Cement Lining for Ductile Iron Pipes vs Carbon Steel Pipes

[SDTH]

Hello All,
In AWWA Standards, the cement lining thickness specified for Carbon Steel Pipes is more than that specified for Ductile Iron Pipes (almost double).
Can anyone explain why?..
Is it because the resistance to corrosion for Ductile Iron material is more than that of Carbon Steel ?



SDTH

 

[LittleInch]

I think so yes and also the DI tends to be thicker than C Stl so any corrosion takes longer to create a hole.

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[EdStainless]

It has mostly to do with stiffness, the thinner steel pipe requires more liner for good integrity.

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P.E. Metallurgy, consulting work welcomed

 

[SDTH]

Thank you,
I would like to know if the reason is stated in any white paper, guide or similar publications..
The standards also don't provide any basis for the thickness.
Probably derived from practice.
I didn't see any details mentioned in DIPRA publications also.



SDTH

 

[cvg]

the steel pipe is much more flexible. often there is a mortar coating on both the exterior and interior (CML&C) this makes the pipe significantly stiffer which protects the coating from cracking