Testing Capabilities & Explanations
FOI offers a comprehensive collection of diesel fuel testing services that have been designed by our chemist to detect storage integrity and classify products by ASTM and industry specifications. Our short and long-term storage packages help predict your product’s remaining service life and product cleanliness as well as ensure compliance with fuel specifications. By familiarizing yourself with the different test and terms on this document you will better learn to trouble shoot possible issues with your fuel.
Like in the practice of medicine trying to figure out what’s wrong with your fuel can sometimes be a challenge. There are hundreds of tests available to help pinpoint what might be negatively affecting your fuel. For the sake of efficacy we have narrowed this document to just over a couple of dozen test that address the issues that most often afflict the fuel industry. Highlighted in red are test that will give us a general diagnostics of your fuel. When we get your fuel sample; we generally run a package that includes several of these test. If for any reason any of these test fail we then contact our client to discuss what route to take with the lab results. Many forensic test are available in order to gather more information if needed.
Troubleshooting Fuel Problems
A fuel pump that delivers normal pressure may still cause drivability problems if it delivers infected fuel into the engine. The following test may therefore be the way to evaluate your fuel’s condition.
Type of Test and Terms
1. Accelerated / Oxidation Stability
Stability-related problems arise when the fuel is stored for a long period of time and may contain inorganic sediment, water, or dissolved metals. The resultant degradation or oxidation of certain reactive compounds (sulfur, oxygen and nitrogen) form soluble and insoluble gum and sediments. The gum and sediment formation can cause darkening of the fuel, filter plugging, lacquering of fuel system components, and a change in fuel properties. The test provides an indicator of the stability of the fuel. Diesel fuel stability can be improved by using antioxidants, which inhibit gum and sediment formation.
2. ANALYTICAL FERROGRAPHY
Analytical Ferrography can predict potential equipment failures or be an effective tool in determining the root cause of failure. AF is a qualitative, rather than quantitative analysis that provides digital imagery of the actual particles present. Powerful magnets trap the ferrous particles, which are then placed on slides for microscopic analysis. Particles are analyzed based on metallic or nonmetallic, alloy via heat treatment, shape, size, color, and if possible, source.
3. DIRECT READ FERROGRAPHY
Direct Read Ferrography is a quantitative analysis of ferrous particles present in used oil. It provides an index of large ferrous >5# particles to small ferrous <5# particles. Because it can identify the amount of ferrous wear occurring within a unit, it is most helpful in illustrating developing trends.
4. ACID NUMBER
Acid Number is the amount of acid present. Numbers higher than that of new lubricant is an indication of oxidation or contamination of some kind.
5. BASE NUMBER
Base Number measures a lubricant’s alkaline reserve, or ability to neutralize acid. When Acid Number and Base Number approach the same number, the oil should be changed or “sweetened,” meaning more new oil should be added.
6. CHLORINE
Chlorine is one of a group of five chemically-related nonmetallic elements – chlorine, bromine, fluorine, iodine and astatine. In certain oils, chlorine compounds are used as EP additives to prevent sliding metal surfaces from seizing under extreme pressure. These compounds react chemically with the metal to form an inorganic film to prevent the welding of opposing asperities (microscopic projections on metal surfaces that result from normal surfacefinishing processes) and the consequent scoring (distress marks or long, distinct scratches on sliding metallic surfaces in the direction of motion) that is so destructive to these metal surfaces under high loads.
7. ELEMENTAL ANALYSIS (24 METALS BY ICP)
Elemental Analysis by ICP (inductively-coupled plasma) detects up to 24 metals, measuring less than 5# in size that can be present in used oil due to wear, contamination or additives. Wear Metals include iron, chromium, nickel, aluminum, copper, lead, tin, cadmium, silver, titanium and vanadium.
Contaminant Metals include silicon, sodium, potassium, molybdenum, antimony, manganese, lithium and boron. Additive Metals include magnesium, calcium, barium, phosphorous and zinc. Elemental Analysis is instrumental in determining the type and severity of wear occurring within a unit. Consult the POLARIS Wear Metals Guide for quick reference to possible wear metal sources.
