There are many reasons why electronic testing is the favoured option over flood testing. These include:
|Characteristic||Electronic test||Flood test|
|Speed of test||Depending upon build-up, areas tested can be of the order of 1,000sq.m, plus, per day by a single tester||
It would be extremely difficult, if not impossible to test such a vast area.
Once the flood test has been imposed, which can take some considerable time in itself, a minimum of 48 hours is then required before releasing, with constant monitoring below.
|Accuracy||Traces breaches with pinpoint accuracy in minutes.||Can take days, weeks even months for water to filter through the membrane and concrete deck to manifest below without any indication as to the source.|
|Leak potential||Minimal water usage, so no internal consequences of leaks.||
Potentially major leaks, which will last until and beyond the time when the area is drained.
Huge potential impact from volumes required in loading and draining.
Major load on structure.
|Building services||No impact||Potential for rainwater pipes to fail while draining|
|Scope||Can test sections from horizontal to vertical, as well as complex details.||Flat/ very low slopes only. General test only.|
|Economics||Relatively low cost||High cost due to time required to fill and drain, plus consultant costs in monitoring. Potential for repeat testing to locate source.|
|Impact on contract||Quick handover of certified watertight installation||Slow, slow progress to handover. Leaks in evidence below will delay that.|