Proper knowledge of a pipeline system not only requires information on water pipes location and data on material, dimension, year of installation, installation depth etc., but also details on pipeline condition. This is why the Austrian ÖVGW W 59 Guideline – Austrian Ö-Norm Standard B 2539 – already demanded a minimum of monitoring and maintenance activities and water loss detection by (then) stateof- the-art methods. The ÖVGW W 63 Guideline released in 1993 envisaged the identification of water losses in a distribution system in percentages, with 12 percent being the optimum. It is know today that this type of information has only limited validity.
In the previous guideline it was also recommended to calculate the water loss in a distribution system by length (m3/h/km). Moreover, reference values for quantity-related water losses had to be entered in a diagram; depending on the type of soil and the specific water flow, these values had to be in the range of 0.45 and 0.05 m3/h/km.
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(Source: aqua press Int. 3/2009, Doris Kasess & Christof Hahn)