Process furnaces or heaters are a critical component found in many petrochemical refineries. Performed properly, infrared inspections of furnace tubes can provide valuable data regarding tube condition and operating temperature.
Process heaters are large, refractory-lined structures used to heat hydrocarbon product during refining. Process heaters are similar to steam boilers in their construction except that hydrocarbon is passed through the firebox tubes instead of water. Safe operation of process heaters requires that tubes operate below their maximum operating temperature. Overheating of tubes can reduce operational life or lead to catastrophic failure.
Measuring tube temperatures is difficult for many reasons. Tubes are often remotely located from inspection ports and are frequently obscured by visually opaque flames. High temperature environments make contact measurements difficult or impossible. Under the right circumstances, infrared thermography can be used to provide qualitative and quantitative data for in-service heater tubes. The following images were taken through viewports on operating heaters.
Thermal image shows normal thermal pattern.
Image taken through opaque flame.
Thermal image shows hotspots caused by internal coke deposits.
Image taken through opaque flame.
Infrared inspection of process furnaces or heaters is one of the most difficult tasks for thermal imaging and infrared radiometry. Accuracy in temperature measurement is of paramount importance since many companies utilize infrared data to determine safe operating limits for in-service heaters.
Far from being a "point and shoot" application, a thermographer needs to understand heater operation and heat transfer as well as issues pertinent to thermography. These include, but are not limited to: infrared camera selection including proper spectral response and spot measurement size; imager calibration; use of filters, windows and heat shields; calculating emittance and reflected temperature; equipment precision and accuracy; and how to obtain reliable reference temperatures to verify proper imager settings.
To help ensure accuracy, thermographers should be trained to at least Level II and, when possible, work with an experienced mentor until they have gained sufficient field experience.
Infrared inspection of process heater tubes is one of the applications covered in the Infraspection Institute Level II Certified Infrared Thermographer® training courses. For more information or course schedules, visit us online at www.infraspection.com or call us at 609-239-4788.
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.
Thermogram shows thermal anomaly at
center of insulated window. Pattern typical of failed IGU seal.
Infrared inspection of insulated windows and building envelopes is one of many topics to be covered during Infraspection Institute’s annual technical conference, IR/INFO 2007 being held January 14 – 17, 2007 in Orlando, FL. For more information or to register, visit us online at www.infraspection.com or call us at 609-239-4788.
Despite unseasonably warm weather this winter, severe weather and its attendant challenges are likely to occur before this season ends. With this Tip, we offer some advice for driving in winter conditions.
Prepare Your Vehicle
Make sure brakes, windshield wipers, defroster, heater and exhaust system are in top condition
Check radiator for coolant level and adequate antifreeze protection. Fill windshield washer reservoir with freeze-resistant fluid
Check tires for proper inflation and tread condition
Carry an ice scraper, brush, and a shovel
Maintain a full gas tank in case of traffic delays or should you need to turn back due to conditions
Keep snow chains handy and in good condition
Driving Tips
Allow enough time. Trips take longer during stormy/icy conditions
Keep windshield and windows clear
Maintain a safe distance from other vehicles; snow and ice make stopping distances much longer
Remember to avoid sudden stops and quick direction changes
Watch for slippery spots. Bridge decks and shady spots can be icy when other areas are not
Be more observant. Visibility is often limited in winter by weather conditions. Slow down and watch out for stopped vehicles and emergency equipment
Lastly, be certain to wear your seat belt. Consult your local weather forecast before you set out and consider postponing your trip if extreme weather is predicted.
For thermographers who must travel between job locations, finding an AC power source for recharging batteries or powering small devices can be a challenge. In some cases, a portable power inverter can provide a solution.
Power inverters are electrical devices that convert DC power from a battery into conventional AC power. Designed to work in most automobiles, portable power inverters can provide AC power for charging portable batteries or operating small AC devices.
Recent advances in technology have resulted in power inverters that are both small and dependable. With prices starting at less than $50, portable power inverters have become surprisingly affordable. Price is largely dependent upon two key specifications: wattage rating and sine wave output.
When choosing an inverter, keep the following in mind:
Prior to selecting an inverter, make sure your AC device(s) can be used safely with an inverter
Choose an inverter with a continuous output rating greater than the connected load. Ideally, inverter rating should be 20% greater than maximum continuous load
Motorized appliances may draw up to seven times their continuous current rating during startup. For such devices, choose an inverter with adequate peak output rating
Small inverters (<400 watts) can be powered from a cigarette lighter socket. Larger models will require direct wiring to the automobile battery with properly sized conductors
Most inverters provide a modified sine wave output which may be incompatible with certain electronic devices such as laptop computers. For these devices, choose an inverter with a pure sine wave output
Inverters can produce enough heat to start a fire. Never overload an inverter or leave it unattended. Lastly, inverters are capable of producing dangerous or lethal voltages. Never use an inverter in a wet location as electrocution may result.
“What's in a name? That which we call a rose by any other word would smell as sweet.” This Shakespeare quote implies that names are not that important; however, Sir William never had a website. In this Tip we discuss the importance of website domain names.
When setting up a website, choosing a domain name is one of the most important considerations. A domain name not only represents your online identity, it can seriously influence the success of marketing a company and its products and services. Prior to selecting a domain name, it is important to understand the short and long-term implications of domain name choice.
A general rule of thumb for domain names is www.yourcompanyname.com. This convention works well if your company name is recognized and/or unique. This can get tricky if your company name is long or contains characters such as hyphens. Domain names can only use letters, numbers, or dashes; spaces and symbols are not allowed.
When selecting a domain name, keep the following in mind:
Keep it short. Although domain names can be up to 63 characters in length, shorter names are easier to remember
Avoid trademarked names. Cybersquatting is illegal and not well tolerated by trademark owners
Register selected domain name(s) immediately. Include all appropriate extensions: .com, .net., .org, .biz
Lastly, be certain to renew domain name registrations on time to avoid loosing your ownership. Expired domain names that are not trademarked can be purchased by a third party and used to point traffic to websites of their choice.
Designing and maintaining an effective website is one of the many topics covered in the Infraspection Institute Level III Best Practices training course. For more information on thermographer training and certification or to register for a course, visit us online at www.infraspection.com or call us at 609-239-4788.
Infrared imaging can be useful for detecting leaks within building sidewalls; however, timing an inspection can be tricky. Controlled wetting of walls can be used to simulate storm conditions during an inspection.
Water spray racks are mechanical devices that permit controlled wetting of a building surface. Spray racks typically consist of lightweight tubing and engineered spray heads spaced at regular intervals. When connected to a water supply and placed in front of a building wall, a spray rack can be used to deliver a deluge of water to an area of interest. The amount of water delivered can be controlled by using different size spray heads and/or varying supplied water pressure.
Spray rack used for controlled wetting of exterior walls
Spray racks are commonly used for testing the water tightness of curtain walls. During an infrared inspection from the interior of a building, spray racks can provide continuous wetting of walls to aid in leak detection. Spray racks can also be used to uniformly saturate a wall when infrared inspections are to be performed at a later time to detect evidence of latent moisture.
