ASME 31.1 & ASME 31.3 1

metcat

One important difference is in the allowable stresses that are found in appendices "A" of these Codes. The allowable stresses of B31.1 are more conservative as B31.1 allowable stresses are based upon a factor of safety of 4 while the B31.3 allowable stresses are based upon a factor of safety of 4.

The B31.1 Code has a much more narrow scope as it is intended to be applied to the piping in (non-nuclear) power plants, district steam heating systems and geothermal heating systems. The B31.3 Code is intended for a much wider application as it addresses petroleum refineries, chemical plants and others. The B31.3 Code addresses very cold (cryogenic) temperature and very hot temperatures. There is a Chapter in B31.3 that addressed internal pressures for class 2500 service and above. The B31.3 Code provides different rules for addressing several different "piping services" from fairly low pressure and low temperature service to the more sever services.

You can find a description of the various ASME B31 Codes for Pressure Piping here:


Regards, John

John,
You wrote
"One important difference is in the allowable stresses that are found in appendices "A" of these Codes. The allowable stresses of B31.1 are more conservative as B31.1 allowable stresses are based upon a factor of safety of 4 while the B31.3 allowable stresses are based upon a factor of safety of 4."

B31.1 allowable stresses are based upon a factor of safety of 4
B31.3 allowable stresses are based upon a factor of safety of 4.

Both say the same thing is there a possible typo in there somewhere?

Thank you Jim,

My bad, I tried to do a cut and paste to expedite the answer.

As you know, I really meant to say:

"B31.1 allowable stresses are based upon a factor of safety of 4 and B31.3 allowable stresses are based upon a factor of safety of 3"

I appreciate your having picked up on that one.

Regards, John

metcat,

Also have a look at this piping course material...


It talks more about B31.1

For B31.1, the min required pipe wt includes allowances for corrosion & erosion, thread or groove depth and manufacturing tolerance. The allowable stresses are lower than those allowde by 31.3. This results in greater wt compared to 31.3.

Also, 31.1 includes an appendix hat defines min reqts for est progrmas for O&M & service, & incl guidelines for record keeping, failure reports, replacement of components, defining qualified personnel, etc. - b31.3 does not cover O&M.

31.3 covers metallic and non-metallic piping as does 31.1, and although 31.3 also does not allow the use of new or used materials of unknown specs (as does 31.1), it does allow the reuse of existing material if the specs are known.

Greg Lamberson, BS, MBA
Consultant - Upstream Energy
Website:

Sorry, I was in a hurry and didn't do much of a spell check.

"hat defines min reqts for est progrmas for" - is defined as "that defines minimum requirements for establishing programs for".

Greg Lamberson, BS, MBA
Consultant - Upstream Energy
Website: