Lifting Lugs & liability

Date 07-30-2009 16:48

I have a question concerning ethics and liability plus I guess I just want vindication on an issue similar to the one just posted about lifting lugs.

We received a large compressor roughly #27,000 assembled. There are 4 lifting lugs for handling 2ea welded to each end.

The lugs are 3” round bar with a flange welded on the ends. The ends welded to the case was beveled roughly ¾” @ 45’ for weld.

Apparently the customer had found cracks or other flaws in the factory welds and had done some NDE and excavation. There was ¾” Fillet weld on top of the bevel weld and customer had ground it all away. All the welds had been ground on and some down below the surface better than ¼” inch with cracks still visible at the bottom of the groove.

The instructions given to me was to continue excavating the cracks until they were gone and then re-weld.

I refused to do as instructed unless an Engineer put in writing that we were to weld over old defective.

My feelings were that if we struck an Arc any where near them we would be responsible as well as liable should one of the lugs breaks off and allow the unit to drop.

I don’t know that for a fact but it seemed to be logical conclusion.

I feel the only way we could handle it was to completely remove them and all the old weld metal, re-prep them before welding them back in place.

I got a lot of blank stares and head shaking before they conceded to give the go ahead mainly because the know how hard headed I can be.

My question---- Is there a code covering this aspect? Seems to me AWS would have something in this area.

Was I just being hardheaded? I already know the answer to that, but was my assumption correct?

By motgar

Date 07-30-2009 18:35

Ron,

Are the cracks located in the round bar to flange welds? (The lifting lug assembly.)

or The flange to shell wall of compressor? (The lifting lug to compressor.)

By RonG

Date 07-30-2009 18:51

The cracks are in the weld that joins them to the Compressor case.

By drewp29 (**)

Date 07-30-2009 20:20 Edited 07-30-2009 20:26

My thoughts are you would then need an ASME 'R' stamp in order to repair those welds anyway since it is being welded to a pressure vessel . . . otherwise, you can't touch them. If you did, then you are liable, in fact just the grinding might require an 'R' stamp . . . I not sure how explicit the ASME code gets. That is, assuming the pressure vessel was built according to ASME Section VIII, then the rules of ASME Section IX would apply.

Edit: AND if you do have an 'R' stamp, then the liability is again in the Engineer's court because they are the ones who have to decide how to remove defective welds and the proper weld repair procedure . . . in which case, the liability is the company's after the stamp is issued for the repair.

Drew

By motgar

Date 07-30-2009 22:48

Thanks Ron. I figured those were the ones. Just wanted to double check.

As far as AWS D1.1 goes, it is not intended for pressure vessel or pressure piping. This may fall more into an ASME application.

Does the compressor have a stamped plate stating it was constructed to ASME code?

Shops need to be authorized by the National Board to make repairs to pressure vessels. Something referred to as an "R" stamp.

I think the main concern is how close the welds are to the pressure boundaries.

By RonG

Date 07-31-2009 02:01

Thank you for your replies.
I don’t believe this comes under ASME's purview. The lugs are on the machines case for erectors use

This is a 4 stage VK centrifugal compressor we are rebuilding in our shop. In our quality manual (ISO) we reference ASME on Welder qualification but the ASME covers very little of what we actually, do mostly Steam and Gas Turbines. Believe it or not the case of a steam Turbine is not considered a pressure vessel

API has a code we use for rotating equipment but there is nothing to cover this.

By motgar

Date 07-31-2009 14:46

Ron,

Well that changes things a bit. Was not thinking of compressor, as a part of a gas/steam turbine.
Sorry for not being of much help to you.

One thing the AWS does have is D17.1, Specification for fusion welding for aerospace applications. Maybe that could give some guidance.

By 803056

Date 07-31-2009 16:07

In general the employee is suppose to do as instructed.

I never had a problem when a welder or shop worker raised an issue of concern.

As an employee, you are not personally liable for your work in a company that is incorporated. A sole proprietorship is a different story.

The compressor shell is a pressure retaining component that I would be loath to weld on without the manufacturer's input. There are occasions where that simply isn't possible, i.e., they may no longer be in business or they simply won't have anything to do with repairs performed by someone else. Can't blame them for taking a stance in the later case.

Any welding to a pressure containing component has to be given special consideration. What is the material of construction? How is welding going to affect the base metal? Is the casing able to sustain the loads (I'm assuming the lugs were added by someone other than the manufacturer)? The list of questions goes on and on and on. They are beyond the purvey of the welder and shop workers. There should be an engineer with the necessary experience involved that can look into the issues that need to be considered.

A welding procedure for the repair should provide sufficient detail that the welder understands what is to be done and how to do it. A repair procedure is often more involved than a WPS used for production welding. If necessary, the repair procedure may have to be qualified before being implemented.

Those welds cracked for a reason. Has anyone determined the cause of the cracks? If not, what makes anyone believe the new welds will work any better than the original welds?

Best regards - Al

By drewp29 (**)

Date 07-31-2009 17:16

When I said 'you' would be liable, what I meant was your company would be liable. The individual employee will not see any backlash if the company tells them to do something that does not conform to applicable code, and the employee follows orders.

I would suggest that they have an engineer, as Al said, with sufficient experience get involved in the repair process, and maybe to look at the lug placement, number, and design to see if it is sufficient for lifting/turning the compressor weight. Maybe adding a few more with the blessing of the Engineer would relieve the stress on the repaired lugs so as to prevent the repair welds from cracking as well.

Maybe API RP 582 would give guidlelines for repair welding? I'm not familiar with it, but here is its description:

This recommended practice, initiated and developed through the joint efforts of API and Process Industry Practices (PIP), provides supplementary guidelines and practices for welding and welding-related topics for shop and field fabrication, repair and modification of:
Pressure-containing equipment (such as pressure vessels, heat exchangers, tankage, piping, heater tubes, pressure boundaries of rotating equipment, and attachments welded thereto); non-removable internals for pressure vessels; structural items attached and related to process equipment; and any other equipment or component item when referenced by an applicable purchase document.
This document is general in nature and is intended to augment the welding requirements of ASME Section IX and similar codes, standards and practices. The intent of this document is to be inclusive of chemical, oil and gas industry standards, although there are many areas not covered, e.g., pipeline welding (see API Std. 1104) and offshore structural welding (see API Spec. 2Z).

Drew

By RonG

Date 08-01-2009 21:05 Edited 08-02-2009 01:31

I was not concern for my self for the liability but for my employers sake as well as my reputation. I removed the 2 worst Lugs and found numerous cracks, inclustions and LOF.

I cant do the welding my self (Union Shop) but I do every thing I can to see that every thing leaving the weld shop stays gone at least till the customer wrecks it again.

Thanks for all the replies.