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8-1 

### Chapter 8 Environmentally Acceptable Lubricants

8-1. General Mi neral-oil-based

lubricating oils, greases, and hydraulic fluids are found in widespread use throughou t Corps of Engineers facilities. However, these products are usually toxic and not readily biodegradable

. Bec ause of these characteristics, if these materials escape to the environment, the impacts tend to b e cumulativeand consequently harmful to plant, fish, and wildlife. Due to these potential hazards, th e Envir onmentalProtection Agency (EPA) and other government regulators have imposed increasingl y stringent regulations on the use, containment, and disposal of these materials. For instance, the EP A requires that no visible oil sheen be evident downstream from facilities located in or close to waterways

. Anothe r regulation requires that point discharges into waterways should not exceed 10 parts per millio n (ppm) of mineral-based oils. Corps facilities such as hydropower plants, flood-control pumping plants, and lock-and-dam sites either are or have the potential to become polluters due to the use of mineral-oil-base d ma terials in these facilities. Grease, hydraulic fluids, and oil leaking from equipment may be carried int othe waterway. Because of the difficulty in completely eliminating spills and discharges of these mineral-oilbased mat erials, and to alleviate concerns about their impact on the environment, a new class o f environmentallyacceptable (EA) materials is becoming available and starting to find increasing use i n se nsitivelocations. EA lubricants, as contrasted to mineral-oil-based equivalents, are nontoxic an d decomposeinto water and carbon dioxide (CO ). EA fluids are frequently made from renewable resources, 2 which reduces dependency on mineral oils. 8-2. Definition of Environmentally Acceptable (EA) Lubricants

a. The l ubrication industry uses a variety of terms to address “environmental” lubricants. A few o f these term s, all preceded by the term “environmentally,” are: “acceptable,” “aware,” “benign,” “friendly, ” “harmless,” “ safe,” “sensitive,” and “suitable.” Two other commonly used terms are “green fluids” an d “food grade” lubricants. The term green fluid is mostly used for lubricants manufactured from vegetabl e oil. Food grade lubricants are rated by the U.S. Department of Agriculture (USDA) and generally are used in t he food industry where incidental food contact may occur. Food grade lubricants may or may no t qualif yas EA lubricants. Indeed, most food grade lubricants are made of U.S.P. White Mineral Oil whic h is not tox ic but does not meet the biodegradability criteria commonly required of EA lubricants

. “Env ironmentally acceptable” is the most commonly used term and is used by some ASTM committees t o address environmental lubricants. This manual uses the term EA. b. Atthe p resent time there are no standards for EA lubricants or hydraulic fluids. Manufacturer s and end users agree that for a lubricant to be classified as an EA type it should be biodegradable an d nontoxic. This means that if a small quantity of EA fluid is inadvertently spilled into the environment, such as a waterway, it should readily break down and not cause harm to fish, plants, or wildlife.

c. U.S

. standards-writing organizations are currently working to develop nationally recognized test s and p rocedures for demonstrating compliance with various environmental criteria such as biodegradability and toxici ty. The ASTM Committee on Petroleum Products and Lubricants has formed a subcommittee , referred to as the Subcommittee on Environmental Standards for Lubricants, which is tasked wit h developing test methods for determining aerobic aquatic biodegradation and aquatic toxicity of lubricants

. The methodol ogy developed by this subcommittee, ASTM D 5864, for determining the aerobic aquati c biodegradati on

of the lubricants, was accepted for standard use by the ASTM in December 1995. Th eEM 1110-2-1424

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8-2 subcommi tteeis also developing a test method for determining the aquatic toxicity of lubricants. Wit h approval of these standards, it is expected that these methods will be used by industry for evaluating an d specifying EA fluids. d. Howeve r, lacking formally approved U.S. test procedures, suppliers of EA lubricants frequentl y use establ ished European standards to demonstrate their products' compliance with U.S. criteria. In thi s manual, references are made to these European standards.

