Internal Piping

By pipewelder_1999 (****)

Date 12-08-2008 15:24

I am not sure what a D1.1 vessel is. I have seen internal piping in ductwork etc, but usually the design drawings referred to a specification that clarified the requirements for piping. I would look at all referenced drawings with attention to the notes. Also look at the piping detail drawings. Do they too specifiy D1.1 ?

D1.1 does allow GTAW to be used as a process.

There are just no considerations for pressure containing components in D1.1

By jwright650 (*****)

Date 12-08-2008 15:50

Hi Gerald,
Yes, I agree with you in that GTAW is a process that is code approved by D1.1(AWS D1.1:2008 paragraph 3.2.2)...however it is not considered a pre-qualified welding process. So, the OP may want to be aware that any WPSs that include the GTAW process must be qualified by testing(AWS D1.1:2008 paragraph 3.2.1).

By pipewelder_1999 (****)

Date 12-08-2008 15:56

Good point. I figured piping and assumed one side no backing, circumferential joints and thus no prequal status their either so left out any refernce to Pwps's.

By jwright650 (*****)

Date 12-08-2008 16:05

on another note.....I haven't heard of a D1.1 vessel either...

I realize that in years past that many people looked to D1.1 the Structural Code-steel for guidance in welding steel, but now with all of the specific specifications and codes out there for all sorts of weldments, so I was kinda surprised to see it put that way.

By ericjames99 Date 12-08-2008 16:22

they do specify D1.1 on the vessel it self, its an atmospheric vessel but not on any of the internal piping prints. aAre internal pipes considered a structural weldment? The problem i am having is We told them We would have to qualify the tig and they didnt want to pay the extra so it was deemed unnessisary because they were to be only leak proof which indicated to me not to D1.1. I had a pressure leak test done and found 2 leaks and there customer told them to x-ray them now. well the x-rays failed as i had thought they would because we were to give them leak proof no code welds in the begining. We had to cut all the piping out of the vessels and now our customers customer is requesting presure piping standards which we outscourced to a company who had procedures in place for that. they are now trying to backcharge us for the piping which went from no code to D1.1 to Pressure Pipe. The original Project Manager for us Quit in the middle of this project so i have little to no comunications. They are trying to say that we couldnt even give them a d1.1 pipe like they asked. They are saying since its on the vessel prints it applies to the pipe. but its not on this piping sub assembly print only leak proof is.

By hogan

Date 12-08-2008 16:58

I think you will want to go back to the beginning. Review the job specs, approved drawing notes and contract. It's hard to weld and test/inspect unless you know exactly what the requirements are.

By 803056

Date 12-09-2008 17:50 Edited 12-10-2008 01:22

Any changes in the contract requirements usually qualifies as an "extra" and that translates into money paid by the "owner" for the changes requested.

Hoppers, bunkers, silos, etc. can be welded to AWS D1.1 requirements and internal piping can be used as structural supports. Piping doesn't necessarily mean a liquid under pressure is to be contained in the pipe. The pipe may be used for any purpose, including the the movement of air or solid materials, i.e., grain, sawdust, sand, etc.

AWS does not require every pipe weld to be a complete joint penetration weld. The extent of welding should have been specified by the drawings or other contract document.

If D1.1 was specified by the project specifications or the by the drawings, and the owner adds the requirements for NDT other than visual inspection, the owner is responsible for the cost of preparing the material for the NDT, the cost of NDT, and the cost to make any repairs as a result of deficiencies identified by the NDT. The exception is if the owner can prove the fabricator was attempting to defraud the owner.

On the surface, your description of what took place sounds like there was a "failure to communicate" the project requirements to the fabricator. The suggestion that you go back to the beginning is sound advice. You need to find out what the original requirements were (in writing) and what changes (in writing) were added by the owner after the contract was "signed".

It is difficult to meet the customer's expectations if those expectations were ill defined to begin with.

Best regards - Al

By Ke1thk

Date 12-09-2008 19:14

Good points.

I'm thinking about the contract process. The customer offers me the part and print with D1.1 on it. I offer to make the part to the print for $10 a piece. The customer accepts.

I look at the print a discover that GTAW requires additional testing. I can either compleate the contract or ask the customer for more money.

Or, I could ask the customer what code should I weld the sub-packet to? I could then inform him about the additional cost.

Our quoting department factors into the bid a fudge factor for speeding tickets.

Keith

By hogan

Date 12-09-2008 19:34

OR
You could actually read the print and make an appropriate bid knowing all of the requirements. Looking more professional in the process. Then you don't have to have that embracing talk with the customer. The one where you tell them you have read the job requirements, and made a bid. Then upon further review you see that there is more to the job than you thought. The customer, already knowing the requirements, will tell you one of two things. "I know I said I would pay you $10 for this widget, but due to your incompetence I will be happy to pay you $1500 in widget qualification fees". The other options is "Maybe you'll throughly read the spec's next time, $10 a widget is what the contract says".