Water damaged EIFS appears warm
after sunset; building imaged from exterior
Because spray rack operation requires special tools and presents unique challenges, it is often best done by a qualified professional. Thermographers performing imaging during or after spray testing should keep the following in mind:
Spray testing can be time consuming due to set up and/or repositioning of spray equipment
Spray testing can cause significant building leakage requiring an interruption of testing
Spray testing can be messy; avoid getting your imager wet
When imaging from the exterior of a building, allow sufficient time for surface to dry and a Delta T to develop
Thermal imaging during spray testing is one of several applications covered in the Infrared Inspections for Home & Building Inspectors training course. For more information call 609-239-4788 or visit us online at: www.infraspection.com
Using Apple Computers
for Infrared Inspection Reports – Part I
Tip written by: Infraspection Institute
Apple Macintosh computers have long been noted for their superior graphics capabilities. Although the Mac platform has been largely ignored by infrared camera manufacturers, Apple computers can provide thermographers with some powerful tools for documenting their findings.
Since post processing software first appeared for thermal imagers, manufacturers have relied exclusively on PC based software for their applications. For some thermal imagers, qualitative imagery can be viewed using a Mac. However, at present, no imaging radiometer stores temperature data in a format that is readable by a Mac. Although this situation is unlikely to change in the near future, Mac computers do offer some distinct advantages for documenting an infrared inspection.
For infrared cameras equipped with a standard video output, infrared imagery can be digitally recorded using a video recorder. Apple’s iLife suite can then be used to import and edit infrared and/or daylight video to produce professional quality videos or DVDs of an inspection.
When documenting infrared data to video, keep the following in mind:
Video is particularly useful when documenting large structures and/or dynamic processes
Clear voice narrations can vastly improve viewer comprehension
Using a fluid head tripod will provide imagery that is smooth and steady
Video recordings are WYSIWYG; be certain that captured imagery contains exactly what you want a viewer to see – color palettes, temperature tools, etc.
Generating standards-compliant reports and video recordings are two of the many topics covered in the Infraspection Institute Certified Infrared Thermographer® Level I training course. For more information on Infraspection training courses or class schedules, call 609-239-4788 or visit us online at: www.infraspection.com.
Temperature can be an indicator of the condition of installed electric motors; however, the best location for measuring temperature is often debated. In this Tip we discuss the best location for measuring motor temperatures.
Measuring motor temperature is often a challenge since electric motors differ widely in their design and construction. While many have suggested measuring the motor casing along the stator, this method does not work well for motors that are fan cooled or exposed to external air currents. For uncooled motors, this approach can produce varying temperature values depending upon the location of the subject temperature readings.
In 1997, a research project led by Infraspection Institute utilized instrumented motors in a controlled environment to determine the effect of excess force on installed motors. One of the primary goals of this research was to identify a location for collecting reliable temperature data.
From our research it was found that measuring the exterior of the motor bellhousing within 1” of the output driveshaft consistently produced temperatures that were within 1 to 2 C of the motor windings and the output side bearing assembly. Temperatures taken at the bellhousing were especially useful for fan cooled motors since this area was unaffected by convective cooling from the fan.
When measuring motor temperatures, keep the following in mind:
Make certain that all thermometers are within calibration and used properly
Motor temperature will vary with load and ambient temperature. Be certain to record both with along motor temperature
Elevated temperatures can be caused by electrical or mechanical defects within the motor and/or defective installations
Motors with elevated temperature should be further investigated for cause and repaired or replaced accordingly
Temperature limits and trending of two of the many topics covered in the Level II Infraspection Institute Certified Infrared Thermographer® training course. For more information on upcoming classes or to obtain a copy of our Cross Technologies Study, call 609-239-4788 or visit us online at www.infraspection.com.
It is said that, “Possession is nine tenths of the law. When it comes to infrared data, ownership is often not that simple. In this Tip we explore the frequently misunderstood topic of infrared data ownership.
Thermograms and hardcopy reports are commonly produced for infrared inspections. Like proud parents sharing photographs of children, thermographers frequently share images, data, and reports with others. During these demonstrations, it is not uncommon to hear thermographers refer to this work product as “my images” and “my reports”. For the purposes of casual conversation, referring to work product in the possessive sense is acceptable; however, the actual owner of such data is often someone else.
Under a principle known as ‘Shop Rule’, data produced by thermographers as part of their duties as an employee belongs to their employer. In general, Shop Rule will always apply unless there is a written agreement to the contrary. For thermographers who work as consultants, a principle known as ‘Works for Hire’ may apply. Under this principle, any work product generated belongs to the client and not the thermographer.
Thermographers who work as consultants should be mindful that contracts and written agreements often have ‘Works for Hire’ clauses. These clauses may appear in the body of a contract or purchase order or be incorporated by reference. Thermographers who wish to retain ownership should address this issue prior to the commencement of any work.
Prior to using infrared data for any purpose other than its original intent, always obtain permission to do so. Employers and clients are frequently willing to grant permission to use imagery provided it does not divulge a trade secret or jeopardize confidential information.
Capturing imagery and preparing reports are two of the many topics covered in the Level I Infraspection Institute Certified Infrared Thermographer® training course. For more information on upcoming classes, call 609-239-4788 or visit us online at www.infraspection.com.
Equipment calibration can have a significant impact on the accuracy of infrared temperature measurement. In this Tip we discuss a simple technique for checking the accuracy of imaging and non-imaging radiometers.
Infrared radiometers must be within calibration in order to accurately measure temperatures. Traditionally, thermographers periodically send their equipment to the manufacturer for calibration. For some, this process can take several weeks and can be rather expensive. As an alternative, savvy thermographers can check the calibration of their instrument quickly and easily using some commonly available items.
In order to check infrared radiometer calibration, you will need at least two targets each with a known temperature and emittance. A simple solution is to use a container of ice water and a container of boiling water with a coupon of Scotch PVC electrical tape affixed to the container’s exterior surface. The size of both targets must exceed the spot measurement size of the instrument being calibrated. Container temperatures may be ascertained with a thermometer, thermocouple or contact radiometer.
Once targets have been prepared, use the following procedure:
Turn radiometer on and allow it to stabilize to room temperature.
Set radiometer perpendicular to target surface
If possible, set radiometer inputs for distance, humidity & air temperature
Aim, focus and calculate Reflected Temperature
Set radiometer emittance control
Scotch 191 tape = 0.97 LW or SW
Ice = 0.98 LW; 0.93 SW
Using subject radiometer, measure temperature of target. For ice water, measure temperature of ice cubes. For hot water container, measure tape coupon.
Compare radiometer’s value with contact temperature reading for each target to ensure that radiometer is within spec
A heated blackbody simulator can be used to check instrument calibration at higher temperatures. Because radiometer calibration is not user-adjustable, it will be necessary to return it to the manufacturer should you find your instrument is out of spec.
Verifying infrared equipment calibration is one of the many topics covered in Infraspection Institute Level II Certified Infrared Thermographer training course. For more on information on thermographer training and certification or to register for a course, visit us online at www.infraspection.com or call us at 609-239-4788.
When purchasing a thermal imager, buyers frequently ask, “Which brand of imager is best?” While this seems like a straightforward question, the answer is not so simple. In this Tip we offer advice for making the correct choice.
As infrared thermography gains wider acceptance, its usage is increasing. Meanwhile, the task of selecting an imager is becoming more difficult. Presently, there is a wide selection of equipment available from a record number of manufacturers. With some manufacturers offering several variants of camera models, there are more choices than ever before.
Procuring an imager is a challenge for many reasons: initial purchase price can easily run into the tens of thousands of dollars, no imager is capable of performing all imaging applications, imager performance varies widely, performance specs are not always available or comparable, and making an incorrect purchase can be costly.