e. Thebase fluids discussed herein may be used for preparation of hydraulic fluids, lubrication fluids, or greases. Environmental tests referred to in this manual are applicable to all three types of products. 8-3. Biodegradation

a. Definition. (1) Biodegra dation is defined as the chemical breakdown or transformation of a substance caused b y organisms or their enzymes. (2) Primary biodegradation is defined as a modification of a substance by microorganisms that causes a change in some measurable property of the substance. (3) Ultimate b iodegradation is the degradation achieved when a substance is totally utilized b y microorganisms resulting in the production of carbon dioxide, methane, water, mineral salts, and ne w microbial cellular constituents. b. Tests. (1) ASTM test method D 5864 determines lubricant biodegradation. This test determines the rate and ext ent of aerobic aquatic biodegradation of lubricants when exposed to an inoculum under laboratory conditions

. The inoculum may be the activated sewage-sludge from a domestic sewage-treatment plant, o r it may be derived from soil or natural surface waters, or any combination of the three sources. The degre e of biodegradab ility is measured by calculating the rate of conversion of the lubricant to CO . A lubricant , 2 hydraulic fluid, or grease is classified as readily biodegradable when 60 percent or more of the test material carbon is converted to CO in 28 days, as determined using this test method. 2 (2) Th e most established test methods used by the lubricant industry for evaluating th e biodeg radability of their products are Method CEC-L-33-A-94 developed by the Coordinating European Council (CE C); Method OECD 301B, the Modified Sturm Test, developed by the Organization fo r Economi c Cooperation and Development (OECD); and Method EPA 560/6-82-003, number CG-2000, th e Sh akeFlask Test, adapted by the U.S. Environmental Protection Agency (EPA). These tests als o de terminethe rate and extent of aerobic aquatic biodegradation under laboratory conditions. The Modifie d Sturm Test and Shak e Flask Test also calculate the rate of conversion of the lubricant to CO . The CE C 2 test measures the disappearance of the lubricant by analyzing test material at various incubation time s through inf

rared spectroscopy. Laboratory tests have shown that the degradation rates may vary widel y among the various test methods indicated above.EM 1110-2-1424 28 Feb 99

8-3 8-4. Toxicity Toxicity of a substance is generally evaluated by conducting an acute toxicity test. While awaitin g acceptance of the ASTM test method for determining the aquatic toxicity of lubricants, the most commo n test methods used by the lubricant industry for evaluating the acute toxicity of their products are EP A 560/6- 82-002, Sections EG-9 and ES-6; and OECD 203. These tests determine the concentration of a substance that produces a toxic effect on a specified percentage of test organisms in 96 hours. The acut e toxicity test is normally conducted using rainbow trout. Toxicity is expressed as concentration in parts per milli on (ppm) of the test material that results in a 50 percent mortality rate after 96 hours (LC50). A substan ce is generally considered acceptable if aquatic toxicity (LC50) exceeds 1000 ppm. That is, a lubricant or a hydraulic fluid is generally considered acceptable if a concentration of greater than 1000 ppm of the material in an aqueous solution is needed to achieve a 50 percent mortality rate in the test organism. 8-5. EA Base Fluids and Additives Base fluids are mixed with additives to form the final products. These additives are necessary because they pro vide the resulting end product with physical and chemical characteristics such as oxidation stability , foaming , etc., required for successful application. However, most additives currently used for mineral

ba sed oil are toxic and nonbiodegradable. Therefore, they cannot be used with EA fluids. Furthermore , sincethe physical and chemical properties of EA fluids are quite different than those of mineral oil, E A flui ds will require entirely different additives. Several additive manufacturers are working with th e lubricant industry to produce environmentally suitable additives for improving the properties of EA bas e fluids. A dditives that are more than 80 percent biodegradable (CEC-L33-T82) are available. Sulfurize d fatty materials (animal fat or vegetable oils) are used to formulate extreme pressure/antiwear additives, and succinic a cid derivatives are used to produce ashless (no metal) additives for corrosion protection

. Suppliers are u sing a variety of base fluids to formulate EA hydraulic fluids, lubricating oils, and greases

. The base f

luid may be the same for all three products. For example a biodegradable and nontoxic este r may be used a s the base fluid for production of hydraulic fluid, lubricating oil, and grease. The mos t popular base fluids are vegetable oils, synthetic esters, and polyglycols.

