Manhole cover material (Cast Iron Vs Ductile )

[mdrehansk]

Hello Every one,
I want to give provide ductile iron cover for manholes in one project but the local specification refer to cast iron.. I think ductile iron cover is better, but I have to convince them..please let me know if you have any better reference material/specifications to help me in this case.

Regards,

 

[JedClampett]

Call Neenah and see what they recommend.

 

[mdrehansk]

if you can provide some references to show which is better.

 

[gerhardl]

Mdrhansk,

In Scandinavia (Norway) the official standard for (street) manhole covers describes ductile iron. I have never heard of problems with this material. The covers have to withstand frost, ice, snow and temperatures down to minus 30 deg C (and more), as well as summer temperatures up to 40 deg C and more on sumwarmed streets. Normal cast iron would be too brittle.

 

[mdrehansk]

gerhardl, thanks you. I have come across the same information.

 

[bimr]

Traditionally, manholes covers were made of grey cast iron. However, ductile iron is considered is a better choice than grey cast iron because ductile iron is stronger and for the same traffic loadings, ductile iron will have less weight and will be easier for workers to remove. Ductile iron is less brittle than grey cast iron, and less susceptible to damage with lower maintenance cost.

 

[mdrehansk]

thank you bimr

 

[racookpe1978]

Likely, the spec was written who wants a "cast" product and "must be iron" ... So obviously, we write it as "cast iron" ... 8<)

 

[cvg]

cast iron has been used for over a hundred years and ductile has not. there is not a huge advantage for one over the other. there may be a cost advantage to allow both in your specification. light weight is not always an advantage, especially if they are located in the roadway. heavier covers are preferred in high traffic areas.

 

[Spartan5]

Not entirely relevant to the question... but this was an interesting read from 10 or so years ago that stood out in my mind that I though I'd share:

New York Manhole Covers, Forged Barefoot in India

http://www.nytimes.com/2007/11/26/nyregion/26manhole.html?_r=0

 

[blacksmith37]

Figures the NYT staff can't tell forged from cast . When i went to school a long time ago ; ductile was a type of cast iron .