Purchasing an imager should be done by assessing your company’s present and future needs, obtaining and comparing manufacturer specifications, and taking time to thoroughly evaluate the imager in the workplace where it will be used. Prior to purchase, the imager and its manufacturer should be carefully evaluated in the following areas:
Evaluate imagers objective and performance specifications
Obtain service and warranty information
Evaluate imager for subjective characteristics
Consider equipment value
Lastly, when considering pre-owned equipment, it is often a good idea to have a title search conducted prior to purchase to ensure that the equipment is free of liens.
Equipment purchase is of the many topics covered in the Level I Infraspection Institute Certified Infrared Thermographer® training course. For more information on upcoming classes or to obtain a copy of our article, Selecting, Specifying and Purchasing Thermal Imagers, call 609-239-4788 or visit us online at www.infraspection.com.
When performing infrared inspections of framed buildings from the interior, thermographers often note that corners appear at a different temperature. With this Tip we explore the reasons for this condition and how to differentiate potential problems from normal conditions.
Corners are a common construction detail found within building walls that utilize frame construction. Corners are typically constructed with vertical framing members that both support the framed wall and provide a nailing surface for interior paneling or drywall. Although details can vary, a typical corner has three vertical studs in close proximity to each other.
More energy loss occurs at corners for two reasons: Studs are more conductive than insulation; and there is little or no space for insulation to be installed wherever corner framing studs are present. Because of this, it is normal to see greater energy loss at corners 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, corners will typically appear cooler than insulated wall cavities. Observed thermal patterns will reverse should the same inspection scenario exist with warm outdoor temperatures.
When thermographically inspecting corner details, it is normal to observe a straight vertical line from floor to ceiling. This vertical line should be confined to the corner itself and not extend onto the flat wall surfaces adjacent to the corner. Amorphous or geometric thermal patterns appearing within or adjacent to corners should be investigated for cause.
Infrared inspection of building envelopes is one of the many applications covered in the Infraspection Institute Level I Certified Infrared Thermographer® training course. For course schedules or to obtain a copy of the Guideline for Performing Infrared Inspections of Building Envelopes and Insulated Roofs, visit Infraspection Institute online at www.infraspection.com or call us at 609-239-4788.
Accurate confirmation of thermal data is a critical step when performing infrared inspections of energized electrical systems. In this Tip we discuss an advanced verification technique known as a voltage drop measurement.
Loose and deteriorated connections are among the most common defects detected during thermographic inspections of electrical systems. Thermal patterns associated with these defects are characterized by heating at, or adjacent to, mechanical connections within the circuit. Loose connections are frequently found at terminals, lugs, fuse clips and splices.
In most cases, thermographers discovering suspected loose connections will document such hotspots and recommend that the observed exception be investigated and appropriate corrective action be performed. Typically, such investigation is performed at a later time with the circuit de-energized utilizing manual inspection or contact resistance testing.
Another method for confirming loose/deteriorated connections is known as a voltage drop measurement. To perform this test, a digital voltmeter is used to measure voltage across the subject connection with the circuit energized and under load. Loose/deteriorated connections will exhibit an increased voltage drop across the connection due to higher resistance. Observed voltage drop values may then be compared to other similar connections under similar load.
Because voltage drop measurements require contact with energized circuits, this testing should only be performed by qualified persons while observing all necessary safety precautions. Lastly, one should be aware that neither temperature nor voltage drop measurements can predict time of failure for any electrical component. Therefore, suspected loose connections should always be investigated for cause and appropriate corrective action undertaken as soon as possible.
Infrared inspection of electrical distribution systems is one of the many applications covered in the Infraspection Institute Level I Certified Infrared Thermographer® training course. For course schedules or to obtain a copy of the Guideline for Performing Infrared Inspections of Electrical and Mechanical Systems, visit Infraspection Institute online at www.infraspection.com or call us at 609-239-4788.
You can’t believe everything you hear. This can be especially true when it comes to performing infrared inspections on flat roofs that contain closed cell foam insulation.
Closed cell foam generically describes several insulation materials commonly found in low slope or flat roofs. Typical materials include urethane foam, isocyanurate foam and, in some cases, cellular glass. Closed cell foam insulations typically offer good R value, are dimensionally stable, and can be used with a wide variety of roofing materials.
Another characteristic of closed cell foam insulations is that they are water resistant. This characteristic, however, only applies to short term exposure to water. When installed in a roofing system and exposed to water for extended periods of time, the cells tend to break down permitting the insulation to become quite absorbent. When this occurs, foam insulation can absorb large quantities of moisture and will exhibit the type of thermal patterns typically associated with absorbent insulations.
Over the years, many have claimed that infrared inspections of closed cell foam roofs are ineffective due to foam’s low absorbency. The thermal image below clearly shows the extent of water damage in a roof constructed with foam insulation.
Light gray areas indicate extent of wet foam insulation in a built-up roof.
Note the solid thermal pattern typical of absorbent insulation.
Thermogram provided by Jersey Infrared Consultants
Initially, thermal patterns associated with latent moisture in roofs containing foam insulation will exhibit ‘picture frame’ signatures. These thermal patterns are due to water collecting at the perimeter of individual boards. As time progresses and the foam loses its water resistance, insulation boards will begin to exhibit the same type of thermal signatures exhibited by wet, absorbent insulations such as wood or glass fiber.
Infrared inspections of flat roofs is one of the many applications covered in the Infraspection Institute Level I Certified Infrared Thermographer® training course. For course schedules or to obtain a copy of the Guideline for Performing Infrared Inspections of Building Envelopes and Insulated Roofs, visit Infraspection Institute online or call us at 609-239-4788.
In his commentary, ‘The 35 Undeniable Truths’, Rush Limbaugh states, “Words mean things.” This is especially true in thermography when it comes to one’s certification.
Certification has long been recognized as an indicator of a thermographer’s formal education and/or qualifications. Certification can have significant financial implications since buyers of inspection services often base purchasing decisions on a thermographer’s level of certification. Unfortunately, misstatements regarding certification, in particular ASNT certification, are quite common.
First of all, ASNT Certification – certification issued by the American Society of Nondestructive Testing - is only available from ASNT Headquarters in Columbus, Ohio. This certification program is designed to provide uniform testing and certification of NDT personnel that is ‘transportable’ when an NDT technician leaves the employ of a company.
The use of the title, ‘ASNT Certified Thermographer’ is incorrect since ASNT does not use or recognize the term ‘thermographer’ in any of its professional designations. The correct term is NDT person or NDT technician.
Although ASNT does offer Level II certification in some NDT disciplines, they presently do not certify anyone below Level III in the Thermal Infrared (TIR) Method. Therefore, titles such as “ASNT Level 2 Certified Thermographer” or “ASNT Level 1 Certified Thermographer” do not exist except on the websites or advertising materials of companies who believe they have earned such titles. There are many examples of such citations ranging from infrared consultants to top executives at infrared equipment manufacturers.
Perhaps the biggest reason that considerable confusion surrounds ASNT certification is that some infrared trainers provide misleading information on this topic. Further compounding this problem is that many thermographers are imprecise when they represent their credentials. Few thermographers who do misrepresent themselves are rarely called to task by their peers or their clients.
Ethics within any profession demand that practitioners always represent their qualifications and credentials accurately. Because words do mean things, thermographers must be careful when representing their qualifications and avoid using titles that do not exist. Accurately describing your certification reflects not only on you but on the credibility of our industry as well.
The topics of ASNT certification and how to establish ASNT-compliant certification programs are two of the many topics covered in depth within the Infraspection Institute Level III 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.
When asked what a thermometer measures, most people will tell you that thermometers measure whatever they contact. The correct answer is a little more complex and is fundamental to understanding and accurately applying contact thermometry.
