Tackling a Leak on a Common Supply Pipe using Ferret
May 17, 2018
Many older properties, particularly terraced houses are served by a Common Supply Pipe. This pipe provides water to a number of houses from a single connection to the public water main. A leak on a Common Supply Pipe could affect one or more properties, resulting in poor pressures and reduced flow rates. Due to their age these pipes are often made of lead or copper; Ferret is ideally suited for working in these pipes.
Briefly, the pipe up to and including the external stop valve is the responsibility of the Water Company. The responsibility of the Common Supply Pipe is shared equally between the property owners served by that pipe. Branch Pipes are the sole responsibility of the property owner served by the branch pipe in question. The diagram below shows a typical arrangement with four terraced properties supplied by a Common Pipe.
In the example above, the leak is located on the Common Pipe in the back garden of House number 3. A major operating benefit of Ferret is that the investigation and leak location can be carried out without having to gain access to each back garden. In addition, because the leak location is undertaken from inside the pipe the need to navigate garden sheds, raised paving and decking and other permanent or temporary structures often found in back gardens is avoided. Such structures could seriously hamper the effectiveness of other leak location techniques like audio or tracer gas as it is necessary to gain access to the ground surface directly above the line of pipe to deliver an accurate result.
How does the Ferret Leak Locator operate?
Once launched, the Ferret balloon will progress down the Common Pipe, towards the Leak, passing through each Branch Tee on its way. A unique feature of the Ferret is that it can detect if a leak is present on a side branch, if it’s not leaking it is quickly eliminated from the survey scope. Another unique feature of the Ferret is its ability to confirm whether a section of pipe is leaking or not by pressure testing the run of pipework between the Ferret Leak Locator and the expanded Ferret balloon. No other leak detection system is able to give a positive “No-Leak” condition in a section of pipeline under investigation. If a situation occurs when an audio or gas injection system is used where no sound or gas is detected, it does not necessarily confirm that there is no leak present.
Once the Ferret has located the leak, the Ferret balloon can be left inflated while a tap at each property can be used to quickly identify who is upstream and downstream of the leak. In the example above, the repair costs would be shared between the property owners of Houses 3 and 4.
In summary the Ferret Leak Locator, with its ability to pressure test sections of common and branch pipes, offers a number of opportunities to water companies, plumbers and leakage specialists to locate leaks on complex shared supplies with reduced time and materials and minimal disruption to customers and their property.