a. Vegetable oils. (1) Ve getableoil production reaches the billions of gallons in the United States. However, due t o techni cal complexity and economic reasons, few are usable for formulating EA fluids. The usabl e vegetable oils offer excellent lubricating properties, and they are nontoxic and highly biodegradable , relatively inexpensive compared to synthetic fluids, and are made from natural renewable resources. (2) Rapeseed oil (RO), or canola oil, appears to be the base for the most popular of the biodegradabl e hydraulic fluids. The first RO-based hydraulic fluids were commercially available in 1985. Laboratory tests have identified limits to the use of this oil, but extensive practical experience has yielded relatively few pr oblems. The quality of RO has improved over time, and it has become increasingly popular, but it ha s problems at both high and low temperatures and tends to age rapidly. Its cost, about double that of mineral oil, still makes it more affordable than many alternative EA fluids. (3) The benefits of RO include its plentiful supply, excellent lubricity, and high viscosity index an d flashpoint. RO is highly biodegradable. One popular RO achieves its maximum biodegradation after only 9 days. RO po ssesses good extreme pressure and antiwear properties, and readily passes the Vicker s 35VQ25 vane pump wear tests. It offers good corrosion protection for hydraulic systems and does no tEM 1110-2-1424

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8-4 attack seal mate rials, varnish, or paint. Mixing with mineral oil is acceptable and has no influence on oi l performance. RO is not water soluble and is lighter than water. Escaped oil can be skimmed off th e surface of water. Molecular weight is high, indicating low volatility and low evaporation loss. (4) Concerns about RO include poor low-temperature fluidity and rapid oxidation at hig h temperat ures. Vegetable oil lubricants, including rapeseed, castor, and sunflower oils, tend to age quickly

. At high temperatures, they become dense and change composition; at low temperatures, they thicken an d gel. Some RO products are not recommended for use in ambient temperatures above 32 E C (90 E F) o r below-6 E C (21 E F), but other products gel only after extended periods below -18 E C (0 E F) and will perform well up to 82 E C (180 E F). The major problem with RO is its high content of linoleic and linolenic fatty acids. The se acids are characterized by two and three double bonds, respectively. A greater number o f these bonds in the product results in a material more sensitive to and prone to rapid oxidation. Thes e problems can be only partially controlled by antioxidants. Refining the base oil to reduce these acid s re sults in increased stability. Testing indicates that vegetable oils with higher oleic content have increase d oxida tivestability. Genetic engineering has produced rapeseed and sunflower oils with high oleic conten t for applications requiring better oxidation stability. (5) Conversion to vegetable-oil-based fluids should present few problems, as all are mixable wit h mineraloil. However, contamination with mineral oil should be kept to a minimum so that biodegradability wil lnot be affected. Special filter elements are not required. Filters should be checked after 50 hours o f operation, as v egetable oils tend to remove mineral-oil deposits from the system and carry these to th e filte rs. Filter-clogging indicators should be carefully monitored, as filter-element service life may b e reduced in comparison to mineral-oil operation. b. Synthetic esters (SE). (1) Synthetic esters have been in use longer than any other synthetic-based fluid. They were originally used as aircraft jet engine lubricants in the 1950s and still are used as the base fluid for almost all aircraf t jet engine lubricants. For EA base lubricants, the most commonly used synthetic esters are polyol esters ; the most commonly used polyol esters are trimethylolpropane and pentaerithritol. (2) Synthetic esters are made from modified animal fat and vegetable oil reacted with alcohol. Whil e there are similarities between RO and SEs, there are important differences. Esters are more thermall y stable and have much higher oxidative stability. (3) SE fluids can be regarded as one of the best biodegradable hydraulic fluids. Synthetic esters wit h suit able additives can also be nontoxic. They perform well as lubricants. They have excellent lubricatio n prope rties: high viscosity index and low friction characteristics. Their liquidity at low and hig h temperature s is excellent, as is their aging stability. Although they mix well with mineral oils, thi s characteristic negatively influences their biodegradability. SE fluids offer good corrosion protection an d lubri city and usually can be used under the same operating conditions as mineral oils. They are applicabl e for extreme t emperature-range operations and appear to be the best biodegradable fluids for heavy-duty o r severe applica tions. Synthetic esters do have higher first cost and are incompatible with some paints , finishes , and some seal materials. However, it may be possible to extend oil-change intervals and partiall y offset the higher cost. (4) Since SE f

luids are miscible with mineral oil, conversion may be accomplished by flushing th e sy stem to reduce the residual mineral-oil content to a minimum. Special filter elements are not required