Contact thermometry is a common technique used in temperature measurement. Thermocouples, resistance temperature devices, thermistors, and bulb thermometers are used to gauge the temperature of a wide variety of objects, materials, and systems. Although each works on a different principle, all contact temperature devices have one thing in common: contact thermometers report their own temperature.
Because contact thermometry is often used by thermographers to confirm radiometric measurements and to calibrate infrared equipment, accuracy is extremely important. To help ensure accuracy when using a contact thermometer, keep the following in mind:
Select thermometer appropriate for task. Be sure to consider sensor size, thermometer sensitivity, operating range, and response time
Prior to use, confirm that chosen thermometer is calibrated and operating properly
Make certain that selected thermometer is in good contact with object
Allow sufficient time for thermometer to achieve thermal equilibrium with object
Prior to using a contact thermometer, make certain that the surface to be measured is safe to touch. Never use a contact thermometer on energized electrical equipment or on any machinery where contact could result in personal injury.
Advanced heat transfer and temperature measurement are some of the many topics covered in the Infraspection Institute Level II Certified Infrared Thermographer® training course. For course schedules or to register for a course, visit Infraspection Institute online or call us at 609-239-4788.
Energy and environmental concerns have caused many facility owners to look to their roofing systems for ways to conserve energy. Modern roofing systems known as ‘cool roofs’ can provide savings; however, they can present challenges for thermographers who inspect them.
Over 90% of roofs in the United States are dark colored. On sunny days, temperatures of these roofs can reach 150º to 190º F causing decreased indoor comfort, increased cooling costs, and premature aging of roofing materials. Advances in roofing technology have led to the development of ‘cool roof’ systems that help to solve these challenges.
Cool roof materials have a high solar reflectance or albedo. Compared to conventional roof materials, cool roofs operate at lower temperatures since they absorb less energy from the Sun. Cool roofs also have a high thermal emittance enabling them to radiate well and shed heat quickly after sunset.
Cool roof membranes are usually made of single-ply rubber or plastic materials such as EPDM, PVC, and TPO. These materials are usually white in color and have a smooth surface. Cool roof coatings or paints are an alternative for existing low-slope roofs.
Although cool roof materials are rated to have a high emittance, thermographers should remember that this value is an average emittance value calculated in a laboratory under ideal conditions and at a perpendicular viewing angle. During an infrared inspection, smooth-surfaced roofs appear quite reflective to a thermal imager due to the low viewing angle that is usually associated with inspections performed on foot from the roof surface. This condition is most severe on cloudless nights when atmospheric humidity levels are low.
Due to the low emittance associated with smooth roof surfaces, thermographers can easily miss the small temperature differentials associated with latent moisture. In order to mitigate errors associated with low emittance, thermographers should choose a short wave (2 to 5.6 microns) thermal imager whenever inspecting a smooth-surfaced roof regardless of membrane color or material.
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.
Thermography is a proven technique for inspecting insulated, low-slope roofing systems. Under the proper conditions, thermography may also be used to inspect uninsulated roofs that are constructed with an insulating deck.
Flat or low slope roofs, also known as insulated roofs, are a common feature found in commercial construction. Applicable construction includes smooth, gravel, or granule-surfaced membranes having a layer of insulation located between the deck and the membrane and in continuous contact with the underside of the membrane.
As an alternative, some roof membranes may be installed without insulation directly over insulating roof decks. Common insulating deck materials include gypsum and lightweight concrete. Typically, these materials are mixed to produce a liquid slurry which is poured and formed in place during construction. After solidifying and drying sufficiently, the roof membrane is laid directly over the insulating deck.
Because wet-applied decks can retain significant quantities of construction water, thermographically inspecting these roofs can be a challenge. In some cases, it may take several months for construction water to dry out making it difficult or impossible to detect thermal patterns associated with water ingress. In other cases, water entering these systems due to a leak may diffuse or dry out quickly.
Selecting optimal site and weather conditions is of paramount importance when performing infrared inspections of uninsulated roofs with gypsum or lightweight concrete decks. Among these are:
Rainfall within previous 48 hours
Completely dry roof surface at sunrise
Daytime high temperatures above 40ºF and little or no wind
Mostly sunny day followed by clear evening with no wind and temperatures above 32ºF
Infrared inspections should be conducted by walking over the subject roof(s) after sunset. The inspection should be methodically conducted and no inexplicable anomaly should be overlooked. All thermal data should be verified by invasive moisture meter readings and core samples. Core samples should be gravimetrically analyzed to ascertain that moisture content is acceptable even if the roof appears to be uniformly dry.
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.
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.
Natural condition
Depressurized condition
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.
Many thermographers are aware of the OSHA and NFPA standards requiring the use of Fire Resistant Clothing. Aside from proper use, care and maintenance are of utmost importance for maintaining the effectiveness of FRC.
Fire Resistant Clothing is required Personal Protective Equipment for many who work in high temperature areas or near energized electrical equipment. If your job requires the use of FRC, there are several important things of which you should be aware.
FRC is not fireproof. It is designed to protect the wearer from burns by resisting ignition during brief periods of high temperature exposure such as electrical arc flashes.
FRC effectiveness can be compromised by age, wear, contamination with flammable materials and the attachment of name patches or embroidery.
FRC can be rendered ineffective by improper cleaning or laundering. FRC should be laundered separately from other garments and in accordance with manufacturer’s recommendations and the requirements of ASTM Standard F1449.
FRC should always be worn as the outer-most garment. If worn over other layers of clothing, the undergarments should be made of natural fiber and completely covered by the FRC. Before wearing FRC, be certain to understand its proper application and limitations and how to use and maintain it properly.
Thermographer safety and the use of PPE 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.
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.
With the onset of warm weather, tornado season has arrived. In an average year, tornadoes in the US cause 80 fatalities and 1500 injuries. Knowing what to do before and during a tornado is crucial for survival.
Tornadoes are nature’s most violent storms. Spawned from powerful thunderstorms, tornadoes can cause fatalities and devastate a neighborhood in seconds. A tornado appears as a rotating, funnel-shaped cloud that extends from a thunderstorm to the ground with whirling winds that can reach 300 miles per hour. Damage paths can be in excess of one mile wide and 50 miles long. Every state is at some risk from this hazard.
Some tornadoes are clearly visible, while rain or nearby low-hanging clouds obscure others. Occasionally, tornadoes develop so rapidly that little, if any, advance warning is possible. The best defense against tornadoes is to be alert to weather conditions and be ready to seek shelter.
Before a tornado, be alert to changing weather conditions.
Listen to NOAA Weather Radio or to local newscasts for the latest information
Watch for approaching storms
Know the danger signs:
Dark, often greenish sky
Large hail
Large, dark, low-lying or rotating clouds
Loud roar, similar to a freight train
If you see an approaching tornado or are under a tornado WARNING, seek shelter immediately.
If you are in a structure, go to a pre-designated shelter area or the center of an interior room on the lowest building level. Get under a sturdy table and use your arms to protect your head and neck. Do not open windows.
If you are in a vehicle, get out immediately and go to the lowest floor of a sturdy, nearby building or a storm shelter. Mobile homes, even if tied down, offer little protection from tornadoes.
If you are outside with no shelter, lie flat in a nearby ditch or depression and cover your head with your hands. Beware of flying debris and the potential for flooding.
For more information on tornadoes and tornado safety, visit the NOAA website.
First impressions not only count but they can last a long time. Bad impressions can last forever especially if their source is constantly in public view on an internet message board.
