×
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

Piping Thickness in ASME B31.3 and B31.1
2

Piping Thickness in ASME B31.3 and B31.1

Piping Thickness in ASME B31.3 and B31.1

(OP)
Hello,

In our piping spec for refinery is written
"As a minimum requirement, piping shall be designed in accordance with ASME B31.3, Process Piping. Steam, boiler feed-water and blow down piping, associated with steam generating equipment shall be designed in accordance with ASME B31.1"

I cheked the thickness calculation for above services (steam, blow down, ...) but they also calculated as per ASME B31.3.
My question is this:
1- Is it required the thickness for steam lines in refinery to be calculated as per ASME B31.3 or not?
2- What is the difference between thickness as per B31.1 and 31.3? which code has more safety factor? which thickness is bigger and why?

Thanks and Regards,  

RE: Piping Thickness in ASME B31.3 and B31.1

What pipe are you using? I am asking about the ASTM pipe (UNS would be good as well)

 

RE: Piping Thickness in ASME B31.3 and B31.1

2
Pavis1968

The ASME B31 Codes for Pressure Piping are voluntary consensus Codes.  ASME cannot make the law; your local government will do that.  The law will result in regulations and one form of those regulations is a Building Code.  Usually, (in most places where the ASME Codes are used) the LOCAL BUILDING CODE will set MINIMUM STANDARDS and in many places in the world the local building Codes will mandate that one or more of the ASME B31 Codes for Pressure Piping be used  ONLY THEN DO THE ASME CODES HAVE THE FORCE OF LAW.

You ask:

1- Is it required the thickness for steam lines in refinery to be calculated as per ASME B31.3 or not?

Is it required by whom?  You must ask your local jurisdiction what Codes and Standards are REQUIRED by them (by you local jurisdiction).  Usually, the owner's specifications and standards will be written in compliance with the requirements of you local jurisdiction (in compliance with the LOCAL LAW).  You will notice that B31.3 states that it is the responsibility of THE OWNER OF THE FACILITY to specify what ASME Code should be used for the physical plant - the owner may mandate the more than one Code or Standard be applied to the design of various units in the refinery (usually, the OWNER's requirements for which Codes and Standards are to be used in the owners refinery are expressed in the company specifications and standards.  It is common practice (in most but not in all) in refineries for the OWNER to specify that the ASME B31 Code for Pressure Piping, B31.1, Power Piping be used for all the piping in the steam / water loop in the boiler house (NOTE that some boiler piping will also have to comply with the ASME Boiler and Pressure Vessel Codes).  The OWNER"S specification for all piping in the refinery outside the battery limits for the boiler house be designed, fabricated, erected, examined and tested in compliance with the ASME B31 Code for Pressure Piping, B31.3, Process Piping (there may be some exemptions for some area in which there is Transportation Piping that complies with either B31.4 or B31.8 (or it may be that there is none of this type of piping within the refinery).

You have stated that the OWNER'S specification requires the application of the B31.3 Code for Process Piping throughout the refinery except for the piping associated with "steam generating equipment".  So, there is your answer.  The OWNER has written a specification / standard that calls for B31.3 to be used for all piping except for steam / water loop piping.

The B31.1 Code includes (in B31.1 Appendix "A") values for allowable stresses to be used in the design of pressure piping.  These allowable stresses are GENERALLY based upon a factor of safety of four.  The B31.3 Code includes (in B31.3 Appendix "A") values for allowable stresses to be used in the design of pressure piping.  These allowable stresses are GENERALLY based upon a factor of safety of three.  GENERALLY then, pressure design of piping designed in accordance with B31.1 will require thicker wall piping for the same pressure/temperature service.  The B31.1 Code Committee is of the opinion that Power Piping should be designed (et. al.) to more conservative standards - THAT is the reason for the difference in the factors of safety.

Pavis1968, there is NO SUBSTITUTE for sitting down and reading the Codes that are required by your local jurisdiction.  It is the RESPONSIBILITY of the piping engineer to completely understand the laws of the local jurisdiction and to completely understand the rules and the design philosophy of the Codes that are required by your local jurisdiction.


John.

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