Hi all,
I have 18in SCH 20 pipe, material A672 C70.(Sc=160.7MPa, Sh=159.6 MPa, Sy=235.8MPa)
When I switch on "factor f" to 1.2 CII shows an error saying

on element 900 and 910 the allowable stress is too great to allow "f" to exceed 1.0. A maximum of "f=1.0" will be used.

I am using B31.3-2008 edition and does B31.3 has any limitation on Allowable expansion stress range?

For reference pls find attached image.

ASME B31.3-2008 states that f cannot exceed 1.0 when Sc or Sh are above 138 MPa. Your Sc & Sh are above 138 MPa.