Humans leave their mark everywhere they go. They leave fingerprints on the things they touch, footprints in the sand where they walk, and personal impressions on those they meet. A less considered type of impression is an ‘internet footprint’ which is created whenever a person posts to public message boards or blogs.
Web posts often make permanent impressions on those who read them. Web posts that are timely, accurate, and professional can serve to help others and create a positive image for their authors. Bad or inappropriate posts can cause permanent damage and even harm one’s business. When posting on the net, following a few simple rules or netiquette can help to avoid creating a bad impression in cyberspace.
Do not post anything you would not (or should not) say in public
Always refrain from using foul, profane, or vulgar language
Do not badger others or attack their personal beliefs
Avoid over exposure. Chronic posting or posting ‘round the clock gives the impression that you have nothing better to do.
Keep in mind that posts can be viewed worldwide across different languages and cultures. Humor and witticism rarely translate well; sarcasm is often magnified.
Lastly, remember to think before you hit the ‘send’ button. Web posts often have an unintended permanence and are available for the world to see. Webmasters are rarely under any obligation to remove or edit posts regardless of how unflattering they may be.
Infrared inspections performed in commercial and industrial settings may require entry into confined spaces in order to inspect equipment. In this Tip, we cover the basics for working safely in confined spaces.
According to OSHA, “A confined space has limited openings for entry or exit, is large enough for entering and working, and is not designed for continuous worker occupancy. Confined spaces include underground vaults, tanks, storage bins, manholes, pits, silos, underground utility vaults and pipelines.
Permit-required confined spaces are confined spaces that:
May contain a hazardous or potentially hazardous atmosphere
May contain a material which can engulf an entrant
May contain walls that converge inward or floors that slope downward and taper into a smaller area which could trap or asphyxiate an entrant
May contain other serious physical hazards such as unguarded machines or exposed live wires
Must be defined by the employer who must inform exposed employees of the existence and location of such spaces and their hazards
What to do:
Do not enter permit-required confined spaces without being trained and without having a permit to enter
Review, understand and follow employer’s procedures before entering permit-required confined spaces and know how and when to exit
Before entry, identify any physical hazards
Before and during entry, test and monitor for explosive hazards as necessary
Use employer’s fall protection, rescue, air monitoring, ventilation, lighting and communication equipment according to entry procedures
Lastly, maintain contact at all times with a trained attendant either visually, via phone, or by two-way radio. This monitoring system enables the attendant and entry supervisor to order you to evacuate and to alert appropriately trained rescue personnel to rescue entrants when needed.”
Thermographer safety 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 or call us at 609-239-4788.
Although thermography is a non-contact test, preparing for an infrared inspection of electrical equipment often requires manual preparation of switchgear components. Unwary thermographers and their assistants can be injured by making contact with cabinets or component surfaces that have become accidentally or unintentionally energized.
Switchgear enclosures and components are generally designed to prevent their surfaces from becoming energized. Under certain circumstances, switchgear enclosures and other dielectric surfaces can become unintentionally energized to significant voltage levels. This potentially lethal condition may be caused by improper wiring, faulty equipment, or contamination due to dirt or moisture.
The image below shows a potential of 265 volts AC between a molded case circuit breaker and ground. This condition was discovered after an unprotected worker received a shock by touching the phenolic breaker handle.
Whenever working on or near energized electrical equipment, keep the following in mind:
Only qualified persons should be allowed near energized equipment
Treat all devices and enclosures as though they are energized
Never touch enclosures or devices without proper PPE
Do not lean on or use electrical enclosures as work tables
Always follow appropriate safety rules
Know what to do in case of an accident
Remember ~
There are old thermographers and
There are bold thermographers; however,
There are no old, bold thermographers.
Thermographer safety 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.
Temperature measurement is recognized in many thermographic applications as a means for gauging the severity of exceptions. For infrared inspections of building envelopes, temperature measurement is frequently of little or no value and may serve to underestimate the severity of certain conditions.
Infrared inspections can be used to detect a wide variety of problems in building envelopes. These conditions include, but are not limited to: air leakage, missing or damaged insulation, latent moisture, and pest infestation. Since thermographic detection of these conditions is qualitative, temperature measurement is not required. In fact, there is no reliable means for correlating temperature with the severity of the aforementioned deficiencies. For conditions such as latent moisture, there is no acceptable temperature limit or differential.
Although temperature measurements are frequently meaningless for building envelope inspections, many thermographers routinely include them in their reports. Unfortunately, this practice can create unnecessary liability for a thermographer and damage his/her reputation if their work product is ever questioned or compared to published standards or accepted industry practice. Presently, published thermography standards and accepted industry practice do not incorporate temperature measurement into building envelope inspections.
When faced with situations where temperature measurement can be useful, thermographers should take steps to ensure the accuracy of their measurements. For non-contact temperature measurements, minimum considerations should include equipment calibration, spot measurement size, target emittance, as well as local weather and site conditions.
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 at www.infraspection.com or call us at 609-239-4788.
For many, it’s that time of year again
when nature’s little wonders come out and remind us
that we need to be a proactive in reducing our exposure to
the flying and crawling types of hazards. In this Tip, we
offer suggestions for dealing with mosquitoes, ticks, and
bees.
Mosquitoes – Nationwide
there are more than 60 different kinds of mosquitoes some
of which are capable of spreading disease. Mosquito larvae
can develop in both tidal and fresh water locations; the
key to minimizing
their population is to reduce the availability of standing/stagnant
water. Treat, remove or drain “water collectors” such
as cans, discarded tires, etc. A single discarded tire can
produce tens of thousands of mosquitoes over the course of
a season! An insect repellant can help protect you from bites.
Ticks – Ticks like
to rest on low-lying brush and “catch a ride” on
a passersby. Areas prone to tick infestation are wooded areas
and low-growing grasslands. The best way to reduce your risk
of tick-bites is to avoid infested areas. When venturing
into tick prone areas, stay in the center of paths, avoid
sitting on the ground, and conduct frequent tick-checks.
Dress properly by wearing a long-sleeved shirt and long pants,
tucking your shirt into your pants and your pants into your
socks. This reduces the skin area exposed to ticks and thwarts
their efforts to crawl onto your skin. Again, an insect repellant
can help protect you.
Bees – Keep a lookout
for nests and the activity associated with them especially
when opening cabinets or enclosures where bees might nest.
For small nests or individual bees, knock down sprays may
be effective. For large nests or colonies, contact a professional
to have them removed.
Medical Attention – Be
alert for signs of an allergic reaction to insect bites
or stings. Non-emergency symptoms vary according to the
type of insect and the individual. Most people have localized
pain, redness, swelling, or itching. Signs of severe reaction
which require immediate medical attention include trouble
breathing, wheezing, shortness of breath, weakness, swelling
anywhere on the face and a tightening throat. In such cases,
seek medical treatment immediately!
Google Earth (GE) has revolutionized the
search engine process for finding properties throughout the
entire US and world. Built upon a platform of aerial photographs,
one can view color images of almost any location they desire.
The “fly-over” date will tell how old an image
is, but in most cases you can find what you are looking for.
Also, the amount of overlap between aerial images as well
as the altitude of the “fly-over” will dictate
the resolution of a particular area viewed.
We
have found GE to be a valuable tool for infrared roof inspections.
We use the measuring tool to get remarkably accurate estimates
of roof sizes to provide pricing to our clients. The measuring
tool can be found in the drop-down menu once an image is
displayed. By dragging the straight measuring line on top
of the roof image, feet or meter values can be obtained.