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8-5 Filters sho uld be checked after 50 hours of operation, as vegetable oil tends to remove mineral-oil deposit s from the system and carry them to the filters.

c. Polyglycols (PG). (1) The use o f polyglycols is declining due to their aquatic toxicity when mixed with lubricatin g additives and their incompatibility with mineral oils and seal materials. (2) Pol yglycolhydraulic fluids have been available for several decades and are widely used , particularly in the food-processing industry. They also have been used since the mid-1980s in construction ma chinery(primarily excavators) and a variety of stationary installations. They were the firs t biodegradable oils on the market. (3) PG fluids have the greatest stability with a range from -45 to 250 E C (-49 to 482 E F). Polyglycols excelwhere fire hazard is a concern. Oil-change intervals are similar to those for a mineral oil: 2000 hours or once a year. (4) PG oils are not compatible with mineral oils and may not be compatible with common coatings , linings, seals, and gasket materials. They must be stored in containers free of linings. Some PG oils do not biodegradewell. The rate and degree of biodegradation are controlled by the ratio of propylene to ethylen e oxides, wit h polyethylene glycols being the more biodegradable. The rate and extent of biodegradabilit y diminish with increasing molecular weight. (5) When a hydr aulic system is converted from mineral oil to PG, it is essential that the oil supplier' s recommendat ions are followed. Normally, total system evacuation and one or two flushing procedures ar e required to avoid any mixing with previously used mineral oil. Mineral oil is less dense than PG fluids, s o any resi dual mineral oil will float to the top and must be skimmed off. According to the manufacturer' s recom mendations, the final residual quantity of mineral oil may not exceed 1 percent of the total flui d volume. Mineral oil must not be used to replace lost PG fluid, and other contamination of PG with mineral oil must be avo ided. Compatibility with varnish, seal, and filter materials also must be considered. Pape r filte rs may need to be replaced with glass-fiber or metal-mesh filters, and these should be checked after th e firs t50 hours of operation. The filters will retain any residual mineral oil and may become clogged

. Because of

their excellent wetting properties, PG fluids tend to remove deposits left from operation wit h mine ral oil, and these deposits are carried to the filter. Polyglycols are soluble in water, so water must b e excluded from the system. d. Water. (1) With the p rospect of increasingly stringent environmental restrictions on the use of mineral-oil

basedhydraulic fluids, water may become a practical alternative. Pure water has poor lubricity and cannot function as a lubricant in the traditional sense, but water has been used as hydraulic fluid in specialty applications where leakage contamination and fire hazard are major concerns. New designs and use o f highlywear-resistant materials have opened up possibilities for new water hydraulic applications. Reasons to use water include the following: (a) Water costs a fraction of mineral oils and other EA fluids. (b) Water disposal has little or no impact on the environment.EM 1110-2-1424

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8-6 (c) Water is nonflammable and can be used where high temperatures and oils could create fir e hazards. (d) Water ha s better thermal conductivity than oil and can transfer heat better allowing smaller heat exchanger to be used. (e) Water’s incompressibility makes it ideal for accurate actuator positioning, whereas oil may b e sluggish and imprecise. (2) Water doe s have several performance drawbacks, however. Conventional hydraulic oil syste m components will not work with water, and modifying oil system components for water has had poor results. Component

manufacturers are now designing parts specifically for water and are having good results. Th e following list describes performance drawbacks of water and solutions for overcoming them: (a) Water has low viscosity, so leakage is a concern. Components with tighter clearances are bein g manufactured to compensate for this. (b) Water h as low viscosity and low film strength, which means lower lubricity and higher wear

. Also, water c orrodes metal parts. Stainless steel and high-strength plastic and ceramic bearings an d component parts designed for high wear resistance are being developed. (c) Water h as higher vapor pressure than mineral oil which makes it more prone to cause cavitation

