2009
January 05, 2009
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Make a New Year’s Resolution for Safety
Tip written by: Infraspection Institute
With the New Year upon us, many of us will follow the tradition of resolving to change or better ourselves. With this Tip, we offer suggestions for making job safety a priority.
The New Year is symbolic for many reasons. For some, the New Year represents a fresh start or new beginning. For others, it provides an opportunity to rededicate one’s self to a set of goals or principles. The New Year provides a perfect opportunity for thermographers to take stock of workplace safety practices and procedures. In doing so, be sure to keep the following in mind:
- Review safety procedures to ensure that they are complete and current
- Ensure that safety training is up-to-date for all personnel including First Aid and CPR
- Physically inspect all Personal Protective Equipment to ensure it is in good condition
- Check calibration and/or replacement dates for all monitoring or test equipment
Lastly, resolve to make safety your number one priority each and every day. Safety is not a poster, a slogan, or a set of actions to be followed only when it is convenient. Rather, safety is way of life that affects not only you but those around you.
Thermographer safety is one of the many topics covered in the Level I Infraspection Institute Certified Infrared Thermographer® training course. For information on thermographer training including course locations and dates, visit us online at www.infraspection.com or call us at 609-239-4788.
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January 12, 2009
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Frostbite & Hypothermia
“Jack Frost nipping at your nose.” These lyrics from a popular Christmas carol evoke romantic visions of winter; however, frostbite and hypothermia are dangerous medical conditions that can present serious safety hazards.
For many, the dead of winter is upon us. Thermographers working outdoors in cold climates can face serious safety challenges due to frostbite and hypothermia. Knowing the symptoms of these conditions and proper treatment is imperative for worker safety.
Frostbite is a severe reaction to cold exposure that can permanently damage its victims. A loss of feeling and a white or pale appearance in fingers, toes, or nose and ear lobes are symptoms of frostbite.
Hypothermia is a condition brought on when the body temperature drops to less than 90 degrees Fahrenheit. Symptoms of hypothermia include uncontrollable shivering, slow speech, memory lapses, frequent stumbling, drowsiness, and exhaustion.
If frostbite or hypothermia is suspected, begin warming the person slowly and seek immediate medical assistance. Warm the person’s trunk first. Use your own body heat to help. Arms and legs should be warmed last because stimulation of the limbs can drive cold blood toward the heart and lead to heart failure. If the person is wet, put them in dry clothing and wrap their entire body in a blanket.
Never give a frostbite or hypothermia victim beverages containing caffeine or alcohol. Caffeine, a stimulant, can cause the heart to beat faster and hasten the effects the cold has on the body. Alcohol, a depressant, can slow the heart and also hasten the ill effects of cold body temperatures.
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January 19, 2009
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Cold Weather Clothing
Last week’s tip discussed the dangers of Frostbite and Hypothermia while working in cold temperatures. This week’s tip covers cold weather clothing.
Cold weather clothing is a matter of functionality not fashion. Clothing needs to be worn in layers in order to trap air which is warmed by the body. When selecting clothing, start with the innermost layer and work outward. The use of multiple layers will trap warm air while providing greater ease of movement. As you add layers, be sure to adjust the next layer’s size accordingly.
The first layer should be made of a synthetic material that will wick perspiration away from the body and maintain its insulating properties when damp. The second layer is your main insulator and should be a breathable material that maintains its insulating properties when wet. Synthetic fleeces or natural wool are good choices. The outermost layer should be breathable and both wind and water resistant.
Head and neck protection is a must since nearly 40% of body heat is lost here. Perspiration is the main enemy of feet. The best footwear will have sturdy outers, good treads and a removable felt liner. Buy extra liners and replace them every few hours. Liners can take a full day to fully dry out so buy enough to get through a typical workday.
Mittens are the warmest but present problems in grasping tools etc. I have found that a heavy duty welder’s glove with cotton or wool gloves lining them provide good warmth and mobility. Buy enough liners to get you through the day. One final note, the body needs fuel to produce heat. Your calorie needs increase in cold weather and require regular replenishment with good wholesome foods.
