Shop Drawings and Pre-Approved Joints

By jrw159

Date 10-24-2008 12:53

Chris,
Please see AWS D1.1 2008 clause 1.6 Welding Symbols. This should help with your problem.

jrw159

By eekpod

Date 10-24-2008 13:40

Thanks, but I'm trying to make it more specific than that. Basically, the pre-qulified joint designations can be determined from A2.4, but I'm trying to make it more streamlined.

For instance , now I get a sinlge bevel weld symbol, and I'm lucky if I get a P.P or F.P in the tail to tell them full or partial pen. But it doesn't tell them how much to bevel the piec if its a partial. If they automatically put the symbol and in the tail put BTC-P4 then we would know which joint.

By jrw159

Date 10-24-2008 14:00

Chris,
This information is required to be in the welding symbol per AWS A2.4 IE depth of bevel, groove angle and root opening.

Basically, D1.1 ties to A2.4, and there are requirements that must be followed to convey the information to the shop floor in a clear and concise manner. I am not sure you can pin them down to a joint designation, although I see the benifits of doing so, but you can for sure pin them down to the required information for welding symbols per D1.1 and A2.4. If the welding symbol has all the required information then that is all that is really needed. I have the same issue from time to time where someone too lazy to warrant their existance behind a desk sends down a shop drawing with nothing but an arrow, referance line and tail, with no information except PJP or CJP in the tail section. I then have all the backup per code to reject this drawing for lack of information, send it back accompanied with a request for information form.

So in short, I do not think there is any way to pin them down for a joint designation, other than somehow working this into the specs as a requirement.

Good luck,
jrw159

By hogan

Date 10-24-2008 14:43

eekpod,
Maybe if you gave them the applicable references as listed in AISC for joints and symbols it would be easier for them to follow. Keep it to one book that they are familiar with using.

By jrw159

Date 10-24-2008 19:13

Chris,
BTW, are you guy's IAS AISC or ISO certified? If so your issue is an easy fix.

jrw159

By welderbrent (*****)

Date 10-24-2008 15:24

With the proliferation of computer usage and lazy programers and/or users many of whom have never cared about the vastness of weld symbols I have found it very frustrating that the majority of welds called out in prints by engineers, architects, and detailers are defaulted to a filet weld. It is too difficult for them to take the time they are being paid hansomely for to use the proper symbol to let us know precisely the weld they actually want at that spot.

I don't know if any of your suggestions will work on them except to refuse to continue the project until the symbols on your set of construction ready prints match the welds requested for the joint type shown.

I have stopped several projects until I have engineer stamped clarification sketches or drawings which the special inspectors and government inspectors can compare to the joint and weld which I was required to produce. Otherwise many of them will stop the job at that point and say that there is a problem.

Have a Great Day, Brent

By gsi

Date 10-24-2008 18:54

Hey Chris,
I have those very issues.
We got together with our shop Inspectors, a few foremen and developed a cheat sheet of the most common stuff we run into. I had all this put on a laminated card 8"x6". I also purchased several copies of AWS A2.4 and A2.1 wall chart. This has been a uphill battle for sometime but after about two years I'm really seeing it pay off. The issues are not gone but are getting better.

Good Luck

By eekpod

Date 10-25-2008 00:31

Thanks guys for all your input.
one issue is that the detailers don't always know what process we use. Depending on which of our shops fabricates the parts its usualy FCAW, but it could be GMAW, so there can be differences between them among a joint configuration. Aditionally the bevel angle vs root opening obvoiusly can vary especially with the tolerances, but again my main intent is to esatablish a basic baseline and work from there.

Time wise, I wish I had time to reject the drawing for insufficient info and send it back. But once it hits the shop floor, I have to have an answer within about 1 hour or else all hell breaks loose because things are getting held up... again I didn't draw it, or check it or approve it, but as a CWI I'm the one they all run to to figure out exactly what they are calling for, other wise who knows how it might or might not get welded. Again, i'm trying to streamline things with about four differnet detailing companies not including our own in house.
Thanks Chris

By welderbrent (*****)

Date 10-26-2008 19:02

Even on easy items of interpretation, I can seldom get an answer back that fast. Thankfully we are a small shop and always have multiple jobs going, so we can let one sit while waiting for an answer and work on something else without major setup or changing of floor space to cause us unneccesary handling time and expense.