We have also used GE to provide base maps
that are taken out into the
field. The roof image can be printed directly
from GE or you can save the image as a .jpeg to your favorite
draw program. Ours happens to be
Look for This
Button
PowerPoint. Information we enter on these
maps includes, infrared and visual image numbers, core/moisture
probe locations and results, and other general observations
about the roof.
Our saved .jpeg roof images are also used
to generate roof drawings for final reports. The .jpeg image
is imported into PowerPoint and then used as a tracing guide
in concert with the multiple line tool to draw the outline
of the roof. Our final thermogram page has a color infrared
and visual photograph, the location of thermal anomalies,
and a “look direction” arrow of the infrared
image on
the roof drawing. If multiple thermograms are required for
a job, PowerPoint allows a slide to be copied and then edited
as needed.
In short, GE has saved us time by
reducing the number of pre-job inspections we would normally
perform to measure out and get a general feel for a roof.
It has also saved us time in the field when measuring and
drawing roof footprints. Finally, it has provided an excellent
resource for generating professional documents for final
reports.
Shipping infrared equipment is a frequent
necessity for thermographers. Taking the time to make certain
that equipment is adequately insured can help prevent bigger
problems in the event of loss or damage.
Many companies insure their infrared equipment
to guard against loss or damage while the equipment is in
use or transit by company employees. Typically referred to
as Inland Marine or Scheduled Equipment, this coverage is
generally purchased in addition to the contents portion of
a company's general insurance policy. In order to be covered,
equipment must be specifically identified by make, model,
serial number and value.
For those who find it necessary to ship
equipment via a third party or common carrier, purchasing
additional coverage known as 'Goods in Transit' may be a
smart move. While many shipping companies offer options for
'insurance', such coverage is often quite limited and may
be insufficient to properly guard against loss. In addition
to providing better coverage, a Goods in Transit policy is
usually less expensive than insurance offered by freight
or parcel carriers.
Regardless of how you insure your equipment,
be certain to review your policy with your insurance professional
and understand exactly what is covered. Lastly, always make
certain that equipment is covered for replacement cost rather
than 'Fair Market Value'.
Care and use of infrared equipment
is one of the many topics covered in the Level I Infraspection
Institute Certified Infrared Thermographer training course.
For more information including course locations and dates,
visit us online at infraspection.com.
The past few years have seen a marked increase
in the use of thermography to help detect the presence of
mold. When working near mold, thermographers should be aware
of the health risks associated with it and take appropriate
safety precautions.
Molds are microscopic organisms found everywhere
in the environment, indoors and outdoors. When present in
large quantities, molds have the potential to cause adverse
health effects. Such effects include: sneezing, cough and
congestion, runny nose, aggravation of asthma, eye irritation
and skin rash. People at greatest risk of adverse health
effects are individuals with allergies, asthma, sinusitis,
or other lung diseases and those with a weakened immune system.
Mold growth is common on organic building
materials that have been wet for sufficient periods of time.
Wetting can be the result of structural leaks, high relative
humidity, or flooding. When present, mold can appear as discolored
areas, woolly mats or a slimy film. Mold is often accompanied
by a foul, musty, or earthy smell.
When working near mold, thermographers should
keep the following in mind:
Hand, eye and respiratory protection
should always be worn
Care should be taken not to disturb
suspect mold areas
Tools or clothing that contact mold
should be isolated and properly sanitized to avoid contamination
of clean areas
Persons accidentally contacting contaminated
areas should immediately wash with soap and water
Lastly, mold can only be positively identified
through proper laboratory analysis. Whenever mold presence
is suspected, verification testing should be performed by
a qualified mold professional.
Detecting latent moisture within structures
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 at www.infraspection.com or
call us at 609-239-4788.
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.
Thermogram
shows hot spots (white) in motor stator due to shorted
laminations.
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.
Petrochemical refineries
provide many opportunities for the application thermography.
At the same time, they also provide unique safety challenges.
In this Tip we discuss safety issues when working around hydrogen
sulfide.
Hydrogen sulfide is a colorless, flammable,
extremely hazardous gas with a “rotten egg” smell.
It occurs naturally in crude petroleum and natural gas, and
can be produced by the breakdown of organic matter and human/animal
wastes such as sewage. Large quantities of hydrogen sulfide
are often produced in refineries. Unintended leaks can allow
hydrogen sulfide to collect in low-lying and poorly ventilated
areas such as basements, manholes, sewer lines and underground
telephone/electrical vaults.
Hydrogen sulfide can be smelled at low levels,
but with continuous low level exposure or at higher concentrations
you lose your ability to smell the gas even though it is still
present. At high concentrations one’s ability to smell
the gas can be lost instantly. NEVER depend on
your sense of smell for indicating the continuing presence
of this gas or for warning of hazardous concentrations.
The health effects associated with exposures
to hydrogen sulfide vary with how long, and at what level,
you are exposed. Asthmatics may be at greater risk. At low
concentrations, hydrogen sulfide can cause irritation of eyes,
nose, throat, or respiratory system. At high concentrations,
shock, convulsions, coma, and death are possible; in some
cases the effects can occur within a few breaths.
Before entering areas with possible hydrogen
sulfide, the air should be tested for the presence and concentration
of hydrogen sulfide by a qualified person using appropriate
test equipment. Testing should also be performed to determine
if fire/explosion precautions are necessary. If hydrogen sulfide
or hazardous gasses are present, the space should be ventilated
until acceptable limits are achieved. In some cases, continuous
monitoring of the work area may be required.
Thermographer safety 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 at www.infraspection.com
or call us at 609-239-4788.
For more complete information on workplace
safety, visit the OSHA
Website.
Tip submitted
by:
Mike Sharlon, President
Thermasearch, Inc.
Infrared inspections of live
transformers require line of sight access to the connections
and windings. Removing covers on energized dry-type transformers
can present shock and arc flash hazards. In this Tip, we discuss
an alternative to removing covers for an infrared inspection.
Many small dry-type transformers feature
removable steel covers that enclose electrical connections
and windings. In general, there are two popular styles of
front covers. The first style has a slit at the top right
and top left edges of the cover. These slits require tilting
the panel sideways to remove them. Attempting to remove such
covers can lead to electrocution or arc flash since some transformers
have energized connections just a few inches below the top
lip of the cover.
To inspect transformers with this type of
cover, leave the top right and top left bolts installed on
the cover and remove the remaining bolts. Gently pull back
the base of the cover a few inches and view the internals
of the transformer with your imager from the bottom right
and/or left corners. For most thermal imagers, this will be
sufficient to detect thermal anomalies.
The second style of transformer cover does
not have the slits that keep the cover from tipping out at
the top. With this type of cover, leave the bottom bolts installed
and gently tip the top of the cover out enough to inspect
the windings and connections. Regardless of cover type, infrared
imaging should only be performed once the cover has been opened
and secured to permit a safe inspection.
Lastly, never remove the top cover to a live
transformer! Depending on transformer design, this can cause
internal components to shift and drop resulting in an arc
flash. For transformers that require removal of the top cover
in order to remove side covers, it is best to de-energize
them for cover removal and replacement.
With much 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.
Infrared thermography is
a useful tool for detecting heat patterns caused by overloaded
electrical circuits. In this Tip we discuss what constitutes
an acceptable load.
Infrared imagers are capable of detecting
thermal patterns associated with several electrical deficiencies
including overloaded circuits. When viewed with an imager,
overloaded circuits will appear warm throughout their entire
length with no discrete hot spots. Since it is not possible
to determine circuit load from a thermal signature, actual
circuit load must be measured with an ammeter.
