Leaks. They’re everywhere, and they’re insidious, sucking energy from your assets and robbing your bottom line. However, these leaks have nothing to do with your intellectual property or trade secrets being revealed on the evening news through disgruntled employees or computer network hacks. These are physical leaks in places like piping, valves and steam traps. Or they could be due to faulty insulation in building envelopes or roof systems. While they don’t occur all at once like a computer hack, they gnaw at your bottom line and gradually eat away more of it away, if you don’t fix them.
- Technologies to find leaks
- Being creative in applying technology
- Buy your own or use a service?
- Working with outside experts
Some leaks are obvious; some are not. Fortunately, tools are available to extend your range of hearing and seeing so you can spot the leaks and get the maintenance department queued up to fix them. And, if they’re not fixed, you can count on the veracity of a corollary of Murphy’s Law: “Left to themselves, all things go from bad to worse.”
The average facility loses about 30 percent of its compressed air to leaks, much of which is undetectable to the ear, touch or sight, according to the US Department of Energy (DOE). At the close of 2007, DOE reported as many as 57 percent of facilities had taken little or no action to fix their leaks. How do they add up? According to Compressed Air Challenge of DOE’s Office of Industrial Technologies, the total cost of 100 psig compressed air has been calculated to be in the general range of 18 to 32 cents per 1,000 cubic foot. Put another way, a quarter-inch diameter leak was calculated to cost $8,382 per year at $0.05 per kilowatt-hour, but what might that cost be in the Northeast or California where energy rates are much higher?
Water leaks don’t get the attention compressed air leaks do, but they can be just as wasteful. For instance, a leading global beverage processor’s bottling plant in Shanyang, China was losing 150,000 liters (34,053 gallons) of treated water per day through a leak in its water system. The facility’s water system was fed by the city’s water supply through a 12-inch lateral service line, which provided water for the plant’s operations, employees and fire protection crews. After searching for several months, crews were unsuccessful in narrowing the search, except for figuring out it was somewhere six feet under a concrete roadway.
The plant called in Echologics, a Mississauga, ON developer of advanced acoustic-based technologies for water loss management, leak detection and pipe condition assessment. The company makes nonintrusive leak detection equipment (hydrophones and software) and provides services as well. Echologics surveyed the plant’s water system and, in less than one day, successfully pinpointed the leak located on a span of pipe underneath the concrete roadway that surrounded the facility. Once the leak was located, service crews excavated the exact location and repaired the pipe. Impressed with the quick and exact locating of the leaky pipe, the Chinese bottler purchased a LeakfinderRT leak detection system for its own service crews.
Although problems with building insulation may not cause the same kind of wasted energy levels that compressed air losses do, a quick comparison of insulation R-values can provide a sense of their costs, keeping in mind that compressors are also used in refrigeration. In the document, “Final Report: Refrigerated Warehouses” published in 2007 by Pacific Gas and Electric, a freezer wall with an R-26 insulation was compared to higher R values for a warm climate such as Fresno, CA. Energy savings with a wall with R-30 insulation would amount to $0.04 per kWh/sq. ft., while an R-50 wall would save $0.15 per kWh/sq. ft. Damage to insulation (e.g., due to ice buildup or rodent destruction) will, of course, decrease the R-value significantly and any potential savings. A consultant versed in audits of refrigerated spaces can easily check for loss locations and pin a relative cost on the losses.
Several suppliers make equipment that’s portable and handy. Generally speaking, two basic technologies can be used to find most leaks—and a few other energy wasters as well. Most leaks (compressed air, gas, water or other fluid) emit a high-frequency noise inaudible to humans, but ultrasonic sensors can “hear” what the human ear misses.
The second technology, IR thermal imaging, can “see” what we can’t—temperature gradients that show a loss or gain in heat energy. (For more information, see the box on page 40: “Thermal imaging beyond building insulation.”)
The costs of ultrasound and IR imaging devices range from the low hundreds to thousands of dollars. Some are for consumer use; others for serious industrial use can withstand rough handling and provide useful data such as converting a compressed air leak into dollars and cents lost per given time period.
Some suppliers provide just one technology, while others offer both as well as other adjunct technologies, all of which can be used to find leaks. For example, Omega Engineering has released its new HHLT-1 handheld ultrasonic leak detector, in addition to the HHLT-2 handheld refrigerant leak detector, which has a solid-electrolyte semiconductor sensor that can detect leaks of all commonly used halogenated refrigerant gases. Besides offering several handheld IR thermometers, Omega sells OSXL-EX series IR imaging cameras, which feature a 3-inch color LCD display with resolutions from 80 x 60 to 320 x 240.
