2018
January 01, 2018
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Make a New Year’s Resolution for Safety
Tip written by: Infraspection Institute
With the New Year upon us, many of us will follow the tradition of resolving to change or better ourselves. With this Tip, we offer suggestions for making job safety a priority.
The New Year is symbolic for many reasons. For some, the New Year represents a fresh start or new beginning. For others, it provides an opportunity to rededicate one’s self to a set of goals or principles. The New Year provides a perfect opportunity for thermographers to take stock of workplace safety practices and procedures. In doing so, be sure to keep the following in mind:
- Review safety procedures to ensure that they are complete and current
- Ensure that safety training is up-to-date for all personnel including First Aid and CPR
- Physically inspect all Personal Protective Equipment to ensure it is in good condition
- Check calibration and/or replacement dates for all monitoring or test equipment
Lastly, resolve to make safety your number one priority each and every day. Safety is not a poster, a slogan, or a set of actions to be followed only when it is convenient. Rather, safety is way of life that affects not only you but those around you.
Thermographer safety is one of the many topics covered in the Level I Infraspection Institute Certified Infrared Thermographer® training course. For information on thermographer training including course locations and dates, visit us online at www.infraspection.com or call us at 609-239-4788.
January 08, 2018
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Frostbite & Hypothermia
Tip written by: Infraspection Institute
“Jack Frost nipping at your nose.” These lyrics from a popular Christmas carol evoke romantic visions of winter; however, frostbite and hypothermia are dangerous medical conditions that can present serious safety hazards.
For many, the dead of winter is upon us. Thermographers working outdoors in cold climates can face serious safety challenges due to frostbite and hypothermia. Knowing the symptoms of these conditions and proper treatment is imperative for worker safety.
Frostbite is a severe reaction to cold exposure that can permanently damage its victims. A loss of feeling and a white or pale appearance in fingers, toes, or nose and ear lobes are symptoms of frostbite.
Hypothermia is a condition brought on when the body temperature drops to less than 90 degrees Fahrenheit. Symptoms of hypothermia include uncontrollable shivering, slow speech, memory lapses, frequent stumbling, drowsiness, and exhaustion.
If frostbite or hypothermia is suspected, begin warming the person slowly and seek immediate medical assistance. Warm the person’s trunk first. Use your own body heat to help. Arms and legs should be warmed last because stimulation of the limbs can drive cold blood toward the heart and lead to heart failure. If the person is wet, put them in dry clothing and wrap their entire body in a blanket.
Never give a frostbite or hypothermia victim beverages containing caffeine or alcohol. Caffeine, a stimulant, can cause the heart to beat faster and hasten the effects the cold has on the body. Alcohol, a depressant, can slow the heart and also hasten the ill effects of cold body temperatures.
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January 15, 2018
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Wind as an Error Source
Tip written by: Infraspection Institute
As individuals, most of us can appreciate the cooling effects of a breeze on a hot summer day. As thermographers, wind represents a greater technical challenge in the form of a potential error source when measuring temperatures radiometrically.
As wind moves across the surface of an object, convective heat transfer occurs. In general, wind will either cool a warm target or warm a cool target. The rate of convective heat transfer will primarily depend upon: velocity of the wind, temperature differential between object and wind, and surface film coefficient of the object.
Wind can significantly alter the temperature of an object while the windy condition is present. Frequently, the effects of wind may remain for a significant period of time after the wind has stopped and the object has returned to its normal temperature.
Because radiometric equipment cannot compensate for the effects of wind on an object, it is best to avoid wind when measuring object temperatures. To eliminate wind as an error source:
- Wait until wind stops
- Temporarily shield target from wind
- Measure downwind side of target provided that object is sufficiently large
Always allow sufficient time for target to return to normal temperature once wind has been eliminated. If it is not possible to avoid wind, one should report wind velocity and direction when recording image data.
Lastly, thermographers should resist any temptation to apply ‘Wind Chill Charts’ to correcting for the effects of wind. Wind Chill charts have been designed to estimate the net effect of wind and ambient temperature on exposed human flesh and are not applicable to inanimate or industrial objects.
The impact of convection on non-contact temperature measurements is just one of the many topics covered in all Infraspection Institute Level II Certified Infrared Thermographer® training courses . For more information on open enrollment classes or our Distance Learning opportunities, call 609-239-4788 or visit us online at www.infraspection.com.
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January 22, 2018
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Improving Accuracy of IR Temperature Measurements
Tip written by: Infraspection Institute
As infrared technology has advanced, radiometers have become a common tool for many maintenance technicians and mechanics. Although radiometers are relatively easy to use, there are several important factors that influence the accuracy of a radiometer’s readings. Infrared radiometers offer several advantages when it comes to temperature measurements.
Measurements are non-contact, non-destructive and can be obtained quickly. Unfortunately, radiometers are not self-diagnostic and cannot warn the operator of erroneous readings. The following are some simple tips that can help to ensure accurate infrared temperature measurements.