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January 26, 2009
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Detecting Delamination of Stucco
With aging infrastructure becoming an increasing concern in many communities, more attention is being focused on the maintenance of building facades. Under the right conditions, thermal imaging can detect evidence of delaminated stucco or concrete finishes on the exterior of masonry buildings.
Over time, buildings that utilize concrete stucco for exterior finishes are subject to failure. One of these failures involves the stucco delaminating from its substrate. Delaminated stucco is a serious safety concern as it can cause serious injury to pedestrians should it fall from any significant height.
When concrete stucco delaminates from its substrate, an air pocket is formed between the stucco finish and the substrate. Because this air pocket acts as an insulator, it will change the thermal capacity and/or thermal conductivity in the area of the delamination. Under the correct weather conditions, thermal imaging can detect evidence of delaminated areas.
In order to detect evidence of delaminated areas using thermal imaging, a temperature differential must be present. Typically, infrared inspections of concrete stucco are performed during evening hours following a sunny day. As an alternative, infrared inspections may also be performed during midday under solar loading conditions. Thermal patterns associated with delaminated stucco will generally be amorphous in shape and will typically appear as cold spots during post-sunset inspections or as hot spots during midday inspections.
When performing infrared inspections of concrete stucco finishes, keep the following in mind:
- Subject surfaces should be clean and dry
- Wall surfaces must be heated uniformly. Areas in shadow or shade may not produce accurate data
- IR inspections are qualitative in nature. Compare similar areas to each other noting any inexplicable temperature differences
Once the infrared inspection has been completed, all thermal anomalies should be investigated for cause and appropriate corrective measures taken.
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February 03, 2009
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Winter Driving Tips
Tip written by: Infraspection Institute
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.
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February 10, 2009
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Easier Than A, B, C
Tip written by: Infraspection Institute
When performing infrared inspections of electrical distribution systems, many people identify the individual phases of polyphase circuits as A, B, and C; others frequently use 1, 2, and 3.
Confusion can arise with alphabetical or numerical labels particularly when switchgear enclosures are inspected from different perspectives e.g. front versus rear. Further confusion can occur when phase rotation has been modified or changed or, in some cases, mislabelled.
Reference errors can be avoided by using terms that cannot be confused such as Left, Middle, Right OR Upper, Middle, Lower. When using such terms, one should always reference where the image was taken from. For outside power lines references such as Street, Center, and Field may be used to identify phases without confusion.
Using the above simple terms can make your reports easier to understand and help to eliminate confusion when repairs are performed.
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 Standard for Infrared Inspection of Electrical Systems and Rotating Equipment, visit Infraspection Institute online at www.infraspection.com or call us at 609-239-4788.
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February 18, 2009
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Spare Parts to the Rescue
Tip written by: Infraspection Institute
Seasoned professionals know the value of spare parts when it comes to facility maintenance. The principle of always being prepared can be successfully applied to an infrared inspection program as well.
Like any electrical or mechanical device, thermal imaging systems are subject to wear and tear. Having user-replaceable spare parts on hand can help prevent unscheduled downtime for your infrared inspection program. Building a spare parts inventory is easy if you follow a few simple steps:
1. Examine your equipment for parts that are subject to physical wear such as eyepieces, switch covers or hand/neck straps.
2. Identify which parts are fragile and are most likely to break such as viewfinders or external monitors.
3. Determine which items are critical to operation such as power/video cables, batteries, fuses, screws and external hardware.
4. Inventory items which are easily misplaced such as lens caps and flash cards.
5. Purchase necessary items as soon as possible to ensure availability of specialty or custom parts. For critical items, be sure to purchase extras.
6. Replace spare parts when utilized to maintain inventory.
After building your spare parts inventory, keep mission-critical components in a safe place or with your imager so that you will have them when needed.
