Thawing pipes

Date 01-29-2002 19:52

You might check out Lincoln Electric. They used to have a very detailed specification/technical bulletin entitled "Thawing Frozen Water Pipes-E695.1" that was a "handout".

If you need a procedure, I've got several.

Have a great day!

By RonG

Date 01-30-2002 13:00

What more would you like to know? It works (like a light bulb) the same as the welding process, difference being you have to much mass to melt rapidly.

The current you would use is the secondary side of the transformer and will work just like the engine driven machine.

Yes but beware, Aluminum is a very good heat sink and has a very low melting temp, and you need to find away to make connections with out arcing. I don't recommend using the primary switch for that task.

By Jorge Giraldo (**)

Date 01-31-2002 01:55

As Seldom said, you can find a chapter with a detailed prodedure about this issue on the book The Lincoln Arc Welding. They include sketches, equipment characteristics, piping diameters, amperages, etc. Tomorrow night I'll give you the exact reference.

Jorge Giraldo
Medellín, Colombia

By Jorge Giraldo (**)

Date 01-31-2002 23:21

The exact reference name is: The procedure handbook of Arc Welding by Lincoln Electric paragraph 13.8-1. You can't use a Constant Voltage Welder, because it has a very high short-circuit current that you couldn't control during the thawing and you can have the risk to melt your pipe. The equipment must be a constant current.

Where do you live? Is it a very common trouble in your country?

Jorge Giraldo
Medellín, Colombia

By Seldom

Date 02-01-2002 01:48

I can’t speak for Gunderr or RonG but my former plant site is in central Michigan (just below the 45th parallel) and freezing of process lines is a common occurrence when the ambient temperature drops below 0ºF and wind velocity picks up. I don’t think it’s quite as commonplace as it was twenty years ago with the advent of better insulating materials and tracer mediums. Regardless, there always seems to be a piece of insulation that’s broken off or an unexpected tracing system failure and you’ve got the recipe for a frozen line or if you were very lucky and real quick, only a frozen tracer!

During my welding career, coming into the plant at 1:00 am with a hard wind dropping the wind chill to -40ºF+ and having to find, thaw, and repair the line in the dark while up in the icy pipe rack so a production plant can get back on line, was one of the least enjoyable duties of a welder in our plant! If it wasn’t readily obvious (missing insulation or spilt) where the frozen section was, flanges had to be broke open or hot-taps performed to find and isolate it. Some times this operation spanned 100’s of yards of pipeline using flashlights and drop-cord lights. Once located, the thawing/welding machine was connected to either side of the frozen section and thawed. Often sets of flanges would have to be installed or a “pup-piece” to complete the repair or “button-up” the isolation procedure if needed depending on whether it was a welded line or a flanged system.

The most common thawing job I seemed to get involved with were 50% caustic lines which froze/setup at 54ºF and you always worried of getting the caustic on your clothing in the dark and then into your eyes!