ASTM A-120 GALVANIZED CHILLED WATER PIPE

[schola]

Dear sirs:

I use to specify ASTM A53 Gr. A or B for chilled water pipes 3" diameter or mayor.

What kind of problems could be arise is ASTM A-120 theraded pipe is used in lieu of A-53 carbon steel, diameters 3" to 6"? 8"?

Thanks,

schola

 

[stanlsimon]

I have not seen anyone spec 6 or 8" threaded pipe for hvac type applications for a long time. A 6" threaded joint requires some serious muscle power to tighten. The plumbers and pipefitters of the 1950's were real men.

Victaulic joints would be much easier.

 

[sterl]

Can you procure A-120 in the large sizes?

I know of sources for 4" & 5" but those sources don't offer fittings in terms of Tees or Elbows.

I know of DWV much larger than that for scissor flange fit but its not pressure pipe.

I don't know of anything in 8" Tapered Thread. Finding a Die might be challenging....Turning it might be too.
I have seen (2) 6" Threaded CS for Potable exactly parallel to each other; we took them out (with a torch and saws) and replaced with 10" SS-316 Sch 10 due to decay and weight considerations...

 

[Whoops]

Anti-freeze and galvanizing do not mix. I think the corrosion inhibitors in most anti-freeze mixtures react with the zinc.

Anything over 1 1/2" (I think) is usually welded here (UK). ABS is commonly used now for chilled water systems.

 

[marcoh]

Why use galvanised pipe for a chilled water system? I assume it is a closed system so once the oxygen has gone from the water there should be minimal corrosion and any decent water treatment regime will limit corrosion to well within acceptable limits.

 

[kepharda]

I agree with marcoh, also with a 6" threaded system would probably be expensive. Lots of labor, and the cost of these large threaded fittings. Welding the carbon steel would seem cheaper.

I don't know about Victraulic with Galvanized Pipe. I haven't tried this, but if you cut the grooves for the Victraulic it would remove the galvanizing and if you rolled them it would seem to flake off. Anyone done this before?

-dave

 

[KiwiMace]

you can hot dip galv the pipe sections after grooving. Agree w marcoh that there is no need for galv pipe on CHW service, unless the corrosion issue is environmental.