2014
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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Infrared Imaging and Mold Detection
Tip written by: Infraspection Institute
As concerns regarding indoor air quality increase, there is increasing concern with respect to mold. Used properly, a thermal imager can help identify areas of potential mold growth.
Mold is a ubiquitous single cell organism that tends to favor moist environments. Of the thousand species of mold found worldwide, many are harmless; however, certain species are toxic. Others can cause chronic health problems in humans.
While thermal imagers cannot detect mold directly, they can often detect evidence of the latent moisture often associated with mold presence. When using a thermal imager to detect latent moisture, keep the following in mind:
- Evidence of moisture can only be detected if a temperature differential exists across the surface of the material being inspected.
- Frequently, a delta T can be created by actively heating or cooling a structure or by relying on solar loading of the subject areas.
- Subject building components should be imaged from both indoor and outdoor aspects under the correct weather conditions.
- Suspected moisture presence must be confirmed by independent means.
- A negative finding for latent moisture does not guarantee that mold is not present.
Since moisture presence is not positive proof of mold presence, further laboratory tests will be required to confirm mold within any moist areas detected.
Using thermal imaging to detect latent moisture within buildings 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 Inspection of Building Envelopes, visit Infraspection Institute or call us at 609-239-4788.
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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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IR Inspections During Motor Rebuilding
Tip written by: Infraspection Institute
Thermography can be a valuable tool for testing and monitoring in-service motors. It can also be a useful tool for detecting hidden problems within motors that are being rebuilt.
Electric motors are a vital component in most industrial facilities. In the event of catastrophic failure, facility managers often elect to rebuild large or special motors. In order to maximize the service life of a remanufactured motor, it is imperative to diagnose and correct faults during the rebuilding process since unresolved defects may shorten the life of a rebuilt motor.
For motor testing, infrared imaging may be conducted by staff thermographers employed by a motor shop or an experienced third party working at the shop. During the rebuilding process, infrared imaging may be used to diagnose problems on incoming motors and to perform quality assurance checks during the rebuilding process.
Upon arrival at the repair facility, a motor is disassembled and the rotor and stator are stripped of their coils. A high current test set is then used to excite the subject components. During excitation a thermal imager is utilized to identify thermal anomalies that are the result of short circuits and/or faulty wiring. These areas are marked so that technicians can make appropriate repairs.
Once the cause of thermal anomalies has been corrected, the rebuilding process will continue. Thermal imaging can be applied incrementally during the rebuilding process to help detect improper wiring or loose connections.
Infrared inspection of electric motors is one of the many topics covered in the Level I Infraspection Institute Certified Infrared Thermographer® training course. For more information or course locations and dates, call 609-239-4788 or visit us online at www.infraspection.com.
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Using and Caring for Lithium-ion Batteries
Tip suggested by Randall D. Cain, American Water Company
Batteries are the lifeblood of portable electronics and thermal imagers are no exception. Understanding how to properly handle and care for modern batteries can prolong their life and prevent damage.
Most thermographers give little thought to equipment batteries until they go dead or fail. Without power, even the most sophisticated thermal imagers are useless. As thermal imagers have evolved, manufacturers have moved to take advantage of advancements in battery technology with many units now powered by Lithium-ion batteries.
Li-ion batteries offer several advantages over traditional batteries of the lead acid, nickel cadmium, or nickel metal hydride types. Primary advantages of Li-ion batteries are excellent energy-to-weight ratios, no memory effect, and a slow loss of charge when not in use.
Li-ion batteries must be handled more carefully than other battery types. Improper storage can shorten their life; improper handling can cause catastrophic failure including igniting or exploding. When handling Li-ion batteries, keep the following in mind:
- Only use Li-ion batteries in the equipment for which they are intended
- Unlike Ni-cad batteries, Li-ion batteries should be charged often and never depleted below their minimum voltage
- Always use the appropriate charger and never allow battery terminals to become short circuited
- For prolonged storage, the battery should be discharged to 40% and stored in a refrigerator
Lastly, avoid keeping or charging batteries in hot environments such as the closed interior of an automobile during the summer months. Many Li-ion battery packs contain protective circuits to guard against an over temperature condition. Should a battery become too hot, its protective circuit will open rendering the battery useless.
