How does low flow leak detection work?

Here's a breakdown of how flow based leak detection works at low flows:

1. Measurement: The system uses flow sensors or water meters to measure the flow of water. Hall Effect flow sensors provide high resolution (many pulses per litre), which is good for real-time viewing and enhances the speed to spot anomalies. Water meters are generally more accurate but have lower resolution (fewer pulses per litre), which can decrease leak detection speed because the system has to wait for more water to pass to get a pulse.
2. Minimum Levels: The system can monitor leaks down to specific low flow rates depending on the sensor or meter size. The ¾”, 1” and 1.25" Hall Effect flow sensors, as well as the ultrasonic meters (1.5"-4") that we typically use monitor flows down to 0.5 litres per minute. The 3/4" and 1" ultrasonic meters we use can monitor flows down to 0.03 litres per minute.
3. Analysis: The system uses machine learning algorithms and dynamic learning modes to establish a baseline of normal water usage patterns. By learning from historic data, it can predict future consumption and identify deviations that indicate leaks.
4. Thresholds: Users can set customizable thresholds for the time and volume of water expected. Alerts are sent when water consumption exceeds these threshold levels. Dynamic thresholds can be learned after just one week of normal usage, setting more detailed thresholds suited to a unique consumption profile.
5. Installation: To maximize low flow detection using flow sensors, installation orientation (ideally vertically up) and having straight pipes upstream (10 pipe diameters) and downstream (5 pipe diameters) are recommended. In this way, the lowest feasible flow rate (for Hall Effect sensors) can be optimised possibly down to 0.2 litres per minute (equivalent to a dribbling tap).

For Hall Effect sensors, there is a feature available in the software called Drip alerts, designed to make the alerts much more sensitive to minuscule events. The algorithm for drip alerts detects when there are more tiny flow spikes (flows less than 0.5 litres per minute) than usual within a specific time window. These tiny spikes can be hard to see among larger flows but become noticeable when zoomed in on graphs. However, drip detection alone should not be solely relied upon as it takes longer to detect leaks due to the tiny volumes involved. Wireless splash sensors or leak cables are considered the best way to catch drips.

To enable drip alerts, you need to use Dynamic alerts and select the 'Drip detection' option during the learning process.