Nomograms

EnviroPressure Pipe Nomograms is based upon the Colebrook-White equation.

1. This diagram is based upon the Manning formula for open channel flow, and assumes that the maximum flowrate in the pipe occurs when the depth of the water in the pipe is the 95% of the pipe diameter.
2. Manning coefficient for clean HDPE is 0.01.
3. Effects of entrance, exit losses, bends, pits, and junctions excluded from the analysis.
4. Assumes clean fresh water flow at 20 degree celcius.
5. For grades above 0.1 and/or flow velocities above 3m/s, local authority approval may be required.
6. Maximum flow velocities above 0.5m/s encourages the self cleaning ability of the pipe, reducing the likelihood of silt deposits.
7. At flow above 7m/s a hydraulic jump may form inside the pipe at change of direction or reduction of pipe gradient.

EnviroPressure Pipe Nomograms are based upon the Colebrook-White equation.

Conditions to using these diagrams:

1. This diagram is based upon clean fresh water flow at 20 degree Celsius in full pipes.
2. Darcy friction factor coefficient for clean HDPE is 0.015.
3. Effects of entrance, exit losses, bends, pits, and junctions excluded from the analysis.
4. For flow velocities below 0.5m/s or above 3m/s, local authority approval may be required.
5. Maximum flow velocities above 0.5m/s encourages the self cleaning ability of the pipe, reducing the likelihood of silt deposits.
6. The head loss does not include the effects of gravity (i.e. any changes in elevation).