Care and usage of infrared test equipment 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 www.infraspection.com or call 609-239-4788.
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Using Switchgear Windows and Ports
Tip written by: Infraspection Institute
As the popularity of switchgear windows and ports grows, thermographers are faced with challenges unique to these devices. In this Tip we examine some of these challenges and provide advice and cautions when imaging through windows and ports.
In an effort to reduce the risk of injuries associated with arc flash, many facilities have installed IR transmissive windows or ports that permit infrared inspections without having to open panel covers. Although windows and ports can provide a measure of safety and help to reduce labor associated with infrared inspections, they pose unique challenges not associated with direct line-of-sight imaging.
Switchgear windows are typically constructed of a metal frame with a fixed IR transparent material that enables an imager to view through them. Switchgear ports consist of a metal frame with small openings through which an imager may be sighted. Depending upon type, some ports have a single hole; others have metal screens containing multiple holes.
Windows and ports will always attenuate infrared energy received by the imager. This attenuation will affect both qualitative and quantitative data; however, the greatest challenge posed by windows and ports involves temperature measurement. Due to their small opening it is not possible to accurately measure temperature through screened ports. Accurate temperature through windows and single opening ports is possible only if the following conditions are met:
- Window opening must be larger than IR lens objective
- Target must be at or beyond imager’s minimum focus distance
- Both window transmittance and target emittance values must be known and properly entered into imager’s computer
- Imager lens must be kept perpendicular to, and in contact with window
When it is not possible to meet all of the above conditions, imagery should be evaluated only for its qualitative value. As always, any inexplicable hot or cold exceptions should be investigated for cause and appropriate corrective action taken.
The Infraspection Institute Standard for Measuring and Compensating for Transmittance of an Attenuating Medium Using Infrared Imaging Radiometers provides procedures for calculating window transmittance which is critical to accurate temperature measurement. To obtain a current copy of the Standard, call 609-239-4788 or visit the Standards area of our online store.
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Equipment Maintenance – Neckstraps
Tip written by: Infraspection Institute
Almost all handheld thermal imagers come equipped with neckstraps as standard equipment. If you utilize the neckstrap supplied with your imager to support or carry your imager, the following tips can help to avoid costly damage caused by an unexpected drop.
1) Many neckstraps are made of relatively thin material. Retrofit thin neckstraps with sturdier material.
2) Check your neckstrap frequently for wear. Neckstraps frequently become frayed where they attach to camera body eyes or snap hardware.
3) Be certain that your neckstrap ends are permanently sewn so that they cannot be pulled apart or separate accidentally.
4) Check snap swivels for condition. Replace worn or inferior hardware with quality materials.
5) Consider adding a second, redundant neckstrap in case the primary neckstrap fails.
6) Periodically check camera body eyes for wear and mechanical integrity. Over time, attachment points that mate with metal hardware can erode; mechanically fastened hardware on your imager can become loose.
Following the above tips can help prevent accidentally dropping your imager and could save you from a costly repair.
Proper use of infrared imagers is one of the many topics covered in the Level I Infraspection Institute Certified Infrared Thermographer® training course. For information on open enrollment classes or our Distance Learning program, visit us online or call us at 609-239-4788.
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The Problem with Solar Loading
Tip written by: Infraspection Institute
Everyone who has performed infrared inspections outdoors on sunny days is familiar with the problem of solar reflections. Compensating for solar reflections is usually accomplished by repositioning the thermal imager to change the viewing angle to eliminate the reflection. For objects exposed to strong sunlight, a more insidious problem can occur in the form of solar loading.
The concept of solar loading is familiar to everyone: objects exposed to the Sun will heat up. In general, dark colored objects absorb the most solar energy and heat faster than light colored objects. If an object absorbs enough heat from the Sun, significant thermal anomalies may be hidden and go undetected.
