2018
Thermal Imager Rental – A Smart Alternative
Tip written by: Infraspection Institute
With prices ranging to over $10,000, a thermal imager can represent a considerable investment. For companies getting started in thermal imaging, renting an imager can provide a cost effective alternative to purchasing a system outright.
Whether you are facing an equipment shortage or looking to evaluate the characteristics of a new imager prior to purchase, renting a thermal imager may provide a solution. In some cases, imager manufacturers will credit short term rental fees toward the purchase price of an imager. As with purchasing an imager, there are several important things to consider when arranging for a rental unit.
To help ensure that you select an appropriate imager for rental, be certain to:
- Identify appropriate spectral response required for project
- Determine if temperature measurement is required
- Evaluate the system for objective specifications
- Ascertain imager compatibility with reporting software
When arranging for a rental, obtain terms and conditions from the rental agency. These should include, but not be limited to: rental period, extension of rental, shipping costs, and requirements for insurance against loss. One should also consider the rental agency’s ability to provide technical support during the rental period.
For more information on choosing an infrared imager, refer to the article, “Selecting, Specifying, and Purchasing a Thermal Imager” available as a free download on this website.
Lastly, the greatest limiting factor in any infrared inspection is the thermographer. For accurate results, infrared inspections should only be performed by properly trained and certified thermographers. For more information on thermographer training and certification, please contact Infraspection Institute.
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Asphalt or Coal Tar – How to Tell the Difference
When performing an infrared inspection of low slope roofing systems, invasive testing is necessary to confirm the composition and condition of roofing system components. As asphalt and coal tar are incompatible materials, it is imperative to use the correct bitumen to ensure the long term integrity of repaired test sites.
Asphalt and coal tar are hydrocarbon materials commonly used for built-up roofing. While both share a common use in roofing, they are very different in their chemical composition. Asphalt is a petroleum distillate and a byproduct of crude oil refining. Coal tar is a bituminous product that is largely insoluble in petroleum distillates.
Odor is one way to differentiate between asphalt and coal tar – tar has a distinctive creosote smell. A more reliable method is to test bitumen solubility in mineral spirits. This simple test can be performed as follows:
- Obtain a small sample (pea size nugget) from the subject roof
- Soak sample in a small amount of mineral spirits in an empty glass container such as a baby food jar
- Stir sample gently for about one minute and note results
If sample dissolves to black liquid – sample is asphalt; if sample remains intact and/or colors mineral spirits to a yellow/green color, sample is coal tar.
Once bitumen type has been determined, one should use appropriate repair materials along with the same bitumen as indicated by the above test. Doing so will help to ensure the long term integrity of repaired test sites.
Infrared inspection of flat roofs is one of the many topics covered in all Infraspection Institute Level I training courses. For more information on thermographer training or to obtain a copy of the Standard for Infrared Inspections of Insulated Roofs, visit Infraspection.com or call us at 609-239-4788.
Splash Protection for Your IR Imager
Taking your infrared imager into dusty or wet environments can have disastrous consequences for your imager. While it is best to wait for such conditions to subside, you can use a polyethylene sheet or trash bag to temporarily protect your imager and accomplish a qualitative inspection.
Since not all imagers and trash bags are created equal, you can follow the following steps to ensure good results.
- Set up imager looking at a thermally stable target with a high emittance. If using an imaging radiometer, note the apparent temperature of the target.
- Select a clean, unused, polyethylene trash bag with a uniform thickness.
- Open trash bag and place over imager. Use only a single layer of the bag plastic to cover the lens.
- Use a rubber band to keep plastic smooth and wrinkle free over the imager lens.
- Image target in Step 1 again and note image quality and apparent temperature.
- Repeat above steps using different brand bags and thicknesses until you find a bag that gives minimal attenuation of image and apparent temperature.
- After selecting the bag that works, trim to fit imager so as to prevent a tripping hazard. If your imager requires air cooling, leave the bottom of the bag open so the imager can ‘breathe’.
- When finished imaging, remove bag from imager and discard.
While not glamorous, this procedure can allow you to successfully perform a qualitative inspection in an environment that might otherwise harm your imager.
Infrared equipment selection and operation are two of the many topics covered in all Level I Infraspection Institute Certified Infrared Thermographer® training courses. Level I training is 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.
Heat Stress & Hydration
Tip written by: Infraspection Institute
An ounce of prevention is worth a pound of cure. In last week’s Tip, we covered the topic of heat stress, its symptoms, and treatment. This Tip focuses on the importance of hydration as a preventive measure.