. Pumps are being manufactured with smoother and larger flow areas and throttling valves are bein g redesigned with innovative flow geometries to mitigate the cavitation potential. (d) Water freezes. Nontoxic antifreezes have been developed to lower water’s “pour point.” (3) The rate and extent to which water hydraulics are adopted depends on the motivation for furthe r technical development and EA additive development by lubricant producers. The driving factor would b e legislation regarding toxic and nonbiodegradable hydraulic fluids. 8-6. Properties of Available EA Products The ecotoxi cological properties, physical properties, and relative costs of the most widely used EA fluids , as compared with conventional mineral-based oils, are shown in Table 8-1. The cost figures do not include the exp enses for changing over to the EA oils, which may be substantial. PG may require total evacuatio n of the sy stem plus one or two flushes. Disposal costs for EA oils may be greater than for mineral oil s bec ause recyclers will not accept them. As previously noted, laboratory tests have shown that th e degradati on

rates may vary widely among the various biodegradation test methods. Table 8-1 indicate s th atthe vegetable oil and synthetic-ester-based fluids, if formulated properly, are readily biodegradable

. Thetoxicity tests show that the base stocks of most EA lubricants are nontoxic. The wide range of toxicity in Table 8 -1 is caused by additives in the formulated products. The following discussion summarize s important properties of EA fluids.

a. Oxidation stability. One of the most important properties of lubricating oils and hydraulic fluids is theiroxi dation stability. Oils with low values of oxidation stability will oxidize rapidly in the presence o f water at el evated temperatures. When oil oxidizes it will undergo a complex chemical reaction that wil l pro duceacid and sludge. Sludge may settle in critical areas of the equipment and interfere with th e lubrication an d cooling functions of the fluid. The oxidized oil will also corrode the equipment

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8-7 Table 8-1 Comparison of Ecotoxicological and Physical Properties of Lubricants
Properties Mineral Oil Polyglycol Vegetable Oil Synthetic Ester Conventional
% Biodegradability 42 - 49 6 - 38 72 - 80 55 - 84 EPA 560/6-82-003 Toxicity , LC50, Trout, EPA 560/6-82- 389 - >5000 80 - >5000 633 - >5000 >5000

1 002 Oxidation Stability , TOST, hours, 1000 - 2000 <500 <75 <500 1 ASTM D 943 Lubricity Good Good Good Good

2 ASTM D 2266 Viscosity Index 90 - 100 100 - 200 100 - 250 120 - 200 2 ASTM D 2270 Foaming , ASTM D 892 Pass Pass Pass Pass

2 Pour Point E C ( E F) -54 to -15 -40 to 20 -20 to 10 -60 to 20

2 ASTM D 97 (-65 to 5) (-40 to 68) (-4 to 50) (-76 to 68) Compatibility with Mineral Oil

- Not miscible Good Good 2 Relative Cost 1 2 - 4 2 - 3 5 - 20

2 Cheng et al., 1994 1 Rhee 1996 2

Oxidation stability is normally measured by test method ASTM D 943. This test, which is commonl y kno wn as Turbine Oil Stability Test (TOST), is used to evaluate the oxidation stability of oils in th e presence of ox ygen, water, and iron-copper catalyst at an elevated temperature. As Table 8-1 shows th e TOST life of m ineral oil is more than 1000 hours. Synthetic esters and polyglycols are hydrolytically les s stable than mineral oils at elevated temperatures, resulting in lower TOST lives. It has been shown that formulated synthetic esters with proper additives will produce high TOST values. Vegetable oils, on th e otherha nd, have a TOST life of less than 75 hours. To improve the TOST life of vegetable oil products , more resear ch must be done on formulating a proper mixture of base oil with a suitable additive package

. Until acceptable commercial formulations are demonstrated, vegetable oils should be confined t o applications involving very dry conditions and low temperatures. b. Lubric ity. Lubricity is the degree to which an oil or grease lubricates moving parts and minimize s wear. Lu bricity is usually measured by test method ASTM D 2266, commonly known as the Four-Bal l Method. Laboratory tests have shown that EA lubricants normally produce good wear properties.

c. Pour point. P our point defines the temperature at which an oil solidifies. When oil solidifies, it s perfo rmanceis greatly compromised. Pour point is normally evaluated by test method ASTM D 97. Th e low -temperature fluidity of vegetable-based fluids is poor compared to other fluids listed in Table 8-1

