Stress relieve to opening connections... 1

[javilingo]

Hello!

In API 650, ap. 5.7.4.3 says "When the shell material is Group IV, IVA, V, or VI, all openning connections requiring reinforcement in a shell plate or thickened insert plate more than 13 mm thick shall be prefabricated into the shell plate or thickened insert plate,..."

The stress relieve is needed for all openning connections requiring reinforcement or for all openning connections requiring reinforcement more than 13 mm ???

Thank you at all!

 

[IFRs]

The criteria is all openings that require reinforcement. You don't have to stress relieve openings that do not need reinforcement. Like small nozzles or couplings. Any nozzle that needs reinforcement has to be stress relieved if the shell is Group IV or higher and the shell is more than 13mm thick.

 

[javilingo]

IFRs, first you said the criteria is "all openings that require reinforcement" and then "Any nozzle that needs reinforcement has to be stress relieved if the shell is Group IV or higher andthe shell is more than 13mm thick"
It seems to be a contradition...

 

[javilingo]

The same in 5.7.4.2 "When the shell material is group I, II, III, or IIIA, all opening connections NPS 12 or larger in nominal diameter in a shell plate or thickened insert plate more than 25 mm thick..."

Should this 25 mm apply to shell plate and thickened insert plate or only apply to thickened insert plate?

Thank you!

 

[IFRs]

The code statements are intended to be taken literally and together in context. The portions of the code say if criteria 1 and criteria 2 and criteria 3 then action. All conditions must be true for the action to be required. I wrote my first response poorly and apologize for the confusion.

You can break it down as follows, but it does not matter in what order you evaluate the criteria:

First, only openings that require reinforcement need to be considered. So, if you have an unreinforced opening you don't have to worry about PWHT. This does not mean that all reinforced openings require PWHT. It only means you have evaluated the first of the criteria.

Second, is the material is Group IV or higher? If not, you can stop here. If so, continue on. This does not mean that all reinforced openeings in material over Group IV require PWHT. It only means you have evaluated the first and second of the criteria.

Third, is the plate over a thickness minimum. If not, you can stop here. If so, continue on. If you have satisfied all three criteria than you need PWHT.

In conclusion, if the opening requires reinforcement and the plate into which it is installed is a certain grade and over a certain thickness, thermal stress relief is required.

It does not matter if the plate into which it is installed is called a shell plate or called a thickened insert plate.

If this is not clear, I must take a course in communication, or stay out of these forums for I do not need to waste your time.

 

[javilingo]

It is very clear now.

I just wanted to be sure of the interpretation because I have many plates of group IV with reinforcements of thickness less than 13 mm and I want to keep a waste.

I am very grateful for your help.