Hello ,

I'm performing a stress analysis of piping connected to four pumps in according to the criteria of the standard B31.4 . In this analysis there is a case with consideration of forces caused by a transient .

With the action of these forces ,in point of junction with reinforcement, the stresses acting are above the permissible values ​​in the occasional case .

Changing the parameter " B31.3 Sustained SIF Multiplier " to 0.75 , the stresses are below the allowable value . In the report " Stresses Extended Report" , all values ​​(Axial Stress, Bending Stress, Torsion Stress, Hoop Stress, Max Stress Intensity, SIF In Plane, SIF Out Plane and Allowable Stress) remain unchanged , except that the Code Stress decreases .

Three questions :

Why a parameter that explicitly references the B31.3 changes the result in a calculation based on B31.4 ?

Is it right to make this consideration in a calculation based on B31.4 ?

Can I use, in this case, the value 0.0001 for this parameter ?

Thanks for any help sent.