Hydraulic friction gradient of water

The hydraulic friction gradient of water in rubber-lined pipes in the range of 2" to 18" is presented in Figures 2-5 to 2-13. Rubber thickness of 6.4 mm (0.25") was assumed for 2", 3", 4", and 6" (up to 150 mm) pipes. Rubber thickness of 9.5 mm (0.375") was assumed for 8" to 24" (200 to 610 mm NB) pipes. HDPE friction head was plotted for similar sizes at SDRll (suitable for 100 psi pressure), to mark the advantages of reduced friction at these sizes using HDPE instead of rubber-lined pipes, wherever it may be appropriate. The design engineer must take in account the pressure limitations of HDPE pipes versus rubber-lined steel pipes. 

These curves and tables allow an easier and accurate determination of the hydraulic friction gradient of water than the Moody diagram. 

FIGURE 2-11 Hydraulic friction gradient of water in 10" and 12" SDRll HOPE pipes. Roughness 1.5 pm (0.00000492 ft). 

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