. How ever, the pour point of vegetable-based hydraulic fluids and lubricants may be acceptable for man y applications. d. Viscosity index. Viscosity index (VI) is a measure of the variation in the kinematic viscosity of oils as the temperature changes. The higher the viscosity index, the less the effect of temperature on it sEM 1110-2-1424

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8-8 kinematic viscosity. VI is measured by test method ASTM D 2270. As Table 8-1 shows, the VI of mos t EA fluids meets or exceeds the VI of petroleum-based fluids.

e. Foaming. The tendency of oils to foam can be a serious problem in lubricating and hydrauli c systems. Th e lubrication and hydraulic properties of oils are greatly impeded by excessive foaming

. Foaming characteristics of oils are usually determined by test method ASTM D 892. Laboratory tests have shown that most formulated EA fluids do not have foaming problems. f. Pai nt compatibility. Some common paints used in fluid systems are incompatible with many E A fluids. When it is anticipated that EA fluids may be used in a fluid system, the use of epoxy resin paint s should be used to eliminate potential compatibility problems.
g. Elast omeric seal compatibility. Polyurethane seals should not be used with EA fluids. Instead , the use of Viton and Buna N (low to medium nitrile) is recommended. EA fluids are compatible with stee l and copper alloys and provide excellent rust protection. The fluid manufacturer must be consulted fo r specific compatibility data for each material encountered in the application. h. Degradabi lity. Since EA fluids are biodegradable they will break down in the presence of wate r and bacteria. Moisture traps in breather intakes and other equipment modifications which will kee p mo isture out of the system should be considered. EA fluids should be periodically monitored to insure that biodegradation is not occurring. 8-7. Environmentally Acceptable Guidelines Atprese nt there are no industry or guide specifications for EA fluids and greases. However, severa l man ufacturers have developed biodegradable and nontoxic fluids for limited applications. In addition , seve ral hydroelectric facilities operated by the Bureau of Reclamation and the Corps of Engineers ar e testing t hese products and are obtaining good results. Until specific standards and specifications ar e developed, it is recommended that the following guidance be used for qualifying the fluids to b e environmentally acceptable:

a. They must be nontoxic. That is, using test method EPA 560/6-82-002, concentrations greater than 1000 ppm of the test material are necessary to kill 50 percent of the test organisms in 96 hour s (LC50>1000). b. They must be readily biodegradable. That is, using the ASTM test method D 5864, 60 percent or more of the test material carbon must be converted to CO in 28 days. 2 8-8. Changing from Conventional to EA Lubricants Plant owners and operators considering a change to biodegradable lubricants and hydraulic fluids should , aboveall, be aware that these products are not identical to conventional mineral oil products. Furthermore, the EA fluids are not necessarily equal to one another. It is important to make a thorough assessment of the req uirements of the specific application to determine whether a substitution can be made, and whether an y compro mises in quality or performance will be compatible with the needs of the user. Switching to EA

- products may require special considerations, measures, or adaptations to the system. Depending on th e application and the product chosen, these could include the following:EM 1110-2-1424 28 Feb 99

8-9 a. Some co mmercially available synthetic ester and vegetable-oil-based lubricants meet th e requir ements of nontoxicity and biodegradability. However, the compatibility of these fluids with existin g materials enc ountered in the application, such as paints, filters, and seals, must be considered. The flui d man ufacturer

must be consulted for specific compatibility data for each material of construction. Th e manufactur er

of the existing equipment must be consulted, especially when the equipment is still unde r warranty. b. Extremecare must be taken when selecting an EA oil or grease for an application. Produc t availa bility may be impacted due to the dynamic nature of developing standards and environmental requi rements. EA lubricating oils should not be used in hydroelectric turbine applications, such as bearin g oil, runner hub oil, or governor oil, until extensive tests are performed. It is recommended that the Corps of Engineers Hydroelectric Design Center be consulted prior to the initial purchase of any EA fluids an d greases for hydropower applications (see paragraph 8-10).

