Welding seam on nozzle ref. pad 1

[cmryu]

Dear sir,

When we need to segment reinforcement pad, please define whether we have to R/T and require welding efficiency F=1
as we know, ASME not define NDE requirement on this.

 

[jte]

See page 3 on

http://www.absa.ca/newsletter/v10-2005/v10-iss4.pdf

and

http://www.absa.ca/IBIndex/IB05-004R1.pdf

for one jurisdiction's take on this situation. Your situation or jurisdiction may have a different opinion.

jt

 

[code1]

cmryu,

As far as I know there is no such requirement.

However, in the reinforcement calculation, you will need to select the joint effeciency for the pad accordingly, whether you are performing RT on the pad before attaching. Obviously, if you are attaching in 2 pieces/ halfs onto the shell/ head then the joint effenciency is as "No R/T."

The weld seam of the pad is normally orientated in the circumferential direction, with two tell tail holes on each halves if they are attached seperately.

Regards.

 

[eliebl]

Please read ABSA's information bulletin. I was employed there when it was published and MANY jurisdictions will require compliance with that bulletin for a design to be acceptable.

EJL

 

[weeeds]

eliebl
What was the reason for ABSA to issue this bulletin?
Were there any problems with spilt pads in the field?

 

[eliebl]

Widla,

To my knowledge there have not been any problems with split reinforcing pads. My biggest concern is that the spilt was not documented on the drawing and as such the designers of the vessel commonly did not know it was happening. The decision to split the pad was made by someone on the shop floor without consideration of weld detal or required NDE.

If I remember correctly one of the driving factors was the fact that there was a weld seam but it was not addresses anywhere by the code. When the code does not address an item a designer could apply U-2(g) but there was little condiseration given to the weld joint and a type 3 (or 2) joint with no radiography was used. This would have resulted in an efficiency for the reinforcing pad of 0.6 or 0.65. This efficiency was not being applied to the allowable stresses of the re-pad.

EJL