Without IR thermography, companies might not know that a motor was running 10 C over its nameplate rating, potentially reducing the unit's life by half.
IR surveys can find abnormal overheating due to loose connections, corrosion, load imbalances and the like in high and low-voltage electrical equipment and systems.
After thermographic imaging, IR consultants furnish customers comprehensive reports that indicate, among other things, temperature rise and severity, causes and recommended actions for repairs.
Many large and medium-sized manufacturing companies in industries such as automotive, extrusion and steel production have professionally conducted infrared (IR) thermographic surveys done on their electrical and mechanical systems, process applications and incoming energy. They do so because these surveys offer a cost-effective, loss-prevention tool for identifying impending failures that could bring production operations to a standstill.
While overheating motors and bad electrical connections may not be what most would consider a "Kodak moment," regularly scheduled IR surveys based on thermographic images of such events reduce downtime and business interruptions, improve the useful lives of equipment, lessen the frequency of unscheduled outages, improve energy efficiency, and prevent property damage and losses. According to Global Risk Consultants, a Clarke, N.J., firm that provides IR surveys, companies can expect professionally conducted IR surveys and careful follow through on findings to save a minimum of $14 for every $1 invested.
IR technology is based on the fact that all objects emit thermal energy (heat) in the form of electromagnetic radiation in the infrared spectrum. The hotter the object, the more intense is the infrared radiation it emits. IR thermography detects and measures such radiation and provides images in spectrographic ranges that exceed those of the human eye. By detecting abnormal areas of temperature, IR thermography becomes a tool for analyzing these areas and diagnosing problems.
Today's infrared cameras provide detailed photographs of each piece of operating equipment and their "heat signatures." The amount of temperature increase over the normal range can be used to indicate a problem's severity.
Correctly interpreted, thermal profiles provide a great deal of information regarding operating conditions of equipment. With this information, consulting firms such as Global Risk Consultants can determine the probable causes of abnormalities and recommend actions to rectify problems.
Experts in the fire loss-prevention sector recognize the benefits of IR scanning and surveys. The National Fire Protection Association's Recommended Practice for Electrical Equipment Maintenance, for instance, states that: "Routine IR inspections of electrical systems should be performed annually. Where warranted by loss experience; installation of new equipment; environmental; operational; or load change condition, more frequent IR inspections — quarterly or semi-annually — should be performed."
In addition to fire hazards, increases in temperature of only 10 C over a motor's rated temperature, for example, could reduce its working life by half, resulting in thousands of dollars in added energy consumption annually. " Most losses resulting from overheating and bad connections usually are not catastrophic, and their costs fall well below insurance deductibles, making them an out-of-pocket expense for companies," says Gordon Grail, a managing consultant in the IR division of Global Risk Consultants.
On electrical equipment and systems, IR surveys typically find abnormal overheating due to loose connections, corrosion, load imbalances and the like in high and low-voltage equipment. For mechanical systems, the surveys identify heat buildup associated with friction and mechanical stress in equipment such as gear sets, pumps, motors and compressors. IR surveys image and diagnose thermal patterns in industrial-process equipment such as presses, forming machines, welders and furnaces, and locate areas of energy loss or gain so that insulation can be optimized and design can be made more efficient. For instance, such surveys could involve building structures, roof-moisture examinations, or analyses of boilers and chillers.
Global Risk Consultants conducts its IR surveys without interrupting normal business operations. It does not contact target objects, which are tested under full load and from a safe distance while they are operating.
After completing a survey, the company delivers a report on its findings in either an electronic or color-print format. Reports include the identification and location of the equipment tested; specific parts or components that exhibit thermal anomalies; increases in temperature and their severity; color thermograms and corresponding visible-light photographs of the equipment; suggestions as to the causes; and recommended actions for improvements for each finding that can help in scheduling and implementing repairs.
According to Grail, shops can purchase a thermography camera and attempt to do their own IR surveys.-However, creating the images and interpreting them requires a trained, noncontactmeasurement technician. For most companies, training an in-house employee for IR surveys done once a year isn't cost-effective, therefore many employ the services of companies such as Global Risk Consultants.
Infrared programs are only as good as the results. Firms must use the right equipment for the thermographer to properly capture, identify, troubleshoot and present findings in a format that can be easily understood by plant managers and maintenance personnel and so that problems can be corrected in a timely manner.
Accurate and realistic data interpretation is crucial for IR surveys, and thermographers should be well-trained and experienced. They should adhere to the Codes and Standards of the National Fire Protection Association, American Society for Testing & Materials, American National Standards Institute and International Electrical Testing Association and be ASNT-TC1a-certified.
Beyond certification, thermographers must be able to observe and comment on not only IR thermal findings, but also on other loss-prevention issues that could affect a facility.
The equipment used for such studies should be state-of-the-art quantitative thermal-measurement instruments with precise target resolution and thermal sensitivity. Besides the IR imager, a digital camera, a computer and specialized software are needed to present findings in a meaningful format. In addition, proper personal protective equipment is needed, and the technician must know how and when it is necessary.
Interpretive software lets thermographers decipher and present results in a finished report ready for downloading into a customer's facility-maintenance computer. From there, the facility manager can generate work orders to have repairs made. The software also should build a database so that all findings can be analyzed in the future and benchmarked. Such analyses help indicate the frequency and depth of future surveys and let corporate risk managers allocate scarce resources effectively.
Some thermographers also use air-borne ultrasonic translators, a new addition-to their arsenal of diagnostic tools. High-quality translators detect electrical arcing, tracking and corona on highvoltage equipment. With these translators, consultants can pinpoint potential problems that may be undetectable by the human eye or IR thermography.
An IR thermographic consultant must have adequate insurance and liability coverage, and a company should request a copy of the valid certificate of insurance from any consultant it may work with. The consultant firm also should provide adequate safety training and proper personal protective equipment based on new exposure requirements in the National Electrical Code. In addition, companies need to ask for written contracts that state exactly the work to be performed, the cost and how conflicts or disputes would be handled.
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