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. If you work or play in hot environments, your body needs a lot more water than you might think.
What is hydration?
Hydration is the process of adding water. Our bodies need water to do many things. In hot environments we need large quantities of water to help keep our bodies cooled to a temperature that allows them to function properly. Heat stress becomes a health and safety concern when the volume of water we need to function drops below the level necessary to maintain homeostasis. We call this low water condition dehydration or under-hydration. The average person is 7% under-hydrated.
How can I avoid being under-hydrated?
Develop the habit of drinking water at routine intervals. One 8 oz. cup every hour on hot days will assure proper hydration.
How will I know if I am properly hydrated?
Check the color of your urine. You are properly hydrated if your urine is clear, copious in volume, and light yellow in color.
What are the benefits of proper hydration?
Staying properly hydrated will help to avoid heat stress and may increase your energy level. For every 1% under-hydration, you lose 5% of your energy potential.
Thermographer safety is one of the many topics covered in the Infraspection Institute Level I Certified Infrared Thermographer® training course. For more information on class locations or our Distance Learning program, visit www.infraspection.com or call 609-239-4788.
Three Legs are Better Than None
When it comes to providing a stable platform for a thermal imager, it’s hard to beat a tripod. As thermal imagers have gotten smaller and lighter, many thermographers have all but forgotten this once requisite accessory that can help provide better quality data while reducing stress.
For many PdM applications that require still images only, using a thermal imager in a hand held configuration is usually sufficient. However, for applications that require imaging from a fixed vantage point over extended periods of time or where videotaping is desired, a tripod can be an invaluable accessory. When selecting a tripod there are several things you should bear in mind:
1. Be sure to select a tripod capable of carrying the weight of your imager.
2. Tripods should connect directly to the imager via a 1/4” x 20 set screw. Tripods with plastic quick releases should be avoided as they are subject to wear and can cause an imager to suddenly fall.
3. Tripods with sturdy hardware and locking systems are more secure and generally last longer than inexpensive models.
4. Fluid head tripods are preferable since they provide smooth motion for videotaping and are less likely to drop an imager if the head is left unlocked.
When carrying a tripod be sure to maintain a safe distance from energized electrical equipment or moving machinery.
Proper use of infrared imaging equipment and accessories is one of the many topics covered in all Infraspection Institute Level I and Level II training courses. For more information on thermographer training and certification, please visit infraspection.com or call 609-239-4788.
Rules of Construction: Special Conditions of the Subcontract
Tip provided by:
Robert J. Incollingo, Esquire
4 Munn Avenue
Cherry Hill, New Jersey 08034
(856) 857-1500
www.rjilaw.com
Otherwise bright men and women sign one-sided contracts, called contracts of adhesion, every day. If you sign a contract of adhesion as a consumer, the law will be on your side if you try to get clear. As a business owner, not so much. This is the kind of problem that comes up over and over. Maybe it’s time for you to experiment with a different approach.
Try this: have special conditions to your subcontract drawn up – a page or so that addresses the things you won’t swallow under any circumstances – and send it back to the prime contractor every time before you sign anything. If you want the edge, use your own preprinted form for this. Present it as your company’s standard form which never changes. Don’t sign any subcontract before the prime contractor signs your special conditions.
Your special conditions – you can call them supplemental conditions if you want – should be designed to operate as the last word on the subcontract documents before any signed change order. Drafted correctly, special conditions may – once signed by all parties – relieve you of some of the unacceptable subcontract terms presented to you by a prime contractor. If you had a lawyer involved every time, your lawyer would sit with you and discuss revising the subcontract terms as presented, and you could send back a marked-up counterproposal or walk away. That would be the best way to approach things. Sending back blanket special conditions for the prime to consider is a distinct second best, but it’s bound to be better than what you’re doing now.
Mid-level employees in a big outfit are likely to run away if you come back at them with a marked-up subcontract, because nobody wants to stick their neck out and depart from the company’s pre-approved form. Neither does anyone feel incentivized or equipped to negotiate all terms of a legal contract. All they want to talk about is scope, time and price. However, if they need you, especially under deadline, a prime contractor’s representatives who would never countersign a messy marked-up version of their own agreement just might accept preprinted “standard form” special conditions.
This Tip of the Week is condensed from the current article on the author’s website, RJILAW.com. It is not intended to constitute legal advice. Always consult a lawyer before signing a legal document.
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.
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Detecting Underground Pipe Leaks
Leaks are a common problem with underground piping systems. Under the correct conditions, infrared thermography can help to detect evidence of leaks from buried piping systems that carry hot or cold product.