Once circuit load is known, a question that
frequently arises is, ‘How much load is acceptable?’
The answer to this question can be found within the National
Electric Code 220-10(b) which provides guidance for circuit
loading.
(b) Continuous and Noncontinuous loads.
Where a feeder supplies a continuous load or any combination
of continuous or noncontinuous loads, the rating of the
over-current device shall not be less than the noncontinuous
load plus 125 percent of the continuous load. The minimum
feeder circuit conductor size, without the application of
any adjustment or correction factors, shall have an allowable
ampacity equal to or greater than the noncontinuous load
plus 125 percent of the continuous load.
NOTE: Exception: Where the assembly
including the over-current devices protecting the feeder(s)
are listed for operation at 100 percent of their rating,
neither the ampere rating of the over-current device nor
the ampacity of the feeder conductors shall be less than
the sum of the continuous load plus the noncontinuous load.
In other words, for most circuits load should
not exceed 80% of conductor ampacity or 80% of the overcurrent
device rating. To help ensure accuracy, electric loads should
be measured with a true RMS sensing ammeter.
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, visit Infraspection
Institute or call us at 609-239-4788.
For many facilities the beginning
of autumn means that heating season is just around the corner.
Infrared inspections can help point out the types of energy
liabilities that can account for significant waste.
With energy costs at an all time high, energy
conservation is more important than ever. With companies looking
for ways to contain costs, energy conservation makes sense.
When properly conducted, infrared inspections can point out
areas of thermal deficiencies or energy loss. When coupled
with timely, effective repairs, considerable savings can be
realized.
There are many areas where infrared inspections
may be performed to help detect excess energy loss. Among
the most common are:
Building envelopes – for
missing or damaged insulation and air leakage
Flat roofs – to detect water
damaged insulation
Steam systems – to detect
defective steam traps
Underground piping – to detect
pipe leaks
Boilers and process equipment –
to detect excess energy loss or air leaks
When it comes to the above inspections,
time is of the essence in order to maximize savings. Infrared
inspections should be carried out as soon as possible. Waiting
until the heating season is well under way often results in
documenting opportunity lost rather than savings realized.
Infrared inspection of building envelopes
and thermal energy delivery systems are two of the many topics
covered in the Infraspection Institute Level I Certified Infrared
Thermographer® training course. This same information
is also covered in our Distance Learning Level I Thermography
course. For more information or to register for a course,
visit Infraspection Institute or call us at 609-239-4788.
To everything there is a
season. The same is true for infrared inspection routes within
facilities where equipment or systems are operated seasonally.
Traditionally, many facilities perform infrared
inspections on an annual basis. While this approach may detect
deficiencies within operating systems, systems not under load
due to seasonal or operational conditions cannot be effectively
inspected.
Examples of seasonally operated equipment
include heating/cooling systems, production machinery, and
the electrical distribution system. Effective infrared inspections
of seasonally operated equipment begin at the planning stages
and should include the following:
Develop an inventory list of equipment
to be inspected
Group seasonally operated equipment into
dedicated routes
Ascertain operating times for subject
systems
Schedule infrared inspections for the
beginning of operating season
Inspect subject systems while under normal
load
Be certain to perform a follow up inspection
for all detected exceptions once necessary repairs have been
completed. As always, remember to observe all necessary safety
precautions before, and during the infrared inspection.
Thermographers often work
in environments that require the use of respiratory protection.
In this Tip we discuss the selection and use of common respirator
types.
A respirator is a device designed to
protect the wearer from inhaling harmful dusts, fumes, vapors,
or gases. There are several types of respirators, each having
a different intended application. Several types are listed
below along with their applications.
Single-strap
dust masks are usually not NIOSH-approved.
They must not be used to protect from hazardous atmospheres.
However, they may be useful in providing comfort from
pollen or other allergens.
Approved
filtering face pieces (dust masks) can be used
for dust, mists, welding fumes, etc. They do not provide
protection from gases or vapors. DO NOT USE FOR ASBESTOS
OR LEAD; instead, select from the respirators below.
Half-face
respirators can be used for protection against
most vapors, acid gases, dust or welding fumes. Cartridges/filters
must match contaminant(s) and be changed periodically.
Full-face
respirators are more protective than half-face
respirators. They can also be used for protection against
most vapors, acid gases, dust or welding fumes. The face-shield
protects face and eyes from irritants and contaminants.
Cartridges/filters must match contaminant(s) and be changed
periodically.
Loose-fitting
powered-air-purifying respirators (PAPR) offer
breathing comfort from a battery-powered fan which pulls
air through filters and circulates air throughout helmet/hood.
They can be worn by most workers who have beards. Cartridges/filters
must match contaminant(s) and be changed periodically.
A
Self-Contained Breathing Apparatus (SCBA) is
used for entry and escape from atmospheres that are considered
immediately dangerous to life and health (IDLH) or oxygen
deficient. They use their own air tank.
Respiratory protection must be worn whenever
you are working in a hazardous atmosphere. The appropriate
respirator will depend on the contaminant(s) to which you
are exposed and the protection factor (PF) required. Required
respirators must be NIOSH-approved and medical evaluation
and training must be provided before use.
Thermographer safety 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.
For more complete information on workplace
safety, visit the OSHA
Website.
To help ensure proper handling
of their equipment, most thermographers who travel by air
opt to hand carry their imagers. Proper planning and preparation
can help avoid delays when passing through security checkpoints.
When traveling by air, hand carrying your
imager is the best way to help ensure that it will arrive
with you and in good working order. Fortunately, most modern
infrared imagers are sufficiently small to be treated as carry-on
luggage. When hand carrying your imager on aircraft, keep
the following in mind:
• Ascertain the number of carry-on
items that your chosen airline allows
• Ensure that your imager’s
carrying case does not exceed maximum size for carry-on
luggage
• Be certain that your imager case
does not contain prohibited items such as tools, pocketknives,
or liquids
• Check Customs regulations prior
to international travel; some countries restrict import/export
of infrared cameras and/or expensive test equipment
• Expect potential delays when passing
through security checkpoints due to any additional screening
that may be required
Lastly, be aware that contaminants
from industrial environments can cause positive test results
during explosives screening. Should your equipment test positive
during screening, remain calm while security personnel sort
things out. Since this can take some time, it is possible
that you will miss your scheduled flight, particularly if
you are on a tight schedule.
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.
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.
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 ultrasound 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 to access subject
traps.
Infrared inspections of steam traps
is one of the many topics covered in the Infraspection Institute
Distance Learning course, Level I Thermography. This same
topic is also covered in our Certified Infrared Thermographer®
training course. For more information, including course locations
and dates, visit www.infraspection.com
or call 609-239-4788.
It’s that time of year
when brightly colored trees remind us that Autumn is upon
us. Taking a few precautions can help to make driving safer
by addressing challenges unique to the fall season.
• Patches of fallen leaves can be
just as treacherous as patches of ice. Fallen leaves retain
large amounts of water and can create a slippery surface.
Drive slowly through them and avoid hard or panic braking.
• Fall brings the first frost. Be
aware of slippery conditions that occur with frost. At freezing
or near freezing temperatures, the moisture on bridges and
overpasses will become ice much more quickly than the approach
roadway. The roadways hold heat and the bridges do not;
you can go from wet roadway to ice in just a fraction of
a second.
• Fall weather such as rain, fog,
sleet and wet snow require full driver attention. Remember
the "two-second rule" when following other drivers,
and in severe weather increase your following distance.
