Copper or Steel Pipe for a buried steam pipe

steamyheat

I need to replace a long section of 3 inch steam pipe (probably steel or wrought iron, house is from 1929) below a slate sunroom floor. There may have been original insulation beneath the slate and concrete, but now the pipe is sitting on dirt. What are your thoughts on replacing with copper pipe versus steel? Problem becomes having the equipment to thread steel. Copper is an easier material to work with but concerned about the soldered connections with steam heat.

Has anyone used copper in this application?

Any advice would be much appreciated!

Danny Scully

Is it a return line or supply?

EBEBRATT-Ed

3" is unlikely to be condensate.

I would stay with steel threaded. Mega press is rated for steam but is limited to 2" as far as I know. Pro press is rated for low pressure steam but it wouldn't be my choice unless their is no other alternative. Solder connections don't hold up on steam supply. Maybe brazing would

Jamie Hall

If you should have to use copper for some reason -- which I don't recommend at all -- you absolutely have to provide for expansion. I can think of several ways to do it, but they are all going to involve some interesting combination of flanged or union fittings at at least one end. You must not put any repetitive torque on a soldered fitting, and it's best not to put any repetitive tension on one, either.

jumper

Supply pipe in dirt rotted away in less than a century? Need a drained conduit?

Pumpguy

Regardless of the pipe material chosen, you might want to look into using an insulating product specifically designed and offered for use with underground piping.

Typically, these products are pour-in-place powered Calcium Carbonate, and are offered as protection against both heat loss and corrosion.

Two brand names of these products come to mind; GILSULATE, and DRITHERM.

Hope this is helpful.

jumper

Pumpguy said:

Regardless of the pipe material chosen, you might want to look into using an insulating product specifically designed and offered for use with underground piping.

Typically, these products are pour-in-place powered Calcium Carbonate, and are offered as protection against both heat loss and corrosion.

Two brand names of these products come to mind; GILSULATE, and DRITHERM.

Hope this is helpful.

Yes it's useful. But the work to trench & bury costs so much more than a conduit ,I can't understand why folks don't bother for the next poor devil who has to replace.

ScottSecor

If I understand correctly the old steel steam pipe lasted over eighty years. I would use steel again, schedule 80 would be best, but I think schedule 40 will be fine. I'd also make sure to use cast iron fittings.

steamyheat

Thank you for all of your comments - they are helpful.

Jackmartin

I do not understand, you use schedule 40 steel pipe, but insist on cast iron fittings ,huh. The reason your pipe lasted so long, is the dead men used high quality mallulable carbon impregnated pipe. The iron content was high. If you are worrying about threading on site do not do it. Victalic is making connectors for two hundred pound saturated steam. Weld what you need groove one end and attach it, and for heavens sake use at least schedule 80 or if you can afford it low quality stainless 304 works nicely and will not brake the budget. All the best Jack