Infrared imager operation and maintenance are two of the many applications covered in the Infraspection Institute Level I Certified Infrared Thermographer® training course. For more information or to register for a course visit us online at www.infraspection.com or call us at 609-239-4788.
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February 23, 2009
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Frequency of IR Roof Inspections
Tip written by: Infraspection Institute
The benefits of thermography for condition assessment of insulated roofs are well documented. Performed on a regular basis, infrared thermography can help to extend the overall life of a roofing system when utilized as part of a preventive maintenance program.
As a building component, roofing systems tend to be out-of-sight and out-of-mind. Despite the critical role they play in keeping a facility dry, many roofs garner little attention until they begin to leak. In order to minimize damage, it is imperative that roof leaks be detected and repaired at an early stage.
Many roofs can gain significant quantities of moisture in a very short period of time. In the case of retrofitted roof systems, whole roof sections can become saturated in a matter of weeks while leaking little or no water into the occupied spaces. By the time a roof leak is noticed within the building, replacement may be the only option available.
For best results, insulated roofs should be thermographically inspected at least twice per year (e.g. Spring and Autumn) in accordance with published standards and guidelines. Semi-annual infrared inspections can help to identify new areas of moisture damage and help to ensure that recent repairs are performing in a watertight manner. Infrared findings should be correlated with a thorough visual inspection and other pertinent data to formulate an effective roof maintenance strategy.
For information on infrared training or certification or to obtain a copy of the Guideline for Performing Infrared Inspections of Building Envelopes and Insulated Roofs, contact Infraspection Institute at 609-239-4788.
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Selecting an IR Training Firm
Tip written by: Infraspection Institute
As thermography has gained in popularity, the demand for training services has also increased. Since operator training can have a profound effect on the success of an infrared program, obtaining quality training is of paramount importance.
At present, there are several firms that offer infrared training and certification. While nearly all infrared training firms refer to their training courses by level (1, 2, or 3), there are no standards which dictate the content of any offered course. As a result, training courses can vary widely between firms.
When choosing an infrared training firm, be certain to:
- Examine course curriculum to ensure that it meets one’s needs
- Ensure that course will be germane to all infrared imagers, regardless of age
- Ascertain if Certification is included with course, its expiration date, and renewal fees
- Determine number of years training firm has been in business – not the cumulative total of staff years
- Insist that instructors be practicing thermographers with documentable field experience in their area of instruction
Lastly, beware of claims that training is “vendor neutral”. It is impossible for training firms to sell infrared equipment or train for equipment manufacturers without being biased. Firms who train for manufacturers work for manufacturers and cannot provide the unbiased information students deserve. Simply put, no man can serve two masters.
Infraspection Institute has been providing infrared training and certification for infrared thermographers since 1980. Our Level I, II, and III Certified Infrared Thermographer® training courses meet the training requirements for NDT personnel in accordance with the ASNT document, SNT-TC-1A. All courses are taught by practicing, expert Level III thermographers whose field experience is unsurpassed anywhere in the world. We teach effective, real-world solutions using the latest standards, software and technology. For more information call 609-239-4788 or visit us online at www.infraspection.com.
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Imager Resolution & The Great Pixel Debate
Tip written by: Infraspection Institute
Resolution is one of the most important objective specifications for any thermal imaging system. Pixel count is frequently offered as a measure of image quality; however, pixel count is only one of many factors that affect imager resolution.
The Focal Plane Array (FPA) detector assemblies used in modern infrared imagers are made up of several tiny, discrete picture elements or pixels. Each pixel is a discrete infrared detector that collects thermal data. Individual pixels are arranged to form an array that ultimately allows the imager to produce a thermal image.
FPA detectors are commonly specified according to pixel count and ratio. Typical detector sizes for industrial imagers range from 160W by 120H to 320W by 240H; some detectors may have more or less pixels. To determine the total pixel count for a detector; the horizontal and vertical values are multiplied.
