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Application Note

Why thermography

is good for yourbusiness

Thermography used to be expensive, difficult, and primarily

used by large industrial facilities and the military.

These days, it’s become much more affordable, easier to

use, and more broadly applied. That means your customers

have heard of it.

It’s a very impressive technol-ogy. Since the tool, a thermalimager, works by producingthermal (heat) pictures of theequipment, your customer canimmediately see the benefits.In one pass through a facility,you can usually find at least onecomponent about to fail. Thismakes for a powerful demon-stration and an easy business

builder. Your advantage as a contractor

is having broad experience withmany types of equipment andfailure scenarios—just like anyother troubleshooting situation,the person behind the imagerneeds to draw on experience tohelp analyze the readings. If thispart of the panel is hot, shouldI investigate the connections orthe load?

Last of all, if you’re alreadysigned-on for regular main-tenance and troubleshooting,adding thermography makessense. You already know thefacility and which units arecritical to performance. You cansimply add thermal inspec-tion to your regular visits andhave the tool available duringtroubleshooting calls. Plus, as

an electrician, you’re uniquelyqualified to work in live voltagesituations—specialty thermogra-phers are not and require clientassistance.

Typical applications

Electrical contractors typi-cally use thermal imagers forpredictive maintenance and

troubleshooting, and sometimesduring installation.For predictive maintenance,

the contractor takes thermalimages of key units (panels,drives, motors, etc.) at least oncea year if not more often, andcompares those images witheach visit. Hot spots that weren’tthere last time indicate problemsin the making to investigatebefore they cause failure. Soft-ware on the thermal imagerhelps you align your images time

after time, so that you’re makingconsistent comparisons. When selling this idea to a

client, here are some additionalthings to consider:• Most equipment’s failure

mechanisms involve a signifi-cant rise in operating tempera-ture long before catastrophicfailure occurs.

• Thermal images are best takenwhile equipment is operationalNo shutdowns needed.

• Thermal images are taken at asafe distance. Minimal safetyrisk (except for live voltage—that still requires full electricalsafety precautions).

• Thermal images can accesscomponents and units nototherwise measurable, suchas ceiling runs.

• Thermal measurements helpdetect imminent failures innearly all types of equipment,from electrical to mechanical,process, electronic, and so on.

• Because thermal inspectionsare fast, they can cover moreground and find problemsin areas that would typicallybe ignored.

Applications for Thermal Imagers

For more information on Thermal Imagers

go to www.fluke.eu/ti



2 Fluke Corporation Why thermography is good for your business

For troubleshooting, taking athermal image of a malfunction-ing unit can often identifythe source of the problem—electrical hotspots can tellyou which phase or connec-tors to check, motor hotspotscan narrow it down to bear-ings, and so forth. Then, afterrepairs, follow up with anotherthermal image and verify thatthe component is no longer over-heating—or that something else

isn’t now overheating, instead.Here’s a summary of principle

applications.• Electrical power distribution

systems: Three-phase systems,distribution panels, fuses,wiring and connections, substa-tions, electrical vaults, etc.

• Electro-mechanical equipment:Motors, pumps, fans, compres-sors, bearings, windings, gearboxes, and conveyors

• Process instrumentation:

Process control equipment,pipes, valves, steam trapsand tanks/vessels

• Facility maintenance: HVACsystems, buildings, roofs,insulation

How it works

Today’s entry-level thermalimagers are compact and easy touse with minimal training. Flukethermal imagers now include

IR-Fusion®*, a technology thatfuses a visual, or visible light,image with an infrared imagefor better identification, analysisand image management.

To capture a specific thermalimage, in most cases, simplysqueeze the trigger. Whenyou’re done, connect the thermalimager to your computer, uploadthe images to the included soft-ware, analyze them more closely,and create report(s) documenting

your findings. The dual imagesare accurately aligned height-ening details, making it mucheasier to spot where furtherinvestigation is needed.

The next few sections in thisarticle mention other things thatneed to be considered whentaking a thermal images.

* The Fluke Ti20 comes with InSideIR™analysis and reporting software with freeupdates for the life of the product.

Emissivity

When you measure surfacetemperature, you’re actuallyreading the infrared energyemitted by that object. Emis-sivity tracks how thoroughlythe surface emits energy. Thestandard emissivity of mostorganic materials and paintedor oxidized surfaces is 0.95.However, certain materials, suchas concrete and shiny metals,are poorer emitters—their

emitted energy doesn’t accu-rately reflect their real surfacetemperature. To get an accuratethermal measurement of thingslike bus bars and any largemetal electrical connectors, youneed to adjust the emissivityvalue on the imager.

