To reduce repair costs and minimize losses in productivity, more manufacturing operations are turning from preventive maintenance (maintenance based on a fixed schedule) to proactive maintenance and predictive maintenance (maintenance based on objectively determined need) in order to protect their high-value assets. Condition monitoring of crankcase, hydraulic, motor bearings and gear lubricants plays an important role in the maintenance of equipment including heavy machinery and plant equipment. Currently, lubrication condition monitoring is typically accomplished by taking samples in a prescribed manner and sending the samples to a laboratory for analysis by an array of analytical technologies.

The recent availability of field-portable, rugged and easy-to-use analytical instruments for use directly at the site of manufacturing operations changes how the condition of in-service lubricants can be monitored. These field-ready analytical tools provide users with near real-time information and allow them to monitor the lube point level of machinery quicker and easier than traditional methods where samples are sent to laboratories for analysis. This results in rapid, actionable decisions, thus enhancing proactive maintenance programs. One of the most widely used and powerful analytical tools for lubrication condition monitoring is Fourier Transform Infrared spectroscopy (FTIR).

Infrared Spectroscopy and Lubrication Condition Monitoring

Infrared spectroscopy is an analysis technology that has been used for more than 50 years in the study of chemistry and chemicals in virtually every field and industry. When infrared radiation passes through a chemical substance, the infrared light interacts with the molecules of the sample and is absorbed in a highly specific manner. This produces a spectrum of the sample, often called a chemical fingerprint, which is directly related to the specific components in the sample as well as their concentration.

When applied to lubrication monitoring, infrared spectroscopy measures many of the key parameters critical to understanding the condition of in-service lubricants. These include the degree of oxidation of the lubricant, the presence of water and/or glycol, the levels of nitration, sulfation, soot, and the amount of anti-wear and anti-oxidants agents present in the lubricant.

Advantages of Real-Time, At-Site Infrared Analysis

Currently, lubrication samples are sent for analysis to an off-site laboratory on a prescribed time schedule. However, the ability of infrared spectroscopy to measure these parameters in real-time and at site has important implications for proactive maintenance. Changes in the performance of lubricants are not linear as a function of time; therefore, the time period between analytical tests should be chosen to reflect the current condition of the lubricant. At-site FTIR analyzers enable lubricants to be analyzed more frequently, which is especially important when previous tests indicate that the lubricant has increasing levels of deleterious byproducts or loss of additives.

At-site FTIR analysis can also help to reduce machinery wear caused by rapid oil breakdown and detect problems that could cause catastrophic failures. For example, an anti-freeze leak will cause excessive levels of water and glycol to be present in engine oil. These can be readily detected by FTIR. By more frequent monitoring of engine oil by FTIR, there is an increased chance that these contaminants will be detected before they have a chance to cause catastrophic damage to the machinery.

At-site FTIR analysis can rapidly ascertain the condition of lubricants in manufacturing and refining equipment located in remote and offshore locations, far away from traditional lubrication analysis laboratories. Real-time analysis minimizes the need to send lubrication samples to off-site labs for condition-based monitoring, which in some cases may be difficult, very costly or result in unacceptable delays in obtaining the results. Equipment in these remote locations may face particularly challenging ambient conditions. The ability to monitor the in-service lubricants more frequently via at-site FTIR can help reduce the likelihood of equipment failure.

At-site FTIR analysis enables personnel to obtain clues and insights into the working condition of a piece of equipment. For example, high levels of soot may indicate that an engine has incorrect fuel-air ratio. Unusual levels of oxidation may indicate that an engine is overheating. The presence of excessive nitration byproducts can be indicative of piston ring blow-by, while the presence of glycol and water may indicate a head gasket problem. Most importantly, FTIR spectroscopy can provide quantitative information about the level of oxidation of the lubricant, the amount of water present as well as track the depletion of anti-wear and anti-oxidation additives.

In addition, on-site FTIR analysis can assist users in determining whether incoming lubricants are properly formulated, not contaminated in shipping or mislabeled, and that the correct lubrication fluid is charged into the machinery. It is critically important to use lubricants that meet the equipment manufacturer’s specifications. At-site FTIR spectroscopy can ensure total quality control of lubricants and other incoming materials.


At-site infrared analysis supports proactive maintenance programs in manufacturing operations, providing immediate insight to the overall condition of lubricating fluids and the equipment that these lubricants protect. At-site analysis also ensures personnel at remote and offshore sites can make rapid, actionable decisions based on objective analytical data in support of proactive maintenance programs to ensure equipment reliability.

About the author:

A.J. Rein, Ph.D., is the vice president of business development at A2 Technologies in Danbury, Conn. A2 Technologies manufactures and develops portable FT-IR spectrometers designed for the analytical needs of the petrochemical, environmental, metals and mining, and general environments where there is a need for analysis. The portable FT-IR analyzers extend the proven capabilities of Fourier Transform infrared technology by rendering sample preparation obsolete and ensuring real-time results. To learn more, visit or e-mail