Recognizing there were no mid-price solutions between FLIR’s top-of-the-line IR imaging cameras and digital IR handheld thermometers, FLIR recently released its TG165 model, which is priced at $499 and is available at most industrial test equipment retailers. Designed to withstand a two-meter fall, the device has dual laser pointers, an IR resolution of 80 x 60 and a range of -13°F to 716°F. A protective case is available for the device.
Priced similarly, Fluke’s VT04 handheld IR imaging camera can overlay a standard video image with varying opacities of the thermal image heat map onto the same image frame. Images from the unit can be saved in either a .bmp format or proprietary .is2 format, which can be loaded into the company’s SmartView software to optimize the visible and IR heat map blending to any level; change the palette, the emissivity and background temperature; and generate a professional report. Fluke also recently introduced its high-end range of Ti90 and Ti95 IR cameras with resolutions up to 1,024 x 768 and wireless connectivity.
In addition, Fluke offers the Amprobe ULD-300 ultrasonic leak detector series, which can be used to detect pressurized gas and compressed air leaks. As a side benefit, this device and others like it can also detect arcing in electrical systems. The detector has a frequency response from 35 to 45kHz and can operate for 33 hours on a 9V battery. One manufacturer used the device to locate and fix 36 air leaks for an annual savings of $4,800. It also installed solenoids to shut off compressed air to equipment that was leaking air when not in use, saving more than $7,000 a year.
UE Systems builds both analog and digital ultrasonic detectors, including its Ultraprobe series, which has been used in predictive maintenance and energy conservation for more than 30 years. The company also provides software that adds a new dimension to energy leaks, determining how much they cost.
Scott Pytel, owner of PdM Solutions in London, ON, has helped a number of food and beverage processors reduce costs primarily due to compressed air leaks. “A broad range of [ultrasonic] devices is available, says Pytel. “The biggest advantage to using ultrasound is you can locate the source of the leak, and you can quantify it.”
CTRL Systems designs and manufactures the UL101 ultrasound detector. The device can be used for leak detection, vacuum leak detection, steam trap inspection, electrical inspection, motor bearing and gear box analysis, valve inspection and more, says Benjamin Fried, CTRL Systems vice president, sales/marketing. “Depending upon the sensitivity, ultrasound detectors can be used for any type of leak that generates ultrasound, that is to say, all the turbulent gas or vacuum leaks, internal fluid and gas bypass leaks through valves and steam traps, and sometimes water leaks under cement.”
As might be expected, with some applications, certain sensing technologies work better than others. Surprisingly enough, some detection technologies can be applied in ways that may not be obvious. “Ultrasound has been successful in finding underground water or gas leaks,” says Fried. “However, due to the nature of ultrasound to attenuate rapidly, to be easily shielded and to stay close to the source of the leak, it is not the best method. The best method would be an amplified low-frequency microphone. However, one would have to deal with competing sounds.”
“Eventually, an air or water leak in a buried line will present itself as a crater above the leak,” says James Yerke, section manager and senior associate of SSOE Group. “However, at that point, it has gone undetected far too long. One of the best ways to find an abnormal condition is to measure and record pressure and flow rate data. A simple trend line will reveal a deviation in flow and/or pressure from the normal range.” That information, however, may not be enough to find the precise location of the leak.
Flow sensing is exactly what the Ecologics solution provides. But it doesn’t only measure flow rate; it can sense the exact location of a leak using sensors (hydrophones) located on each end of a line and more points in between for accuracy. In the Chinese beverage company water leak situation described earlier, software analyzed the sound patterns from each end and made distance calculations based on the speed of sound and the comparison of sound from both sensors. The software then determined exactly where the leak was located.
Normally, an IR imaging system is a good choice to locate problems with building insulation—walls (envelope), floor or roof. “Quantifying a thermal leak either in a building envelope or process is typically done by calculation,” explains SSOE’s Yerke. “Information on variables such as bin weather data or heating degree days, surface area and material thermal resistance is needed to quantify energy loss.” (Ed: The bin method refers to a procedure where monthly weather data is sorted into discrete groups [bins] of weather conditions. Each bin contains the number of average hours of occurrence during a month or year of a particular range of weather conditions.)
Mays Consulting & Evaluation Services, Inc. in Delaware, OH states that building envelope surveys are accurate and representative for the time of a survey. In addition, the firm recommends that when conducting a building envelope survey, it’s essential to have a temperature differential of at least 30°F from the interior to the exterior wall.
“An instrument such as an IR thermal camera can be helpful with qualitative information, that is, what the surface temperature is compared to the adjacent area,” adds Yerke. “Quantifying the magnitude of energy losses requires knowledge, the application of the other variables mentioned and a calculation.”
