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→Green Roof Leak Detection Testing
==Green Roof Leak Detection Testing==
==Green Roof Leak Detection Testing==
On buildings featuring a green roof, a waterproofing membrane layer that covers the whole roof is essential to prevent water damage to the building. In some cases, a root barrier layer is also a part of the green roof design that protects the waterproofing membrane from being penetrated by roots and degraded by soil microbial activity. On top of these protective layers are the water retention and drainage layer, filter cloth, growing media and plants, making it impossible to visually inspect them for damage or leaks. There are two main approaches to leak detection for green roofs – flood tests and low-voltage leak detection tests.
===Flood Tests===
Flood tests for detection of green roof leaks can be conducted as part of Construction inspections, prior to planting. The test requires an experienced professional to narrow down a small area where the leak may be originating from. The suspected area is isolated from the rest of the roof, the roof drains are plugged, 10 cm of water depth is introduced and observations are made. Once the leak is found, the area is opened up and the waterproofing membrane is repaired. This process is time-consuming and costly, as the leak is not always found during the first round of patch flooding (US GSA, 2011).
===Low-Voltage Leak Tests===
The low-voltage leak detection test utilizes electricity to locate water penetrations through the waterproofing membrane. Such leak detection systems can also be referred to as Electric Field Vector Mapping (EFVM®) systems. They require a grounded, conductive material be directly below the waterproofing membrane, such as reinforced concrete or metal, and that the membrane be a nonconductive material. During roof construction and prior to green roof installation, a conductive wire is looped around the surface of the waterproofing membrane and connected to an impulse generator.
Testing involves the inspector or leak detection technician introducing a low-voltage, pulsating electric charge onto the surface of the waterproofing membrane which should be moist at the time. A watertight membrane will isolate the potential difference between the wetted surface and the underlying grounded conductive material layer, while breaches in the membrane will cause an electrical connection to occur. The inspector or leak detection technician reads the directional flow of current with a potentiometer to locate the point of entry with pinpoint accuracy. Low-voltage leak detection tests can be performed before and after a green roof is installed. As such, the location of leaks can be very precisely located and repaired with minimal disturbance to the rest of the roof (US GSA, 2011).
===Testing & Inspection Types===
It is important to test green roofs for leaks as part of Construction, Assumption and Verification
inspections.
*As part of '''Construction inspections''', testing confirms that the roof layers have been installed correctly and that it is ready for planting.
*As part of '''Assumption inspections''' it helps determine if the green roof is ready to be assumed by the property owner/manager/municipality.
*Tests may also be done as part of Verification inspections (i.e., every five years) to check for leaks, and as part of FIT work to locate and repair leaks discovered through visual inspection work.
==Cistern Pump Testing==
==Cistern Pump Testing==