When a leak develops in a buried piping system, fluid is lost to the surrounding earth. If a leak from a heated or cooled piping system is sufficiently large, a temperature change will occur at the surface of the ground in the vicinity of the pipe leak.
Leaks from buried piping are generally characterized by amorphously shaped thermal anomalies that appear along the pathway of the subject piping system. The ability to detect a pipe leak will be influenced by several interdependent factors including, but not limited to: pipe operating temperature, pipe system construction, burial depth, amount of loss, soil type and moisture content, and ground cover.
Infrared inspections of buried piping systems are best performed late at night with calm wind conditions. Inspections may be performed on foot, from a motor vehicle or from an aircraft. Performing the inspection late at night will eliminate the effects of solar loading and solar reflection.
During the inspection, the thermal imager is maneuvered over the pathway of the pipeline. Well-defined straight lines that correspond to the location of the buried lines generally indicate a healthy piping system. Amorphously shaped thermal anomalies that cannot be explained in terms of piping system construction or features may be indicative of pipe leaks and should be marked and subsequently investigated for cause.
Infrared inspection of underground piping systems is one of the many topics covered in all Infraspection Institute Level I training courses. For class locations and dates or information on our convenient, Distance Learning courses, visit us online at www.infraspection.com or call us at 609-239-4788.
Monochrome or Multi-Color?
Tip written by: Infraspection Institute
With most thermal imagers capable of displaying images in monochrome or multicolor, many new thermographers ask which color palette is the best choice for effective imaging. The answer will depend on a number of factors including application, delta T associated with the exception, and personal preference.
Because it is usually less confusing than multicolor palettes, grayscale may be better suited for some applications. Additionally, applications that have a large delta T associated with exceptions or where target recognition is important may be better suited for grayscale imaging. Such applications include electrical distribution systems, building envelopes inspected from the interior of the structure, and low slope roof inspections.
Multicolor palettes offer an advantage when imaging targets having a small delta T associated with exceptions or when imaging targets with several discrete temperature zones. Typical applications include mechanical systems, refractory systems, building envelopes inspected from the exterior, and medical/veterinary applications.
For hardcopy reports, printing monochrome images can result in lower cost than multicolor reports. Lastly, the choice to use monochrome or multicolor is largely a matter of personal preference. Thermographers should always use a palette which best represents the observed thermal patterns and provides data that are easily understood.
Infrared camera operation 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 or our convenient Distance Learning Program, visit us online at www.infraspection.com or call us at 609-239-4788.
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Labor Day
Tip written by: Infraspection Institute
The month of September is a month of transition for many Americans. With this Tip, we cover the transitional holiday known as Labor Day.
Generally recognized as the end of the summer travel season, early September marks the beginning of NFL and college football seasons, the start of the school year, and for some, the last opportunity to sport white clothing. Most of these traditions are centered around the final major holiday of summer, Labor Day.
With its origins dating back to the 19th century, Labor Day is a celebration of the American labor movement and is dedicated to the social and economic achievements of workers. It constitutes a yearly national tribute to the contributions workers have made to the strength, prosperity, and well-being of their country.
Once celebrated with parades and speeches, Labor Day is now observed with picnics and family gatherings as many Americans take advantage of a long weekend. Wherever your travels take you this holiday, take a moment to reflect upon the contributions made by workers that have helped to shape our country and continue to keep it strong.
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September 03, 2018
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School’s Open – Drive Carefully
Tip Provided by American Automobile Association
By early September, over 55 million children across the United States will head back to school. With 13 percent of those children typically walking or biking to their classes, drivers should be especially vigilant for pedestrians before and after school hours. The afternoon hours are particularly dangerous – over the last decade, nearly one in four child pedestrian fatalities occurred between 3 p.m. and 7 p.m.
Launched in 1946, the American Automobile Association’s School’s Open – Drive Carefully awareness campaign was created as a way to help reduce child pedestrian fatalities and injuries. Here are several recommendations from AAA regarding ways drivers can help to keep kids safe:
- Slow down – Speed limits in school zones are reduced for a reason. A pedestrian struck by a vehicle traveling at 25 mph is nearly two-thirds less likely to be killed compared to a pedestrian struck by a vehicle traveling just 10 mph faster.
- Come to a complete stop – Research shows that more than one-third of drivers roll through stop signs in school zones or neighborhoods. Always come to a complete stop, checking carefully for children on sidewalks and in crosswalks before proceeding.
