Can anybody help me how to have a longitudinal welding done on a cross country pipeline for electrical tracing. ASME 31.8 does not allow longitudinal welds, it recomends encircling member over the bare pipe.


The solution is either we change the thickness or put an encircling member both of which we cannot do.

Can CAESAR II help us in some way? Is there any other way of getting it done?

Can Caesar II help you out on a welding problem??????

I know that CAESAR does not have the capability to handle this kind of situation but my question was also like how can we go about solving this problem?

Any idea?

Haven't done much cross-country piping, but I'm not sure why longitudinal welding would be required for electrical tracing. A full-length longitude weld is needed only if the pipe has a seam that way, parallel to its length, and the Code deosn't allow it because miles of full-length weld are almost certain to crack over time. But the pipe conducts electricity its whole length regardless of whether the weld is a conventional seam or a full-length weld.

If you have an outside line (like for communication or heat tracing) then that line doesn't need (or want) a full length weld to hold it to the pipe: Use a short tack every 3-4 feet (4 cm per meter, actual interval depends on the cable's weight. But don't weld the cable itself if it is insulated: you'll still need a bracket on the pipe.)

I have scanned through my copy of B31.8 I have the following questions:

Just what type of electrical tracing are you trying to weld on?? Provide sketch of proposed weldment.

What paragraph of B31.8 were you reffering to in your opening comment?

What is the pipe ASTM grade you are working with?

My apologies upfront in I guess being pretty much ignorant of your application, but I was just curious why whatever you are dealing with must be welded to the (existing?) piping?

This reminds me of skin-effect electrical heat tracing. In this application, small tubes are welded longitudinally onto the proces pipe and then a conductor is pulled through. The physics of the heat tracing is that the inductance of the pipe causes the pipe wall to be heated when an alternating current is passed through the conductor.

If this is what you are doing, then the welds are not pressure-containing, and may be treated as attachment welds. Since the small tubes and the process line are both within the insulation blanket, and have continuous physical contact along the length of the pipe, and bear no structural load, there are no loads to consider other than the (small) additional mass as it applies to seismic analysis. Therefore, as attachments only, the welds are subject to the same rules as the welds for a lifting lug one would use solely to lift the pipe into (or out of) place. And, with no structural loads to be applied, your basic need is for a sort of electrical continuity.

If this is NOT what you are doing, please disregard my comments.