As there is no way to compensate or correct for solar loading, the most prudent course of action is avoidance. Solar loading can be avoided by imaging on cloudy days, at night, or early in the morning. Solar loading can also be overcome by shading an exposed target and waiting for the object’s temperature to return to normal.
Identifying and overcoming environmental error sources such as solar loading is one of the many topics covered in depth within the Infraspection Institute Level I Certified Infrared Thermographer® training course. For more information on course dates or to register for a course, call 609-239-4788 or visit Infraspection Institute online.
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September 01, 2014
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Preventing Lyme Disease
Tip content provided by: WebMD.com
For thermographers who work outdoors, exposure to Lyme disease can pose a significant health hazard. In this Tip, we discuss this serious disease, its symptoms, and ways to help prevent it.
What Is Lyme Disease?
Lyme disease is a serious infection transmitted to humans and other mammals via the bite of deer ticks that are infected with the spirochete bacteria, Borrelia burgdorferi. The animals that most often carry these insects are white-footed field mice, deer, raccoons, opossums, skunks, weasels, foxes, shrews, moles, chipmunks, squirrels, and horses. Lyme disease is not contagious between persons.
Where Is Lyme Disease Found?
Lyme disease has been reported in nearly all states in the United States, although most cases are concentrated in the coastal northeast, Mid-Atlantic States, Wisconsin, Minnesota, and northern California. Lyme disease is also found in large areas of Asia and Europe.
What Are the Symptoms of Lyme Disease?
In the early stages of Lyme disease, you may experience flu-like symptoms that can include a stiff neck, chills, fever, swollen lymph nodes, headaches, fatigue, muscle aches, and joint pain. You also may experience a large, expanding skin rash around the area of the tick bite. In more advanced disease, nerve problems and arthritis, especially in the knees, may occur.
How Is Lyme Disease Diagnosed?
The easiest way for a doctor to diagnose Lyme disease is to see the unique bull’s-eye rash. If there is no visible rash (as is the case in about one-fourth of those infected), the doctor might order a blood test three to four weeks after the onset of the suspected infection to look for antibodies against the bacteria.
How Is Lyme Disease Treated?
In its early stages, Lyme disease can be effectively treated with oral antibiotics. In general, the sooner such therapy is begun following infection, the quicker and more complete the recovery. For advanced cases, intravenous antibiotics may be necessary.
How Can I Prevent Getting Lyme Disease?
Essential to prevention is the avoidance of deer ticks. Although generally only about one percent of all deer ticks are infected with the Lyme disease bacterium, in some areas more than half of them harbor the microbe. Deer ticks are most often found in wooded areas and nearby grasslands, and are especially common where the two areas merge.
Try these tips to prevent tick bites when working in tick prone areas:
1. Wear long sleeves and light colored clothing in order that ticks can be seen more easily
2. Wear your shirt tucked into your pants, and your pants tucked into your socks or boots.
3. Apply tick repellents with DEET to your clothing, shoes and socks before going out.
4. Check yourself, family, and your pets routinely for ticks, especially after a trip outdoors.
5. Shower and shampoo your hair if you think you may have been exposed to ticks.
6. Check your clothes for ticks and wash them immediately in order to remove any ticks.
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September 08, 2014
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School’s Open – Drive Carefully
Tip written by: Infraspection Institute
For many areas, September is a month of transition – cooler weather, leaves turning color, and children returning to school. In this Tip we offer some advice for keeping school students safe.
Over 56 million students are projected to be enrolled in U.S. schools this fall; over 70 percent will be under 15 years old. According to the National Highway Traffic Administration, one-fifth of all children 14 years of age and younger who die in motor vehicle crashes are pedestrians. On average, one pedestrian is killed in the United States every two hours.
Morning can be a dangerous time for children, as they travel to the bus stop, ride their bike to school or walk along their routine path. Afternoon introduces additional risks as the ring of the final bell marks the sound of freedom for school-age children. Unfortunately, children are often distracted by thoughts of playtime or are unable to accurately judge traffic situations while on their journey home.