- Target should be stationary and at a stable temperature with a dry surface
- Radiometer lens should be clean and free from obstructions
- Radiometer batteries should be fully charged
- IR temperature measurements should be made perpendicular to target
- IR radiometer should be operated at a distance to ensure that spot measurement size is smaller than the target
- Accurate emissivity and reflected temperature values should be input into the radiometer’s computer
Whenever possible, infrared readings should be correlated with known temperature values. If a discrepancy is observed, it could be due to a procedural error in measurement or the radiometer may require calibration.
For more information on infrared temperature measurement, or to obtain information on thermographer training and certification, contact Infraspection Institute at 609-239-4788 or visit us online at www.infraspection.com.
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January 29, 2018
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Images and Reports – Who Owns Them?
Tip written by: Infraspection Institute
It is said that, “Possession is nine tenths of the law. When it comes to infrared data, ownership is often not that simple. In this Tip we explore the frequently misunderstood topic of infrared data ownership.
Thermograms and hardcopy reports are commonly produced for infrared inspections. Like proud parents sharing photographs of children, thermographers frequently share images, data, and reports with others. During these demonstrations, it is not uncommon to hear thermographers refer to this work product as “my images” and “my reports”. For the purposes of casual conversation, referring to work product in the possessive sense is acceptable; however, the actual owner of such data is often someone else.
Under a principle known as ‘Shop Rule’, data produced by thermographers as part of their duties as an employee belongs to their employer. In general, Shop Rule will always apply unless there is a written agreement to the contrary. For thermographers who work as consultants, a principle known as ‘Works for Hire’ may apply. Under this principle, any work product generated belongs to the client and not the thermographer.
Thermographers who work as consultants should be mindful that contracts and written agreements often have ‘Works for Hire’ clauses. These clauses may appear in the body of a contract or purchase order or be incorporated by reference. Thermographers who wish to retain ownership should address this issue prior to the commencement of any work.
Prior to using infrared data for any purpose other than its original intent, always obtain permission to do so. Employers and clients are frequently willing to grant permission to use imagery provided it does not divulge a trade secret or jeopardize confidential information.
Capturing imagery and preparing reports are two of the many topics covered in the Level I Infraspection Institute Certified Infrared Thermographer® training course. For more information on upcoming classes, call 609-239-4788 or visit us online at www.infraspection.com.
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February 05, 2018
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Preventing Carbon Monoxide Poisoning
Tip written by: Infraspection Institute
Carbon monoxide (CO) is an odorless, colorless, and tasteless gas that can be deadly. Knowing the symptoms of CO poisoning and how to prevent it can save your life or the lives of those around you.
Carbon monoxide (CO) is a toxic gas which interferes with the oxygen-carrying capacity of blood. Small amounts of CO are in the air whenever fuel is burned. These amounts are usually not harmful. However, if fuel-burning equipment or appliances aren’t working properly or are misused, too much CO can build up in the air and cause CO poisoning.
Symptoms of CO Exposure
- Headaches, dizziness, and drowsiness
- Nausea, vomiting, and tightness across the chest
CO is non-irritating and can overcome persons without warning. Symptoms can occur immediately or gradually after long-term exposure. Severe carbon monoxide poisoning causes neurological damage, illness, coma, and death.
Preventing CO Exposure
- Don’t leave vehicles or other diesel or gasoline powered engines running in a garage
- Never use a generator indoors or in enclosed or partially enclosed spaces such as garages, crawl spaces, and basements
- Make sure all fuel-burning equipment and appliances are maintained and operated properly. Such equipment includes fireplaces, furnaces, water heaters, stoves, space heaters, and clothes dryers.
- Install carbon monoxide detectors in every area of your house or business making certain to check the batteries regularly
If you think high levels of CO are in your home or business, move outdoors! Should a person become unconscious, immediately move them to fresh air and call 911.
For more information on workplace safety, visit the Occupational Safety and Health Administration website at www.osha.gov.
February 12, 2018
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Thermal Imaging Basics
With tremendous emphasis placed upon the sophistication of today’s modern thermal imagers, it’s easy to forget the basics of thermal imaging. Regardless of imager age or sophistication, there are several basic concepts that can vastly increase the accuracy and success of an infrared inspection.
1. Select the proper spectral response imager for the application.
2. A clear line of sight to the target is required with no obstruction of the imager lens.
3. Imager optics must be clean and calibrated to the imager being used.
4. Target should be dry and at a stable temperature.
5. Imager focus is imperative to accurate diagnosis and temperature measurement. Be sure to focus imager and the viewfinder as well.
6. Knowing the construction, operation and characteristics of the system being inspected is vitally important to anticipating thermal patterns and performance.
7. Adverse atmospheric conditions such as wind, humidity, or solar reflection and solar loading should be avoided.
8. For electrical and mechanical equipment, the systems must be energized and under load; for structural inspections, a delta T of 10 C (18 F) is desired.
9. Discriminating small temperature differentials across targets with low emittance values can prove quite difficult.
10. Whenever safely possible, cross reference observed infrared temperature values with accurate contact temperature readings.
When performing any infrared inspection, be certain to take all necessary safety precautions and always work safely.