8. FIRE POINT
Fire Point is the minimum sample temperature at which vapor is produced at a rate sufficient to sustain combustion for at least 5 seconds.
9. FLASH POINT
Flash Point is the lowest temperature at which the vapors of a combustible liquid will ignite momentarily in air. Low diesel fuel flash points indicate contamination by more volatile fuels such as gasoline. For Flash Point by Pensky Martens and Flash Point by Cleveland Open Cup, refer to ASTM Guidelines for minimum flash point requirements.
10. FTIR
FTIR (Fourier Transform Infrared Spectroscopy or Full Spectrum Scan) is a test where infrared light absorption is used for assessing levels of soot, sulfates, oxidation, nitro-oxidation, glycol, and fuel and water contaminants.
11. FUEL DILUTION
Fuel Dilution is the amount of raw, unburned fuel that ends up in the crankcase. It lowers oil’s viscosity – creating friction related wear almost immediately – and also decreases unit load capacity. POLARIS reports fuel dilution in % of volume.
12. GLYCOL
Glycol is a test used to check oil for contamination from a glycol product such as antifreeze or water/glycol in an oil environment.
13. NITRATION
Nitration indicates excessive “blow-by” from cylinder walls and/or compression rings. It also indicates the presence of nitric acid, which speeds up oxidation. Too much disparity between oxidation and nitration can point to air to fuel ratio problems. As oxidation/nitration increases, so will total acid number and viscosity, while total base number will begin to decrease.
14. OXIDATION
Oxidation measures the breakdown of a lubricant due to age and operating conditions. It prevents additives from performing properly and therefore allows acid content and viscosity to increase.
15. PARTICLE COUNT
Particle Count is the measurement of all particles that have accumulated within a system, including those metallic and nonmetallic, fibers, dirt, water, bacteria and any other kind of debris. It is most useful in determining fluid and system cleanliness in such filtered systems as hydraulics, turbines, compressors, auto/power shift transmissions, recirculation systems and filtered gear systems with a fluid viscosity of less than ISO 320.
16. PARTICLE QUANTIFYING
Particle Quantifying (Ferrous Density) exposes a lubricant to a magnetic field. The presence of any ferrous metals causes a distortion in the field, which is represented as the PQ Index, an arbitrary unit of measurement that correlates well with DR ferro large. Although PQ does not provide a ratio of small to large ferrous particles, if the PQ Index is smaller than FE ppm by ICP, it’s unlikely there are any particles larger than 5 microns present. If the PQ Index increases dramatically while the ICPs FE ppm remains consistent or goes down, larger ferrous particles are being generated and further testing or diagnostics are recommended.
- pH pH is a measure of oil’s alkalinity or acidity. It indicates the intensity of acidforming or base-forming materials present.
18. SOOT
Soot is also reported in % of volume and can indicate reduced combustion efficiency. Soot can be caused by over-fueling, air restrictions, blow-by, excessive engine brake use and/or excessive exhaust back pressure.
19. STRONG ACID NUMBER
Strong Acid Number is the quantity of strong acid or strong base, expressed in equivalent numbers of milligrams of KOH, required to neutralize strong acid (pH 4/g) constituents.
20. STRONG BASE NUMBER
Strong Base Number is the quantity of strong acid or strong base, expressed in equivalent numbers of milligrams of KOH, required to neutralize base (pH 11/g) constituents.
21. VISCOSITY
Viscosity measures a lubricant’s resistance to flow (fluid thickness) at temperature and is considered an oil’s most important physical property. Depending on lube grade, viscosity is tested at 40 and/or 100 ° Centigrade and reported in Centistokes.
22. VISCOSITY INDEX
Viscosity Index represents oil’s change in viscosity with respect to changes in temperature. The viscosity index of oil is determined experimentally by testing its viscosity at 40°C and 100°C.
