Abstract: A leak in the membrane of a generally horizontal roof support deck includes dividing the membrane into separate zones and locating a sensor to detect moisture underneath the membrane. A unique digital code address is assigned to sensor where inputs of the sensors are connected to a single power and signaling cable system using a daisy chain. The serial bus controller is to interrogate each of the sensor devices using the address to identify zones where moisture is detected. A transmitting antenna is provided at each sensor which is switched on when moisture is detected for detecting of the sensor from above the membrane by a utility locate device to confirm the location of the sensor.

Abstract: A leak in the membrane of a generally horizontal roof support deck includes dividing the membrane into separate zones and locating a sensor to detect moisture underneath the membrane. A movable scanning device carried by a worker has a power supply antenna for supplying power by an electromagnetic wave to the sensor and the worker moves the scanning device to selected ones of the zones. At each selected zone the power supply antenna activates the sensor in the zone and the sensor to emits signals related to the moisture underneath the membrane as detected by the sensor device which are detected and recorded at the mobile scanning device.

Abstract: A leak in the membrane of a generally horizontal roof support deck includes dividing the membrane into separate zones and locating a sensor to detect moisture underneath the membrane. A unique digital code address is assigned to sensor where inputs of the sensors are connected to a single power and signaling cable system using a daisy chain. The serial bus controller is to interrogate each of the sensor devices using the address to identify zones where moisture is detected. A transmitting antenna is provided at each sensor which is switched on when moisture is detected for detecting of the sensor from above the membrane by a utility locate device to confirm the location of the sensor.

Abstract: A leak in an electrically conductive membrane attached on top of a horizontal roof deck is located by a manually operable carriage which is swept over the upper surface of the membrane on the roof deck. A measuring and switching circuit generates a voltage having a positive attached to the roof deck and a negative attached to conductive brushes on the carriage. The brushes are arranged to form an outer peripheral contact with an inner contact inside the outer contact. There is provided a diode switched into the sensing circuit from the inner conductive brushes so as to reduce the voltage across the deck and the inner brushes relative to the outer brushes. Thus the presence of a leak is detected by the outer set of conductive brushes at distance from the leak and by the inner conductive brush when directly over the leakage site.

Abstract: A leak in an electrically conductive membrane attached on top of a horizontal roof deck is located by a manually operable carriage which is swept over the upper surface of the membrane on the roof deck. A measuring and switching circuit generates a voltage having a positive attached to the roof deck and a negative attached to conductive brushes on the carriage. The brushes are arranged to form an outer peripheral contact with an inner contact inside the outer contact. There is provided a diode switched into the sensing circuit from the inner conductive brushes so as to reduce the voltage across the deck and the inner brushes relative to the outer brushes. Thus the presence of a leak is detected by the outer set of conductive brushes at distance from the leak and by the inner conductive brush when directly over the leakage site.