An ultrasound technique may not seem like an obvious means of proving the efficacy of envelope insulation, but it can help. “Ultrasound, like a thermal camera, [can be] used to find failures in insulation by placing an ultrasound generator on the inside of the building and using a receiver from the outside to indicate and locate the escaping ultrasound along the window and door insulation,” says Fried. “Ultrasound can be used regardless of temperature differential. However, there is no possible way to quantify the leak rate.”
No doubt, very large processors have the number of plants and available funds to justify adding a technician or two to the maintenance staff to concentrate on finding energy leaks. Pytel explains it’s the small to medium-sized processors that find it easier to call in an outside service on a regular basis.
According to Pytel, it’s not uncommon for a processor to spend a thousand dollars for an outside technician to come in, do the testing, label the leaks and their priorities, and file a report. In many cases, the maintenance department will follow the technician, fixing the leaks as they’re found. Does this approach pay for itself? Pytel estimates a day spent in the plant looking for leaks usually finds at least $10,000 worth of compressed air savings, but that figure can go as high as $50,000 per year.
Some A&E and construction firms have groups who can perform this work. “SSOE offers a variety of energy-related services to assist clients in reducing energy consumption,” says Yerke. “We offer consulting services and engineering for energy conservation strategies, renewable resources, feasibility studies, energy audits and upgrading facilities with proven energy-efficient technologies.”
Interstates Companies provides instrumentation calibration services, energy monitoring services and compressed air leak audits, as well as other energy management services, says Adam Dittbenner, service department manager. “Interstates’ calibration services ensure existing devices and instrumentation for measuring air/water/gas/electrical usage are accurately measuring the flow as well as reporting this data to any other monitoring equipment.” The company can monitor utility usage temporarily or on a permanent basis, whichever is required.
“At Gray Construction, we’re always researching new tools and innovations to help meet our customers’ needs more effectively,” says Trey Griffith, Gray Construction manager, quality management systems. Gray’s Quality Management System (QMS), which integrates iPads for project documentation across any job site, includes a low-temperature section that detects thermal breaks and other related issues. In terms of building envelopes, Gray incorporates thermal imaging to review all freezer and cooler spaces to help detect thermal leaks before they occur.
The CTRL Systems UL101 ultrasound detector is part of a turnkey program for compressed air energy savings. The program includes the installation of power/pressure/flow monitoring on each compressor to provide a baseline, post-modification results and ongoing measurement for sustainability or notification to perform a leak test, says Fried. The company provides additional services for processors that don’t have the time or in-house expertise to perform leak detection and repairs.
Sometimes, large processors find it easier to work with an experienced firm that can expand coverage to other plant locations, rather than setting up an in-house department. For example, Fried reports that a major beverage company has begun a turnkey process using a UL101 ultrasonic detector and power monitoring for leak detection at all of its facilities in North America. The initial site has reduced its compressor energy usage by 20 percent, while a second site has decreased its usage by 25 percent. Some plants have leaks in potentially explosive areas. “We work with oilseed companies with hazardous areas in their facilities due to flammable/explosive chemicals used in the process,” says Interstates’ Dittbenner. “Correcting energy leaks in hazardous areas requires special safety procedures and equipment. Interstates has experience working in hazardous areas as well as access to intrinsically safe equipment rated to work in these areas.”
While a processor may start out looking for obvious energy leaks, an outside expert can often identify several other areas where energy can be saved. For example, SSOE assisted a global cereal manufacturer with energy conservation services and identified ways to save over $1 million a year on water heating, steam production and natural gas use.
Yet, some processors may choose to purchase their own leak detection equipment due to its affordability. “Having in-house maintenance equipment and services can be advantageous when the processor is ready to dedicate individuals to the task and sets up a project team,” says PdM Solutions’ Pytel. “Some of the tools are designed specifically for maintenance needs [e.g., FLIR has many small handheld IR cameras], which can complement everyday maintenance requirements.”
PdM Solutions also offers training on the equipment for processors that want to start their own in-house program for finding energy leaks. What Pytel sees as a pity is the processor that buys several IR imaging tools and ultrasonic devices, only to let them collect dust on the shelf.
Thermal imaging beyond building insulation
A thermal IR imaging system can help identify problem areas where energy is being leaked or wasted by:
Source: Fluke Corporation
“Final Report: Refrigerated Warehouses,” Pacific Gas and Electric Company, Feb. 2007.
“Improving Compressed Air System Performance: A Sourcebook for Industry,” US Department of Energy’s Office of Energy Efficiency and Renewable Energy and Compressed Air Challenge, Nov. 2003.