23. WATER
Water in oil decreases lubricity, prevents additives from performing properly and furthers oxidation. Its presence can be determined by Crackle (hot plate) or FTIR (full spectrum scan) and is reported in % of volume.
24. WATER BY KARL FISCHER
Water by Karl Fischer measures water by titration and is reported in either ppm (parts per million) or % by volume.
DIESEL FUEL ANALYSIS
25. ASH
Ash can result from oil, water-soluble metallic compounds or contamination (dirt or rust). By knowing the amount of ash forming material in a product, it can be determined if a product is suitable for a given application.
26. AEROBIC BACTERIA
Aerobic Bacteria testing determines the presence of bacteria and how many colonies there are.
27. API GRAVITY
API Gravity is the measure of a diesel fuel’s density, or weight per volume; the higher the API Gravity, the less dense the fuel. API Gravity can provide valuable information about a fuel’s composition and performance characteristics including power economy, low temperature properties and smoking tendencies.
28. BACTERIA, FUNGI, AND MOLD
Bacteria, Fungi and Mold are indications that fuel storage tanks have not been properly maintained. Water can build up at the bottom of storage tanks and create an excellent breeding ground for biological growth.
29. BTU (PER GALLON)
BTU (per gallon) is a conversion from BTU per pound.
30. BTU (PER POUND)
BTU (per pound) is the quantity of heat required to raise the temperature of one pound of water 1°F at 60°F and at a pressure of one atmosphere.
31. CETANE INDEX
Cetane Index is a measure of a diesel fuel’s ignition quality. The limit for a #2 diesel fuel is a Cetane Index of at least 40.
32. CLOUD POINT
Cloud Point is the temperature at which wax crystals begin to form.
33. COLD FILTER PLUG POINT
Cold Filter Plug Point determines the temperature of a fuel at which wax crystals form to the extent that they plug fuel filters.
34. DENSITY
Density is a quality indicator for fuels where it affects storage, handling and combustion and measures density of a fluid.
35. DISTILLATION
Distillation temperature is the temperature at which 90% of the fuel volume can be distilled off. This temperature is directly related to the fuel’s volatility and therefore, it’s Cetane Index, density, flash point and viscosity as well. A #2 diesel fuel’s minimum distillation temperature is 282° C – its maximum is 338° C.
36. FLASH POINT
Flash Point is the lowest temperature at which the vapors of a combustible liquid will ignite momentarily in air. Low diesel fuel flash points indicate contamination by more volatile fuels such as gasoline. For Flash Point by Pensky Martens and Flash Point by Cleveland Open Cup, refer to ASTM Guidelines for minimum flash point requirements.
37. LUBRICITY
Lubricity is a measure of the ability to affect friction between and wear to surfaces in motion under load. Diesel fuel injection components have some reliance on the lubricating properties of diesel fuel. Lack of lubricity in a fuel can shorten the life of fuel system components.
38. POUR POINT
Pour Point is the lowest temperature at which fuel will still pour. Using ASTM D 97, which measures the pour point of any petroleum product (such as diesel fuel), pour point is the lowest temperature at which movement of the test specimen is observed.
39. SPECIFIC GRAVITY
Specific Gravity is the ratio of the mass of a given volume of product and the mass of an equal volume of water, at the same temperature. It can be determined by a hydrometer, a graduated float weighted at one end that provides a direct reading of specific gravity depending on the depth to which it sinks in the liquid.
40. SULFUR
Sulfur content will affect SOx emissions and can have adverse effects on many NOx and PM emission reduction devices. The amount of sulfur allowed in diesel fuel is regulated by the government. Bulk delivery of diesel fuel should be tested to include sulfur levels.
41. THERMAL STABILITY
Thermal Stability is a percentage range assigned to a fuel based on its tendency to produce asphaltenes at high temperatures. Asphaltenes are tar-like, resinous substances most often responsible for clogging fuel filters. Fuel with a Thermal Stability of 80% or greater should not cause filter clogging. Fuels between 60% and 80% could have a marginal affect and values less than 60% will significantly reduce filter life.
