One can find on web an interesting presentation of WRC 107 by Mr. Delaforce in CAUX 2014. I think is in line with the traditional view of WRC usage.

But the truth is WRC does not touch the stress category. And probably would be hard just reading WRC 107 to understand the difference between 1kN shear force by piping sustain case and 1kN shear force by restrained expansion of piping, since WRC 107 assumed that shear force is transmitted to the shell "entirely by membrane shear force". Yes, traditionally we make a difference saying one is originated by force and other is strain controlled and self-limited- but here this criterion appears to be so thin, thinking that sustain load is due to the mass and gravity acceleration which are still stable in this world.
Anyway, my remarks will not solve the problem and probably the future is performing elastic-plastic analysis. Here my doubts would be that probably after performing such analysis we'll be ready to forget that engineering is not only calculation but also having wisdom to move potential troubles in places where risk is not so high.