Weldolet weld to manifolds or header for ASME Scet-I 2

[2468jjcr]

Dear Sir,

1. How to justify weld thickness(Nominal) of weldolet weld to manifolds or header.

2. Refer to the notes within Table PW-39 for exemption PWHT, what paragraphed we shall use for weldolet.

Thanks for any answers.

 

[metengr]

See below for background information on weldolet use and welding;

http://www.bonneyforge.com/

Regarding PWHT for fittings;

see Note 1 (k) in Table PW-39.

 

[CodeRef]

There is a lot of confusion in the interpretation of PW-39 in regard to "o-let" or couplings welded to header pipe and the requirement for PWHT or the exemption thereof.

First, keep this in mind, the notes in Table PW-39 apply specifically to the fabrication of the boiler proper and parts thereof and do not apply to the external piping as defined in the Preamble.

With that said, Note 1(a) of PW-39 addresses circumferential butt welds in pressure parts (which includes pipe tubes, or headers) and allows an exemption for these welds under certain conditions. Now, as you have discovered, there is no mention of combination groove and fillet welds in attaching couplings and "o-lets", to a pipe or header, only vessels. Because this type of weld is not specifically addressed, it is interpreted as meaning there are no exemptions for these combination groove and fillet welds.
However, some have determined that PW-39 allows an exemption from the PWHT requirements for coupling and "o-let" to pipe combination groove and fillet welds by applying the rules of Note 1(a) to branch connections.

In my opinion, you cannot use Note 1(a) and apply it to branch connections in pipes, tubes and headers.

Here is an interpretation on the issue.

Subject: PG-39.7 and Table PW-39, Postweld Heat Treatment Requirements

Question (1): Is a weld attaching a welding branch fitting, tube or coupling, to a header, drum, or tubular manifold considered to be a circumferential butt weld as described in Note (1) (a) within Table PW-39?

Reply (1): No, a "circumferential butt weld" as used in Section I is a weld between two cylinders which have the same or parallel axes, not welds between cylinders whose axes are at right angles.

Question (2): Does PG-39.7 require postweld heat treatment of such connections?

Reply (2): Yes, unless specifically allowed otherwise.

You will have to make a determination as to if Table PW-39 is specifically addressing your concern..... Good Luck...



There are three kinds of people in this world; those who can count and those who can't.

 

[2468jjcr]

Million thank, Codejackal

Can you tell me the specify Interpretation Volume number. (For mine reference

Regards.

 

[CodeRef]

Interpretation: I-01-29
Subject: PG-39.7 and Table PW-39, Postweld Heat Treatment Requirements
Date Issued: December 31, 2002
File Number: BC02-4028


There are three kinds of people in this world; those who can count and those who can't.