Emissivity values for manymaterials are published incharts. If you can look up theemissivity value for an object,you can adjust the imagerappropriately. Or, you can learnto adjust the emissivity whileyou’re taking the image. Forexample, for shiny fuse capsthe emissivity might be only0.6. If you know that, you canchange the imager’s emissivityfrom 0.95 to 0.6 and see the realtemperature.

Level and gain When the image field includes awide range of temperatures, leveand gain help you focus on themost important temperatures.

Most users work in automaticmode, where the thermal imager

automatically assigns a tempera-ture range based on the thermalscene it sees. If the imagersenses a range from 80 degreesto 120 degrees, the camera willautomatically display a tempera-ture range between 75 degreesand 125 degrees.

If, however, you look at ascene in automatic mode withsomething cool in the foregroundand something very hot in thebackground, the color palettewill be spread across a widerange of temperatures and theresolution will be poor. In suchcases, you can manually adjustthe level and gain to view justthe temperatures of the hot orcool object.

Choosing an imager

Obviously, there are many kindsof thermal imagers to choosefrom. Here are some factors toconsider when deciding whatkind of imager best fits yourbusiness model. The Fluke



3 Fluke Corporation Why thermography is good for your business

website (www.fluke.com/ther-mal_imaging) has an on-lineselection tool that will assist youto find the right thermal imagerfor your application. There is

also a video you can order foradditional assistance.

Radiometric When you look at an image on adigital screen, you’re really look-ing at thousands of individuallittle points of color. In the sameway, radiometric thermal imag-ers capture temperature data foreach of the thousands of pointsin a thermal image. A non-radiometric imager only providestemperature data for a few focal

points. Why does this matter? Well, back at the computer, youcan zoom in and out of a radio-metric image, exploring any partof the image in more detail, and

you can also change the emis-sivity or temperature range, tobetter analyze the results. Thatmeans you don’t have to get theperfect image on-site, which is a

big time-saver.Thermal (temperature)sensitivityUnless your customers producevery complicated, smallcomponents or have very heatsensitive applications, youvery likely do not need the topmodels on the market. Mostcontractors do fine with a ther-mal sensitivity range of -10 °Cto 350 °C (14 °F to 662 °F).

Pixel resolution

A high resolution screen andimage looks nicer and is moreimpressive. However, thosepixels cost money—the higherresolution your image output,the more the thermal imager isgoing to cost. If you’re primarilylooking for hotspots in electri-cal and mechanical applications,chances are, you don’t reallyneed the highest resolutionavailable. You need enoughresolution to compare one unitto another or to previous images,and that’s what the entry-levelunits are designed to do.

Other basic featuresAny imager you buy should offerthe following:• Adjustable emissivity

• Selectable temperature (C or F),

• Level and gain control

• Accuracy within± 2 % or ± 2 °C

• Repeatability within± 1 % or ± 1 °C

• Rechargeable battery pack(minimum 3 hour life)

• Laser sighting and aprotected lens

• One year warranty

Many imagers also include theability to set alarms for prob-lematic temperature levels andto upload previous images foron-site comparison.

TrainingMost entry level imagers comewith a user manual and someform of interactive training, andthat’s usually all you’ll need to

get started on an entry-levelimager. Medium to high endimagers are more complicatedand should therefore includeat least two days of in-persontraining from a reputable train-ing firm. Beyond that, you cantake full training courses tobecome certified in thermog-raphy—Level I is basic, and atLevel II and III you can start call-ing yourself a thermographer.

Software

You’re going to need softwarewith any thermal imager youbuy, so here are the key points toconsider. Is the software includedin the price? Are future updatesfree of charge as well? Do youhave to buy licenses for multipleteam members to load it? Does iteasily create good-looking reportsfor customers? These questionsare important because good soft-ware is essential for maintainingthe client relationship.

SummaryReally, there’s nothing holdingyou back. Contractors canreadily purchase affordablethermal imagers, quickly trainon the basics, and immediatelystart using the tool to improvetheir client services. The moreyou use it, the more skilledyou become.

Fluke Corporation PO Box 9090, Everett, WA USA 98206

Fluke Europe B.V. PO Box 1186, 5602 BDEindhoven, The Netherlands

For more information call: In the U.S.A. (800) 443-5853 orFax (425) 446-5116In Europe/M-East/Africa +31 (0) 40 2675 200 Fax +31 (0) 40 2675 222In Canada (800)-36-FLUKE orFax (905) 890-6866From other countries +1 (425) 446-5500 orFax +1 (425) 446-5116 Web access: http://www.fluke.com

©2006-2007 Fluke Corporation.Specifications subject to change without notice.12/2007 2788354 A-EN-N Rev B PUbID:11226-en

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