a break point between the piping code and the civil/structural code. Pipe supporting elements, which include attachments to the pipe, the support element such as a rod or a stool, and the attachment to the structure are within the scope of ASME B31.1. The previously mentioned references, including MSS SP-58 and MSS SP-69 are all applicable and allowable stresses and fabrication requirements are provided in ASME B31.1.

The structure is within the scope of AISC, a civil code. This includes supplementary steel, including frames which the pipe may sit on or hang from. So design, including allowable stresses, and fabrication rules such as welding requirements are governed by the applicable civil code.

The piping designer needs to provide the loads that the pipe will exert on the structural elements to the designer of the structure, so the structural elements are appropriately designed. Don't forget lateral loads due to friction when specifying these loads.

 

[ilovechickens]

MJC

Are you still interested in selling your piping/pipe support book?

I could be interested if you have an email address I can get in touch with you on.

Thanks