Keeping the following in mind can help protect everyone’s safety:
- Slow down in or near school and residential areas.
- Drive with your headlights on – even during the day – so children and other drivers can see you.
- Look for clues such as School Safety Patrols, Adult Crossing Guards, bicycles, and playgrounds, which indicate children could be in the area.
- Always stop for school buses that are loading/unloading students.
- Limit distractions such as cell phones, CD players or other devices that cause you to take your eyes off the road.
- Practice extra caution in adverse weather conditions.
- Pay particular attention near schools during the morning and afternoon hours.
- Scan between parked cars and other objects for signs that children could dart into the road.
Remember, school’s open – drive carefully. You can make a difference just by staying alert and taking the extra care while driving where children are present. For more info on driving safety, contact the Mid-Atlantic AAA.
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September 15, 2014
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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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September 22, 2014
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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 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.
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September 29, 2014
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IR Inspections of Liquid-filled Transformers
Tip written by: Infraspection Institute
A thorough infrared inspection of an electrical transformer can point out symptoms of loose connections as well as other possible problems. When performing an infrared inspection of a liquid-filled transformer, be certain to include not only the primary and secondary connections but also the following items as well:
- Inspect neutral and grounding connections for hot spots
- For transformers with separate tanks for each phase, compare phase tanks to each other. Transformers with balanced loads should exhibit similar temperatures between tanks.
- Qualitatively inspect radiator sections. Radiator tubes should be uniform in temperature and, in most cases, should operate above ambient temperature.
- Compare transformer operating temperature to nameplate rating. For long term service, transformers should not operate above their maximum rated temperature.
- Compare tap changer tank to main body of transformer. For properly operating tap changers, tap changer tank should not appear warmer than main body of transformer.
In conjunction with the infrared inspection, cooling fans and or pumps should be checked for proper settings and operation. Finally, transformers require proper air circulation for cooling. To help ensure maximum airflow, transformer radiators should be unobstructed and free from dirt and debris.
Infrared inspections 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, Skype 609-239-4788.
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October 06, 2014
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Using a Blower Door During an IR Inspection
Tip written by: Infraspection Institute
Data obtained during infrared inspections can often be improved by incorporating other tools. When it comes to building inspections, a blower door can be useful in detecting air leakage sites and helping to gauge the airtightness of a building.
Air leakage is often a major source of energy loss in buildings. Although an infrared imager can help detect evidence of air leakage sites, it cannot pinpoint all air leakage sites nor can it quantify the amount of air leakage occurring. Many thermographers overcome these limitations by utilizing a blower door in conjunction with their infrared inspection.
A blower door consists of an instrumented, high volume fan that is temporarily placed in a doorway to create a positive or negative pressure within a building. In depressurized mode, the blower door simulates a wind blowing equally on all sides of the building. Conducting an infrared inspection with the building depressurized enables a thermographer to detect air leakage sites that would not be visible under natural conditions. With special software, it is possible to estimate the relative leakage of a structure as well as the total area of all leak sites.
A blower door can provide a thermographer with some advantages; however, there are challenges associated with their use. Using a blower door during an infrared inspection represents a “worst case” scenario and may not be indicative of natural conditions. This may invalidate thermal imagery that is destined for use in a legal case. Since blower doors can cause backdrafts from fireplaces, stoves, and heating equipment, they should be operated only by persons who are properly trained in their application and use.
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 register for a course, visit Infraspection Institute or call us at 609-239-4788.
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October 13, 2014
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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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October 20, 2014
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Determining Neutral Plane Location
Tip written by: Infraspection Institute
Thermographically detecting air leakage sites within buildings is dependent upon proper site and weather conditions and imaging vantage point. Determining the location of a building’s neutral plane is key to ascertaining the correct vantage point for thermal imaging.