Imager manufacturers often cite pixel count as a measure of imager resolution. Imager sales are won and lost as entire ad campaigns focus heavily on this single objective specification. Actually determining resolution is not that simple.
Although resolution generally increases with the number of pixels, there are several other factors that influence image clarity or resolution. These include, but are not limited to, pixel viewing angle, imager optics, signal-to-noise ratio and the imager’s display screen.
When evaluating an imager for resolution, physically try the imager under actual working conditions. Imagers that produce clear images should be sufficient to the task regardless of pixel count.
To better understand imager resolution, read the article, Selecting, Specifying and Purchasing Thermal Imagers available from Infraspection Institute. To obtain a copy of the article, call 609-239-4788 or visit us online at www.infraspection.com.
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The Power of Inductive Heating
The magnitude and intensity of inductive heating should not be underestimated when performing infrared inspections of electrical switchgear. Inductive heating is derived from the proximal interaction of non-current carrying devices with the magnetic field around energized conductors that are under load.
Inductive heating affects ferrous metals and causes inexplicable heating of non-current carrying components. The intensity of heating is a function of the amount of current passing through the conductor and rather than the voltage class. In some cases, the affected components can reach temperatures in excess of several hundred degrees.
During a recent inspection at a power generation plant, two examples of inductive heating where observed near the plant’s step-up transformers. Images captured showed intense heating on a non-current carrying support pole and bus transition box, both of which were close to iso-phase bus entering a13kV to 230kV step-up transformer. Temperatures documented on these devices were in excess of 400°F. Being the starting point of transmission service, a heavy current load would be expected on energized equipment.
Often, engineering designs on switchgear enclosures and other electrical equipment do not take into consideration the interaction of non-current carrying ferrous devices within electro-magnetic fields. In some cases, these situations can pose safety hazards when the affected component is in contact with combustible materials or heats structures that are accessible to human contact. When faced with perplexing heat patterns on components that should not be hot, inductive heating may be to blame.
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Preventing Workplace Falls
“Watch Your Step”. Sage advice that we’ve heard a million times; however, falls continue to be one of the most common workplace accidents. Following a few simple steps can help thermographers to prevent most falls.
Each year falls in the workplace account for over one million injuries and several hundred fatalities. Even a simple slip can cause serious injuries. Many falls can be prevented by following some basic rules:
- Identify all potential tripping and fall hazards before work starts
- Look for fall hazards such as unprotected floor openings/edges, shafts, skylights, stairwells, and roof openings/edges
- Use appropriate fall protection equipment; inspect equipment for defects prior to each use
- Never use boxes or chairs in place of an appropriate ladder or stepstool
- Secure and stabilize ladders before climbing them; never stand on top rung or step of a ladder
- Use handrails when going up/down stairs
- Practice good housekeeping – Keep floors dry and free of clutter such as cords, hoses , and cables
- Keep walkways free of snow and ice
Lastly, be sure to use sturdy footwear appropriate to the task. Work boots and shoes should be laced and tied to prevent tripping and to afford proper support. When it comes to fall protection, an ounce of prevention is worth a pound of cure. For more information on workplace safety standards and fall protection, visit www.osha.gov.
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Choosing and Maintaining Your Domain Name
Tip written by: Infraspection Institute
“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.
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NFPA 70E & Infrared Thermography
Tip written by: Infraspection Institute
On September 5, 2008, the eighth edition of NFPA 70E Standard for Electrical Safety in the Workplace became available superceding all previous editions. This latest edition of NFPA 70E contains several important changes and specifically addresses thermographic inspections of energized electrical systems.
Since 1979, the National Fire Protection Association has published the document, NFPA 70E. Since its initial publication, this safety standard has been renamed, expanded, and extensively revised. NFPA 70E is applicable to any workplace and is intended for use by employers, employees, and OSHA, among others.