Infrared theory and imager operation are two of the many topics covered in the Infraspection Institute Level I Certified Infrared Thermographer® training course. For more information including course locations and dates, visit Infraspection Institute online at www.infraspection.com or call us at 609-239-4788.
February 19, 2018
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Infrared Inspections of Spandrel Glass Panels
Tip written by: Infraspection Institute
Thermal imaging is widely used to detect evidence of excess energy loss in building envelopes. Under proper conditions thermal imaging may be used to detect excess energy loss through spandrel glass panels.
Glass curtain walls are a common feature found on modern commercial buildings. Opaque glass panels called spandrels are used to cover materials or prevent construction elements from being viewed from the exterior of the building. Examples of such areas include areas between floors, hung ceiling areas, knee-wall areas below vision lights, and sometimes even columns or partitions.
Depending upon building construction, spandrel glass may be installed as single-thickness panes, as part of insulating glass units, or as laminated glass. When installed as single pane units, spandrel panels are often insulated to prevent excess energy loss; however, construction details will vary between systems.
When performing an infrared inspection of spandrel glass panels, keep the following in mind:
- Prior to the infrared inspection, ascertain building usage and construction. Be aware of HVAC settings and how they are likely to affect observed imagery.
- Spandrel glass panels can vary widely. Determine panel construction and characteristics prior to the inspection.
- When imaging from a building’s exterior, significant errors can be introduced by hot/cold reflections from nearby structures or the sky.
- Because spandrel glass often has a low emittance; detected exceptions are likely to have low temperature differentials.
Infrared inspections of spandrel glass should be performed during evening hours with an inside/outside temperature differential of at least 10ºC. Exceptions associated with spandrel glass may appear as hot or cold depending upon building usage, imaging vantage point, and panel construction. As always, detected exceptions should be investigated for cause and appropriate corrective measures taken.
Infrared inspection of building envelopes is one of the many topics covered in the Infraspection Institute Level I Certified Infrared Thermographer® training course. For more information or to obtain a copy of the Standard for Infrared Inspection of Building Envelopes, visit us online at Infraspection Institute or call us at 609-239-4788.
~ Tip suggested by Kevin Richardson
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February 26, 2018
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Spring is the Time for Infrared Roof Inspections
Tip written by: Infraspection Institute
With the onset of warmer weather, the harshness of winter is but a fading memory for most. Left undetected, the damage caused by winter’s fury is a reality that can lead to premature roof failure. Fortunately, an infrared inspection of your roof can detect evidence of problems before they can get out of hand.
Performed under the proper conditions with the right equipment, an infrared inspection can detect evidence of latent moisture within the roofing system often before leaks become evident in the building.
The best candidates for infrared inspection are flat or low slope roofs where the insulation is located between the roof deck and the membrane and is in direct contact with the underside of the membrane. Applicable constructions are roofs with either smooth or gravel-surfaced, built-up or single-ply membranes. If gravel is present, it should be less than ½” in diameter and less than 1” thick.
For smooth-surfaced roofs, a short wave (2-5.6 µ) imager will provide more accurate results especially if the roof is painted with a reflective coating. All infrared data should be verified by a qualified roofing professional via core sampling or invasive moisture meter readings.
Infrared inspection of flat roofs and proper equipment selection are two of the many topics covered in the Infraspection Institute Level I Certified Infrared Thermographer® training course. For more information or to obtain a copy of the Standard for Infrared Inspection of Insulated Roofs, visit Infraspection Institute or call us at 609-239-4788.
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Gauging Solar Loading
Tip written by: Infraspection Institute
Did you know that an automobile can be used to gauge solar loading? Under the correct conditions, a parked car can serve as a cheap, but effective, pyranometer.
Many types of infrared inspections rely on solar loading to heat the target so that infrared imaging may be performed successfully. Applications include, but are not limited to, low slope roof inspections, concrete bridge decks, storage vessel levels and latent moisture within building sidewalls. Ensuring that enough solar loading has occurred is imperative to collecting good data.
Good solar loading conditions are easy to recognize – long days with bright sunny skies, low humidity and no wind. More tricky is being able to determine if less than optimal conditions are allowing for appreciable solar gain.
A time tested method for gauging solar loading is to check the interior of a parked automobile. With the engine stopped and the windows and doors closed, allow the vehicle to sit in the sun for up to an hour. Immediately upon opening the door, check to see if the vehicle interior has exceeded outdoor ambient temperature. If a noticeable difference is not detected, feel the dashboard to see if it has warmed. If not, it is likely that appreciable solar loading has not occurred and it may be best to reschedule your solar driven inspection for another day.
Active thermography, including how use the Sun to create desired temperature differentials, is one of the many topics covered in all Infraspection Institute Level I training courses. For more information on thermographer training including our Distance Learning Courses, visit Infraspection Institute online or call us at 609-239-4788.
Infrared Inspection of Capacitors
Capacitors are devices commonly found in AC electrical distribution systems where power factor correction is required. Like any electrical component, capacitors need to be regularly checked for proper operation. Infrared thermography can be used to rapidly inspect capacitors from a safe, remote distance.