Air leakage can account for significant energy losses within buildings. Such losses occur as unconditioned air moves through the building’s thermal envelope into conditioned spaces. For heated low-rise structures, air typically infiltrates at lower elevations and exfiltrates at higher elevations. Simply defined, the neutral plane is the elevation within the structure where no air leakage occurs since indoor/outdoor air pressure is balanced.
Determining neutral plane location can often be more art than science. Among the many factors that influence the location of the neutral plane are: building construction, building height, inside/outside temperature differential, and the operation of the building’s HVAC system. Wind speed and direction can also influence the location of a neutral plane.
To help determine the location of a building’s neutral plane, use your thermal imager to investigate likely air leakage sites such as electrical receptacles on exterior walls. If you detect evidence of air infiltration at these sites, move upward to the next floor of the structure. Once above the neutral plane, evidence of air leakage sites will generally not be thermographically detectable unless a negative pressure is created with a blower door or the building’s HVAC system.
Infraspection Institute has been training and certifying infrared thermographers worldwide since 1980. Infrared inspection of building envelopes is covered in depth in all of our Level I training courses. For more information on our Certified Infrared Thermographer® or Distance Learning courses, call us at 609-239-4788 or visit www.infraspection.com.
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October 27, 2014
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Gauging When IR Inspection Window Opens/Closes
Tip written by: Infraspection Institute
Solar-driven infrared inspections of insulated structures and roofs must be performed when sufficient Delta T is present. Knowing how to gauge when this window of opportunity is present is critical to the accurate collection of data.
Infrared inspections of structures often utilize solar loading to create temperature differentials necessary for the inspection. Common applications include moisture inspections of roofs and walls, structural inspections of CMU walls, and gauging product levels in tanks and silos. Often, these types of infrared inspections are performed during evening hours following a sunny day while the structure is cooling.
The time frame during which solar-driven infrared inspections may be accurately performed is often referred to as the ‘scanning window’. The scanning window is said to be open when conditions permit the collection of accurate data. A number of interdependent factors will determine when the scanning window opens and closes. These include, but are not limited to: target construction, amount of solar loading, local weather conditions, and imager sensitivity.
To determine when the scanning window opens, a thermographer should initially isolate an area with a small delta T indicative of an exception. For moisture inspections, this might be an area that is confirmed to be minimally wet. Using this area as a benchmark, the thermographer can periodically re-check this area during the inspection to determine if a Delta T remains. In general, the disappearance of a Delta T in the benchmark area will indicate that the scanning window is closing.
Infrared inspections of building envelopes and roofs are two of the many topics covered in the Infraspection Institute Level I Certified Infrared Thermographer® training course. For more information on other course offerings, call 609-239-4788 or visit us online at Infraspection.com.
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November 03, 2014
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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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November 10, 2014
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Calculating the Value of an Electrical Hotspot
Tip written by: Infraspection Institute
What is the financial liability of a hotspot within an electrical system? Probably less than you think since electrical hotspots waste surprisingly little energy even when operating at high temperatures.
Over time, many have stated that the cost of infrared inspections can be justified through the detection and subsequent repair of hotspots associated with loose/deteriorated electrical connections. Although these types of defects can produce temperature rises of hundreds of degrees, the amount of energy wasted in the form of excess heat is often surprisingly small.
When detected in their formative stages, loose/deteriorated connections may contribute to only a few watts of energy loss. Even large temperature rises associated with significantly degraded connections will usually produce energy losses of less than 100 watts. We can calculate the financial impact of such an exception as follows:
0.1 kw x 24 hours = 2.4 kwh per day
876 kwh per year x $0.14 per kwh = $122.64 per year
It is important to note the above illustration is for an extreme hotspot operating undetected 24 hours per day for an entire year. While the above potential savings may seem significant, it would be hard to justify the expense of an infrared inspection program based upon energy savings alone. Justification would be even harder if the dissipated energy were only a few watts.
The real value of information obtained from infrared inspections comes from reducing unscheduled downtime, increasing reliability, improving safety, and avoiding losses associated with catastrophic failure.
