Leak Location Q & A
We've all heard that the three most important ingredients to a successful business are location, location, location. Read on to see how acoustical leak location can offer excellent opportunities for enhancing profits for companies of all sizes.
Q: How can acoustical leak location systems boost my business?
A: Three ways:
• Precision. The right equipment not only accurately locates leaks in cast-iron, copper, steel and PVC lines, but also pinpoints problems in a wide variety of work, soil and surface conditions.
• Speed. The latest technology lets you target problems fast - eliminating tedious guesswork and cycling jobs more rapidly.
• Professionalism. Customer problems are quickly, precisely and competently solved - enhancing your expert reputation.
Q: How do acoustical leak location systems pinpoint problems?
A: Two ways:
• Effective sound filtering.
• Special sensor technology.
You almost never hear the steady drip, drip, drip of leaky faucets during the day. But at night - when the house is quiet and free of distracting noises - they're loud and clear. Moreover, you can easily locate the problem tap. Right?
That's because ambient daytime noise like talk, television, traffic and toddlers can interfere with sounds of leaks. Yet what if the leak isn't in a sink down the hall, but beneath concrete and 6 ft. of water-soaked soil?
Advanced acoustical leak location systems do more than just amplify problem sounds. They also filter out all extraneous noises that compromise your ability to hear leaks themselves, so you can clearly hear the gurgling or hammering of cracked pipe beneath the surface.
Q: How do filters and sensors work?
A: The most effective systems filter out the ambient noise with a digital sound spectrum analyzer, which mutes extraneous sounds interfering with leak location. Using a combination of audio filters to muffle ambient noise, it lets operators more easily hear the whoosh or hiss of water leaks. The more filters a system employs, the more reliably it removes superfluous sounds.
With unwanted noise neutralized, special sensors can then precisely target leak location. Ground sensors locate problems through hard surfaces like concrete, asphalt and tile. Probe sensors locate leaks through soft surfaces like grass or carpet - or can be used as contact probes on above-ground pipes or hydrants. Both sensor types should feature shock-resistant housings to further reduce ambient noise.
Q: How do I locate a leak?
A: Factors such as water pressure, pipe material and depth, soil density and structure, and surface type (concrete, grass, etc.) affect leak noise intensity and frequency.
First, learn what to listen for. Leak sounds are created by three different situations:
• Pipe vibration: The loudest and easiest problems to locate, these are caused by water forced through a crack in the pipe, making whooshing or hissing sounds.
• Adjacent material: The substance encasing lines can produce distinctive leak noises. Leaks striking rock or gravel create hammering or knocking sounds. But water hitting loose, sandy or water-saturated soil makes little or no noise, making location difficult.
• Underground cavities: Water flowing through a soil cavity will create a gurgling sound, such as a small stream or brook.
Second, surfaces will affect the amplification of leak noises. Hard surfaces such as concrete will resonate with the sound of a leak for 5 ft. to 10 ft. around the water pipe. Grass and earth, by contrast, can stifle amplification. Selecting the proper surface sensor, ground or probe, will improve results.
You can train your ears. Set up the water leak locator with the probe sensor attached. With the probe bar's tip touching the cold water line under a sink, carefully turn the valve until water just dribbles from the faucet. This simulates a leak sound. Then note the difference as you fully turn the spigot on and off.
Time, distance and pipe material play roles, too. Newly buried lines produce muffled leak sounds that often prove hard to find. Old pipes leaking for some time, likewise, absorb leak vibrations, further compromising location. Problems in deeply buried conduits are also more difficult to trace. And don't forget pipe composition itself.
Q: How do different types of pipe affect acoustical leak location?
A: Knowing the type of pipe and employing proper filtering can also facilitate acoustical leak location.
Metal pipes transmit sounds at higher frequencies. In cast-iron, copper and steel pipes, you likely hear leak noise in the range of 500 Hz to 1,500 Hz. In PVC pipe, leak sounds resonate in the range of 70 Hz to 850 Hz.
Choosing the right combination of high-end and low-end filtering will remove the extraneous noises of equipment, wind, traffic, etc. To filter out all the higher and lower frequencies, push the high and low frequency buttons on the digital sound spectrum analyzer until the indicator lights are on those frequencies.
Q: Can I do anything to amplify leak sounds?
A: Absolutely! In fact, the higher the water pressure, the louder the leak sounds.
And you can amplify leak noise by simply injecting air into the water line. This will increase water pressure at the problem's site, noticeably improving your prospects of pinpointing even the most difficult leaks.
Case in point: cracks in deeply buried conduits. Because soil quickly absorbs sound, problems in lines below 8 ft. will prove difficult to find. Boosting water pressure in such situations will magnify leak noise and your chances of location.
But be careful! Adding more than 10 to 15 psi of air above incoming water pressure could damage the seals in a building's plumbing fixtures.
Q: What's the procedure for pinpointing a leak?
A: The most common indicators of hidden leaks are surges in water bills or sounds of constantly running water. Inspect areas with older plumbing, leak histories and, naturally, recent excavations. Assume a leak if a water meter still registers flow with all building valves closed.
If you don't see obvious evidence of a major problem, such as water “ponding” or loud leak noise, launch a leak survey. Use the probe sensor and probe bar to inspect the hydrants and main valves. If you hear a leak sound at one spot, check lines running in all directions from that point. The problem is usually found between the loudest and second loudest survey locations.
Then start focusing your search. It's much easier to find a leak if your sensors are placed over the pipe. Using a digital pipeline locator and transmitter, determine the water line route. Attach transmitter leads to each end of the pipe to be traced, and turn on the transmitter. Fire up your locator, and set frequency to “pipe location mode” to match the transmitter. Mark the surface as you determine the water line's path.
Select the appropriate acoustical leak location sensor, either probe or ground. Then walk the line, taking a reading every couple feet. Follow water flow from upstream to downstream and note each reading.
Do not adjust the volume control. To make accurate comparison readings, volume must remain constant. When you approach the problem, you may be able to discern leak location by hearing alone. If you cannot rely on hearing alone, use the LED meter indicator to help target the strongest signal in the area. The rest is purely “process of elimination.”
Taking It Step By Step
1. Start by setting the filters to 700 Hz Low and 1,500 Hz high - the most common leak sound frequencies.2. Make direct contact with the probe sensor and probe bar to all sink lines, hot water heater lines and hose bibs. This will provide the leak's general location.
3. Once location is found, attach either the ground sensor or the probe sensor - depending on the surface. Select the ground sensor to trace water leaks through hard surfaces such as concrete, asphalt or tile. Choose the probe sensor for problems beneath soft surfaces such as grass or carpet or for use as a contact probe on above-ground pipes or hydrants.
4. Pinpoint the leak by moving the sensor directly over the water line every couple feet. As you near the actual leak, the sound will increase in the headphones and the LED meter indicator.
5. Once the leak has been pinpointed, mark its location. You should be within 1 ft. of the leak.
6. If muffled leak noise or ambient sounds interfere with your ability to target the problem, amplify leak sound by adding air to the line, as mentioned above - making it easier to find.
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