Galvanised Steel Pipe Internal Roughness? 2

[jbag]

I perform calculations on a regular basis for water and compressed air supply to underground coal mines. The standard piping used for these services is victaulic galvanised steel pipe and as a basis for the calculations we have tried to determine a suitable internal surface roughness for this type of pipe.

I have contacted the manufacturers of the pipe and they will only give me the pipe roughness after it has been milled and before it has been galvanised.

Does anyone have any references that give the internal surface roughness of galvanised steel pipe?

Thanks very much,
James

 

[rconner]

Flow properties actually achieved may be dependent on a great many variables; however, see Appendix C of extensive online viewable book at

http://www.haestad.com/books/pdf/awdm.pdf.

 

[ione]

For absolute roughness and galvanized steel you can consider 0.0003 in.

Cameron Hydraulic Data (chapter 3) may help you.

 

[katmar]

ione, I suspect that value of 0.0003 inch should be 0.0003 foot. I use 0.15 mm, which would be equivalent to 0.0005 ft or 0.006 inch. A typial figure for new commercial steel pipe (ungalvanized) would be 0.0018 inch and I doubt whether galvanising would make it that much smoother.

Katmar Software
Engineering & Risk Analysis Software

http://katmarsoftware.com

 

[ione]

katmar,

you are absolutely right (e=0.0003 foot)

Regards

 

[jbag]

Thanks Ione and Katmar.

Kind regards