The 2009 edition of NFPA 70E contains several changes over the 2004 edition. Among these changes are:
- Several key definitions have been revised
- Article 350 R&D Laboratories has been added to Chapter 3
- Chapter 4 has been deleted from the 2009 edition
- The 2009 edition contains an Introduction, 3 Chapters, and 15 Annexes
Perhaps the most significant change to NFPA 70E is that thermography is specifically addressed as a task. Table 130.7(C)(9) Hazard Risk Category Classifications provides Hazard/Risk categories ranging from 0 to 3 depending upon the type of equipment being inspected.
While Table 130.7(C)(9) may be used for certain tasks, it does not cover all inspection scenarios. For tasks not listed in Table 130.7(C)(9) or for power systems with greater than the assumed maximum short circuit current capacity or with longer than the assumed maximum fault clearing times, an arc flash hazard analysis is required.
The application and use of NFPA 70E are specifically covered within Infraspection Institute’s online short course, NFPA 70E – Are You in Compliance? Available 24 hours per day, this 45 minute course focuses on the history and application of 70E, changes included in the current edition, and how it applies to thermographers. For more information or to register, please visit: http://www.successiries.com/SuccessIRies_105.html.
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Checking IR Equipment Calibration
Tip written by: Infraspection Institute
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 specifically covered within Infraspection Institute’s online short course, How to Check Infrared Equipment Calibration. Available 24 hours per day, this 27 minute course focuses on the simple, yet effective techniques for calibrating infrared equipment. The techniques demonstrated are complaint with accepted industry practice and ISO standards. For more information or to register, please visit: http://www.successiries.com/SuccessIRies_108.html.
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Infrared Imaging and Spray Testing of Walls
Tip written by: Infraspection Institute
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 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.
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
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Is Distance Learning Right For You?
Recent advancements in technology are reshaping traditional approaches to education. Students are now able to study a wide variety of subjects, including thermography, from virtually anywhere in the world.
Distance learning may be defined as any situation where the student and the instructor are in physically separate locations. Distance instruction may be live or pre-recorded and can be delivered via video presentations, remote teleconferencing, and web-based presentations.
Distance learning provides several advantages over the traditional classroom setting. Chief among these are the elimination of travel costs, 24 hour availability, and increased convenience in scheduling. The availability of Distance Learning courses for thermography is particularly beneficial to thermographers with hectic schedules.
When selecting Distance Learning courses for thermography, be sure to determine the following:
- How and when is course delivered
- Length of course and curriculum
- What standards does course curriculum conform to
- Are experienced instructors available to answer questions
- Does course qualify toward thermographer certification
- Experience of training firm in providing thermographic instruction
Infraspection Institute offers a wide variety of Distance Learning courses for thermography. Courses include: Certification Prep, Applications and Industry-Specific Courses. All courses are ASNT compliant and are taught by Level III Infraspection Institute Certified Infrared Thermographers® each having over 20 years experience. For more information or to register for a course call us at 609-239-4788 or visit us online at Distance Learning offered by Infraspection Institute.
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How to Survive a Shrinking Maintenance Budget
Maintenance departments face many challenges. One of the toughest challenges is securing adequate funding when money is tight. In this Tip, we discuss several ways to make sure you get the biggest bang for your maintenance buck.
Companies are always on the lookout for ways to improve the bottom line. Reducing costs during an economic downturn has a long history; however, one must be careful which costs are reduced. Those who do not appreciate the value of a maintenance program often seek to reduce expenditures by indiscriminately slashing the company’s maintenance budget.
A directive to reduce maintenance costs need not spell disaster. In fact, it can provide an opportunity to improve program performance by reviewing how maintenance dollars are spent and the value provided by various activities. When times are lean, the following areas can provide opportunities for improvement.
- Review maintenance procedures for effectiveness and eliminate outdated practices
- Utilize predictive and condition based monitoring tools to work smarter, not harder
- Focus on training to ensure that employees have knowledge and skills to work efficiently
- Make certain that maintenance expenditures are charged to appropriate business units
Lastly, be certain to communicate the function and importance of maintenance and to all parties involved. Bad times are always followed by better times and it is important to ensure that companies emerge with a strong infrastructure, a solid workforce, and a reputation for delivering quality products or services intact.
