Tracing pipes material

[imatasb]

Dear colleagues,

We are designing a 8" pipe that needs to be steam traced (low pressure steam 4 barg). The specification of the pipe is ASTM A-312 Type 304 (stainless steel).

According to the customer specification all the tracing tubes should be done in 1/2" 150# carbon steel (ASTM A-53 Gr.B Type S).

The mounting procedure specifies that spacers should be installed to guarantee no contact between both pipes.

All this makes sense to me, but I would like to know your views about this question and whether there are any cases in which tracing should be done with stainless steel pipes)

Cheers

 

[ione]

Considering your steam pressure you can go with copper tubing or with stainless steel TP 316. Carbon steel not properly the most recommended choice.

 

[SNORGY]

I would be inclined to use SS tracer material. In the long run, it's probably an economic wash between going that route versus going CS with spacers. Moreover, when the insulation gets installed and they start tightening the bands on the outer cladding, then if they happen to be mid-span between the spacers on the tracing, the contact that they are trying to avoid will happen anyway - unless the tracer to piping gap is such that the insulation then gets awkward to install.

Regards,

SNORGY.

 

[Duwe6]

U.S. industry standard for steam tracing is 304 or 316 tubing, typically 3/16" diameter. Using C/S and carefully installing standoffs, and accomodating this bulge in the insulation may actually have as high an installed cost as s/s tracing.

One should be very careful trying to reinvent the wheel. You probably cannot improve on it.

 

[rmw]

Yeah, this is making something hard out of something simple.

rmw

 

[11echo]

I could live with the 1/2" C.Stl. tracing, but with the fitting used with this line it would be hard to get the piping to "kiss" the 8" line, plus all the connection joints would be under the insulation. This is where the leaks are going to happen. I don't agree with 3/16" Dia S.Stl tubing, steam is a nasty commodity, and would have that size plugged in months, I'd suggest 3/8" Dia. S.Stl. tubing. Now two other points "IF" you use S.S. tubing ...tubing comes in 40ft. joints, so you're going to have to use end connectors to joint the sections ...no big deal. However this is a location for a leak, so bend the tubing at these joints so it's outside the pipe insulation ...so maintenance people can easily see if the joint is leaking or not. ALSO this tubing is normally banded to the piping approximately every 5ft. ...or so. Tool pusher can get abit heavy handed doing this strapping/banding operation, so put 2 each 3" to 4" long pieces of re-bar next to the tubing where the band goes over the tubing. This will keep the band from crushing the tubing. The re-bar has to be same size or one size larger. Good Luck!

 

[Duwe6]

Sorry! The 3/16" was a typo/oops. Standard size is 3/8" OD.

 

[unclesyd]

If you are going to use standoffs you will probably need to a heat transfer compound (HTC). The standoff has to be rugged, not welded to the pipe. We try to avoid standoffs.

On lower required temperatures we use SS tubing installed with Swagelok fittings. Our higher temperature lines are traced using the CSI ControTrace system.

http://www.csiheat.com/sites/csi/services_support/installation_troubleshooting.aspx