PWHT for a vessel by internal burner technique

[eegyman5000]

we are about making PWHT for a c.s vessel of 133 mm thickness by internal burner technique.
of course saddles will not reach temperature for PWHT process,the question is where can i find the exemption from PWHT for non-pressure parts like saddles in ASME VIII DIV.1

 

[vesselfab]

the code addresses the pressure containing parts only.

there is no exemption, simply because, it does not apply

 

[metengr]

ASME B&PV Code, UCS-56.

 

[vesselfab]

i hope that you and your people performing the internal burn PWHT are very experienced in this.

direct flame impingement can cause localized extreme hot spots.

even heat distribution is critical.

thermowell placement is critical.

hopefully you have a plan

 

[unclesyd]

Here is a company that has done some PWHT for us. We also have used them for refractory dry out and break in. In our case they had they equipment and the people to go with it.
There are several others that are well versed in the art.

http://www.hotwork.com/html/hpi_vesselpostweldheat.htm

 

[gr2vessels]

vesselfab,
You have now, all this morning, the best example why to avoid buying from China... I wonder if the person signing off their inspection paperwork knows the company address...

 

[stanweld]

eegyman5000,
As metengr stated, review Table UCS-56 Notes (2)(a)and (2)(b) if vessel is in non-lethal service. If in lethal service review the Notes under (2)(c). Note (1) permits PWHT at lower temps per Table UCS-56.1.

Finally, why do you assume that the attachment weld to the pressure part will not reach the minimum hold temperature? Having performed the PWHT as described on similar vessels, it was no problem to meet the hold temperature at the locations described since the outside surface is completely insulated. T/C's should be mounted on both ID and OD surfaces.