ASME BPVC Section 1 PG-31.4

[maxsp]

Hi All

I am new here/first post
I am looking at calculations for a section 1 boiler. In consideration of a weld under PG-31, in particular g-1, PG-31.4 includes a line "If a value of m less than 1 is used in calculating t, the shell thickness, ts, shall be maintained along a distance inwardly from the inside face of the head equal to at least 2*sqrt(d*ts)."

My question here is: Isn't m always less than 1 because m = tr/ts where ts is the specified thickness and tr is the minimum required thickness?

Also my understanding of this is that one cannot have any openings in the shell along the length from the inside of the rear head. Can anyone verify or clarify that?

Thanks in advance

 

[david339933]

Standard Designation: BPV Section I
Edition/Addenda:
Para./Fig./Table No:
Subject Description: Section I, PG-31.4, Openings in Headers
Date Issued: 05/26/1988
Record Number: BC88-060
Interpretation Number : I-86-85
Question(s) and Reply(ies):
Question: May a fully reinforced opening be placed in a header shell with a flat head attached per Fig. PG-31, sketch (g), in the area where PG-31.4 requires that the full shell thickness be maintained?

Reply: Yes.