Designing and maintaining an effective infrared inspection program is one of several best practices covered in the Infraspection Institute Level III Certified Infrared Thermographer® training course. For more information, including course locations and dates, please call 609-239-4788 or visit www.infraspection.com.
Additional articles on this subject are available from Maintenance Technology Magazine.
- How to Cut Your Maintenance Budget (Without Cutting Your Throat)
- A Survival Guide for Impending Cost Reduction
Temperature Limits for Drive Belts
Temperature is frequently used to gauge the condition of motors and power transmission equipment. In this Tip, we discuss the effect of heat on flexible drive belts and temperature limits for them.
Drive belts are an integral component on many types of machines. Despite the critical role they play in machine operation, V type drive belts tend to out-of-sight and out-of-mind until they fail. In most installations, belt temperature largely influences the life installed V belts.
As a rule of thumb, properly applied and maintained belts should not exceed 140º F (60º C), assuming an ambient temperature of less than 110º F (43º C). It should be noted that belt life can be greatly reduced by higher operating temperature. In fact, for every 18 F (10 C) increase in belt temperature, belt life is cut in half.
There are many factors that contribute to high belt operating temperature including, but not limited to: ambient air temperature, machine design, installation, alignment, and belt tension. Overheating belts can be readily detected with an infrared imager. Once detected, overheating belts should be investigated for cause and proper corrective measures undertaken as soon as possible. Doing so can help prevent unscheduled downtime and may prolong belt life.
Temperature limits for mechanical equipment is one of the many topics covered in the Infraspection Institute Level II Certified Infrared Thermographer® training course. Classes are held regularly throughout the year and are also available through our web-based Distance Learning Program. For more information, please call 609-239-4788 or visit www.infraspection.com.
Understanding Emissivity
Emissivity refers to an object’s ability to radiate infrared energy. Because infrared instruments measure radiant energy, it is imperative for a thermographer to understand emissivity and how it can vary.
All objects above 0 Kelvin radiate infrared energy. The amount of energy radiated is dependent upon an object’s temperature and emittance. Increases in temperature and/or emittance will increase the amount of infrared energy radiated.
Although many equate emissivity to values published in emittance tables, emissivity is a dynamic characteristic and is influenced by several factors. Among these are:
Wavelength – For most objects, emissivity varies with wavelength.
Object Temperature – Changes in object temperature cause changes in Emissivity
For clean metals, E increases with temperature rise
For dielectrics, E decreases with temperature rise
Viewing Angle – Imaging at angles other than perpendicular causes changes in Emissivity
Target Geometry – Target shape affects Emissivity. Compared to a flat surface,
Concave shape increases E
Convex shape decreases E
Surface Condition – Surface roughness, texture, or condition (dirt, oxidation or paint) can significantly affect Emissivity
Although thermographers frequently obtain emittance values from published tables, this practice can introduce significant temperature measurement errors since emittance tables cannot account for several of the above factors. Because of this, calculating emittance with one’s thermal imager will help to ensure measurement accuracy.
A simple procedure for calculating emittance may be found in the Standard for Measuring and Compensating for Emittance Using Infrared Imaging Radiometers available from Infraspection Institute. For more information or to place an order, call 609-239-4788 or visit us online at www.infraspection.com.
How to Deal With Emittance
The perpetual question among those using radiometric equipment is, “What emittance value should I use?” In this Tip, we address several options for providing emittance values.
Emittance is a numerical value between 0 and 1.0 indicating an object’s relative ability to radiate infrared energy. Most radiometers allow the user to input emittance values into the radiometer’s computer. Utilizing correct emittance values is imperative for accurate non-contact temperature measurements.
