Ductile Iron or Steel Pipes
Ductile Iron or Steel Pipes
(OP)
For a large wastewater project in North America, for large pipes (diameter 30"- 48"),under low operating pressure conditions, is it cheaper to use steel pipes instead of ductile iron pipes?
Thanks in advance
Thanks in advance





RE: Ductile Iron or Steel Pipes
Ductile iron is probably cheaper for standard service.
Call some manufacturers and find out.
RE: Ductile Iron or Steel Pipes
corrosion?
underground?
length?
type of soil?
RE: Ductile Iron or Steel Pipes
The recent book "Trenchless Technology" by Najafi and Gokhale, in a section that discusses pipe materials in at least a little more depth than a great many prior textbooks and references, starts out with the interesting statement, "Trenchless construction methods cannot be successful without quality pipe." Frankly, I believe this is true of any construction methods and pipeline projects!
For a case in some points I am aware of a substantial 21st century wastewater project not long ago in the size range you discuss, with many accounts including what can be observed at ht
In short, a large wastewater project was initially designed with metal pipe, but was allowed to be actually built with cheaper alternatives/sections of new pvc and hdpe pipes, respectively offered up by contractor(s). There were issues, shall we say, with both of these types of plastic pipe sections in young service (some of which were quite nasty and also drew the less flattering attention of newspapers and bloggists). The problematic plastic pipelines were replaced, one section with new steel pipe and one with ductile iron. While I believe it was reported the re-building went more smoothly (although obviously at substantial additional time and/or cost), the chosen new steel pipe installation also promptly failed at least once, to kind of add insult to injury, with newspaper reporting at least one resident was again "fuming" (so to speak).
While I am not aware of any problems with the ductile iron part or line since, I guess I wouldn't necessarily put problems beyond such either!!
"Our lives begin to end the day we become silent about things that matter." Dr. Martin Luther King, Jr.
RE: Ductile Iron or Steel Pipes
pressure? 150 ft of head
corrosion?
underground? above grade but inside a building
length? 1000 ft
type of soil? Not applicable
RE: Ductile Iron or Steel Pipes
RE: Ductile Iron or Steel Pipes
The word "cheaper" has so many meanings. Do you mean the price of the pipe delivered to site, the total installed cost or the life cycle cost?
When you say "in a building" I presume if it supported above grade and thus the frequency of supports would rule out PE?
GRP could be considered but needs a high degree of design inconjunction with the manufacturer.
Have you considered spiral wound stainless steel? this has been successfully used in many plants carrying sewage or industrial waste water. The thinner wall thickness is adequate for lower pressures and thus costs can be kept down. The pipes can be welded or joined using Victaulic type couplings. SS pipes do not need to be painted in plant like steel or ductile iron. They cetainly dont need the restraints of ductile iron pipe to withstand pressure.
"Sharing knowledge is the way to immortality"
His Holiness the Dalai Lama.
http://waterhammer.hopout.com.au/
RE: Ductile Iron or Steel Pipes
Depending on the type of process line involved and other factors, common contemporary linings for wastewater applications are cement mortar lining, ceramic epoxy, and glasslining (the latter for specific process lines like some primary sludge and scum etc., wherein no other piping material or linings have demonstrated comparable non-oleophilic nature, overall performance, and also maintenance capability e.g. with steam cleaning etc., if ever needed). Exposed process piping is traditionally furnished with special primers for compatible finish coatings of paint, in most cases not necessarily that it is "needed" for corrosion protection, but instead primarily to comply with process piping color-code requirements/practice and/or aesthetics.
You may want to visit with experienced personnel of plants that have been run continuously for substantial lengths of time, experienced engineers who have long been responsible for specifying the piping of such, and discerning review of standards and educational materials including these and other forums etc. for specific guidance concerning materials for specific processes.
RE: Ductile Iron or Steel Pipes
Consider PVC
RE: Ductile Iron or Steel Pipes
RE: Ductile Iron or Steel Pipes
"Sharing knowledge is the way to immortality"
His Holiness the Dalai Lama.
http://waterhammer.hopout.com.au/
RE: Ductile Iron or Steel Pipes
Only put off until tomorrow what you are willing to die having left undone. - Pablo Picasso
RE: Ductile Iron or Steel Pipes
In the latter regard, I am also aware of an incident in per account at http://c
While it is admittedly not the same sort of "plant", I will also note the contemporary, real cost of accidents working around pipes can now be quite substantial, which is revealed in the similar sounding accident etc. report at http://www
Again, I am aware of a great many other unfortunate accidents etc. from working around/with weak pipes. While the actual cost and time/distraction to all parties and their management personnel who happen to be somehow around/involved, as well as who is responsible and/or pays for same, can be endlessly debated, I don't believe anyone really wants to be in such "Whauhauppened?" situations.