How many welders

By hlshawjr Date 08-08-2005 01:09

Is there a requirement stipulating the number of welders required to weld certain diameters of pipe? I know there are company requirements such as 14" or greater two welders are required to make the weld. I am interested in information that is documented in welding codes or other entities such as DOT that have requirements for this. Currently I have a contractor welding pipe greater than 14" and is using two welders for the bead and hot pass, and ocassionaly a fill pass, then having one welder fill and cap. Is there any requirement to hold this contractor to a minimum of two welders until the weld is completed? We are using the 1104 code for this work. Any replies would be greatly appreciated.
Thank you,
H.S.

By rodofgod (**)

Date 08-11-2005 22:25

Hi!

Whilst I can not answer to the code you are working to, general procedure for large bore welds usually insists on a 'Balanced' weld! This means an equal 'heat' input into the weldment for the duration of the welding time.
I feel that if you did a bit of research, You would find plenty of info regarding code requirerments!
Depending on thickness etc, You really need two welders on a 14" butt regardless!

Regards

By G.S.Crisi (****)

Date 08-11-2005 22:54

No, the applicable piping codes (ASME B 31, API 1104 etc.) say nothing on how many welders at the same time must perform a weld on a large diameter pipe. This is a question that should be stated on the WPS (Welding Procedure Specification), usually prepared by the contractor and approved by the client.
It's certainly a good practice to weld large diameter pipes by means of two welders working at the same time, 180 degrees apart.
I myself have done like that back in my days of erector engineer, but for pipes 24 inches and larger. However, I don't have anything against using it for 14 inches piping, as in your case.
Apart from granting a more uniform heat input, as rodofgod says, you'll prevent the pipes from getting out of alignment during welding.
Giovanni S. Crisi
Sao Paulo - Brazil

By JTMcC

Date 08-12-2005 01:00

That's standard procedure, 2 bead hands, 2 hot pass hands and 1 firing line hand per joint. There are normally enough firing line hands to keep up with the front end.

JTMcC.

By JTMcC

Date 08-12-2005 23:05

The grade of your pipe will make a difference. Some companies will require 2 welders per joint for fill/cap on higher grade pipe such as X60 and up.

JTMcC.