Abstract
M.Ing.
The aim of this investigation was to determine the N1 value in the relationship between pressure and flow for different types of water reticulation pipes with different forms of fractures. The relationship is defined as:
Once these N1 values are established, they can be used as an indication for better pressure management in water reticulation networks. This investigation was limited to three types of pipe with diameter 110 mm and wall thickness of 4 mm:
• uPVC
• Cast iron
• Steel
And three different forms of failures:
• Round holes
• Longitudinal splits
• Circular cracks
Pressure step testing was used to obtain experimental data. During analysis of the data, Cd was calculated from the initial area of a fracture and kept constant thereafter. Conclusions could be drawn about similar type pipes with similar fractures and comparisons could be made between all the samples as well as previous studies. Generally it seems that longitudinal splits lead to the most excessive leaking, followed by round holes and then the circular cracks. A summary of typical N1 exponents found is shown below:
• uPVC pipes with round holes 0.48 - 0.49
• uPVC pipes with longitudinal splits 0.89 - 1.26
• uPVC pipes with circular cracks 0.31 – 0.48
• Cast Iron pipes with round holes 0.43 – 0.44
• Cast Iron pipes with longitudinal splits 0.42 – 0.46
• Cast Iron pipes with circular cracks 0.41 – 0.43
• Steel pipes with round holes 0.42 – 0.44
• Steel pipes with longitudinal splits 0.39 – 0.45
• Steel pipes with circular cracks 0.38 – 0.48