C-Factor Testing

Hazen-Williams Formula

Pressure vs Elevation

Pressure Losses vs Distance

“Minor Losses”

Hydrant flow picture-0 flow

Hydrant flow medium rate

Hydrant flow-high rate

Pressure loss vs Flow Rate

Reynold’s Experiment

Sand roughness

• PVC 1.5 X 10 exp (-3)

• Copper 3.05 X 10 exp(-2)

• Steel 2.8 X 10 exp (-2)

• Lined Cast .1

• Cast .2

• Concrete .3

• Cement .4

C factor

• “A smoothness” coefficient

• Higher C means Lower losses

• Depends on material, finishing when new

• Depends on material, age, chemistry, microbiology when old

• Minor imperfections, scums, can have a great effect

C factor Depends on Diameter

• Low diameters mean low c-factors

• Small imperfections are meaningful

• Turbulence is more widespread

C-Factors for 6” pipe

• Unlined cast 125

• Lined Cast 133

NEW 30 years

• Unlined cast 125• Lined cast 133• Scraped cst 116• Pigged cst 104• DICL 149• PVC 150• CPP 150 (Large dia)

• 70-90

C-Factor Test Procedures

• Long piece of pipe

• Dead ended so flow is in one direction

• Known, Constant diameter

• Minimum of valves, bends, tees, etc