What is nominal wall thickness in B31G

[Muhammad Ijaz]

Please clarify the following:

Nominal wall thickness of pipes specified in ASME B31G is nominal wall thickness calculated by B31.8 or installed nominal thickness in field.

Please reply with references.

 

[1503-44]

Nominal wall thickness is what you see printed on the pipe wall thickness tables in the steel mill's and pipe supplier's catalogues. I think no reference for that is really needed.

Reality used to affect the way we thought. Now we somehow believe that what we think affects reality.

 

[Muhammad Ijaz]

Dear 0.00,

I understand that your point of view is "nominal wall thickness referred for Level 0 Evaluation in B31G is installed pipe nominal thickness and not B31.8 nominal thickness".

Please confirm.

 

[1503-44]

What do you think "nominal" means?

What nominal wall thickness was specified on the purchase order for the pipe that you installed?
What nominal wall thickness is marked on the installed pipe's exterior surface?
What nominal wall thickness is shown on the installed pipe's design drawings?
What nominal wall thickness is shown on the installed pipe's fabrication isometric dwg?
What nominal wall thickness is given in Table 1 of ASME B36.10

Nominal means "name" for the wall thickness. It does not mean actual wall thickness.

Reality used to affect the way we thought. Now we somehow believe that what we think affects reality.

 

[Muhammad Ijaz]

Thickness specified on drawing is 7.9 mm.

One more question is

What is circumferential oriented corrosion extent as per B31G?

We understand that if corrosion (e.g. pits) is located at angle of more than 45 deg to longitudinal axis of pipe. Please confirm.