If you are being tailgated, let the other driver pass.
• Later sunrises and earlier sunsets
can create sun glare. Be sure your windows are clean, inside
and out, and have sunglasses handy. If you're driving away
from a low sun, glare will not be a problem for you, but
it can be for the drivers approaching from the other direction.
It may help to use your low beam headlights, allowing you
to be seen more readily.
• In most areas, animal collisions
are at their peak in the fall. Be on guard when traveling
through areas where wildlife is likely to cross the road.
Common sense along with the basics
of safe driving - always wearing a safety belt, driving alert
and sober, and driving at safe and legal speeds - can help
you travel safely in the fall.
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.
For many thermographers,
scaffolds provide a means for accessing remote areas and equipment.
In this week’s Tip we cover safety tips applicable to
these common workplace structures.
According to OSHA, supported scaffolds consist
of one or more platforms supported by outrigger beams, brackets,
poles, legs, uprights, posts, frames, or similar rigid support.
The requirements for scaffolds are as follows:
• Guardrails or personal fall arrest
systems for fall prevention/protection are required for
workers on platforms 10 feet or higher
• Working platforms/decks must be
planked close to the guardrails
• Planks are to be overlapped on
a support at least 6 inches, but not more than 12 inches
• Legs, posts, frames, poles, and
uprights must be on base plates and mud sills, or a firm
foundation; and, be plumb and braced
Workers using scaffolds must be properly
trained. Such training must include:
• The hazards of the type of scaffolding
being used
• Maximum intended load capacity
• Recognizing and reporting defects
• Fall hazards
• Electrical hazards including overhead lines
• Falling object hazards
• Other hazards that may be encountered
Thermographer safety is one of the topics
covered in all Infraspection Institute Certified Infrared
Thermographer® training courses. For information on thermographer
training and certification, visit us online at www.infraspection.com
or call us at 609-239-4788.
For more complete information on workplace
safety, visit the OSHA
website.
For many thermographers,
scaffolds provide a means for accessing remote areas and equipment.
In this week’s Tip we cover additional safety tips applicable
to these common workplace structures.
The Occupational Safety and Health Administration
recommends that scaffolds and scaffold parts be inspected
daily, before each work shift, and after any event that may
have caused damage.
Check to see if powerlines near
scaffolds are de-energized or that the scaffolds are at
least 10 feet away from energized powerlines.
Make sure that tools and materials are
at least 10 feet away from energized powerlines.
Verify that the scaffold is the correct
type for the loads, materials, employees, and weather conditions.
Check footings to see if they are level,
sound, rigid, and capable of supporting the loaded scaffold.
Check legs, posts, frames, and uprights
to see if they are on baseplates and mudsills.
Check metal components for bends, cracks,
holes, rust, welding splatter, pits, broken welds, and non-compatible
parts.
Check for safe access. Do not use the
crossbraces as a ladder for access or exit.
Check wooden planks for cracks, splits
greater than one-quarter (1/4) inch, end splits that are
long, many large loose knots, warps greater than one-quarter
(1/4) inch, boards and ends with gouges, mold, separated
laminate(s), and grain sloping greater than 1 in 12 inches
from the long edge and are scaffold grade lumber or equivalent.
If the planks deflect one-sixtieth (1/60)
of the span or 2 inches in a 10-foot wooden plank, the plank
has been damaged and must not be used.
Check to see if the planks are close
together, with spaces no more than 1 inch around uprights.
Check to see if 10-foot or shorter planks
are 6 to 12 inches over the center line of the support,
and that 10-foot or longer planks are no more than 18 inches
over the end.
Check to see if the platform is 14 inches
or more away from the wall or 18 inches or less away if
plastering or stucco.
Check for guardrails and midrails on
platforms where work is being done.
Check for employees under the platform
and provide falling object protection or barricade the area.
Make sure that hard hats are worn.
Use braces, tie-ins and guying
as described by the scaffold’s manufacturer at each
end, vertically and horizontally to prevent tipping.
Thermographer safety is one of the topics
covered in all Infraspection Institute Certified Infrared
Thermographer® training courses. For information on thermographer
training and certification, visit us online at www.infraspection.com
or call us at 609-239-4788.
For more complete information on workplace
safety, visit the OSHA
website.
Savvy business owners are
always on the lookout for new business opportunities. Thermography
can be a particularly good fit for building and home inspectors
seeking to expand their services and generate new revenue.
The past few years have seen tremendous growth
in the use of thermography for building inspections. Greater
public awareness and lower equipment costs have induced many
home and building inspectors, damage restoration specialists
and pest management professionals to add thermography to their
services.
The income potential for thermographers is
significant. Depending upon services offered and rate structure,
a single thermographer is capable of generating $250,000 per
year in revenue. This potential can be influenced by a number
of factors including one’s choice of infrared imaging
equipment. Prior to purchasing equipment, one should keep
the following in mind:
• Determine your firm’s capabilities
with respect to expertise and manpower.
• Conduct a marketing study to determine
what services you will offer. In particular, look for services
that will repeat annually and/or provide the greatest revenue
with the least amount of sales effort.
• Entry level equipment can limit
one’s capabilities and revenue potential. Try to anticipate
your equipment needs for at least three years and purchase
accordingly.
Despite claims to the contrary, thermography
is not a ‘point and shoot’ technology. In addition
to thorough knowledge of the systems or structures being inspected,
thermographers should be trained in infrared theory, heat
transfer concepts, equipment operation and selection, current
industry standards, and report generation. For those lacking
experience, training should be completed prior to purchasing
equipment.
Infrared inspection of buildings and
their subsystems 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.
Blackbody simulators are
essential tools for checking the calibration of infrared imagers
and radiometers. One alternative to purchasing a blackbody
simulator is to make your own.
In order to provide accurate temperature
values, infrared imagers and radiometers must be calibrated
on a periodic basis. During the calibration process, blackbody
simulators provide targets with a known temperature and a
known emittance.
Thermographers wishing to perform a calibration
check of their instruments may elect to purchase a blackbody
simulator. Several models are commercially available with
prices ranging up to several thousand dollars. As an alternative,
thermographers may elect to make their own simulator from
commonly available items. This may be accomplished as follows:
• Procure a 2 liter square metal
can and a 60 Watt electric aquarium heater. Can opening
must be large enough to allow heater to be inserted into
can opening.
• Cover the exterior of the can with
Scotch #191 PVC electrical tape.
• Fill the can with water to within
1” of the top and insert aquarium heater. Avoid causing
can to overflow.
• Energize heater and set to desired
temperature. Be certain to allow sufficient time for can
temperature to stabilize.
When performing a calibration check of infrared
equipment, set the subject radiometer’s emittance control
to 0.97. Ascertain the can temperature using a thermocouple.
Compare the two values and note any differences.
Lastly, be certain to work safely. In particular,
avoid fully immersing any aquarium heater not designed for
immersion. Be certain to disconnect the aquarium heater from
its power source and allow it to cool prior to removing it
from the can.
Equipment calibration is one of the
many topics covered in the Level II 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.
We
have found GE to be a valuable tool for infrared roof inspections.
We use the measuring tool to get remarkably accurate estimates
of roof sizes to provide pricing to our clients. The measuring
tool can be found in the drop-down menu once an image is
displayed. By dragging the straight measuring line on top
of the roof image, feet or meter values can be obtained. 
on
the roof drawing. If multiple thermograms are required for
a job, PowerPoint allows a slide to be copied and then edited
as needed. 
