Water Leak Detection in Commercial Buildings

Using the latest technology avoids significant costs and harm to people and property
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Sponsored by WATTS Water Technologies, Inc.
By Peter J. Arsenault, FAIA, NCARB, LEED AP
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Quality Standards

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.

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 routinely 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.

Photo courtesy of WATTS Water Technologies

Wireless water sensors that can be programmed to allow for a delay between the initial audible alarm and when messages are sent (in the event of a false alarm event) are more likely to be heeded when an actual alarm event occurs.

Photo courtesy of WATTS Water Technologies

A flexible, configurable system allows for changes, such as bathroom remodeling or upgrades or other direct changes to building plumbing systems.

Leak Detection Alarm

When any of the endpoints detect a leak or abnormality, an audible alarm is set off. At the same time, a wireless message is sent from the sensor to its closest hub, down the building to the base station, and out to the cloud. Three types of messaging then happen simultaneously to communicate the message that a leak is detected:

  • Phone: A phone call is made, typically to the security desk, although the building owner or manager ultimately decides who receives calls.
  • Email: E-mail messages are sent to preselected personnel.
  • Text: SMS text messages are sent to preselected personnel.

This immediate notification system to multiple people in multiple ways helps to ensure that a leak can be responded to promptly.

Alarms Versus Alerts

It is worth noting that in addition to an alarm indicating that a leak has been detected, the system can also send alerts which are informational messages. Examples of alerts include a low battery in one of the endpoints or a loss of communication with a device for some reason.

If there is any concern about false alarms, it is good to know that they can be controlled. In many commercial buildings, a significant concern can be the ability to easily silence a sensor that is accidentally set off. For example, if the sensor is on the floor of a kitchen or restroom, janitorial staff can unintentionally cause the alarm to go off by hitting it with a mop or spreading cleaning water on the floor. In cases like this, having a delay is important, but the event should be recorded for tracking purposes. If it happens too often, the sensor should be moved to a different location. The delay period on the sensors should be configurable, because while a 15-second delay may be appropriate for sensors in the restroom, no delay should be used for sensors in an electrical room or other critical areas.

Flexibility Based on Modular Design

All buildings have the need to change over time, particularly as their operations, use, or occupants change. Therefore, any system in a building needs to be able to change easily and readily with it. Accordingly, wireless water leak detection systems have been designed to be easy and inexpensive not only to install initially, but also to modify over time, in any size or age of building. A look at some of the common things to consider when doing modifications follows.

  • Adding sensors is the most common need such as when new plumbing is added or modified. Flexibility in this case relies on the ability to install additional sensors without the need for an electrician – in other words, increase the area being monitored without requiring additional electrical power. For simplicity and best practices, look for a system that automatically registers with the nearest hub device when it is activated. Also, consider the number of sensors that a total system can support before requiring additional communication equipment. In general, a good system can handle about 400 sensors per base station.
  • If sensing cables are used as part of the system, then look for sensing cables that work seamlessly with the existing endpoints. There are other considerations for sensing cables, too, such as whether or not they are suitable for applications that include walls in chase areas, subfloors, plenums, drain pans, and around pumps, appliances, and HVAC equipment. Since the dimensions will matter, look for sensing cables that are available in multiple lengths and can support “daisy chain” installations from a central point. Durability is important here, so rugged materials, such as HDPE polymer that can provide corrosion resistance and hold up over the long term, are important. Relatedly, the mating connectors for sections of cables should be water resistant to prevent inaccurate readings. Finally, the cables should be easy to install and/or reinstall in order to be fully reusable after any leak events.
  • Electronic valve controllers can be included as part of a new or existing system with the ability to stop the flow of water to one or more valves – both by automatic operation and by a manual control. The manual operation will require that a person first inspects the valve before it is reset to be sure all leaks are contained and repaired. The automatic/electronic operation provides multiple benefits to the building owner or operator—the most significant of which is the short time from when a leak is first detected to when the valve is fully closed, and the leak stopped. Since the valve controller is one of the end points of the overall system, all activity is visible, easy to manage, and event tracking is provided via the system software. Notifications are also provided, just like any other alarm when it shuts off a valve. It is also possible to provide for a delay time to silence the sensor manually and keep the valve open if that is determined to be a need. As part of the larger system, there should be automatic, periodic cycling of all of the valves to ensure their continued functionality, and they should all be certified to be safe for use with potable water.

Selecting the most appropriate electronic valve controllers for specific locations involves consideration of several criteria. First, address the number of valves that a device can control or whether internal relays are involved. Some may also have the ability to serve a sensor itself or be connected to a sensing cable for extended reach. A purely practical concern will be the pipe sizes that the valve is installed on (e.g., diameters from 0.5 to 2 inches) that need to be addressed and supported. Ultimately, the focus is on the ability for the valve controllers to automatically shut off the flow of water when a leak is detected. While simple monitoring around the clock is sufficient for many situations, a shut-off valve may be warranted to protect entire buildings, critical areas without 24/7 security personnel, or when the presence of water would create a safety hazard (as in a switchgear room).

Photo courtesy of WATTS Water Technologies

Electronically controlled valve controllers and valve shut-offs are an integral part of a complete, effective, wireless water leak detection system.


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Originally published in Architectural Record
Originally published in September 2022