A better method over simple observation is to have a device available that triggers an audible alarm if a leak occurs, much like a smoke alarm alerts people to that hazard. Water alarms, sometimes called “screamers,” are inexpensive point sensors that are placed on the floor–if they detect water, then they sound an alarm or “scream.” These alarms use 1980s technology and are stand-alone devices, i.e., they are not connected either to each other or to any other monitoring system. They obviously are only effective if someone is within earshot to hear it, understands what it is for, and can act on it. Hence, these qualities make them suitable for single-family residential use but not as well-suited for commercial use.

More up-to-date water leak sensors are electronic and attach wirelessly to a larger leak monitoring system. In that situation, they are well suited to commercial building systems that incorporate a total, coordinated, wireless solution. However, it is important to recognize that not all leak detection and notification systems are the same. For example, if the system only sends a text or email, the recipient may overlook that notification, especially if it occurs at night. Systems that also initiate alarms and telephone calls are obviously more likely to actually alert a person who can respond.

Photo courtesy of WATTS Water Technologies

There are distinct types of flow meters which can either be invasive or noninvasive to the existing plumbing system.

Sensing Cables

Another common commercial building solution is to use a sensing cable that can sense water at any point along the wire or an attached sensor. This approach normally requires electrical power to each wire or sensor, so that needs to be planned and designed accordingly. While the cables can cover a large area, if there is limited power, then additional electrical wiring is needed which can be costly. Therefore, they are mostly used in computer server rooms and data centers where lots of power and wiring are already available and there is a need for extensive water leak detection. Sensing cables can also be good for placement in tight, hard-to-reach areas, although once installed, they may be difficult to maintain and access. They can be attached to a stand-alone alarm or integrated as part of a larger, wireless leak detection system.

Flow Metering

Another choice to detect a potential leak uses a sensor on supply water piping to monitor the flow in the amount of supply water. The sensor is tracking for any unexpected increase in the amount of water flowing over time through the piping–a possible sign of a leak in the line somewhere. The goal is to sense water that is coming out of the pipe, not just flowing through the pipe. However, since it is only measuring water flow in a piping system, it does not locate where the leak is occurring.

There are three types of flow sensing, also called flow metering. The first type is wrapped around an existing utility meter and reads inflow to the building. This is a noninvasive approach that keeps the existing plumbing intact. The second type is wrapped around, or ‘clamped-on’ a pipe, instead of the meter and is similarly noninvasive. The third type is installed as a submeter and interrupts the pipe for the meter installation.

In terms of effectiveness, all three of these flow meter types can detect a leak significant enough to increase the water flow in a building or a subsystem. However, if there is only a slow drip, that would not be readily detected by most meters unless it can discern small changes in flow. In a typical 1.5-inch-diameter pipe, for example, the flow meter needs to be extremely sensitive to discern between 10 gallons per minute (gpm) and a potentially damaging 10.05 gpm. The best ones to specify to perform to an elevated level are “smart and wirelessly connected” as part of an overall leak detection system and not just a stand-alone piece of plumbing.

WIRELESS WATER LEAK DETECTION SYSTEMS

The most up-to-date option for leak detection and water efficiency control is a wireless, sensor-based system that connects individual sensors and flow meters to a central communication hub.

Wireless systems can be installed and operate anywhere that a wired system can installed but for significantly less cost since there is no wiring needed. It can also be installed in many places where wired systems are not practical. These systems use cloud-based IoT (Internet of Things) technology often combined with radio frequency (RF) network systems in the building. Just like a smoke or fire detection system, these wireless systems act automatically to sense water leaks and notify building personnel by phone call, text, and email of the precise leak location. An internet cloud platform is available that provides remote monitoring anywhere in a building 24/7 and informs building staff when and where leaks are occurring before they become a flood. If needed, electronically controlled shutoff valves can also be added to the design to shut off water flow automatically. Valves can be programmed to close upon the alarm from one or many sensors in a given area or floor.

Factory Mutual (FM) is one of the largest global commercial insurance carriers known for providing clients with engineering solutions to reduce risk. They operate an Approvals Certification program for manufacturers to have their products independently tested for use in buildings. FM Standard 7745, “Approval Standard for Liquid Leak Detectors,” establishes the benchmarks for best-in-class certification for water leak detection equipment. When specifying or incorporating a wireless leak detection system, the label “FM Approved” indicates that a system meets the stringent FM standard 7745 and receives the certification mark.

Photo courtesy of WATTS Water Technologies

A complete water leak detection system includes sensors, flow meters, and valve controllers all tied to a central hub or platform that can alert appropriate personnel if water use is irregular.

How It Works

A wireless leak detection system fundamentally involves battery powered leak detection sensors located throughout the building that are connected wirelessly to distributed hubs (typically every 1-2 floors). The hubs are then connected to a central building base station. Communication inside the building is routed through radio frequency (RF), not wi-fi, because communication ranges are often required in the hundreds of feet. RF is in the sub-1000 MHz─the lower the frequency, the longer the effective distance.

The RF backbone of the system includes the strategically located base station, which communicates via RF to the required number of hubs located as needed throughout the building. The hubs in turn communicate wirelessly to potentially hundreds of endpoints located throughout their area of coverage. These endpoints can be sensors, electronic valve controllers, and, most recently, flow meters.

The base station itself is plug powered and is the only piece of equipment connected to the internet via ethernet wiring or a cellular data connection. If preferred, the base station can connect to the cloud via cell modem or wi-fi. This connection allows facility management personnel to communicate remotely with the system to monitor its performance or receive alerts.