ASME Sec. IX Diameter limits

No.

Best regards - Al

Please read Section IX first, and then ask a question.

I am copying here Interpretation IX-80-08.

Interpretation: IX-80-08
Subject: Section IX, Welder Performance Qualification
Date Issued: February 27, 1980
File Number: BC-79-341


Question (1): Is a welder required to take a "small diameter" pipe test to weld a "saddle in" [full penetration through shell as in Fig. UW-16.1, sketch (c) of Section VIII Division 1] when the diameter of the hole in the head or shell is less than 2-7/8 in. O.D.?


Reply (1): No, when the weld preparation is made in the head or the shell.

Question (2): Is a welder required to take a "small diameter" pipe test to weld a "saddle on" (full penetration through the nozzle as in Fig. UW-16.1, sketch (a) of Section VIII - Division 1) when the diameter of the nozzle is less than 2-7/8 in. O.D. and the weld prep is made on the nozzle?

Reply (2): Yes.

Question (3): What thickness of plate (test coupon) would a welder have to make his performance qualification test welds on to qualify for production welding of two 1 in. plates to be attached perpendicularly to each other by two partial penetration welds of 3/8 in. each?

Reply (3): The performance qualification test coupon would have to be a minimum of 3/16 in. thick
Nasir
Welding Engineer
DESCON ENGINEERING LIMITED
PAKISTAN

Answer is yes.

I agree with David. Section IX is very misleading and not sure why it hasn't been revised regarding diameter limits. Interpretation IX-80-67 also is clear that diamter limits for "Set-In" nozzles such as Fig. UW-16.1(c) are not appicable. These interpretations are over 30 years old and still valid.

Status: Currently Valid
Status Description: See also IX-80-35


Interpretation: IX-80-67 (see correction below)
Subject: Section IX, Nozzle to Shell Connections
Date Issued: December 8, 1980
File Number: BC-80-675
Related Documents: IX-80-35

Question: When nozzle or branch connections are attached to the wall or head of a pressure vessel, what are the basic criteria establishing procedure and performance qualification requirements, assuming impact testing is not a requirement?

Reply: Where the nozzle is attached to the vessel by welding completely through the thickness of the vessel wall, the procedure shall be qualified for the thickness of the vessel wall penetrated by the nozzle or attachment. Where additional metal is placed on either the interior or exterior of the vessel wall in the form of fillet welds, they shall be considered as having been qualified by the procedure qualification covering the thickness of the vessel wall. Performance qualification for this weldment may be made in plate to cover the appropriate thickness of the vessel wall and the position in which the weld is being made. Diameter is not a factor.

Where the nozzle or attachment is welded to the vessel wall by welding through the thickness of the nozzle or attachment, the procedure qualification shall be made for the thickness of the nozzle or attachment wall at the time of welding. Performance qualification for this condition shall be made with the appropriate diameter pipe weld as required by QW-452.3 with the range of thickness of weld metal qualified determined by the thickness of the nozzle or attachment wall at the time of welding. Any fillet welds, both procedure and performance, will have been qualified when qualifying for the full penetration welds involved.

ATTENTION

The foregoing Interpretation has been further considered, and the following corrected Interpretation sent to the inquirer.

Correction Issued: March 12, 1981

Question: When nozzle or branch connections are attached to the wall or head of a pressure vessel, what are the basic criteria establishing procedure and performance qualification?

Reply: For groove weld procedure qualification, the base metal thickness range for all base metals being joined in addition to the deposited weld metal thickness range for each process used must be qualified in accordance with QW-451 (see QW-202.4). Also, see exemptions in QW-202 for fillet weld procedure qualifications.

For groove weld performance qualification, the deposited weld metal thickness range must be qualified per QW-452, and where the nozzle or attachment is welded to the vessel wall by welding through the thickness of the nozzle or attachment, a "set-on connection" performance qualification shall be made with the appropriate diameter pipe as required by QW-452.3. [highlight #FCE94F]Where the nozzle or attachment is welded to the vessel wall with the weld preparation made on the vessel wall, a "set-in" connection, diameter is not a factor. See QW-303 for exemptions for fillet welds.[/highlight]

Keep in mind that if you are using a "set-on" nozzle or O-let type fitting as illustrated in Fig. UW-16.1(a) then diameter limits apply.