- Eliminate distractions – Research shows that taking your eyes off the road for just two seconds doubles your chances of crashing. Children can be quick, crossing the road unexpectedly or emerging suddenly between two parked cars. Reduce risk by not using your cell phone or eating while driving.
- Watch for bicycles – Children on bikes are often inexperienced, unsteady, and unpredictable. Slow down and allow at least three feet of passing distance between your vehicle and a bicyclist.
Lastly, always maintain a safe distance from a stopped school bus. Be on the lookout for children boarding or exiting school buses.
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September 10, 2018
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Using an Isotherm to Detect Potential Condensation Sites
Tip written by: Infraspection Institute
Condensation on interior building surfaces can lead to a variety of problems including conditions conducive to mold growth. Used properly, the isotherm feature found on many infrared imagers can be utilized to spot potential condensation sites.
Simply put, dew point is the temperature at which water vapor in the air will cause condensation to form on a surface. When interior building components are cooled to dew point temperature or lower, water vapor will precipitate out of the air causing water to form on the subject component.
For building envelopes, chronic condensation on interior drywall surfaces can cause unsightly staining by trapping dust or smoke particulates in these areas. Chronic condensation on organic building components is also conducive to mold growth. Condensation often goes unnoticed until building occupants notice stains associated with the aforementioned conditions. Fortunately, a thermal imager can be used to detect condensation problems before they become serious.
To utilize a thermal imager to detect potential condensation sites, identify the dew point temperature for the room or areas that you are inspecting. Set your imager’s isotherm function to appear at, and for several degrees below, the dew point temperature. As you inspect high emittance building surfaces from the interior of the building, note any components that cause the isotherm to appear. These areas should then be further investigated for cause and appropriate action taken.
When using an isotherm, be sure to practice proper measurement techniques giving particular consideration to viewing angle, spot measurement size and emissivity settings.
Infrared inspections of building envelopes is one 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 or call us at 609-239-4788.
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September 17, 2018
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Autumn IR Inspections to Assess Roof Condition
Tip written by: Infraspection Institute
With parts of the US experiencing record setting heat, it is hard to think about winter. For many, autumn provides a perfect opportunity to conduct infrared inspections of flat roofs to help ensure that they are ready for the upcoming colder months.
Summer can be especially tough on roofing systems. High temperatures, building movement, and UV radiation often cause cracks and splits in the waterproofing system. Left undetected, these cracks and splits can lead to roof leaks and premature roof failure. Performing an infrared roof inspection prior to the onset of colder weather can detect evidence of problems and help to direct repair efforts.
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. For many locations, autumn provides perfect conditions for conducting an infrared inspection and performing any necessary roof repairs.
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 register for a course, visit Infraspection Institute or call us at 609-239-4788.
September 24, 2018
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The Problem with Glass and Plastic
Glass viewing windows and plastic safety barriers are common features found on medium and high voltage electrical enclosures and devices. Although glass and many plastics are transparent in the visible spectrum, they are opaque in the infrared spectrum.
Because infrared equipment cannot accurately see through glass or plastics, infrared inspections must be conducted with these materials out of the line of sight of the infrared test equipment. When plastic barriers are present, try the following:
- Shift your viewing angle to try to see around or behind the barrier
- Have the qualified assistant temporarily remove the barrier observing proper safety precautions
- If barrier is short and the subject device is connected to insulated conductors, image conductors and report any inexplicable temperature rise.
When safety glass view ports are encountered in switchgear enclosures, it will be necessary to have the qualified assistant open/remove the subject panels. If this cannot be done due to safety interlocks, other types of electrical testing should be performed during regularly-scheduled PM shutdowns. As always, any obstructed equipment or equipment not inspected should be noted as such in the final written report.
Infrared inspection of electrical equipment is one of the many topics covered in the Infraspection Institute Level I Certified Infrared Thermographer® training course. This same subject is also the focus of our 16 hour application course, Infrared Inspection of Electrical Systems. For more information or to register for a course, call us at 609-239-4788 or visit us online at infraspection.com.
October 01, 2018
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Training – A Wise Use of Year End Budget Money
Tip written by: Infraspection Institute
When it comes to spending year end budget monies, the phrase “Use it or Lose it” often applies. Training can be a wise choice for those looking to reduce a budget surplus.
Staying within budget is a constant challenge for maintenance managers. For many, it seems that there is never enough money in the budget. On occasion, however, it is possible to experience a surplus in one’s budget when nearing year end.
When faced with a budget surplus, it is imperative to fully utilize allocated financial resources. Failure to do so can cause a reduction in future budgeting if management perceives that your department is over funded. When searching for wise choices for year-end spending, training is always a good option.
