Machinery Lubrication magazine published by Noria Corporation
Issue link: https://www.e-digitaleditions.com/i/875060
56 | September - October 2017 | www.machinerylubrication.com 56 | September - October 2017 | www.machinerylubrication.com BACK PAGE BASICS precursory test of new oil, flash point can also be utilized in used oil analysis to detect fuel dilution, base oil cracking and contamination. Volatility The Noack volatility test was developed by Dr. Kurt Noack in the 1930s and first used in Europe. It was introduced as a way to reveal the evaporation loss of lubricating oils. In 1984, Al Amatuzio began using the test in the United States to determine the performance of motor oils. Volatility testing became stan - dard for North America in 1992 with the creation of the American Petroleum Institute's SH/International Lubricant Standardization and Approval Committee's GF-1 oils, which set the bar for the current standards in envi - ronmental emissions and fuel economy. Volatization is a term used to describe the "boiling off " of lighter molecules in fluids. It is closely related to oil consumption in auto - mobile engines. The test simulates the oil's reaction to internal temperatures associated with piston rings and cylinder walls. Known as ASTM D5800, the Noack volatility test reveals the evaporation loss of lighter oil molecules and additives at high temperatures. Depending on the method, a measured sample quantity is placed in a crucible or reaction flask and heated to 250 degrees C (482 degrees F), with constant air flow drawn through for 60 minutes. Assessing the before and after weight will determine the evaporation loss. There are three dif ferent procedures for ASTM D5800: Procedure A, which uses the Noack evaporative testing equipment; Procedure B, which employs the automated non-Wood's metal Noack evaporative appa - ratus; and Procedure C, which utilizes the Selby-Noack volatility test equipment. Procedure A was first introduced in the 1930s using a toxic mixture of compounds known as Wood's metal for sample heating. Wood's metal, also called Lipowitz's alloy, contains bismuth, lead, tin and cadmium. The toxicity comes from the lead and cadmium. The Selby-Noack test was developed in the mid-1990s by Theodore Selby and his colleagues using a noble metal heater. It elim- inates the need for Wood's metal and utilizes a collection of evaporated material for later analysis. This is particularly useful in identifying elements such as phosphorus, which is known to lead to premature failure of catalyst systems. Volatility testing plays an important role in engine lubrication where high temperatures occur quite frequently. Evaporation losses can be seen in the amount of oil consumption or the need for top-ups. This can also result in a change in the oil's properties, as additives may evaporate during the volatilization process. As lighter molecules "burn off " or evapo - rate, heavier molecules remain, causing a shift in the fluid's viscosity. Leaving behind heavier or "thicker" oil can contribute to reduced fuel economy due to added viscous drag as well as poor oil circulation throughout the engine, greater oil consumption, higher wear rates and increased emissions. Tests That Serve a Purpose Flash point and volatility tests ser ve a purpose, just for different conditions. They are also related. After all, for an oil to reach its flash point, it must first volatize. While the flash point tells you very little about an oil's volatility, an oil's volatility can tell you a lot about its flash point. Volatility testing has proven that with better base oils, improved emissions and fuel economy will follow. Keep in mind that synthetic lubricants generally have higher flash points and do not begin to evaporate until a much higher temperature is reached. On the other hand, mineral oils may start to vaporize much earlier than their flash points. If you are dealing with hazardous conditions, a flash point test is a staple that simply must be conducted. About the Author Garrett Bapp is a technical consultant with Noria Corporation, focusing on machinery lubri- cation and maintenance in support of Noria's Lubrication Program Development (LPD). He is a certified lubrication specialist through the Society of Tribologists and Lubrication Engineers (STLE) and holds a Machine Lubrication Tech- nician (MLT) Level II certification through the International Council for Machinery Lubrication (ICML). Contact Garrett at gbapp@noria.com. While the flash point tells you very little about an oil's volatility, an oil's volatility can tell you a lot about its flash point. 84% of lubrication professionals do not conduct flash point or volatility testing to assess new or used oil, based on a recent poll at MachineryLubrication.com