A method is provided for detecting and quantifying leaks in a gas network under pressure or vacuum. The gas network includes one or more sources of compressed gas or vacuum; one or more consumers or consumer areas of compressed gas or vacuum applications; pipelines or a network of pipelines to transport the gas or vacuum; a plurality of sensors which determine one or a plurality of physical parameters of the gas in the gas network. The gas network has controllable or adjustable relief valves and the method involves a training phase and an operational phase.