UG-90(c)(1)(-l), UG-46 1

[JamesKerr]

Hello I'm looking for opinions in regards to the following question,

May visual examinations to satisfy UG-90(C)(1)(-l) be made after final closure, using the inspection openings in UG-46?

Here are two thoughts for consideration;
- That the openings reference in UG-46 are only for in-service inspections to verify corrosion and erosion and that they have no place in fabrication.
- UG-97(a), Conditions do permit a "more" complete inspection earlier in fabrication, however the argument is that if we continue with fabrication it will no long be permit entry, but the inspection openings are
still available for the Inspector.


Thank-you

 

[r6155]

The inspection opening should be large enough to allow entry for the inspector.

Regards

 

[SnTMan]

May visual examinations to satisfy UG-90(C)(1)(-l) be made after final closure, using the inspection openings in UG-46?

I don't see why not assuming that access is adequate for said examination, and given concurrence of the Inspector. Question: What constitutes "final closure" for the vessel in question?

- That the openings reference in UG-46 are only for in-service inspections to verify corrosion and erosion and that they have no place in fabrication.

I don't think I'd agree with that statement.

Re UG-97(a), I'd think "final closure" would not be construed as a bolted joint, but rather attachment of a non-removable component; head, tubesheet, etc.

Perhaps relevant interpretations exist, I can't say.

Regards,

Mike

The problem with sloppy work is that the supply FAR EXCEEDS the demand

 

[marty007]

When trying to understand the code rules, sometimes it's valuable to look at an extreme case...

How would you propose to perform the internal inspection of an 8" diameter pressure vessel fabricated with pipe and two welded pipe caps?

Manway? Nope - too small.
Body flange? Not available.

UG-97(a) says you need to perform "as complete an examination as possible... before final closure". So, for a vessel like this, our shop would weld all nozzles into the pipe and pipe caps. Then, we would weld one of the pipe caps onto the pipe. At this point, we call in the AI to perform the internal inspection prior to welding on the second pipe cap.

After the second head is attached, the only way to inspect the internal surface of the final closure seam is to look through the inspection openings (or other piping nozzles on the vessel).

So yes, the UG-46 openings can be used for internal inspection. But, I think they could only be used for the internal inspection of the closing seam. All other internal inspection should be done prior to the final closure weld.

 

[r6155]

JamesKerr
Can you tell us the diameter of the pressure vessel?

Regards

 

[JamesKerr]

Thank-you for your opinions everyone.

The final closure in our scenario: the two heads are installed at the same time in a press. The girth welds have backing, only the long seam of the shell section needs to be inspected.
The diameters range from 30" to 48" and from 5' to 12' long.

Marty007, I understand the use of teh inspection opening for the closing circ in smaller vessels. Unfortunately I have people trying try to apply it to much larger vessels.

Regards

 

[r6155]

Long seam of the shell is inspected before welding the heads.

Regards

 

[JamesKerr]

Currently all our inspections are being done before closing.

However we've recently bought a competitor making the same product. The other company AI does all his inspections though a single coupling hole after assembly. The new company is paying for a AI three mornings a week. Our company is paying for 40 hours a week for a similar production level.

You can understand why the administration and accounting department is trying to figure out why we are spending so much more money for what is supposed to be a equal acceptance standard.

Thank-you

 

[david339933]

UG-97 - When conditions permit entry into the vessel, as complete an examination as possible shall be made before final closure.

 

[r6155]

Inspections shall be performed as manufacturing progresses, according to an inspection plan approved by the customer.

Regards

 

[SnTMan]

JamesKerr, it may be due to a difference in philosophy between the Inspectors...

The problem with sloppy work is that the supply FAR EXCEEDS the demand

 

[Don56]

Section VIII is for new construction, not in service inspections unles referenced by the NBIC, so UG-46 applies to new construction.

 

[david339933]

Yes, Sec. VIII is new construction, but the purpose of inspection openings is for in-service. If service is not corrosive, an inspection opening is not required.

 

[r6155]

@ david339933
You are some confused.
UG-46 is for ACCESS or inspection openings.
Several pressure vessel for non corrosive service require access opening for : trays, cleaning, filters, mixers, types of internals….etc.
Also during fabrication you need to make welds inside, inspections after PWHT, etc

Regards

 

[JamesKerr]

r6155

My understanding was more aligned with david339933.

My interpretation of UG-46(a) is that if your vessel is subject to corrosion, abrasion or erosion you should allow a service access or inspection opening for cleaning and examination. The context of the paragraph leads me to believe that UG-46 is dedicated to ensuring foresight is given to the in-service aspect of the vessel.

Let me now your thoughts.

 

[r6155]

@ JamesKerr
Good engineering practice is welding from both sides. Is your intention to weld the head 48" diam from outside only?

Regards

 

[JamesKerr]

r6155
yes with backing

 

[SnTMan]

JamesKerr, UG-46 requires inspection openings when certain conditions apply. It does not prohibit them when said conditions do not exist.

r6155, yes, double welding is generally considered "good practice". But there are numerous circumstances where it is not possible, and numerous classes of work where it is unnecessary. We know almost nothing about the OP's vessels...

The problem with sloppy work is that the supply FAR EXCEEDS the demand

 

[david339933]

r6155...have you actually built any vessels?...or do you just search keywords in a pdf of the Code? Type II circ seams are extremely common...especially for the closing seam, when all other internal welding is completed. A lot of vessels do not have inspection openings. "Non Corrosive Service" is put on the data report and they are not required.

 

[XL83NL]

@r6155; my thoughts are the same as David regarding access and inspection openings. Why would the code require you to apply a few extra nozzles if theyre only used once and for one purpose only?
Access and Inspection, to my understanding, refers to the possibility to inspect and access the vessel once it’s in service.

Huub
- You never get what you expect, you only get what you inspect.