ASME BPVC Lethal Service requirements

[TylerM]

Hello everyone,

I have a pressure vessel designed to the ASME code and stamped for lethal service (L-stamp) it has been operating for over two decades with no real problems but during a recent shutdown and inspection it was discovered that an inlet/outlet pipe was not attached with a full penetration weld but with a single sided fillet weld on the outside. Obvious this is a huge code violation because all welds in a lethal service system needs to be full penetration to reduce the risk of a weld failing and releasing lethal chemicals into the air/environment and possibly causing serious harm/death to personnel.

My question is if we want to deactivate the system should we cross out (score out) the L-stamp to signify that this vessel is no longer rated for lethal service (because it was never correctly build).

Also, if we want to continue using this vessel after fixing the code violation (Via cutting out the fillet welds and making them full penetration, and going through the process of R-stamping it) is it alright to leave the original L-stamp on the nameplate?

Thank you for your insight,
Tyler

 

[MJCronin]

Just out of curiosity, what do the design drawings show for the weld ? Were the drawings PE stamped ?

Or, was the vessel constructed in accordance with the design drawings ?

What about the U-1 data report ? Is the sheet signed by an authorized inspector ?

MJCronin
Sr. Process Engineer

 

[TylerM]

MJCronin, I believe the drawings had full penetration welds on it.

My reasoning on why it didn't get welded correctly is because there are components inside the vessel that would make it almost impossible to weld correctly and that the welder was just lazy. We have a few vessels with this problem and you can see him "attempting" the correct weld on one of the vessels then giving up and doing only external fillet welds on the rest.

The vessel was inspected and signed off per the U-1 data report.

 

[r6155]

1) Try to contact with the fabricator and the authorized inspector that signed the report (exist?)
2) Contact an lawyer

Regards
r6155

 

[XL83NL]

What is an L-stamp? Never heard of that.

 

[cbPVme]

The nameplate requires the letter L stamped on it when the vessel is intended for lethal service.

 

[XL83NL]

I know, but I wasnt aware of any stamping requirement. I only know of the actual ASME Certification Mark to be stamped, but I guess the OP meant the nameplate bears the letter L as per UG-116(c).

 

[r6155]

Lethal service is a serius problem, some people are irresponsible: fabricator, authorized inspector, and others to be investigated. The irresponsibles must be sanctioned.

Regards
r6155

 

[metengr]

Revision to an ASME nameplate is prohibited. Your option would be to have an NB R-Stamp nameplate attached to the PV to indicate new design conditions, an alteration from original. However, I would first check with the regulatory body, if applicable, or insurer before doing anything.

 

[metengr]

My reasoning on why it didn't get welded correctly is because there are components inside the vessel that would make it almost impossible to weld correctly and that the welder was just lazy.

As I thought more about the above.... was this inlet/outlet pipe added after the vessel was constructed/stamped and placed in-service, especially for a 20 year period? I would think that during original fabrication, the inlet/outlet pipe would have been done without vessel internals. I suppose anything is possible but it does seem rather odd to me.

 

[MJCronin]

I agree with r6155 and metengr ..... This could get legal really fast.

ASME rules are hard and fast.

Unlike house plans, pressure vessel drawings and U-1 reports are legal documents and not design suggestions ..... especially for vessels stamped for LETHAL SERVICE.

If modifications were made after the vessel was in service, then the Repair Stamp rules apply.

We are dealing with serious safety issues here ..... IMHO, incomplete welds on a vessel are like putting a bullet in the chamber of a gun

MJCronin
Sr. Process Engineer