When determining emittance values for a target, there are five accepted ways to obtain an emittance value. These methods are listed below in order of increasing complexity and accuracy.
- Use General Default Values. Organics are generally > 0.80. Metals can vary widely from < 0.1 to > 0.90
- Use Emittance Tables. Be certain to use tables that match your radiometers spectral response and your target’s temperature.
- Estimate Emittance. Choose representative sample and test for emittance value. Use these values whenever similar object is encountered in the future.
- Modify Surface to a Known Emittance Value. Use tape, paint, or powder with known E. Prior to modifying any surface, be certain it is safe to do so.
- Measure Emittance Value. Use subject radiometer to measure target E value. This practice is preferred as it provides the most accurate emittance values.
The procedure for measuring emittance values is described in detail in the Standard for Measuring and Compensating for Emittance Using Infrared Imaging Radiometers available from Infraspection Institute. For more information or to order a copy, call 609-239-4788 or visit us online at www.infraspection.com.
How to Calculate Emittance
Utilizing correct emittance values is imperative for accurate non-contact temperature measurements. Knowing how to accurately calculate emittance values can help to ensure the accuracy of infrared temperature measurements.
Although thermographers frequently obtain emittance values from published tables, this practice can introduce significant errors. Following the procedure listed below, it is possible to accurately calculate the E value of an object.
Equipment Required:
- Calibrated imaging radiometer with a computer that allows thermographer to input Reflected Temperature and Emittance values
- Natural or induced means of heating/cooling target to a stable temperature at least 10ºC above/below ambient temperature
- Calibrated contact thermometer
Method:
- Place imaging radiometer at desired distance from heated/cooled target. Be certain that target is larger than imager’s spot measurement area. Aim and focus imager on target
- Measure and compensate for Reflected Temperature
- Place imager crosshairs on target
- Use contact thermometer to measure target temperature at location of imager crosshairs. Remove contact thermometer
- Without moving imager, adjust E control until observed temperature matches value obtained in Step 4 above. The displayed E value is the Emittance value for this target with this imaging radiometer. For greatest accuracy, repeat above three times and average the results.
Note: This procedure requires contact with the object being measured. Be certain to observe all necessary safety precautions prior to making contact with target.
The above procedure is described in detail in the Standard for Measuring and Compensating for Emittance Using Infrared Imaging Radiometers available from Infraspection Institute. For more information or to order a copy, call 609-239-4788 or visit us online at www.infraspection.com.
Ensuring Payment for Your Services
Tip provided by:
Robert J. Incollingo
416 Black Horse Pike
Glendora, NJ 08029
856-234-3800
www.rjilaw.com
1. Acquire and use a graduated set of collection letters for your delinquent accounts. Sample collection letters are readily and freely available on the internet, starting with a gentle reminder and increasing in impatience until the matter must be referred out to an attorney. Copy your lawyer with your final collection letter. Many times, a cc: line on the bottom of the letter is all it takes to convince your debtor that he’s had his last warning. Don’t forget to actually send the copy.
2. Early on, a telephone call should be made to catch any mistakes in the system, such as wrong addresses or accounting, and to find out if there is an acceptable reason for the delay in payment. Most people pay their debts unless something prevents them. You may be willing to accommodate their problem for a defined period.
3. Don’t forget to provide in your contract or purchase order for the recovery of attorneys’ fees in the event you have to sue. Most times, the thought of picking up the other side’s legal bills is enough to prevent delinquency all by itself. Remember, however, that unless the customer signs the contract, the attorneys’ fees clause will probably be worthless.
4. Keep copies of the checks you receive. In the event you need to sue to collect on a debt, the information found on a check will help you quickly locate and levy on the account. A bank levy is the easiest way to get real dollars to satisfy your judgment.
5. Discount your expectations. Collection agencies and attorneys don’t work for free, so compromise may be your best course. Figure on backing down to a sum which approximates your likeliest recovery less the expected costs to get there. When you’ve settled on a number you won’t walk away from, remember that terms of payment on time are still negotiable. That’s why they call them lump sums – installments are just easier to swallow.