42. WATER & SEDIMENT
Water & Sediment in fuel can cause corrosion, wear, bacterial growth and premature fuel filter clogging. The amount of water in fuel should not exceed 500 ppm (0.05%). Sediment should be no greater than 100 ppm (0.01%).
COOLANT ANALYSIS
43. Antifreeze %
(Ethylene or Propylene Glycol) levels should range between 40% and 60% to ensure proper freeze point protection. A high percentage of glycol can cause additive drop out and shorten coolant life.
44. BOIL POINT
Boil Point is calculated from glycol %, boil point indicates at what temperature a coolant will boil at sea level.
45. CALCIUM CARBONATE
Calcium Carbonate can be calcium from source water and contributes to the hardness of the water.
46. CARBOXYLIC ACID
Carboxylic Acid testing determines if the amount of carboxylic acid required by an organic acid coolant is present, or if there is contamination from a conventional coolant.
47. CONTAMINANTS
Contaminants include Nitrites, Nitrates, Chlorides & Sulfates. Nitrites and Nitrates are metal-protecting chemicals in Supplemental Coolant Additive packages. Chlorides and Sulfates are outside contaminants. Chlorides can come from source water or air leaks. Sulfates can also come from source water or combustion gas leaks. Both have the potential to form acids.
48. CORROSION INHIBITORS
Corrosion Inhibitors are chemicals in Supplemental Coolant Additive packages that are designed to lay a protective film on various metals to inhibit corrosion.
49. ELEMENTAL ANALYSIS BY ICP
Elemental Analysis by ICP identifies metals that are typically the product of corrosion such as iron, aluminum, copper, lead, tin, zinc and silver. Also included are inhibitor additives such as silicates, molybdenum/molybdates, phosphorus/phosphates and boron/borates.
50. FREEZE POINT
Freeze Point is the temperature at which the liquid solidifies. Freeze point is a function of the glycol concentration in the engine coolant.
51. GLYCOLATES, ACETATES, FORMATES & OXYLATES
Glycolates, Acetates, Formates and Oxylates are acids that form as a result of coolant degradation.
52. NITRATE
Nitrate is an inhibitor for aluminum and solder corrosion protection. The conversion from nitrite to nitrate can indicate an electrical ground problem within the cooling system.
53. NITRITE
Nitrite is an inhibitor for cast iron, steel and liner cavitation protection. Excessive levels can lead to solder corrosion.
54. pH
pH is a measure of the coolant’s acidity or alkalinity. Whereas a coolant’s neutralization number is related to the quantity of acid or base forming materials in a solution, pH indicates their intensity. Coolant pH range should remain between 7.5 and 11 to provide adequate corrosion protection.
55. RESERVE ALKALINITY
Reserve Alkalinity testing determines the base or alkaline reserve in a fluid. It can be done on many fluid types but is most commonly used for metalworking fluids.
56. SCA NUMBER
SCA Number (Supplement Coolant Additive) Number represents the level of coolant additive required for adequate liner pitting protection. A level of 2.5 is ideal for extending coolant life. SCA can be in the form of an additive that is added to the coolant or from a water filter time release system.
57. SPECIFIC CONDUCTANCE
Specific Conductance is a coolant’s ability to resist carrying an electrical current between dissimilar metals. Excessive levels can be due to improper source water, high metal corrosion or over-treatment with SCAs.
58. TOTAL DISSOLVED SOLIDS
Total Dissolved Solids such as inhibitor chemicals, silicates, contaminants and water hardness compounds can lead to water pump leakage. TDS levels should not exceed 4%. If leakage occurs, drain coolant and flush pump with tap water.
59. TOTAL HARDNESS
A source water’s hardness is determined by the amounts of calcium and magnesium present.
60. VISUALS
Visual inspection identifies outside contamination sources or coolant degradation. Oil and fuel contamination can destroy rubber seals and changes in color may indicate changes in chemical composition or possible mixing of formulations. Foaming causes loss of heat transfer. Odor helps confirm the source of contamination and/or degradation sources.