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 17, 2014
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Detecting Delamination of Stucco
Tip written by: Infraspection Institute
With aging infrastructure becoming an increasing concern in many communities, more attention is being focused on the maintenance of building facades. Under the right conditions, thermal imaging can detect evidence of delaminated stucco or concrete finishes on the exterior of masonry buildings.
Over time, buildings that utilize concrete stucco for exterior finishes are subject to failure. One of these failures involves the stucco delaminating from its substrate. Delaminated stucco is a serious safety concern as it can cause serious injury to pedestrians should it fall from any significant height.
When concrete stucco delaminates from its substrate, an air pocket is formed between the stucco finish and the substrate. Because this air pocket acts as an insulator, it will change the thermal capacity and/or thermal conductivity in the area of the delamination. Under the correct weather conditions, thermal imaging can detect evidence of delaminated areas.
In order to detect evidence of delaminated areas using thermal imaging, a temperature differential must be present. Typically, infrared inspections of concrete stucco are performed during evening hours following a sunny day. As an alternative, infrared inspections may also be performed during midday under solar loading conditions. Thermal patterns associated with delaminated stucco will generally be amorphous in shape and will typically appear as cold spots during post-sunset inspections or as hot spots during midday inspections.
When performing infrared inspections of concrete stucco finishes, keep the following in mind:
- Subject surfaces should be clean and dry
- Wall surfaces must be heated uniformly. Areas in shadow or shade may not produce accurate data
- IR inspections are qualitative in nature. Compare similar areas to each other noting any inexplicable temperature differences
Once the infrared inspection has been completed, all thermal anomalies should be investigated for cause and appropriate corrective measures taken.
Infrared inspection of building envelopes is one of the many topics covered in all Infraspection Institute Level I training courses. For a class schedule or to register for a Distance Learning course , visit Infraspection Institute online or call us at 609-239-4788.
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November 24, 2014
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Thanksgiving Safety Tip
Tip written by: Infraspection Institute
When it comes to heat transfer and safety, thermographers traditionally think of the workplace. With the Thanksgiving holiday upon us, neither of these topics should be overlooked when it comes to preparing the holiday feast.
According to estimates from the Centers for Disease Control, approximately 76 million Americans become ill each year as a result of foodborne pathogens. Of these, approximately 5,000 die. Proper hygiene practices before, during, and after food preparation can reduce the risk of food poisoning.
As part of their nationwide Be Food Safe public education campaign, the US Department of Agriculture offers four simple tips for safe food preparation:
Clean – Wash hands, surfaces and utensils often to avoid spreading bacteria when preparing food.
Separate – Use different cutting boards for raw meat, poultry, seafood and vegetables. Keep raw turkey away from vegetables and side dishes that won’t be cooked.
Cook – You can’t tell it’s done by how it looks! Use a food thermometer. Every part of the turkey should reach a minimum internal temperature of 165ºF.
Chill – Keep the refrigerator at 40ºF or below to keep bacteria from growing. Pumpkin pie should always be refrigerated and all food should be refrigerated within two hours.
If deep fried turkey is your preference, be sure to observe all safety precautions and never leave your fryer unattended. For more information on food safety, visit the US Department of Agriculture website.
From all of us at Infraspection Institute, Happy Thanksgiving to all of our readers and friends! May you enjoy a safe and happy holiday in the company of those you love.
~ Jim and Christopher Seffrin ~
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December 01, 2014
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Why Your Business Needs a Website
Tip written by: Infraspection Institute
In general, thermographers are quick to embrace new applications, ideas, and technology. Although most consumers use the web prior to purchasing goods or services, many infrared companies do not have a web presence.
As the internet has matured, consumers have come to rely on the worldwide web for information. Over 90% of consumers use the internet when researching new products or services. The majority of their business goes to companies that have a professional web presence. Companies that do not have websites are losing businesses to companies that do.
A properly designed website can improve productivity and help increase sales. By providing prospects with information, your sales force can spend less time educating prospects thereby freeing up valuable time for closing sales.
