PWHT vessel manway in situ after repairs

[fortmceng]

Hi All,

I have a vertical vessel 70 ft tall (60inch ID x 1" thk wall)where one of the manway is located almost 35 ft down from top of the vessel. We are doing some repairs on the manway neck and it would require PWHT due to service requirement. I am just wondering whether I need to support the vessel top section while we do PWHT on the manway or is it not required. Any directions from experienced pressure vessel engineer's as to how to evaluate would be great. My concern is that during PWHT the area around manway might undergo some deformation as there would be a constant compressive load acting downward while the manway area would be soften during heat treatment.
Manyway size is 20" and Temperbead is not an option.

Thanks in advance

 

[unclesyd]

How much welding did you do on the shell, repad, etc?
Or where was the actual welding?

What is the material?

Are you using a commercial heat treating company to do the work?

i would definately appraise them of your concerns.

Normally you can take out a good section out of of a column without any problems. It is hard to tell without drawings or sketches as what needs to be considered.

 

[metengr]

Manyway size is 20" and Temperbead is not an option.

Please explain why this is not an option? Do you understand the temper bead method and the fact that it is endorsed by the National Board Inspection Code (NBIC) as an alternative welding method? A second option is to use local PWHT as described in the NBIC, Part 3 or Part RD. Using ASME B&PV Construction Code PWHT requirements in this instance can result in harm to an in-service vessel. I would carefully think this through before deciding on using a circumferential band for PWHT.