SPECIALTY TESTING
61. 4 BALL WEAR TEST
4 Ball Wear Test (ASTM D 2266) determines a lubricant’s anti wear properties under boundary lubrication (metal to metal contact). Three steel balls are clamped together to form a cradle upon which a fourth ball rotates on a vertical axis. The balls are immersed in the oil sample at a specified speed, temperature and load. At the end of a specified test time, the average diameter of the wear scars on the three lower balls is measured.
62. CARBON RESIDUE
Carbon Residue (Conradson/Ramsbottom) is the percent of coked material remaining after a sample of lubricating oil has been exposed to high temperatures under ASTM D189 (Conradson) or ASTM D 524 (Ramsbottom). Results are reported as a percentage of the weight of the original sample. As far as the affect of residue on performance, one opinion is that the type of carbon is of greater importance than the quantity. Since compounded oils contain metallic additives that generally leave a residue, other testing should be done to also identify the type of residue rather than just the amount.
63. COPPER CORROSION
Copper Corrosion testing evaluates a fluid’s tendency to corrode cuprous metals. Results are based on the matching of corrosion stains and are often reported on a pass or no-pass basis. Noncorrosiveness should not be confused with rust inhibiting, which is the protection of a surface from a particular contaminant, such as water, rather than the lubricant itself.
64. DENSITY
Density is a quality indicator for fuels where it affects storage, handling and combustion. Measures density of a fluid.
65. FOAM
Foam testing determines the foaming characteristics of a lubricant or fuel oil by blowing air through a sample at a specified temperature and measuring the volume of foam produced as described in ASTM D 892. Foaming can result from excessive agitation, improper fluid levels, air leaks, contamination or cavitations – the pitting or wearing away of a solid surface as a result of the collapse of a vapor bubble. Foaming can cause sluggish hydraulic operation, air binding in oil pumps and tank or sump overflow.
66. GRAVIMETRIC SOLIDS
Gravimetric Solids – a filter patch is tare weighted and sample is passed through the filter and then re-weighed to get a % Solids result.
67. MICROPATCH
MicroPatch requires a prepped sample be passed through a .8# absolute filter then examined through a microscope. Results are interpreted and prepared on a separate report with digital imagery similar to an Analytical Ferrograph.
68. PHOTO MICROGRAPH
Photo Micrograph is similar to Micro Patch except only photos are taken. There is no interpretation or separate report.
69. PENTANE INSOLUABLES
Pentane Insoluble’s (coagulated/un-coagulated) identifies contaminants in used oil. The oil is first diluted with pentane so it loses its solvency for certain oxidation resins (light yellow to dark brown solid or semi-solid materials composed of carbon, hydrogen and oxygen). This dilution also causes the precipitation of such extraneous materials as dirt, soot and wear metals or pentane insoluble’s.
70. RPVOT
RPVOT (Rotary Pressure Vessel Oxidation Test) measures the oxidation stability of turbine oil. The sample is placed in a container, which is then placed in a heated bath, charged with oxygen and pressurized while a constant elevated temperature is maintained. Oxidation stability is expressed in terms of the time required to achieve a specified pressure drop.
71. RUST
Rust results from the chemical reaction between water present in a lubricant and metal.
72. SULFATED ASH
Sulfated Ash is a test used to indicate the concentration of known metallic additives in new oils.
73. TRAMP OIL PERCENT
Tramp Oil Percent is the amount of undesired oil scum in a system, such as lubricants or hydraulic fluids that mix with rolling oil systems in cold mill areas.
74. TOLUENE INSOLUBLES
Toluene Insoluble’s (coagulated/un-coagulated) are the solids remaining after oxidation resins, or pentane insoluble’s, have been diluted with toluene. Insoluble resins are the difference in weight between the pentane insoluble’s and the toluene insolubles.
75. Water Separability
Water separability characteristics by ASTM D-1401 measures a fluids ability to shed water. It also is commonly referred to as a Demulsfication