Capacitors are wound devices that are electrically connected between potential and ground. Capacitors used for power factor correction are generally encased in painted, rectangular steel canisters and often have two equal sized bushings for electrical connections. In a three phase circuit, there may be several capacitors connected to each phase.
The most common failures of capacitors are loose/deteriorated bushing connections, open circuits due to internal winding failure, and open supply circuits. When inspecting capacitors, be sure to:
- Visually inspect capacitor bodies. Capacitors should not be misshapen/swollen.
- Thermographically inspect capacitor bodies. Capacitors should be warmer than ambient air temperature and exhibit equal temperatures across all phases.
- Check bushing and wiring connections for hotspots.
Images courtesy Dan Playforth.
Any thermal anomalies detected should be investigated and corrected as soon as possible. Capacitors operating at ambient temperature should be corrected immediately as imbalanced capacitance can be more detrimental than having no capacitors at all.
Infrared inspection of electrical distribution systems is one of the many topics covered in the Level I Infraspection Institute Certified Infrared Thermographer® training course. For information on thermographer training or to obtain a copy of the Standard for Infrared Inspection of Electrical Systems & Rotating Equipment, visit us online at: www.infraspection.com or call us at 609-239-4788.
Non Uniformity Correction
Tip written by: Infraspection Institute
Focal plane array detectors are standard components for most commercial thermal imagers. One feature common to all FPA imagers is a function known as non-uniformity correction.
Using an FPA detector in the construction of an imager provides high resolution and other advantages. One disadvantage is that FPA detectors tend to “drift” during imager operation. When the pixels of an FPA detector drift, their response to the radiant energy emitted by an object changes.
As an FPA detector drifts, the displayed image will develop areas with inexplicably hot or cold pixels. Drifted pixels cause the appearance of hot/cold artifacts within the image and cannot be relied upon for accurate temperature measurements. Depending upon imager type and ambient conditions, significant drift can occur within a very short period of time.
To correct for drift, all FPA imagers have a function known as non-uniformity correction. Simply put, NUC is a feature that ‘resets’ the image by aligning all detector pixels to the same value. Depending upon imager model, the NUC process may be an automatic feature of the imager or a manual function performed by the thermographer. Performing a non-uniformity correction may require several seconds to complete; during this time imaging is not possible.
During the NUC process, a high emittance object of uniform temperature is temporarily placed within the optical path of the imager. When the NUC process is activated, the imager’s computer electronically adjusts the gain of all detector pixels to a uniform value thereby removing errors caused by detector drift. A NUC should be performed at regular intervals during imager operation or whenever hot/cold artifacts appear within the image.
Infrared imager operation is one of the many topics covered in the Level I Infraspection Institute Certified Infrared Thermographer® training course. For information on our open enrollment or Distance Learning courses, please visit us online at www.infraspection.com or call us at 609-239-4788.
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Measuring Motor Temperatures
Tip written by: Infraspection Institute
Temperature can be an indicator of the condition of installed electric motors; however, the best location for measuring temperature is often debated. In this Tip we discuss the best location for measuring motor temperatures.
Measuring motor temperature is often a challenge since electric motors differ widely in their design and construction. While many have suggested measuring the motor casing along the stator, this method does not work well for motors that are fan cooled or exposed to external air currents. For uncooled motors, this approach can produce varying temperature values depending upon the location of the subject temperature readings.
In 1997, a research project led by Infraspection Institute utilized instrumented motors in a controlled environment to determine the effect of excess force on installed motors. One of the primary goals of this research was to identify a location for collecting reliable temperature data.
From our research it was found that measuring the exterior of the motor bellhousing within 1” of the output driveshaft consistently produced temperatures that were within 1 to 2 C of the motor windings and the output side bearing assembly. Temperatures taken at the bellhousing were especially useful for fan cooled motors since this area was unaffected by convective cooling from the fan.
When measuring motor temperatures, keep the following in mind:
- Make certain that all thermometers are within calibration and used properly
- Motor temperature will vary with load and ambient temperature. Be certain to record both along with motor temperature
- Elevated temperatures can be caused by electrical or mechanical defects within the motor and/or defective installations
- Motors with elevated temperature should be further investigated for cause and repaired or replaced accordingly
Temperature limits and trending are two of the many topics covered in the Level II Infraspection Institute Certified Infrared Thermographer® training course. For more information on upcoming classes or to obtain a copy of our Cross Technologies Study, call 609-239-4788 or visit us online at www.infraspection.com.
Do You Have the Correct Time?
Tip written by: Infraspection Institute
Most modern thermal imagers have the ability to record time and date along with thermal images. Taking a moment to ensure that the correct time and date are displayed on your imager before you begin your inspection can help to avoid wasted time and the collection of inaccurate data.
Having the correct time associated with your imagery is important for several reasons. With correctly dated imagery, it is possible to:
- Accurately document when the inspection was performed
- Easily store and uniquely reference image files
- Record the duration of a thermal event
It is always good practice to consciously check your imager’s clock each time you start your imager and make any necessary adjustments. Be certain to check your clock periodically during your inspection and whenever you restart your imager such as after a battery change or power interruption.
