carbon steel vs stainless steel pipe
carbon steel vs stainless steel pipe
(OP)
I am piping cooling tower water supply (600 gallons per minute) header. Supply and return will be about 100 ft. long. I can get sch 10s Stainless Steel for about $59 per foot. Customer intially wanted me to investigate CPVC, but it would require a larger pipe to keep velocities down and sch 80 so it was pretty expensive for PVC at about $55 per foot.
The other option would be carbon steel, but I am more than a little concerned about corrosion, sure the water will be treated, but it is an open cooling tower, so in my limited experience (4 years) there is always corrosion.
My question is this is there a carbon steel pipe that would be economical to install instead of the Stainless Steel that wouldn't corrode quickly?
Also, this pipe will be welded, please do not suggest threading.
thanks for any help
The other option would be carbon steel, but I am more than a little concerned about corrosion, sure the water will be treated, but it is an open cooling tower, so in my limited experience (4 years) there is always corrosion.
My question is this is there a carbon steel pipe that would be economical to install instead of the Stainless Steel that wouldn't corrode quickly?
Also, this pipe will be welded, please do not suggest threading.
thanks for any help





RE: carbon steel vs stainless steel pipe
I agree with you that threaded pipes should be avoided at these sizes.
Katmar Software
Engineering & Risk Analysis Software
http://katmarsoftware.com
RE: carbon steel vs stainless steel pipe
If you are concerned about the corrosion, you can use a heavier pipe thickness or go with the stainless. Stainless would be considered a step up above the standard pipe material.
You are correct in that it is not a good idea to consider CPVC for this application. CPVC would be considered as a step down in quality.
RE: carbon steel vs stainless steel pipe
Does anyone have some similiar experience that could tell me if this will be a big issue or not?
thanks,
RE: carbon steel vs stainless steel pipe
RE: carbon steel vs stainless steel pipe
RE: carbon steel vs stainless steel pipe
FIled fitting and welding stainless is a lot more efficient. Having to wait weeks for DICL make spools is a risk and costly in time.
Geoffrey D Stone FIMechE C.Eng;FIEAust CP Eng
www.waterhammer.bigblog.com.au
RE: carbon steel vs stainless steel pipe
While certainly not denying the utility of steel, or for that matter stainless steel, pipes in e.g. some plant piping applications ductile iron pipes have a quite good record of application and durability in particularly large water, wastewater plants, pump stations, and other applications in the USA (that has not yet been matched by the thinner and unlined SS). It is possible as you may infer that the availability of substantial, normally responsive fabrication facilities in the form of large manufacturers in this country, as well as even local fabricators in many areas familiar with the material, may be a factor in this substantial utilization. However, I just wanted to clarify a couple points. As I attempted to explain in my first post, innovations over many years in even ductile iron systems have made it possible to accomplish e.g. “closures”, with lengths of piping “cut to suit in the field (“CTSIF”) or other modifications, without the need of ordering specially fabricated “spools” from the factory. This can actually now be accomplished in many different ways -- with various types of grooved pipe systems, rodding with sleeves or couplings, flanged adaptors and restrained flange adaptors from various vendors and with various restraint features (some for even quite high pressure ratings for even large pipes), and even innovative adaptation [for even very high pressures in all sizes of pipe] of very positive decades old practices of factory or field welding quite strong restraint rings and collars to the outside of the pipe some distance upon the barrel of suitably gauged pipes (to allow say for adjustable cutting of that barrel for shorter length adjustment and restraint with threaded rods). See an example of the latter structure at ht
[Incidentally, I understand labor costs are quite significant in many areas of the USA as well. While construction cost estimating is admittedly not my specific area of expertise I would be quite surprised if stainless steel pipe field welding production/cost could come anywhere close to the field productivity of particularly grooved ductile iron systems, that normally assemble in just a few minutes with a couple bolts!]
RE: carbon steel vs stainless steel pipe
For the project, my recommendation to the customer was stainless because of the relatively short length of the pipe run (~200 ft) and small difference in cost (about $23/ft). I haven't recieved a reply back yet so we will see.
thanks again,
-dave
RE: carbon steel vs stainless steel pipe
RE: carbon steel vs stainless steel pipe
RE: carbon steel vs stainless steel pipe
Temps will be below 100 F
The Pipe run isn't to be buried.
The minimum velocities that they recommended is a good tip, fortunately I had already designed for about 7 ft/s.
I have experience with designing piping systems, just not cooling water, so I do understand the complexities of installing welded piping.
RE: carbon steel vs stainless steel pipe
RE: carbon steel vs stainless steel pipe
I ended up at almost exactly the spec you proposed.
I have also made it clear to the owner the need for water treatment once the system is assembled and even put him in contact with a couple of treatment companies.
Hopefully this will be enough
-dave