Fit-up Inspection - Who?What?Why?Etc.

Date 04-15-2007 14:52

Hi folks-
This question falls in the "why do we do it this way/why don't we do it that way" category and most of the time I have gotten answers of the type, "cause that's the way we always did it" or "we never did it that way before";

In my shop, fit-up inspection is called for even before tacking; we don't have a separate tack inspection - our next inspection is root inspection and then of course a final. I am hoping for your suggestions on the value of fit-up inspection or any other thoughts concerning this.

And my question(s) is:
1. What does "fit-up" inspection mean in your shop (Do you have a fit-up inspection)?
2. Is there a Code requirement to perform a fit-up inspection?
3. Who is responsible to conduct it?
4. More importantly what should be inspected at fit-up?
5. Lastly, how much time is spent waiting for "fit-up" to be inspected?

WEBMASTER - I am hoping to get several points of view on this from the trades perspective as well as from the inspector point of view so please permit my double posting in that forum also. Thankyou.

And thanks in advance to all who reply.
Tom

By jon20013 (*****)

Date 04-16-2007 11:57

Here's my take:

1. What does "fit-up" inspection mean in your shop (Do you have a fit-up inspection)? Response: We have fit-up inspections at every joint and it entails making sure the joint is fit in accordance with our WPS and also that the materials haven't been damaged during fit-up.
2. Is there a Code requirement to perform a fit-up inspection? Response: I'm not sure "requirement" is the correct term, AWS D1.1 states that the Inspector is responsible for a variety of in-process inspections (which includes fit-up) but it does not state any quantities to check... nor am I familiar with any other Code that speocofcally places a Hold Point on fit-up.
3. Who is responsible to conduct it? Response: In my own opinion, first line inspection is always the welder, followed by a supervisor or peer... finally, the Inspector has (again, in my own opinion) ultimate responsibility for this activity.
4. More importantly what should be inspected at fit-up? Response: Making sure the fit is in accordance with the approved WPS.
5. Lastly, how much time is spent waiting for "fit-up" to be inspected? Response: This would vary from shop to field and vice versa. May be a matter of minutes or in extreme cases, hours.

By js55

Date 04-16-2007 13:59

In my opinion fit up inspection, for most environments, of each and every joint is overkill, and most likely unproductive. Verification of WPS requirements as jon mentioned is certainly required by code, as with volts, amps, travels speeds, etc., but I believe that most of them assume a random inspection.
It should be up to your Manual and Inspection Procedures to determine the extent necessary, because, in the end, no matter what inspection you require, if production personnel wish to circumvent the procedure they can. At some point you always have to trust that your personnel are doing it right, unless you have an inspector for every production hand.
If you find your level of inspection is inadequate you can always increase surveillance, or concentrate on those individuals of special concern.
I think it is important that you write into your Manual that welders, fitters, etc. be responsible for their own work, as jon mentioned, and indoctrinate them as such. And then verify with independent QC inspection over the top of that.

By jon20013 (*****)

Date 04-16-2007 15:14

Jeff, I most definately agree, fit-up of each and every joint is overkill and unproductive. In my particular case, it's only because our VP of Quality Assurance demands fit-up of everry joint. His excuse is we have to provide an opportunty for our ANI to apply hold points as he sees fit. I argued he can still do that but the VPQA is one of the Owners of my company so my argument fell on deaf ears....

By js55

Date 04-16-2007 15:58

jon,
Yeah, your VP's defense is not only thin, it makes no sense. Especially since the hold point process takes place at the ANI drawing review stage, so what does in shop inspection ahve to do with it?

By tom cooper (**)

Date 04-16-2007 23:34

Thanks guys, you told me more or less what I was hoping to hear.
Best regards,
Tom

By Tommyjoking (****)

Date 04-19-2007 09:55

The only thing i can say on this is....

It can save rework....if the fit up is bad and you weld it what does it take to correct it? Answer: a lot more work than it took to make sure it was ready to weld. Quality control depnds on the job....if your fitting a million dollar joint then it should be inspected....if your fitting $2000 dollar joint then its probably a waste of time.

By MDG Custom Weld (***)

Date 04-19-2007 13:22

Does the cost of a joint really matter?

Yes, I agree that the cost of rework goes up with the cost of the joint, but does quality, liability, and/or potential failure care if it's a $100 joint or a $1,000,000 joint? You are to inspect as the contract documents, code, or internal standards dictate, not on the cost of the part produced.

By scrappywelds (***)

Date 04-24-2007 00:42

I do field work either pipe or boiler tube welding. We do the fit-up inspection on high quality X-Ray work (B1.1). The pipe or tube fitter make the joint up sets the acepted gap for the code or welders preferance anywhere from 1/16 to 1/4. Checks for internal high-lo, plumb, level, square, and proper measurements. at this point the QC can inspect or not. If not the welder will start tacking the joint up and untill there is 4 tacks in the joint, as long as they don't make the 4th tack they can refuss the weld if its not to their liking. On the other hand don't bitch if ya don't like it after the 4th tack. At this point the inspector can check the jiont and they usaully do. The welder then leaves a "window" in the root so the inspector can check it and if they like it sew it up and finish welding the joint out or till a pre-set hold point.