If your imager frequently displays incorrect time, it may be indicative of a defective or dead internal battery. To help avoid this problem, arrange for replacement of internal clock batteries whenever you have your imager serviced or repaired.
Infrared imager operation and use are two of the many topics covered in the Infraspection Institute Level I Certified Infrared Thermographer® training course. For more information or to register for a course visit us online at www.infraspection.com or call us at 609-239-4788.
How Close Do You Need to Be?
One of the most frequently asked questions in thermography is, “How close do I need to be to my target?” The answer depends upon target size and the type of data that are desired.
Appropriate distance is largely dependent upon three factors: target size, IR equipment optics, and detector resolution.
With qualitative thermal imaging, the maximum viewing distance is achieved where the object and any possible anomalies can be clearly resolved. If a target cannot be clearly distinguished, it will be necessary to move closer or to use a telephoto optic.
When using an imaging radiometer, obtaining accurate temperatures will require substantially shorter distances than those required for thermal imaging. Obtaining accurate quantitative data requires that the radiometer’s spot measurement size is smaller than the area being measured. If it is determined that the radiometer’s spot size is larger than the area being measured, it will be necessary to move closer or use a telephoto optic calibrated for the imager.
Because there is no method for correcting for errors caused by imaging at excessive distances from a target, it is imperative to always ensure appropriate distance prior to recording images.
Spot measurement size and its impact on accurate temperature measurement is one of the many topics covered in the Level II Infraspection Institute Certified Infrared Thermographer® training course. For information on thermographer training or to obtain a copy of the Standard for Measuring Distance/Target Size Values for Infrared Imaging Radiometers, visit us online at www.infraspection.com or call us at 609-239-4788.
The Weakest Link
Tip written by: Infraspection Institute
We’ve all heard the phrase, “A chain is only as strong as its weakest link.” When it comes to thermography, the weakest link is frequently not the test equipment but rather the thermographer.
All too often, many facility managers are led to believe that infrared imagers are fully automatic instruments that require nothing more than “point and shoot” operation. While thermography is a science, it is also an art or craft requiring a skilled human operator for both conducting the inspection and interpreting the data obtained.
In order to achieve maximum effectiveness, thermographers need to have an understanding of infrared theory, heat transfer concepts, equipment capabilities and limitations, and environmental conditions, as well being knowledgeable about the system(s) being inspected.
Whether you are setting up an infrared inspection program or maintaining one, thermographer training should not be overlooked. Obtaining quality training is an investment that can pay huge dividends by maximizing the effectiveness of thermographers and eliminating your weakest link.
Infraspection Institute offers Level I, II, and III training and certification for thermographers worldwide. Our infrared training courses meet the requirements for training of NDT personnel in accordance with the ASNT document, SNT-TC-1A and ISO standards.
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The Importance of Context
Tip provided by:
Robert J. Incollingo, Esquire
4 Munn Avenue
Cherry Hill, New Jersey 08034
(856) 857-1500
www.rjilaw.com
“(E)xperts agree that while there is a theoretical basis to thermography, there is no provable use for it …” Thermographic Diagnostics v. Allstate, 125 N.J. 491, 593 A.2d 768 (1991).
The foregoing is an actual quote from a New Jersey Supreme Court opinion. That case has been cited in at least 21 subsequent cases in New Jersey, New York, and Pennsylvania, and has never been overruled.
I would like to point out, however, that the statement was written by a judge who quoted from another case opinion written by a second judge who quoted a third judge who was distilling the opinion of a witness for the losing side of a trial that neither the first nor the second judge played any part in. Moreover, you’ve now read the quote completely out of context. The full sentence is:
“After describing the testimony of most of plaintiff’s and defendants’ expert witnesses, id. at 212-20, 530 A.2d 56, the Law Division offered this synopsis of the expert testimony:
“To summarize the medical testimony, the defendants’ experts agree that while there is a theoretical basis to thermography, there is no provable use for it by the practicing physician today.”
I should also point out that neither the first fragmentary quote nor the complete one represents the holding of Thermographic Diagnostics v. Allstate Ins. Co., so whether the case was ever overruled or not is a red herring and completely beside the point. I should further point out that I could have made all of this up. I read of lot of law and it wouldn’t have been that difficult.
In these narrow bandwidth times of tweets and sound bites, thermographers do well to take note amidst the cries of “Fake news!” how context, whether for a statement or an image, can make all the difference in the world to true meaning.
How did it all turn out? Finally, the New Jersey Supreme Court stated it was satisfied that the “trial court’s finding that thermography has medical value as a diagnostic procedure was supported by substantial, reliable and credible evidence.” 125 N.J. 491, 513, 593 A.2d 768 (1991).
One for our side.
Bob Incollingo is an attorney in private practice in New Jersey, and a regular speaker at Infraspection Institute’s IR/INFO Conference. He has been widely recognized since before the turn of the century as the world’s leading authority on thermography law, which he contends does not exist. RJILAW.com
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April 30, 2018
Sponsored by: Keysight Technologies
When Should You Upgrade Your Imager?
