ROUGHNESS

[elena74]

Hi,
probably this seams a very stupid questions, I know, but I can't avoid thinking I'm making an huge mistake and I need a help.
First of all, sorry for my English, I'm Italian.

I'm modelling a district heating network and I decide to use EPANET; I utilized it at the University and I forgot something, I think.

I want to use the D-W formula for head-loss calculation in the SI system and here's the question: the value EPANET's manual gives for steel pipe is 0.15 feetx10^-3, but which is the value in the SI system? Is it right to convert the value in mm (0.045mm) or I must leave 0.15?

Tanks to everyone will answer me; he will finally gifts me quit nights!
Elena

 

[cvg]

try this

http://www.engineeringtoolbox.com/darcy-weisbach-equation-d_646.html?mobile=false

 

[katmar]

Elena, your conversion is correct. The value for the roughness of 0.00015 feet converts to 0.045 mm in the same way that any "length" type parameter would be converted. By the way, these are typical values that are used for roughness of new steel pipe by engineers every day.

Katmar Software - Engineering & Risk Analysis Software

http://katmarsoftware.com

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