c. Accelera ted

fluid degradation at high temperature, change of performance characteristics at lo w temperatur e, and possible new filtration requirements should be investigated carefully. The oxidation rat e of vege table-based EA lubricants increases markedly above 82 E C (179.6 E F), and lengthy exposure at th e low temperature can cause some products to gel. d. On a hy draulic power system, when changing over to EA lubricants, the system should b e thoroughly drai ned of the mineral oil and, if possible, flushed. Flushing is mandatory if diesel engine oi l was the previous hydraulic fluid. This will avoid compromising the biodegradability and low toxicity of the EA fluids. D isposal of the used fluids should be in accordance with applicable environmental regulation s and procedures.

e. More frequent filter changes may be necesary. f. Moisture scavengers may be necessary on breather intakes to keep water content in the lubrican t low.
g. Temperature controls for both upper and lower extremes may need to be added to the system. h. Redesign of hydraulic systems to include larger reservoirs may be necessary to deal with foamin g problems. i. The use of stainless steel components to protect against corrosion may be necessary. j. The numb er of manufacturers who produce EA hydraulic fluids, lubricating oils, and grease s co ntinues to expand. Names of the manufacturers include some well known companies that have markete d lubricants f

or many years as well as a large number of smaller companies that appear to specialize in E A products. Some of these companies also market specialty EA products such as gear oils, wire rop e lubricants, air tool lubricants and cutting and tapping fluids. EA turbine oils exist; however, to date, non e of the oil suppliers has recommended these products for hydroelectric power plants. 8-9. Survey of Corps Users

a. A survey of al l Army Corps of Engineers districts was conducted to determine how extensively alternative lu bricants are being used, and with what results. A follow-up with manufacturers of some o f the pro ducts revealed that many installations that reported using environmentally acceptable product sEM 1110-2-1424

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8-10 actual lywere using food-grade lubricants made from synthetic oils or mineral oils. Neither of these bas e materials is readily biodegradable. b. Theuse of environmentally friendly lubricants at Corps of Engineers installations still is far fro m widespread. Six Corps districts reported using biodegradable oils in one or more applications. The longest use to date has been about 5 years.

c. Several installations reported using rapeseed-based oils as hydraulic fluids. The products are being used in N ashville District in hydraulic power units operating at 53.06 l/min (14 gpm) and 172.4 bar (250 0 psi), in lock gate operating machinery in Huntington District and in pressure-activated pitch controls in a pumping plant in Little Rock District. The Wilmington District has converted almost all of the hydraulic s in wa terfront and floating plant applications to rapeseed oil products, and the Alaska District reports usin g rapeseed oils in excavators, cranes, and dredges. d. NashvilleDistrict also reported using rapeseed-based lubricants in gate and valve machinery, while Roc k Island District uses them to lubricate gate lift chains. Other districts reported having specified EA

- oils for specific applications, but have not yet put the new equipment in operation.

e. Ope rators of installations using the EA products generally are satisfied with their performance an d are c onsidering expanding their use. Some operators who installed heaters or coolers to accommodat e fluids with limited temperature ranges report increased equipment life because the moderate temperature s reduce stres s on the pumps. Although the same environmental regulations apply to reporting and cleanu p of all spills, an environmental agency's response to a spill sometimes does take the “environmentall y acceptable” nature of the fluid into account. One user observed that a spill in quiet water gelled on th e surface “like chicken fat,” making cleanup easy. Finally, most operators report that installation o f rapeseed-based oil in a mineral-oil system is as easy as any other complete oil change. f. Overall, the most positive reports on EA fluids were applications in closed hydraulic systems. I n systems open to the environment, degradation and temperature sensitivity cause problems. Exposure t o water also can spur biodegradation of the lubricant while in service, a problem of particular significance i n hydr opower

applications. The only two failures of the fluids reported in the Corps of Engineers surve y were cases of contamination that caused the fluids to biodegrade while in use. 8-10. USACE Contacts

a. Addit ionalinformation on hydropower applications can be obtained from the Hydroelectric Desig n Center, CENPP-HDC, at P.O. Box 2870, Portland, OR 97208. b. Information on the survey, other EA applications, and associated new lubricants and technologie s can be obtained from the U.S. Army Construction Engineering Research Laboratories, CECER-FL-M, P

. 0. Box 9005, Champaign, IL 61826-9005.