Have a Great Day, Brent

By hogan

Date 10-31-2008 21:15

Chris,
I'll try to attach a pic I scanned of our drawings, look at detail A. I have our detailer list the the joint detail, in this example it's TC-U4a-GF. On a side note the "GF" means that you can use either GMAW or FCAW - same tolerances. Additionally I have any NDT listed in the symbol. This also helps let the know if a weld will be tested. All jobs are sent to me for review prior to hitting the shop floor. During my review I will attach all applicable WPS' to the drawings. This has help to avoid most of the problems you seem to be experiencing.

Attachment: dwg.pdf (289k)

By geralderik (*)

Date 11-04-2008 17:24

It's very interesting the level of details in USA. The level of detail in Peru is not advanced.

Dear Crhis put more pictures or drawing please,

Best Regard

By Metarinka (****)

Date 10-31-2008 20:17

I've had similar experiences coming onboard as a welding engineer and having to review thousands of legacy prints. It went as far as having 2 engineers specify SEAM welds, even though we have no seam welding equipment. I made several cheat sheets as well as gave a basic class to all the engineers on proper symbol use. I also made a packet of common joint details from d1.1 and where they are normally applied on our products.

I think specifying the joint detail in the tail is good idea, but that still leaves soom room to interpretation as well as tolerances. Basic things like bevel angle etc should be included on the print.

By ziggy

Date 10-31-2008 01:10 Edited 10-29-2009 07:05

eekpod,

Two questions every fabricator must ask themselves is: 1. "Who knows our means and methods in the shop better than we do?" Answer "No one" and 2) "Can we improve on our means and methods?" Answer "Absolutely"

So why allow a detailer (in-house or sublet) to select the welded joint design for the fabricator? I am not talking about the engineer's responsibility but the detailer selecting the CJP or PJP joint design for the shop's use to achieve the engineer's design. And I am not knocking all detailers; but there are many detailers who have not only never stepped foot into a shop but also who do not understand erectability issues and create a world of trouble for the fabricator!

Here are some methods that some fabricators are using to control the detailers:

1. They have a practical detailing standard that is issued to all detailers, in-house and sublet. In the detailing standard the fabricator tells the detailer who selects the welded joint design - the fabricator;

2. They do not allow the detailer to select the welded joint design, whether qualified or pre-qualified. All the detailer indicates on the shop drawing is whether or not the groove weld is CJP or PJP;

3. They review all groove welds on shop drawings PRIOR TO EOR APPROVAL. Included in this review is key shop personnel so they can help reach a decision on whether or not the weld is achievable, practical and cost effective;

4. They stipulate in the purchase order and/or sub-contract with the outside detailer several things like, a) detailer must adhere to fabricator's current detailing standards, b) detailer cannot sublet the fabricator's work to another detailer without the approval of the fabricator, c) fabricator will provide the appropriate WPS for groove welds, et al.

The fabricator must control the detailer. Otherwise, the fabricator will continue to get burnt on detailing issues arising from incorrect, impossible and/or outrageously expensive welded joints that some detailer dreamed up.

The first rule that the drafting "captain" explained to me was: "It ALWAYS fits on paper...so don't pay any attention to the shop's gripes!" That's how I learned the trade...and then I had to unlearn it!

That's my two cents. Best wishes on controlling those detailers eekpod.

ziggy

By jwright650 (*****)

Date 10-31-2008 12:58

Very good input ziggy,
Here at work we incorporated a Detailing Manual with our shop preferences included as typical welding details....works great as long as the detailer follows them...LOL

Chris, I understand that when the shop starts asking questions, the clock starts ticking and the shop's man hours per ton starts to get out of whack...for every question, you have people standing around, and then finally when they can't figure out what is intended, you have their supervisor or QC involved, and by the time the detailer is questioned and has time to respond....that man hour clock has really gotten wound up tight.