Sorry for my late reply...

ASCE 7 addresses the *0.7 or /1.4 issue in at least two places - Setions 12 & 13 - generally, apply these factors when using Allowable Stress Design (ASD). As far as I know - if pulling data from ASCE 7 to apply to pipe stress analysis, use 70% of teh ASCE 7 load.

That will give you the appropriate moment for stress.

But...

Not the right structural response for displacement and equipment load.

There is an update to B31E. Paragraph 3.1 now defines the a-p and R-p values for (welded steel) pipe. These values will give a larger displacement and load while also increasing the moments for stress. But these increased stresses are also used with the larger allowables defined for piping in B31E. So, if using B31E allowable stresses, you must use the B31E parameters.

I believe these disconnects (strength design vs stress design and stress vs. structural response) are teh reason why B31.3 does not reference B31E directly.