Websites can provide new revenue opportunities. There are relatively few services or products that can’t be sold over the internet. Your website can be used to directly sell your company’s products or services. Additional revenue may be generated through participation in affiliate sales programs.
Another advantage of websites is the ability to compete with much larger companies. A company does not need a tremendous amount of capital or manpower to have a successful web presence. Your website can work 24/7 providing information and accepting orders from clients worldwide.
Because your website represents your company’s public image, it is imperative that you invest the time and money to properly establish your website. Often the best approach is to hire a professional web designer to help you design, publish, and maintain your website.
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December 08, 2014
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Why Headers Appear Cool
Tip written by: Infraspection Institute
In business, it is frequently said that cooler heads prevail. When performing infrared inspections of building interiors, window and door headers are often more prevalent.
Headers are a common construction detail found within building walls that utilize frame construction. Headers are horizontal framing members that are typically located at the top of window and/or door openings. In load bearing walls, headers are typically constructed of framing members that are stronger than vertical framing members.
When fabricating headers in wood frame construction, it is common to utilize framing members that are wider than vertical members. These are then often doubled in thickness and placed at the top of the window or door opening. Because headers are typically wider and/or double thickness, there is usually less cavity space for insulation to be installed wherever headers are present. In these circumstances, it is normal to see greater energy loss wherever headers are present when compared to a properly insulated wall cavity.
When performing an infrared inspection of framed walls from the interior of a building with cold outdoor temperatures, headers will typically appear cooler than insulated wall cavities. Observed thermal patterns will reverse should the same inspection scenario exist with warm outdoor temperatures.
For best results, a minimum inside/outside temperature differential of 10ºC is recommended when inspecting buildings with framed wall construction. Proper conduct of infrared inspections is addressed in the Standard for Infrared Inspection of Building Envelopes. Copies of the standard are available through the Infraspection Institute Online Store.
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December 15, 2014
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Detecting Electrical System Overloads
Tip written by: Infraspection Institute
Statistically, overloaded circuits are the second most common cause of exceptions found during infrared inspections of electrical systems. Although overloads are quite common, they can be tricky to accurately diagnose.
As electrical current flows through a conductor, heat is generated. As circuit load increases, so does the amount of heat. Electrical circuits are designed so that loads will not exceed the circuit’s ability to safely carry a sustained load and the amount of heat associated with such load.
Typically, overcurrent protection devices such as fuses or circuit breakers are designed to protect circuits from overload conditions. These devices will interrupt the circuit when the current reaches a predetermined level for a specified period of time.
Serious problems such as fires can be caused by sustained overloads. Such overloads may be caused by: improperly sized wiring, and improperly sized or defective overcurrent protection. Fortunately, a thermal imager can be used to detect the thermal patterns associated with sustained overloads.
When using a thermal imager to detect potential overloads, one should keep the following in mind:
Overloaded conductor(s) will be uniformly warm throughout entire length
For polyphase circuits, all conductors may be uniformly warm
Depending upon ambient conditions and imager settings, overloaded circuits may not appear remarkably warmer than adjacent circuits
Because an infrared imager cannot measure electrical current, suspected overloads must be confirmed with an ammeter while observing all requisite safety precautions. For greatest accuracy, a true RMS sensing ammeter is recommended. Circuits found to be overloaded should be immediately investigated for cause and corrected.
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.
December 22, 2014
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Files Worth Saving
Tip written by: Infraspection Institute
With year-end in sight, many will begin the annual process of clearing out files and getting ready for the upcoming year. In this week’s Tip, we share some thoughts on files that you may wish to keep.
Recently, while cleaning out some old personal files, my family came across a classic Christmas poem that had been transcribed by my grandmother many years ago. The poem titled, “Jest ‘Fore Christmas” is a 19th century Eugene Field poem that recalls simpler times. The poem’s central character is a boy named William. It is likely that this particular work had caught my grandmother’s attention since her husband and oldest son were both named William.
Now as we read the yellowed and fragile notepaper that bears our grandmother’s distinctive handwriting, we can recall many fond memories of her and our family, especially during Christmas.