Thermographic training is a sound investment for initiating a PdM program or expanding an existing one. Whenever considering infrared training be certain to:
- Examine course curriculum to ensure that it meets your needs
- Ensure that course will be germane to all infrared imagers
- Determine course locations or availability of Distance Learning courses
- Ascertain if certification is included with course, its expiration date, and renewal fees
- Insist that instructors be practicing thermographers with documented field experience in their area of instruction
Infraspection Institute has been providing infrared training and certification for infrared thermographers since 1980. Our Level I, II, and III Certified Infrared Thermographer® training courses meet the training requirements for NDT personnel in accordance with the ASNT document, SNT-TC-1A. Certification and applications courses are offered as open enrollment or on-site classes or through our Distance Learning program. All courses are taught by expert Level III thermographers whose field experience is unsurpassed anywhere in the world. For more information call 609-239-4788 or visit us online at www.infraspection.com.
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October 08, 2018
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High E Targets for Measuring Component Temperatures
Tip written by: Infraspection Institute
Low emittance can introduce significant error when performing non-contact temperature measurements of electrical and mechanical system components. Affixing high emittance coupons to component surfaces can provide a solution.
Temperature measurements are often useful in assessing the condition of components and systems. Because many electrical and mechanical components are constructed of shiny metal, obtaining accurate infrared temperature values is often impossible. Affixing coupons of tape or paint with known emittance values is a proven method for increasing measurement accuracy.
There are a number of inexpensive materials that can be used to modify component surfaces. These include Scotch 191 PVC tape (E 0.97), and Wahl flat black paint (E 0.95). Affixing coupons of these materials to areas of interest provides a known emittance and ensures that future temperature measurements are made in the same spot.
Prior to modifying any surface, keep the following in mind:
- Always obtain permission to modify any component(s)
- Ascertain that subject surfaces are safe to touch
- Check target temperature to ensure modifying material will not melt or catch fire or damage the component
- When using tape, be sure to install without air gaps
- Ensure that coupon is sufficiently large for intended radiometer’s spot size
Lastly, contaminants from industrial environments can cause the emittance of modifying materials to change over time. If so, it may be necessary to reapply the modifying material periodically.
Infrared inspection of electrical and mechanical components is one of the many topics covered in the Infraspection Institute Level I Certified Infrared Thermographer® training course. For more information or class locations and dates, visit www.infraspection.com or call 609-239-4788.
October 15, 2018
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Infrared Inspection of Ballasted Roofing Systems
Infrared inspections can help to detect latent moisture within smooth or gravel-surfaced insulated roofing systems. For roofs covered with high-density ballast or pavers, other forms of non-destructive testing such as capacitance or nuclear gauge testing may provide better results.
For infrared inspections performed during post-sunset hours from the exterior of a building, the collection of accurate infrared data is highly dependent upon roof construction. Applicable roof construction is as follows: Built-up or single-ply membrane installed over, and in continuous contact with, a layer of insulation or an insulating deck. Roof may be smooth, granule-surfaced or gravel-surfaced. If gravel-surfaced, stones should be pea sized or smaller with a thickness of less than one inch.
Roofs covered with concrete pavers or river washed ballast (walnut-sized or larger rock) are not candidates for an accurate infrared inspection. In general, the presence of ballast materials will mask the small temperature differentials associated with latent moisture since they are capable of absorbing large amounts of solar energy during daylight hours.
For some ballasted roofs, it may be possible to detect limited thermal patterns associated with latent moisture; however, this is highly dependent upon roof construction, ballast thickness and density, and local weather conditions. In most cases, the presence of ballast will prevent a thermographer from accurately detecting thermal patterns associated with latent moisture.
For ballasted roofs, it is often prudent to utilize either a capacitance or nuclear gauge instead of thermal imaging. In the hands of a competent technician, these technologies will usually provide more accurate data for detecting evidence of latent moisture within ballasted roofing systems.
Infrared inspection of flat roofs is one of the many topics covered in all Infraspection Institute Level I training courses. For more information on thermographer training or to obtain a copy of the Standard for Infrared Inspections of Insulated Roofs, visit Infraspection.com or call us at 609-239-4788.
October 22, 2018
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Autumn is the Time for Steam Trap Testing
Tip written by: Infraspection Institute
With the onset of seasonably cooler weather, autumn is the time to prepare your steam system for the upcoming heating season. Testing your steam traps before the season begins can help to pinpoint costly leaks before the heating season begins.