Bob Incollingo is an attorney in private practice in New Jersey and a regular speaker at Infraspection Institute’s annual IR/INFO Conference.
Heat Stress & the Human Body
For many, the peak of Summer brings high temperatures to the workplace. For others, high temperatures in the workplace are an everyday occurrence. Understanding heat stress and its attendant safety challenges is crucial for those working in hot environments.
What is heat stress?
Heat stress is a physical hazard. It is caused by environmental conditions and results in the breakdown of the human thermal regulating system.
What are the symptoms of heat stress?
There are various degrees of heat stress. Each has its own unique symptoms. The most common form of heat stress is heat exhaustion. Symptoms of heat exhaustion include dizziness, confusion, headaches, upset stomach, weakness, decreased urine output, dark-colored urine, fainting, and pale clammy skin.
What do I do If I think I am experiencing some form of heat stress?
Act immediately –
- Advise a co-worker that you do not feel well
- Move to an area away from the hot environment
- Seek shade and cooler temperatures
- Drink water (1 – 8 oz. cup every 15 minutes) unless sick to the stomach
- Have someone stay with you until you feel better
What should I think about before working in a hot environment?
Before working in a hot environment, consider the type of work to be performed, duration of time to be spent in hot areas, level of physical activity, and other nearby hazards. Always use appropriate PPE and work together as a team.
Heat Stress & Hydration
An ounce of prevention is worth a pound of cure. In last week’s Tip, we covered the topic of heat stress, its symptoms, and treatment. This Tip focuses on the importance of hydration as a preventive measure.
What is heat stress?
Heat stress is a physical hazard. It is caused by environmental conditions and results in the breakdown of the human thermal regulating system. If you work or play in hot environments, your body needs a lot more water than you might think.
What is hydration?
Hydration is the process of adding water. Our bodies need water to do many things. In hot environments we need large quantities of water to help keep our bodies cooled to a temperature that allows them to function properly. Heat stress becomes a health and safety concern when the volume of water we need to function drops below the level necessary to maintain homeostasis. We call this low water condition dehydration or under-hydration. The average person is 7% under-hydrated.
How can I avoid being under-hydrated?
Developing the habit of drinking water at routine intervals. One 8 oz. cup every hour on hot days will assure proper hydration.
How will I know if I am properly hydrated?
Check the color of your urine. You are properly hydrated if your urine is clear, copious in volume, and light yellow in color.
What are the benefits of proper hydration?
Staying properly hydrated will help to avoid heat stress and may increase your energy level. For every 1% under-hydration, you lose 5% of your energy potential.
Heat Stress & Hydration
Tip suggested by: Randall D. Cain, American Water Company
An age-old challenge for thermographers is the ability to annotate or mark objects to make them easier to identify in recorded imagery. One possible solution is to mark targets with an ink pen with low emittance ink.
Many thermographers have long sought ways to mark targets in such a fashion that numbers or text can clearly be seen with a thermal imager. Over time, some thermographers have used paints with emittances that contrast sharply with the objects being marked. In these cases, text and/or numbers painted on the target are clearly visible within resulting thermal imagery and recorded thermograms.
Recently some thermographers have reported good results in utilizing a Sharpie permanent felt-tip marker in silver color. The low emittance of the metallic ink contrasts markedly with high emittance targets allowing annotations to clearly appear within thermal images. In many cases, the silver ink can also be clearly seen in daylight images as well. An example can be seen below.
One should be aware that Sharpie markers are permanent unless the ink is applied to a removable material such as tape or labels affixed to the target. Prior to marking any target, be certain it is safe to do so and that marking will not permanently damage the target.
For more information on thermographer training and certification or to obtain a copy of the Guideline for Infrared Inspections of Electrical and Mechanical Systems, call Infraspection Institute at 609-239-4788 or visit us online at wwww.infraspection.com.
