Leak Detection Division Saves Dollars and Time
28.11.02

Recently,a contractor to the Christchurch City Council discovered a leakage problem with the new multimillion-dollar leisure pool.  The $12 million pool was nearing completion then, during commissioning and testing, leaks were discovered in the concrete-encased PVC pipework running underneath it. The pipes had been tested when they were installed but were damaged subsequently during the pools construction. 

With the official opening drawing closer, all options were considered. First thoughts for repair centred on a complete excavation of the pool area. As the pool had already been tiled, this would have been an expensive and lengthy setback.

However the most favoured option was the use of ADR’s Leak Detection Division’s specialised Casella Spectrascan instruments. The pool was emptied and staff from ADR used their AquaCorr Correlator, Ground Microphone and MicroSound acoustic loggers to locate the leaks. These instruments were able to listen through the various materials of the pool for the characteristic sound made by the leaks.

The AquaCorr Correlator and Ground Microphone were used to find two initial leaks. These leaks were isolated but instrumentation indicated that there was still another, large leak. Those familiar with leak detection will know that large leaks often make less noise and are therefore harder to locate than smaller leaks.  

Compounding the leak problem was that sub contractors were completing sections of the new pool and  two of the existing pools were still in operation. This situation  created high levels of background noise that made it impossible to track further leaks using the correlator although the area had been narrowed down to one side of the wave pool. 

To circumvent this problem, ADR staff decided to use their MicroSound noise loggers comprising a microphone, battery, transmitter and special circuitry. These devices were programmed to monitor and record sounds in the pipework every 5 seconds over a two-hour period between 2:00 am and 4:00 am.

The loggers were placed on each of the water outlets in the section of the wave pool thought to be still leaking. The loggers were left unattended overnight and next morning the data was collected. Analysis of the data easily located the remaining leak.  

This meant that only the areas showing a positive leak indication were opened up for repair, which greatly reduced the amount of remedial work required. This effectively kept the cost and time of repair to an absolute minimum. 

Although the commencement of operations had to be delayed, the official opening took place much sooner than first  thought possible. Thanks, in part, to the effectiveness of the ADR leak detection staff and equipment and staff.