With the holidays and busy year end schedules upon us once again, we invite you to take the time to make special memories with family and friends and to file them in your heart so that you may easily find them in the future.
As we enjoy this holiday season, we extend a heartfelt Thank You to all of our readers, friends, and associates throughout the world for everything that you do for us all year long. May your holidays be filled with peace and joy and your New Year with good health and happiness.
~ Jim Seffrin & Family
Jest ‘Fore Christmas
by Eugene Field (1850-1895)
Father calls me William, sister calls me Will,Mother calls me Willie, but the fellers call me Bill!Mighty glad I ain’t a girl—ruther be a boy,Without them sashes, curls, an’ things that ‘s worn by Fauntleroy!Love to chawnk green apples an’ go swimmin’ in the lake—Hate to take the castor-ile they give for bellyache!’Most all the time, the whole year round, there ain’t no flies on me, But jest ‘fore Christmas I ‘m as good as I kin be!
Got a yeller dog named Sport, sick him on the cat;First thing she knows she doesn’t know where she is at! Got a clipper sled, an’ when us kids goes out to slide,’Long comes the grocery cart, an’ we all hook a ride! But sometimes when the grocery man is worrited an’ cross,He reaches at us with his whip, an’ larrups up his hoss, An’ then I laff an’ holler, “Oh, ye never teched me!” But jest ‘fore Christmas I ‘m as good as I kin be!
Gran’ma says she hopes that when I git to be a man, I ‘ll be a missionarer like her oldest brother, Dan, As was et up by the cannibuls that lives in Ceylon’s Isle, Where every prospeck pleases, an’ only man is vile! But gran’ma she has never been to see a Wild West show, Nor read the Life of Daniel Boone, or else I guess she ‘d know That Buff’lo Bill an’ cowboys is good enough for me! Excep’ jest ‘fore Christmas, when I ‘m good as I kin be!
And then old Sport he hangs around, so solemnlike an’ still, His eyes they seem a-sayin’: “What’s the matter, little Bill?” The old cat sneaks down off her perch an’ wonders what’s become Of them two enemies of hern that used to make things hum! But I am so perlite an’ tend so earnestly to biz, That mother says to father: “How improved our Willie is!” But father, havin’ been a boy hisself, suspicions me When, jest ‘fore Christmas, I ‘m as good as I kin be!
For Christmas, with its lots an’ lots of candies, cakes, an’ toys, Was made, they say, for proper kids an’ not for naughty boys; So wash yer face an’ bresh yer hair, an’ mind yer p’s and q’s, An’ don’t bust out yer pantaloons, and don’t wear out yer shoes; Say “Yessum” to the ladies, and “Yessur” to the men, An’ when they ‘s company, don’t pass yer plate for pie again; But, thinkin’ of the things yer ‘d like to see upon that tree, Jest ‘fore Christmas be as good as yer kin be!
December 29, 2014
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Infrared Inspections of Process Equipment
Tip written by: Infraspection Institute
Infrared thermography offers good potential for detecting energy losses from process equipment and piping as well as some symptoms of pipe deterioration.
It is important to remember that thermography is a line-of-sight technology that detects thermal patterns and associated temperatures across the surface of an object.
Subsurface characteristics or defects cannot be detected by thermography unless they cause a temperature differential of at least 0.1 Celsius degrees across the surface of the object being inspected. Presently, interior corrosion detection is best detected with ultrasonic thickness testing; exterior corrosion may be detected by visual examination.
Thermography may prove useful if corrosion is being caused by water saturated insulation surrounding your process piping. If this is the case, water saturated insulation should show excess energy loss at the point where the water is entrapped. It will be necessary to visually inspect the pipe to confirm the actual condition of the pipe.
When performing thermal imaging, be aware that weather conditions such as solar gain, wind and atmospheric attenuation can adversely affect your results. Be certain that your imaging system is capable of detecting the anticipated defect by understanding how emissivity, spectral response and spot size will affect your inspection.
Infrared inspections of process equipment 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.