Traditionally, two different non-destructive technologies have been employed to test steam systems – contact ultrasonics and temperature measurement. Used individually, each of these techniques has limitations that can lead to false positive and/or false negative results. Combining temperature measurement with ultrasound can result in a highly accurate test method by following a few simple steps:
- Measure trap inlet to ensure that temperature is above 212º F. If trap inlet is below 212º F, ascertain why steam is not reaching trap
- Listen to the trap outlet with contact probe of ultrasonic unit. Continuous hissing or rushing sounds usually indicate a failed trap
- Ascertain that trap is cycling periodically. Frequent cycling may be caused by an undersized or worn trap
- Tag defective traps and document in written report
- Re-test defective traps after repair to ensure effectiveness of repair
Always be sure to follow appropriate safety precautions especially when working with high pressure steam or when using ladders or lift equipment.
Infrared inspection of steam traps is one of the many topics covered in the Level I Infraspection Institute Certified Infrared Thermographer® training course. For information on thermographer training including our Distance Learning Courses, visit us online at www.infraspection.com or call us at 609-239-4788.
October 29, 2018
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From the Top Down
“From the top down” describes an approach for managing companies. It may also describe an effective way to perform infrared inspections.
During the performance of infrared inspections of electro/mechanical equipment in high-rise facilities, efficiently moving between floors can be a challenge. Waiting for elevators can be especially time consuming; climbing stairs with tools and instruments can be physically taxing.
One solution is to begin the infrared inspection at the uppermost floor or roof level. Upon completing the inspection of all equipment on the subject floor, proceed to the next lower floor via the stairwell. Doing so usually requires less than a minute, compared to the lengthy wait often required to catch an elevator.
When using stairways to move between floors, make certain that:
- Affected personnel are notified of the inspection activities
- Inspectors have keys or doorway lock combinations to enter occupied spaces from the stairwell
- Fire/security alarms will not be tripped when moving into or out of stairwells
- Tripping hazards are not created by test equipment or tools
Upon leaving a subject floor via the stairwell, check to ensure that doorways close completely and lock in accordance with site security requirements. For more information on performing infrared inspections of electrical and mechanical systems, contact Infraspection Institute at 609-239-4788 or visit us online at: www.infraspection.com.
November 05, 2018
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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.
November 12, 2018
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Emissivity Settings for Building Inspections
Tip written by: Infraspection Institute
A common question among thermographers who perform infrared inspections of buildings is, “What emissivity setting should I use?” While this might seem like a straightforward question, the answer is not that simple.
Recent years have seen a dramatic increase in the use of thermography as a building diagnostics tool. While many applications are qualitative, there are occasions when quantifying temperature can be useful. In order to accurately perform non-contact temperature measurements, one must input the correct emittance value into a radiometer’s computer.
While many equate emissivity to values published in emittance tables, emissivity is a dynamic characteristic that is influenced by several factors. These include: wavelength, object temperature, viewing angle, target shape, and surface condition. Each of these factors can vary between projects or during a given inspection.
Further compounding the challenge is the fact that not all imagers are created equal. Imagers lacking corrective inputs for atmospheric attenuation and/or reflected temperature often require an exaggerated emittance value be utilized.
When performing an infrared inspection of buildings, keep the following in mind:
- For qualitative inspections performed with an imaging radiometer, leave the imager’s E control set to 1.0. If possible, turn off all temperature measurement tools.
- In general, dielectric materials will have a relatively high emittance; shiny surfaces and glass will be quite reflective.
- Viewing angle and reflected temperature can greatly influence the effective emittance of a material. In particular, smooth-surface roof membranes and building sidewalls can be quite reflective when imaged at low viewing angles often associated with ground-based inspections.
Lastly, emittance values obtained from published tables can introduce significant temperature measurement errors. Whenever possible, one should calculate emittance values with the subject imager and cross verify observed temperatures with contact thermometry.
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November 19, 2018
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IR Inspections of Single Phase Power Panels
Tip written by: Infraspection Institute
Determining exceptions in single phase power panels is often challenging due to the absence of appropriate reference components. In this Tip, we offer suggestions for properly inspecting these panels.
Infrared inspections of single phase circuits are often challenging due to the absence of similar components under similar load. Unlike polyphase panels, single phase power panels typically contain circuits of different sizes. Oftentimes, these circuits are under widely varying loads. Depending upon power usage, many circuits may be under zero load causing other circuits to appear quite ‘hot’ by comparison.
Overloads confirmed with ammeter.
