When referring to the measurement uncertainty of infrared radiometers, many manufacturers state instrument accuracy as “± 2%”. The significance of this specification is often poorly understood causing many to overestimate the accuracy of non-contact temperature measurements.
An accuracy statement of “± 2%” is actually an abbreviated statement. The full statement is “± 2% of target temperature or 2º C, whichever is greater”. The full statement is required since measurement accuracy generally decreases with lower temperature targets. Furthermore, an accuracy of “± 2%” would place accuracy at 0% when measuring targets operating at 0º!
With respect to accuracy statements, it is also important to note that manufacturers test infrared instruments under laboratory conditions using high-emittance, blackbody simulators in a controlled environment. As a result, manufacturers derive accuracy specs under ‘best case’ conditions which may not be possible to duplicate in a given work environment.
To help ensure measurement accuracy, thermographers should:
Always measure perpendicular to the target
Correctly set radiometer inputs for emittance, reflected temperature, distance, and humidity
Ensure target size is adequate for subject radiometer’s spot measurement size
Lastly, real-world challenges can create situations where it is not possible to measure temperatures to the accuracy level promised by an instrument’s spec sheet. These challenges include, but are not limited to, hot or cold ambient temperatures, and the use of different lenses or filters. Whenever accurate infrared temperature measurement is not possible, one should consider using contact thermometry instead.
Join Infraspection Institute’s Course Reseller Program
Proper training is essential to the success and longevity of any infrared inspection program. If you are a professional thermographer, distribute infrared or related test equipment, or are involved in professional training, we can help you to increase both sales and profits. An affiliation with Infraspection Institute can also help to increase your company’s visibility without compromising your credibility.
With the proliferation of cheaper infrared cameras, competition has become more fierce and profits more scarce. Offering training can not only expand your services and increase profits, it can help provide a long-term relationship that keeps your clients ‘on the farm’ and close to you.
Because Infraspection Institute do not sell infrared equipment, our courses are presented without marketing hype. Since we are not affiliated with infrared equipment manufacturers, you can rest assured that your clients are not being hijacked by a competitor. Best of all, you have several options to choose from including open enrollment classes, on-site courses, and our convenient web-based Distance Learning courses.
One of the most challenging aspects of an infrared inspection occurs when a qualified assistant must outline exceptions on the surface of the ground or an insulated roof.
Thermographers who perform infrared inspections of flat roofs or underground piping systems often outline the perimeter of exceptions with spray paint. Directing a qualified assistant to accurately outline exceptions can be both time-consuming and frustrating. The following suggestions can help to speed inspections while preserving coworker relations.
When using spray paint to mark at ground level, use a spray paint and dispenser designed for the task
Make sure surfaces to be marked are clean and dry and will not be damaged by spray paint
Never spray paint where wind may carry paint to unintended surfaces
When outlining the perimeter of an exception, use a series of dots to outline the most prominent features of the exception. These dots can then be connected with a solid line once their location is deemed satisfactory. Depending upon weather and target conditions, spray painted lines will often show clearly within the thermal image.
Infraspection Institute are pleased to announce that our annual Advanced Training Conference, Technical Symposium and Technology Expo, IR/INFO 2018, will be held January 21 – 24, 2018 in New Orleans, Louisiana. Now in its 29th year, IR/INFO features four days of networking, learning, and fun in a relaxed, yet professional, family atmosphere.
We are presently seeking papers and presenters for IR/INFO 2018. Invited topics include, but are not limited to: safety, emerging applications, building sciences, related NDT, case histories, as well as tips and tricks.
Presentations are typically 20-25 minutes with 5 minutes for Q & A time with the audience. All papers and presentations will be published in the IR/INFO Proceedings. The deadline for abstract submissions is July 31.