UCS-56 PWHT 1

[Horty]

I have a vessel that is 3/4" thick P1 G1 material. time at temperature as per UCS-56 stated 1 Hr per in, 15 minutes min. Does this get a 45 minute hold time, or the 15 minutes min? Same question for mandatory 1.5" is that 90 mins? or 1 and 15 minute minimum intervals like it does for Above 2"?

 

[metengr]

45 minutes For the 3/4" material. Follow the pattern.

 

[Mec.tec]

45 minutes minimum for 3/4'' and 90 minutes minimum for 1.5''.Above 2'' we get an exemption by covering a thickness of 1'' in 15 minutes.15 minutes time is the lowest possible holding time w.r.t the thickness.

 

[Horty]

Thank you, thats what were doing, but I audited another company and they were not...
Have a good one

 

[GenB]

Guys. A bit confusing. As I understand it, the standard and usual normal holding time is one hr per inch but what about the option of 15 min min? Means that if the procedure is written as above the shop has an option of using the lower 15 to 60 minutes, it may not be advisable but satisfies the Code. And not an exception just for over one inch as some one stated.

 

[metengr]

The option of 15 minutes minimum is not an option. If the material is 1/2" the hold time is 30 minutes. If the material is 1/4", the hold time is 15 minutes. If the material is 3/16" or less, the hold time is 15 minutes minimum, period.

If the material is over 2", the added thickness is done by 15 minute increments.