With any technology, change is inevitable. Advances in infrared imager technology now provide thermographers with new equipment choices on a semiannual basis. With more choices than ever, it is important for thermographers to be able to determine when they should upgrade their imager.
With the recent introduction of 640 x 480 pixel imagers, many have suggested that thermographers with older imaging systems will suffer a loss of business to those with newer equipment. While increased resolution may seem desirable, of greater importance is matching infrared equipment to the task at hand. For imaging large objects or imaging at close range, imagers with lesser resolution may be sufficient to the task.
In addition to improved image quality, there are technical and sound business reasons to consider an upgrade. These include, but are not limited to, the following:
- Increased portability, functionality, and/or ease of use
- Improved measurement accuracy
- Better availability of service, parts, and calibration
- New business opportunities afforded by new equipment
- Customer demand for new features and benefits
Depending upon the age of existing equipment, there may be financial advantages to upgrading or acquiring new equipment. Typically, a professional accountant can offer the best advice in this area.
Infrared equipment selection and operation are two of the many topics covered in all Level I Infraspection Institute Certified Infrared Thermographer® training courses. Open enrollment classes are available at several locations each month and through our Distance Learning Program. For information on thermographer training including course locations and dates, visit us online at www.infraspection.com or call us at 609-239-4788.
IR Inspections of Photovoltaic Systems
Tip written by: Infraspection Institute
With interest in renewable energy at an all-time high, photovoltaic systems have become a common sight worldwide. Infrared inspections can be used for quality assurance inspections of new installations or to monitor the performance of existing ones.
Photovoltaics is a method of converting solar energy into electricity. A photovoltaic system uses an array of several solar panels each of which is comprised of several solar cells. When exposed to sunlight, the solar cells produce direct current electricity. This DC power can then be converted to AC power for local use or to supply a power grid.
Defective cells or wiring within solar panels can cause hotspots that compromise the power output of the panel. Such hotspots are readily detected with a thermal imager while the panel is exposed to sunlight. Performed from either the topside or underside of panels, infrared inspections provide the most cost effective method for detecting defects within installed panels.
Thermogram courtesy Testo India
When performing an infrared inspection of an installed PV system, keep the following in mind:
- Determine best vantage point for the IR inspection
- Inspections should be performed on a sunny day when winds are calm
- Qualitatively inspect panels looking for inexplicable hot or cold spots
- Be sure to include the electrical conductors and distribution equipment that connect solar panels to the electrical system
Lastly, make certain to observe all safety precautions during the infrared inspection especially when working from an aircraft or an elevated vantage point. Personnel should also take care to avoid electrical hazards when working near exposed, energized electrical conductors.
Infrared inspections of photovoltaic panels is one of the many topics covered in the Level I Infraspection Institute Certified Infrared Thermographer® training course. For information on thermographer training or to obtain a copy of the Standard for Infrared Inspection of Installed Photovoltaic Systems, visit us online at www.infraspection.com or call us at 609-239-4788.
Lightning Safety
Tip written by: Infraspection Institute
Lightning is one of the most spectacular natural phenomena. For thermographers who work outdoors, it can present a serious safety hazard. This week’s Tip discusses how you can protect yourself from this serious safety hazard.
Each year, lightning kills an average of 67 people in the United States; hundreds more are injured. Few people really understand the dangers of lightning. Many who fail to act promptly to protect their lives and property don’t understand the dangers associated with thunderstorms and lightning.
Thunderstorms are most likely to develop on warm summer days and go through various stages of growth, development, and dissipation. On a sunny day, as the sun heats the air, pockets of warm air start to rise in the atmosphere. When this air reaches a certain level in the atmosphere, cumulus clouds start to form. Continued heating can cause these clouds to grow vertically upward in the atmosphere into “towering cumulus” clouds. These towering cumulus clouds may be one of the first indications of a developing thunderstorm.
During a thunderstorm, each flash of cloud-to-ground lightning is a potential killer. The determining factor on whether a particular flash could be deadly depends on whether a person is in the path of the lightning discharge. In addition to the visible flash that travels through the air, the current associated with the lightning discharge travels along the ground. Although some victims are struck directly by the main lightning stroke, many victims are struck as the current moves in and along the ground.
Lightning can strike as far as 10 miles away from the rain area in a thunderstorm. That’s about the distance you can hear thunder. When a storm is 10 miles away, it may even be difficult to tell a storm is coming.
IF YOU CAN HEAR THUNDER, YOU ARE WITHIN STRIKING DISTANCE. SEEK SAFE SHELTER IMMEDIATELY!
The first stroke of lightning is just as deadly as the last. If the sky looks threatening, take shelter before hearing thunder. Once indoors, stay away from windows and doors and avoid contact with anything that conducts electricity. Wait at least 30 minutes after the last clap of thunder before leaving shelter.
For more info on lightning safety, visit: www.lightningsafety.noaa.gov
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May 21, 2018
Tip provided by Wayne Swirnow
IR Image Capture & Tuning
A Thermographer is like a professional photographer – both communicate a message about their subjects through imagery. Similar to photography, focus, composition, and exposure of thermograms are important since they are often the main vehicle that a Thermographer uses to convey information.
