See red!

by Eric Bevevino

Don’t try to see in the dark — using Infrared Thermography in conjunction with oil and vibration analysis renders a better picture of equipment condition

Infrared Thermography (IRT) is a third of the triad of procedures used in predictive maintenance—the other two being vibration analysis and oil analysis. With its origins in aerospace, the use of non-intrusive thermal imagers is now widespread in many industries.

Thermal imaging devices collect and convert the thermal infrared radiation that objects emit or reflect into images that you can see on a computer screen or viewer. If viewed in black and white, hotter spots appear white — the cooler an area is, the darker it appears. If the image is in color, different bands of color represent different temperatures.

Thermal imagers with temperature measurement capability are used in many non-destructive testing situations. Thermographic cameras can record heat signatures that identify hot spots on pieces of equipment. The temperature usually indicates either a lack of lubrication or higher friction. If a seal is leaking, or a bearing needs grease, there would be some type of heat generation and the temperature would show up dramatically hotter.

A missed opportunity occurs if thermography is not used in conjunction with vibration and oil analysis to assess the internal condition of a piece of equipment. Used individually, these techniques can be very effective, but together, as a triad, they represent a powerful analytical tool that helps your maintenance department move from PM (preventive maintenance) to RCM (Reliability Centered Maintenance).

Comparative IRT
The most common of several IRT techniques is comparative thermography that is used to give an estimate in place of absolute thermal measurements in less than ideal situations found quite often in the field. Comparative thermography comes in two flavors — quantitative and qualitative.

Quantitative thermography compares a piece of equipment’s temperature to an earlier determined baseline of that or similar equipment, which can be used to determine how severely a piece of equipment may have been damaged.

Qualitative thermography compares the infrared pattern of one component to an identical or similar component under similar conditions, which can identify a problem, but cannot provide a level of severity. In instances where the information being gathered is not necessarily needed to diagnose a problem or for recommending a specific correction, then qualitative thermography may be sufficient.

It’s all about the baseline
The importance of establishing a baseline measurement cannot be understated, particularly when critical plant equipment is involved. When future IRT readings are examined, they will be compared to earlier readings and it will be possible to determine any developing problems early on that may prevent the need for any major maintenance that requires shutting down the equipment — not to mention any catastrophic failures.

IRT and lube troubleshooting
Because IRT has the ability to pinpoint specific locations, it is a powerful tool that is helpful in solving temperature-related lubrication issues.

A lubricant is designed to reduce friction and carry heat away from the lubricated point. Thermography can show if someone is using a lower quality or inferior product. When a product is placed in a piece of equipment, a visible decrease in temperature occurs right away. This decrease in temperature is an indicator of success and/or safe operation of the plant.

Eric Bevevino is the reliability solutions manager for Chevron Products Company. If you have lubrication questions, contact Coach Bevevino by phone at or by E-mail .

This article appeared in the  February/March 2006 issue of MRO Today magazine. Copyright, 2005.

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