Prior to performing an infrared inspection of single phase panels, make certain that the panel is under adequate load. When inspecting, keep the following in mind:
- Inspect panels in an orderly fashion working from line to load side for all circuits. When possible, compare similar components under similar load to each other.
- Inspect each overcurrent device for uneven heating between the line and load side connections. Check all connections within the panel to ensure that hot spots do not exist.
- Check warm conductors for load using a true RMS sensing ammeter. Don’t forget to include neutral conductors.
- Document all exceptions with a thermogram, control photo and all pertinent data including time, date, and load conditions.
- Be aware that some devices such as GFCI breakers may normally appear warm due to their construction and/or operation.
Lastly, be certain to observe all necessary safety practices when working on or near energized electrical equipment.
Infrared inspection of power 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.
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November 26, 2018
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How to Calculate Emittance
Tip written by: Infraspection Institute
Utilizing correct emittance values is imperative for accurate non-contact temperature measurements. Knowing how to accurately calculate emittance values can help to ensure the accuracy of infrared temperature measurements.
Although thermographers frequently obtain emittance values from published tables, this practice can introduce significant errors. Following the procedure listed below, it is possible to accurately calculate the E value of an object.
Equipment Required:
- Calibrated imaging radiometer with a computer that allows thermographer to input Reflected Temperature and Emittance values
- Natural or induced means of heating/cooling target to a stable temperature at least 10ºC above/below ambient temperature
- Calibrated contact thermometer
Method:
- Place imaging radiometer at desired distance from heated/cooled target. Be certain that target is larger than imager’s spot measurement area. Aim and focus imager on target
- Measure and compensate for Reflected Temperature
- Place imager crosshairs on target
- Use contact thermometer to measure target temperature at location of imager crosshairs. Remove contact thermometer
- Without moving imager, adjust E control until observed temperature matches value obtained in Step 4 above. The displayed E value is the Emittance value for this target with this imaging radiometer. For greatest accuracy, repeat above three times and average the results.
Note: This procedure requires contact with the object being measured. Be certain to observe all necessary safety precautions prior to making contact with target.
The above procedure is described in detail in the Standard for Measuring and Compensating for Emittance Using Infrared Imaging Radiometers. Copies of the Standard are available from the Infraspection Online Store or by calling 609-239-4788.
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December 03, 2018
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Infrared Inspections of Conveyor Bearings
Tip written by: Infraspection Institute
If your facility utilizes conveyor systems for moving product, you may be able to use your thermal imager to locate defective bearings.
Many conveyor systems utilize a large number of rolling element bearings to support rollers or conveyor belting. Depending upon the size of the facility, a conveyor system may contain thousands of rolling element bearings. Due to the vast number of bearings, inspecting them can be an enormous and time consuming task.
Because bearing wear is usually accompanied by a rise in temperature prior to failure, infrared imaging can be used to detect overheating bearings. The infrared inspection is performed by comparing similar bearings under similar load. Bearings appearing inexplicably warm can be noted for further investigation.
When performing your infrared inspection, bearings should be operating at normal speed and you must have line-of-sight access to the subject bearings. Since the infrared inspection is performed from ground level without special preparation, the inspection can be performed quickly.
When performed by an experienced, certified thermographer, infrared inspections can provide a cost effective method for helping to eliminate unexpected failures and improving your production uptime.
Infrared inspection of bearings is one 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 Infraspection Institute or call us at 609-239-4788.
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December 10, 2018
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IR Inspections of Timber Framed Buildings
Tip written by: Infraspection Institute
Well known for its ruggedness and distinct architectural features, timber frame construction is a popular choice for commercial and residential buildings. Used properly, thermal imaging can be used to detect evidence of excess energy loss within these unique structures.
Timber framing is a building construction method that utilizes heavy, squared-off timbers rather than dimensional lumber such as 2x4s. Timbers are carefully fitted and secured using mortise-and-tenon joints often held together by large wooden pegs. The use of timber framing was common for wooden buildings constructed in the 19th century and earlier.
When utilizing timber frame construction for conditioned buildings, particular attention must be paid to the construction of exterior walls and the roof to minimize air leakage. Failure to do so can result in significant comfort and performance issues. The dark areas in the thermal image below are the result of significant air leakage within a timber framed building.
In addition to detecting air leakage sites, thermal imaging can also reveal energy loss due to missing, damaged, or misapplied insulation. The thermal image below shows an exterior wall and roof of a timber framed building where traditional framing was used for sidewall and roof construction. The dark areas show significant energy loss.