The following tips will help ensure the quality of thermal images:
- Ensure that the image is in focus. High pixel count imagers are still “low resolution” compared to even the lowest cost daylight cameras. Typical infrared images may not seem very “clear” to an end user who has no experience interpreting thermograms. Capturing images which are even slightly out of focus will degrade their clarity and can compromise the accuracy of radiometric data embedded within the thermogram.
- Show your target as large as safely practical. Ideally, the target should fill up a significant portion of the imager’s display screen. Select an imaging distance and lens to ensure that the target is big and clear in the imager’s viewfinder. By using the maximum amount of pixels across the target, you provide the best optical and thermal resolution and minimize measurement errors due to spot size limitations.
- Adjust imager Level and Gain settings to provide the most dynamic range of color for the object. Adjust the imager to use most of the color on the object and limit how much color is used for the background unless it is important to also show some background information. This approach will give images the best contrast while conveying the most thermographic information to the recipient of the report.
There are many philosophies on how to best thermally tune images and one may be more appropriate than another depending on the application and what the Thermographer is trying to show the end user. One approach is to treat tuning as a dynamic element, tuning for each image taken. Another is to tune all images the same so a large set of images all have the same temperature span which makes them easier to compare when viewed as a set.
For instance, if a specific exception within a structure’s wall is the target, tuning the image to best show that local area of interest may be appropriate. An example of this would be to tune the image so that the details of an insulation void within a wall, or a thermal bridging element are well defined using the most amount of colors across the smallest temperature span to clearly illustrate the exception. However, if the task is to image a side of an entire building then you may choose to sacrifice some local thermal contrast to achieve a more uniform presentation down the length of a building wall by tuning all images to the same span and level.
For a comprehensive report of a building you may need both globally tuned lower dynamic range images taken sequentially down the side of a building and high dynamic images of specific areas on that wall which have been finely tuned to best show that particular exception.
In electrical work, each image is typically tuned for a specific target. In this application, it is critical to finely tune the image such that it is possible to see from where heat is being generated in a group of connections or components.
The job of the Thermographer is to locate exceptions and present them to the end user through report imagery. Images which are clearly focused, well-composed, and properly tuned will convey the most information and require the least amount of explanation.
Applying Thermography
Tip written by: Infraspection Institute
Thermography is a versatile nondestructive test technique that has a wide variety of applications. In short, thermography can be applied to any situation where knowledge of heat patterns and associated temperatures across a surface will provide meaningful data about a system, object, or process.
In thermography, there are two basic approaches to evaluating data. Qualitative thermography or thermal imaging relies on observing thermal patterns and noting any inexplicable differences or anomalies. Quantitative thermography adds non-contact temperature measurements to thermal images.
Many systems produce heat as a byproduct of operation. Such systems include electrical distribution systems, machinery and insulated structures. These systems are generally inspected during normal operation once line-of-sight access is obtained.
Thermography can also be applied to systems that do not produce heat as a byproduct of operations by actively heating and/or cooling the target and observing the resulting images. Systems that are candidates for active thermography include building facades, low slope roofing systems, storage tanks and composite materials.
When heated or cooled properly, thermal patterns caused by changes in the thermal conductivity or capacitance of the subject system can provide evidence of internal structures, water infiltration, or contaminants. The use of active thermography is growing, especially for inspection of composite materials used in the aircraft, aerospace, and marine industries.
Both active and passive thermography are covered in depth in the Infraspection Insitute Level I Certified Infrared Thermographer® training course. For more information on our Level I open enrollment or our Distance Learning courses, please visit the Infraspection website.
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Calculating Infrared Inspection Program Payback
Calculating savings and/or avoided costs is one of the most difficult tasks associated with an infrared inspection program; however, doing so is required in order to gauge how effective a program is.
In short, there is no way to calculate the exact value of the findings of an infrared inspection other than allowing the component run to failure and adding up the subsequent losses. Unfortunately, this is not a practical approach to maintenance.
As an alternative, there are several methods that professionals use to estimate program savings. A brief description of each of the most common methods is listed below:
1. Summary of Findings – A report comprised of the deficient items found during a given time period. Reports may be by the day, month, year, etc. This type of report does not provide any financial data.
2. Performance Effectiveness Ratios – Use accounting data to trend how an infrared inspection program impacts an overall maintenance program. Typically calculated for a single facility over an extended period of time. Improvements in efficiency can be compared to similar facilities or to the performance history of the subject facility.
3. Avoided Costs Method – A summary of the estimated cost of repairs for breakdown versus proactive repair efforts. Typically, proactive repairs are always cheaper since the outage can be planned and the cost of the actual repair is usually less since the subject equipment often suffers far less damage when not allowed to run to catastrophic failure.
4. Permanent Improvement Method – This is a summary of the financial impact on a given facility due to the implementation of an infrared inspection program. For example, infrared can be used to supplement a maintenance program by directing repair efforts to only those areas in need of attention rather than periodic application of labor-intensive manual work. In such cases, the cost difference between the two methods results in a savings every time the manual maintenance procedure is avoided in the future.
