Machinery Lubrication magazine published by Noria Corporation
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certain defined requirements while EFLs are lubricants that might have some good environmental qualities but may or may not meet the stan- dard. Now that we know the difference between EALs and EFLs, let's examine some of the standards that must be met to qualify a lubricant as an EAL. To lower the threat in an aquatic environment, the chemical compound the lubricant started out as must be able to be broken down. Biode- gradability is the measure of this breakdown by microorganisms, and it plays a big part in EALs. ere are two types of biodegradation: Primary and Ultimate. Primary biodegradation is breaking off a piece of the chemical compound's make-up. When this happens, the chemical compound can no longer perform the function it was created to do. Ultimate biodegradation is the complete breakdown of a chem- ical compound into carbon dioxide, water, and mineral salts. Primary and Ultimate biodegradation together can be classified as the physical break- down of the lubricant. e method in which the breakdown occurs is classified as Inherent biodegradation and is determined by the compound's ability to break down in any number of biodegradability tests. In addition, a lubricant is said to be Readily biode- gradable where a part of the compound is biodegradable within a specific time using a specific test method. To be classified as an EAL, a lubricant must contain a certain percentage of readily biodegradable material. Due to the potential for harm to plants and wildlife in the water, an EAL must have low toxicity. ere are a few distinct types of aquatic toxicity tests that can be performed, some are done to determine the lubricant's toxicity to fish while others are used for plants. ese tests range in length from 48 -96 hours Rather than a passing or failing grade, the results of the test are typically displayed as either high or low toxicity. If we were going to look at toxicity levels of different lubricating base oils from high to low it would be as follows; mineral oils, Polyalkylene Glycols (PAG), synthetic esters, and vegetable oils. Bioaccumulation Bioaccumulation is the gradual accumulation of substances like a lubricant's constituent chemicals in an organism. In EALs it is desirable to have an extremely low bioaccumu- lation potential, as this will enable the lubricant's compounds to break down at a faster rate. Compounds like mineral oils that have a higher potential for bioaccumulation can cause more harm. Because they don't readily break down, the compounds in these lubricants stack up over time and create a cumulative threat to the environment. Also, worth noting is that water solubility and bioaccumu- lation are inversely related; if the water solubility of a lubricant is high the rate of bioaccumulation will be low. While the use of lubricants on vessels is unavoidable, the VGP helps reduce the negative effects that can be posed to the aquatic environment. By examining the chemical makeup of the allowable lubricants and identifying a set of standards that these lubricants must meet, their potential for harm has been lowered. e VGP was created to help govern vessels over water, but it also serves as a good reference point to learn more about EALs in general. ML About the Author Travis Richardson is an associate technical consultant for Noria Corpo- ration. He holds a Level II Machine Lubrication Technician (MLT) certifi- cation and a Level II Machine Lubricant Analyst (MLA) certification through the International Council for Machinery Lubrication (ICML). Contact Travis at trichardson@noria.com. BACK PAGE BASICS 36 | September - October 2020 | www . machinerylubrication.com