Air conditioning and heating systems in buildings that have special inventories or which are especially vulnerable to the effects of water damage can have leakage-protection installed. The system automatically monitors flow in supply and return pipes. In case of divergences, it shuts off both supply and return.
The entire system can be protected, or just those parts of the system that are in vulnerable areas. Flow meters are installed in the supply and return pipes to help the system function. A leakage is registered if the water flow measured in the supply pipe is greater than the flow measured in the return pipe. The system is then closed using motor valves to shut down the supply and return flow and if required, by switching a pump off.
Leakage-protection should be fitted on the smallest pipes possible. This is because a leakage is first registered when the difference in flow between the supply and return is significantly larger than the measurement uncertainty of the flow meters. In the case of large pipe dimensions this would involve significantly large leakage volumes.
Flow meters can be supplied with a number of humidity sensors, which can be placed in locations that are especially vulnerable to water-damage caused by a leakage.