For best results, thermal imaging of timber framed buildings should be performed from the inside of the building when there is an inside/outside temperature differential of at least 10 Celsius (18 F) degrees. Thermal imaging may be performed under natural conditions or while the building is depressurized. Imaging should be scheduled to avoid errors due to solar loading of the building’s walls and roof.
Infrared inspections 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 or to obtain a copy of the Standard for Infrared Inspection of Building Envelopes, visit us online at www.infraspection.com or call us at 609-239-4788.
December 17, 2018
Sponsored by: Testo Inc.
Imager Resolution & The Great Pixel Debate
Tip written by: Infraspection Institute
Resolution is one of the most important objective specifications for any thermal imaging system. Pixel count is frequently offered as a measure of image quality; however, pixel count is only one of many factors that affect imager resolution.
The Focal Plane Array (FPA) detector assemblies used in modern infrared imagers are made up of several tiny, discrete picture elements or pixels. Each pixel is a discrete infrared detector that collects thermal data. Individual pixels are arranged to form an array that ultimately allows the imager to produce a thermal image.
FPA detectors are commonly specified according to pixel count and ratio. Typical detector sizes for industrial imagers range from 160W by 120H to 320W by 240H; some detectors may have more or less pixels. To determine the total pixel count for a detector; the horizontal and vertical values are multiplied.
Imager manufacturers often cite pixel count as a measure of imager resolution. Imager sales are won and lost as entire ad campaigns focus heavily on this single objective specification. Actually determining resolution is not that simple.
Although resolution generally increases with the number of pixels, there are several other factors that influence image clarity or resolution. These include, but are not limited to, pixel viewing angle, imager optics, signal-to-noise ratio and the imager’s display screen.
When evaluating an imager for resolution, physically try the imager under actual working conditions. Imagers that produce clear images should be sufficient to the task regardless of pixel count.
To better understand imager resolution, read the article, Selecting, Specifying and Purchasing Thermal Imagers available from Infraspection Institute. To obtain a copy of the article, call 609-239-4788 or visit us online at www.infraspection.com.
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December 24, 2018
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IR Inspections of Insulated Windows
Tip written by: Infraspection Institute
Infrared inspections of building envelopes can provide evidence of excess energy loss through walls, doors and roofs. Under the right conditions, thermal imagery can also provide evidence of excess energy loss through insulated window assemblies.
Insulated windows are a common feature found on modern commercial and residential structures. Unlike single pane windows, insulated windows are manufactured with an Insulating Glass Unit (IGU). An IGU typically consists of two or more layers (lites) of glazing separated by a spacer along the edge and sealed to create a hermetically sealed air space between the layers. IGUs are then encased within a sash or fixed frame in order to facilitate installation.
In order to increase the insulating performance of an IGU, the air space between the lites may be filled with air or inert gases like argon or krypton. Typically the spacer is filled with desiccant to prevent condensation. For some IGUs, most of the air is removed to further reduce convection and conduction through the finished IGU.
Over time, IGUs seals can fail causing inert gas to be lost and/or allowing humid air to enter the assembly. Unless condensation occurs between the lites, failed IGUs are difficult to detect; however, they may be readily detected using a thermal imager under the proper conditions.
Infrared inspection of insulated windows and building envelopes is one of many topics to be covered during Infraspection Institute’s annual technical conference, the 30th Annual IR/INFO being held January 20 – 23, 2019 in New Orleans, LA. For more information or to register, visit us online at www.infraspection.com or call us at 609-239-4788.
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December 31, 2018
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Focus, Focus, Focus
Tip written by: Infraspection Institute
Proper image focus is still one of the most important aspects of performing an infrared inspection. A clear image not only allows for optimal problem diagnosis, but it is also critical to accurate temperature measurement.
Clear focus is not difficult to achieve if you follow a few simple steps:
- Get as close as safely possible to your target.
- Take time to carefully focus for optimum clarity. This may take some practice if you have a motorized focus mechanism.
- Ascertain that your target is stationary.
- Only shoot from a stable platform. If imaging from a motor vehicle, it may be desirable to shut off the engine to avoid vibration.
Be sure your imager is steady as you capture the image. Gently push the store button rather than punching it. If using a handheld imager, consider using a tripod or monopod to help stabilize your imager.
Once you’ve stored an image, recall and check for clarity. If the results are less than perfect, start over. In addition to greater accuracy, capturing clear images makes it easier to convey information to the end user and/or the person who will eventually perform corrective actions.
Infrared imager operation is one of the many topics covered in all Infraspection Institute Level I training courses. For more information on open enrollment classes or our Distance Learning courses, visit us online at www.infraspection.com or call us at 609-239-4788.
