Repad welded up without weep hole. Any detrimental effects from the lack of a weep hole?

[jeevesme]

We had a contractor install a 4" 316l branch connection with a repad on a 12" 316l Line. The repad does not have a weep hole. Apparently it welded up fine. We PT'd it to make sure there were no cracks. Typically we would have the prep area thickness tested and PTd, then the root pass PT'd, then the final PT'd. Then once the Repad was installed, we would PT that as well. Our M.I. dept. was not aware of the work so no inspection was done at all.

My question is, since the repad welded up okay, would there be any detrimental effects on the welds simply from having no weep hole?


EDIT: Just to clarify, this is 316L and built to B31.3. I rejected the fabrication and the Owner-User Engineer over-ruled me.

 

[pennpiper]

jeevesme,
The best advice is:
1. Discard this assembly
2. Require the contractor to provide a complete set of procedures for welding , inspection and testing.
3. Require the contractor to re-qualify their Staff (involved in this project)
4. Monitor the remake of the assembly and require stop points for proper inspection.

Sometimes its possible to do all the right things and still get bad results

 

[jeevesme]

I found this during the PSSR, reported it to the area engineer, and he okayed it (against my recommendation) for operation. The wheels are already in motion to prevent a reoccurrence. I'm trying to determine what the possible effects are from welding a repad on without any kind of venting.

 

[weldstan]

If you operate at temps above the boiling point of water there is a potential for water entrapped to flash to steam and fracture the pipe or the repad weld. Obviously the higher the temp the greater the chance of failure. There is also potential for corrosion should any moisture present contain chlorides.

 

[DekDee]

If the welding was in accordance with B31.3 then it would not comply.

Reinforcing pads and saddles shall have a good
fit with the parts to which they are attached. A vent
hole shall be provided at the side (not at the crotch) of
any pad or saddle to reveal leakage in the weld between
branch and run and to allow venting during welding
and heat treatment.

As you have not posted relevant construction code it is a bit hard to comment.
How will you determine any possible future leakage between run and branch pipe ? (especially as you state you did not test the weld before installation of the reinforcing pad)

 

[pmover]

jeevesme,

think of this matter from the standpoint of when this joint/fitting fails and the subsequent investigation is launched, what supporting NDE documentation can you furnish to the investigators that this joint/fitting complied with applicable codes/standards?

your employer is responsible and bullshit rolls downhill. think and then act responsibly.

good luck.

 

[LittleInch]

As the post from dekdee says, in part the weep hole is there to prevent gas bubbles from appearing in the weld metal at the final point of closure or prevent the weld metal from being drawn into the weld whilst still molten.

Long term the issue is as noted - it provides evidence of weld cracking in the main weld.

Can't you retro drill it?

I would get your recommendation in writing somewhere and then print it and keep it safe.

almost certainly no problem, but on the off chance...

BTW what's PT ?? RT, UT, MPI, Dye Pen I've heard of but PT?

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[Caloooomi]

BTW what's PT ?? RT, UT, MPI, Dye Pen I've heard of but PT?

PT = Penetrant testing in EN standards, BS EN ISO 3452-1

 

[DekDee]

As noted above when/if the brown stuff hits the fan there will be many in upper management looking to pin the blame on someone below them.
You have done the right thing by raising your concerns but as LI has recommended - get something in writing (even if only an e-mail).
CYA - three very important letters,
Cheers,
Shane

 

[jeevesme]

I sent an email of my recommendation right after being over-ruled to others in the company just to make sure everyone knew I rejected the fab, for the CYA and to make sure everyone was on the same page just in case anything were to happen.

 

[JStephen]

Internal pressure acting all around the inside of a cylinder tends to round it out.
If you have uniform pressure around most of the cylinder, and one part without any pressure, that part will tend to flatten in.
If you weld a repad, and there is a leak between the cylinder and the repad, but no leak between the repad and the exterior, the result is that section of cylinder has equal and opposite pressures acting inside and out, which sums to zero pressure in that area.
So, it should try to flatten that spot and transfer load from the cylinder to the repad, which the repad is not designed for.
IE, a leak in the wall in that case could make a difference in the stress distribution, rather than just being a leak.