Diesel Testing Program
A routine diesel fuel or kerosene sample will be analyzed for most or all of the following parameters to meet specifications established in ASTM D975 (Diesel) or D3699 (Kerosene).ASTM methods may be obtained by phone, fax or email from either the Reno or Las Vegas laboratories or by directly contacting ASTM International, or the volume may be purchased from:
100 Barr Harbor Drive
West Conshohocken, Pennsylvana 19428
Flashpoint by ASTM D93
Flash point is defined as the temperature to which a fuel must be heated to produce an ignitable vapor-air mixture above the liquid fuel when exposed to an open flame. Flash point is important primarily from a fuel-handling standpoint. Too low a flash point will cause fuel to be a fire hazard, subject to flashing, and possible continued ignition and explosion. In addition, a low-flash point may indicate contamination by more volatile and explosive fuels, such as gasoline. A very important reason to maintain the flash point as high as possible is due to the electrostatic hazards in pumping distillate fuels.
The flash point as specified is not directly related to engine performance. It is, however, of importance in connection with legal requirements and safety precautions involved in fuel handling and storage, and is normally specified to meet insurance and fire regulations.
Distillation by ASTM D2887
Volatility of a diesel fuel is measured by distillation. While volatility has no direct affect on power or economy, less volatile (higher boiling) fuels normally have a higher heating value and thus performance is indirectly affected. Starting and warm-up are better with higher front-end volatility (lower 10% distillation temperature), and deposit formation, wear, and exhaust smoke are increased, in some engines, by higher 90% and end points. Failure to meet distillation requirements would contribute to increased emissions of pollutants.
The fuel volatility requirements depend on engine design, size, nature of speed and load variations, and starting and atmospheric conditions. For engines in services involving rapidly fluctuating loads and speeds as in bus and truck operation, the more volatile fuels may provide best performance, particularly with respect to smoke and odor. However, best fuel economy is generally obtained from the heavier types of fuels because of their higher heat content.
Cetane Screen by Near Infrared Spectroscopy
Cetane number is a measure of the ignition quality of the fuel and influences combustion roughness. The cetane number requirements depend on engine design, size, nature of speed and load variations, and on starting and atmospheric conditions. Increase in cetane number over values actually required does not materially improve engine performance. Accordingly, the cetane number specified should be as low as possible to assure maximum fuel availability.
Cetane Index is specified as a limitation on the amount of high aromatic components in Grades No. 1-D S15, No. 1-D S500, No. 2-D S15 and No. 2-D S500.
Sulfur by ASTM D5453
Sulfur is an element that is normally found in varying amounts in all petroleum products. As a result of combustion, sulfur compounds of an acidic or corrosive nature are produced and contribute to combustion chamber and valve deposits, exceptional wear on the engine, and increased atmosphere pollution.
Through recent EPA regulations, the sulfur limit for on-highway diesel fuels (Ultra Low Sulfur Diesel, or ULSD) has been reduced to 15 ppm. Kerosene is allowed to have higher sulfur levels, but there is a maximum allowed for kerosene, as well.
The effect of sulfur content on engine wear and deposits appears to vary considerably in importance and depends largely on operating conditions. Fuel sulfur can affect emission control systems performance. To assure maximum availability of fuels, the permissible sulfur content should be specified as high as is practicable, consistent with maintenance considerations.
Kinematic viscosity by ASTM D445
Kinematic viscosity is an important physical property of a diesel fuel affecting injector lubrication and fuel atomization. Diesel fuels with extremely low viscosities may not provide sufficient lubrication for the closely-fit pumps and injector plungers. They can promote abnormal wear and cause injector leakage and dribbling leading to loss of power and smoke problems. Improper viscosity leads to poor combustion, which results in loss of power and excessive exhaust smoke.
For some engines it is advantageous to specify a minimum viscosity because of power loss due to injection pump and injector leakage. Maximum viscosity, on the other hand, is limited by considerations involved in engine design and size, and the characteristics of the injection system.
Water/sediment by Visual Inspection
Water and sediment in fuel is one of our program's most frequent consumer complaint. As most are aware, water makes a very undesirable fuel and sediment has a tendency to clog filters and jets. ASTM requires fuel oils to be visually free of undissolved water, sediment, and suspended matter. The presence of water and/or sediment can lead to improper motor operation and thus excess emissions of pollutants.