D 10.12 Pipe Welding

By ganglywrench Date 05-14-2015 19:39

Our metal fabrication shop produces custom armatures from a variety of carbon steel sections and we are having some issues clarifying the proper code for armatures made from mild steel pipe. These armatures are usually part of a larger assembly of fiberglass or other coverings that are bolted to concrete slabs or mounted to walls as per contract; they are more sculptures than anything else. They are structural in the sense that they need to withstand either the wind load or seismic loads that the local codes require. The AWS codes seem to have a hole for pipe work that is not part of a pressure assembly. We would like to use our certified welders that qualify under D1.1 but do not want to have to put a piece of plate at each pipe joint which is what we do now. We have a new job coming down the pike that requires rather complicated pipe armatures and I want to help clear up the current confusion. Does anyone know if there is a work around for this type of pipe work?

Thank You,

Ganglywrench, New York

By 803056

Date 05-14-2015 21:25

AWS D1.1 has provisions for tubular connections whether they are tubular members to plate or tubular member to another tubular member. The design provisions are addressed in Clause 2. The qualification requirements for WPSs that are not prequalified addressed in Clause 4.

The conditions of prequalification are addressed in Clause 3. if you cannot meet all the conditions of prequalification, the WPS must be qualified per the requirements of Clause 4.

You are correct in your assessment that AWS D1.1 does not address systems that are pressurized and covered by another code such as ASME pressure piping codes.

Best regards - Al

By welderbrent (*****)

Date 05-15-2015 00:38

Ganglywrench,

WELCOME TO THE AWS WELDING FORUM!! And it's new format as well.

The D10 materials that you reference in your title line are reference works only, as opposed to the codes and standards of other sections.

D1.1 Structural Steel appears to be the best place for your work to be classified. Their impact would be structural even though they are not a supporting part of a building. They sure don't fit under Automotive, Bridge, Machinery, etc. And they would not fit into classifications per ASME, API, or other pipe related codes either.

So, as such, we must deal with what we have. The product then being fabricated and inspected under the D1.1 code your welders would be fully qualified to weld it if they are currently qualified to weld to D1.1. There may be additional testing to do if you have pipe fittings that need qualification not covered by a plate test. And, as Al stated, you may need PQR testing per Clause 4 if you can not come up with a joint, process, and total fabrication that is pre-qualified per Clause 3.

To fully answer and/or give any further guidance we really need some additional info:
Type/grade of pipe; joint, welding process, overall product configuration (we may be able to offer suggestions for new design that would make the joints pre-qualified), etc.

A picture would be great but not always possible. Drawings work also.

He Is In Control, Have a Great Day, Brent

By ganglywrench Date 05-15-2015 12:21

Brent and Al,

Thanks for your quick responses. I have attached a sketch of a typical armature that we would produce. The sketch is simplified, the one dimension is for reference, but it gets the idea across. Usually we would specify a flare bevel around the full circumference at each pipe seam. The welder would bevel the edge with a grinder or bench tool tack the pieces together then complete the welds. Would something like this be covered by D1.1? Most of our work is done under D1.3 because we often do not exceed 3/16" thick material but our welders are qualified up to 1/2" thick material for D1.1 work.

.

Thanks,

Ganglywrench

Attachment: TREESPINESKETCH.pdf (16k)

By 803056

Date 05-15-2015 15:11

Flare bevel? Unless your welders are doing something out of the ordinary, I suspect the preparation for the butt joints are V-grooves.

If the goal is to achieve CJP on the butt joints, you will have to qualify both the WPS and the welders for open root groove welds on pipe of the appropriate diameter and wall thickness if you elect to follow AWS D1.1.

If you haven't done so already, get a copy of D1.1 and study it closely.

Your sketch was just what we needed to help point you in the right direction.

Best regards - Al