Scratch on external wall of Pressure Vessel Head 2

[azmirosman]

Dear All,

I would like to get assistant on the dented at external pressure vessel head.

During level 2 of structure installation (in Module), the existing pipe support is resting on the top head of the pressure vessel.

Existing pipe support is prewelded at another structure at level 2 and accidentally i believed there was force from the support to the vessel head.

And after remove the pipe support, we performed inspection at clashing area and found that there is some scratch that preliminary measurement of depth is about 0.8 mm to 1.2mm.

We will call AI and vessel fabricator to inspect and provide judgment and solution.

However, before we come to discussion, i would like to know any reference or standard that i can refer regarding requirement of maximum depth of external wall.

From my understanding, i only can find tolerance of roundness in UG-81.But nor able to find any clause that refer to dent and depth for external wall.

Appreciate if anybody can assist.

I attach here picture before and after remove the clash pipe support.

https://files.engineering.com/getfi...ead-ae778093efa4&file=IMG-20230515-WA0007.jpg

 

[r6155]

Can you tell us actual thickness and required thickness of head?

Regards

 

[azmirosman]

Hi,

Actual thickness after forming : 25.44 mm
Required thickness : 21.36 mm

Thanks

 

[r6155]

Well.
I suggest:
1) grind flush
2) Liquid penetrant
3) No need to weld to restore thickness.
4) Repair the paint.

Regards

 

[0707]

yes smoth grind as r6155 says

 

[azmirosman]

Thank You all for the advice.

This vessel already Hydrotested.

If grind smooth, it is consider hot work that require re-HT?

 

[TGS4]

If the vessel is already hydrotested, then this is no longer an issue regarding the Code of Construction. This is a fitness-for-service matter and should be handled as such. The advice provided by r6155 is sound - and no need to re-perform the pressure test.

 

[r6155]

Structural integrity is not affected, so hydrostatic testing is not required.
This repair must be documented, check with the inspector.

Regards