Tech Topic: Leak Detection
It’s made of metal; its circuits gleam…
You obviously can’t find a water leak just by looking at a puddle on the ground and assuming there’s a leak below it, the experts say. The water could have flowed from some other point to that point on the surface. So, you really need to know where that leak is. To do that, you need a really quality leak detection system.
Drain inspection is a visual process. You send cameras down pipes to get a clear picture of what’s clogging or intruding into lines. Leak detection is a different animal entirely. Pinpointing leaks in water lines is all about the audio. You aren’t looking for leaks. You’re listening for them.
Electronic amplification equipment and pipeline locators replace the trial and error method alternately called “search and destroy” or “bang and bash.” Instead of old school guesswork—digging or breaking into a wall where a leak is likely until you find the culprit—trained technicians can track leaks to within a few inches. The basic components of a detection system are an amplifier, headphones, high frequency audio filtration and sensors designed for different environments. Experts advise adding a pipe locator to the detection equipment package. Before you do any digging, it’s important to locate all utility lines along with water lines.
There’s a learning curve with leak detection equipment, the experts say. Ideally, there’s a training period that walks you step by step through the process that takes you from “we know there’s probably a leak” to “here’s the precise spot where the leak is.” The plumber or technician needs to learn how the equipment works, how to use it, how to listen, what sounds you’re listening for, and what each sound means in each environment.
Leak sounds are created by three different situations: The vibration of the pipe caused by water being forced through a crack in the pipe, said to be the loudest and easiest leak, it sounds like a “whoosh” or a hiss. Water forced through a crack and moving into surrounding soil is affected by the type of material around the pipe. If that material is rock or gravel, you hear a hammering or thumping sound. Last, water flowing through the soil cavity around a pipe creates a gurgling sound like a small stream or babbling brook.
What are some of the telltale signs that there’s a leak that needs to be located? Look for an escalating water bill, water meter reading changes when you aren’t using any water; wet, spongy or discolored areas; foul odors from floors or drains; or warm spots especially on concrete. Start with older parts of the plumbing, spots with a history of leaks or any place there’s been recent excavation.
- To conduct a water leak survey, make direct contact with the sensor probe or magnet base to all sink lines, water heater lines, hose bibs, hydrants and main valves. The spots with the loudest leak sounds will give you a general location of the leak.
- When you hear the sound of the leak, check water lines running in all directions from that point. The leak location is usually found at the loudest and second loudest sound locations. Now, you can begin to narrow your search and isolate the leak.
- To accurately pinpoint the leak, you must have an accurate location of the pipeline. You can locate the route of the water line by using a hotspot transmitter and pipe locator. The transmitter energizes the pipe so the locator can find it. Then, as you walk over the area, the locator display will indicate the location, direction, and depth of the pipe. Now that you know the path of the buried water line, you can pinpoint the source of the leak.
- Select the sensor that matches the surface on which you are locating: use the ground sensor with the three-pronged metal base to locate through hard surfaces, like concrete and tile. For areas covered by loose soil, grass or carpeted floors, use probe rods onto the bottom of the ground sensor. You can also use the probe rods to listen to valves and hydrants or treat the sensor magnet onto the ground sensor.
- Next, walk the line, placing the sensor and listening for the leak. Move a few feet and take a reading. Move a few feet and take your next reading. Follow the water line and note the intensity of the leak sound at each reading. The sound will get louder in the headphones as you get closer to the leak.
- Once you’ve narrowed your search area, move the sensor over the water line in one-foot increments. Once you locate the leak, mark the spot.
- If the sound isn’t loud enough to positively pinpoint the leak or of there is too much extraneous noise interference, you can use a sound amplification manifold. You attach the SAM to a nearby hose bibb, and then attach an air compressor and force compressed into the system. Don’t exceed 10 to 15 PSI above the building’s water pressure indicated on the SAM gauge.
Automatic leak detection
Plumbers can also introduce their regular client list to automatic leak detection.
Extensive damage and expensive repairs follow interior structure flooding, both from natural events or leaks from water-using appliances and water supply pipes within a home. We’ve all seen what can happen when a leak from a water line, ruptured water tank or overflowing appliance goes unnoticed for hours, days or weeks. Clients come home and find several inches of water soaking into walls, floor and furnishings.
Enter automatic leak detection, alarms and automatic water shutoff. This form of leak detection and property protection is aimed at flood detection and control. Not only are victims of such interior flooding keen to avoid a repeat, home and business insurers now are beginning to mandate installing automatic detection systems to mitigate water damage and ensuing repair costs. These systems include an array of sensors that detect leaks in appliances or water lines. Systems are designed to also automatically turn off the water supply when a leak is detected to mitigate the damage from flooding.
Typically, an alarm box sounds an audible alarm when sensors placed in the area of potential leaks come in contact with water or other liquids. Systems also can be equipped to turn off the water supply to specific sensored appliances such as water heaters, water tanks, sinks, toilets, water filtration systems washing machines and dishwashers. There also are total water main leak detection and shut-off systems.