5. Statistics Based Method – This method is based upon insurance industry statistics associated with loss claims that have been paid to clients over a several year period. This method takes into account the value of the overall facility along with the severity of the problem. While this method is not as accurate as the Avoided Cost Method, it can be applied quickly and easily with a minimum of effort. Infraspection Institute’s Exception® Pro software utilizes this method for calculating savings as one of its standard features.
Each of the above methods varies in the information provided as well as the ease of use and accuracy. We cover each method in depth in our Level III Certified Infrared Thermographer Course.
When calculating savings, we recommend that thermographers consult with their end user and choose one of the above methods that will best suit his/her needs and consistently apply the chosen method over time. While you will not be able to calculate savings exactly, you should obtain a good indication of the value of your program.
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Why GFCI Devices Appear Warm
When performing an infrared inspection of an electrical panel you may notice that the phenolic bodies of Ground Fault Circuit Interrupters appear warm. This same condition may also be observed on self-contained GFCI receptacles. This condition is usually due to the construction of the device itself.
In order to monitor the amount of current flowing through the supply and neutral conductors of a circuit, GFCI devices have small transformers built into them. These transformers can cause the body of the GFCI to run several degrees warmer than ambient temperature. Depending upon the settings of your thermal imager, these devices may show a marked contrast to their surroundings.
When inspecting GFCI devices, compare the thermal patterns of these devices to other similar devices under similar load. When inspecting GFCI breakers, be sure to inspect the load side connection at the GFCI device as well as the neutral bus bar connection for the subject breaker.
Infrared inspection of electrical distribution systems is one of the many topics covered in the Level I Infraspection Institute Certified Infrared Thermographer® training course. For information on thermographer training or to obtain a copy of the Standard for Infrared Inspection of Electrical Systems & Rotating Equipment, visit us online at www.infraspection.com or call us at 609-239-4788.
Heat Stress & the Human Body
Tip written by: Infraspection Institute
For many, the peak of Summer brings high temperatures to the workplace. For others, high temperatures in the workplace are an everyday occurrence. Understanding heat stress and its attendant safety challenges is crucial for those working in hot environments.
What is heat stress?
Heat stress is a physical hazard. It is caused by environmental conditions and results in the breakdown of the human thermal regulating system.
What are the symptoms of heat stress?
There are various degrees of heat stress. Each has its own unique symptoms. The most common form of heat stress is heat exhaustion. Symptoms of heat exhaustion include dizziness, confusion, headaches, upset stomach, weakness, decreased urine output, dark-colored urine, fainting, and pale clammy skin.
What do I do if I think I am experiencing some form of heat stress?
Act immediately –
- Advise a co-worker that you do not feel well
- Move to an area away from the hot environment
- Seek shade and cooler temperatures
- Drink water (1 – 8 oz. cup every 15 minutes) unless sick to the stomach
- Have someone stay with you until you feel better
What should I think about before working in a hot environment?
Before working in a hot environment, consider the type of work to be performed, duration of time to be spent in hot areas, level of physical activity, and other nearby hazards. Always use appropriate PPE and work together as a team.
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Inspecting Shaded Building Elevations
Tip written by: Infraspection Institute
Infrared inspections of building exteriors often rely on solar loading to create temperature differentials necessary to detect damage or defects. A common challenge for thermographers is inspecting building elevations that do not receive direct sunlight.
Infrared imaging is a proven technique for testing building sidewalls. Inspecting buildings during evening hours following a sunny day can reveal the presence of structural details, missing or damaged insulation, or latent moisture. These conditions are detectable due to changes in the thermal capacitance or conductance of the walls.
When using solar energy to drive an infrared inspection of building sidewalls, it is normal for a building to heat unevenly. Typically, east elevations receive the least direct sunlight, while the south and west elevations receive the most. For many northern latitudes, north elevations do not receive direct sunlight.
Fortunately, it is not necessary to receive direct sunlight in order to drive an infrared inspection. Provided that the building is not in close proximity to other structures or heavily shaded areas, it will receive indirect heating from nearby objects such as the ground. For elevations that are heated indirectly, it is important to note that they will exhibit weaker thermal patterns when compared to other exposures that receive direct sunlight.
When using solar loading to drive an infrared inspection, keep the following in mind:
- Choose an evening when weather conditions are optimal – sunny day followed by a cool clear evening with no wind
- Begin infrared inspection on the North elevation and continue in a clockwise fashion around the exterior of the building
- Depending upon wall construction, type of defect, and local weather conditions, it may be necessary to begin prior to sunset
Lastly, be aware that thermal patterns associated with defects may only appear for a short period of time on the North and East elevations. All thermal anomalies should be investigated for cause and appropriate action taken.
Infrared inspection of building envelopes is one of the many topics covered in the Level I Infraspection Institute Certified Infrared Thermographer® training course. For information on thermographer training including course locations and dates, visit us online at www.infraspection.com or call us at 609-239-4788.
