Active leakage control in low pressures - It can be done!
Leakage and Pressure
Water when leaving the pipe creates an ‘energy’ and it is this energy that is transferred through the water and the pipe wall by the means of acoustic sound. This acoustic sound depending on the material of the pipe work either dissipates over a long distance or is absorbed very quickly into the pipe wall. The effect being that for metallic or hard walled pipes the sound transfer is extremely good and for non metallic or soft walled pipes extremely bad.
Another consideration that has to be considered is that of pressure and size of orifice. The higher the pressure and the smaller the leak the greater the noise or ‘energy’ is created this is reduced depending on the orifice size or pressure.
The greater the sound or ‘energy’ = high pressure + small orifice
It can be seen from the table below what it is that is ideal for leakage location or detection
Scandalised Approach for Successful ALC
The approach now commonly promoted is that of LLP
The explanation of each of these is explained below.
All of the methods below are restricted to the pipe material and acoustic noise transversal of the pipe wall material over distance.
A method of narrowing down the location of the leak by various means to include but not restricted to the list below.
Step Testing – narrowing down the area by means of isolating parts of the distribution system.
Acoustic noise logging – deployment of noise loggers that identify constant noise during the preset hours that may be a leak or indicate a leak may be present. These may be left permanently deployed or adopt the ‘lift & shift’ technique.
All fittings survey – listening on all stop cocks and mains fittings with a manual listening stick to identify leaks mainly on property side.
Mains fittings only survey - listen on all mains fittings with manual listening stick to identify leaks mainly burst water mains.
District Metered Area- a methodology where flows into an area are monitored and after allowances are deducted for known domestic and commercial usage then the quantity that is left is converted to known performance indicators which enables the areas to be ranked from best to worst performing relevant to the amount of Real Losses ( leaks).