Aviation Gas & Jet Fuel Testing Program

A routine aviation gasoline sample will be analyzed for most or all of the following parameters to meet specifications established in ASTM D910 (Aviation Gasoline). A routine jet fuel sample will be analyzed for most or all of the following parameters to meet specifications established in ASTM D1655. 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:

ASTM International
100 Barr Harbor Drive
West Conshohocken, Pennsylvania 19428

Aviation Gasoline

Vapor Pressure by ASTM D5191

Vapor Pressure is a physical measure of gasoline volatility. High vapor pressures and a low distillation temperature for 10% evaporated both help cold starting.

Whereas the vapor pressure of automobile gasolines vary throughout the year, aviation gasoline has a set minimum and maximum which remain constant.

Distillation by ASTM D3710

The "distillation" standard is one of several tests used to address gasoline's vaporization characteristics. It is very important that a fuel's tendency to evaporate is controlled to certain standards. A fuel's ability to vaporize or change from liquid to vapor is referred to as its volatility.

The tendency of a fuel to vaporize is also characterized by determining a series of temperatures at which various percentages of the fuel have evaporated (boiling temperatures). The temperatures at which 10%, 50%, and 90% evaporation occurs are often used to characterize the volatility of gasoline.

The 10% evaporated temperature is directly affected by the seasonal blending of the gasoline. This temperature must be low enough to provide easy cold starting, but high enough to minimize the vapor lock and hot weather driveability problems. Most cool weather driveability problems occur from the use of summer season gasoline in the winter months. This is especially true in premium grades, which normally have a high 10% evaporated temperature.

The 50% evaporated temperature must be low enough to provide good warm-up and cool weather driveability without being so low as to contribute to hot driveability and vapor locking problems. This portion of the gasoline greatly affects fuel economy on short trips.

The 90% and end-point evaporation temperatures must be low enough to minimize crankcase and combustion chamber deposits, as well as spark plug fouling and the dilution of engine oil.

If the end-point temperature exceeds the ASTM maximum requirement, it is usually because of the presence of a distillate fuel such as No. 2 diesel. This contamination can be directly attributable to the delivery of diesel prior to the delivery of the gasoline. This problem is avoided if care is taken in handling the product.

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.

Water/Sediment by Visual Inspection 

Water and sediment in fuel is 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, carburetors and injectors. ASTM requires gasoline to be visually free of undissolved water, sediment, and suspended matter: it shall be clear and bright at ambient temperatures or 70° F, whichever is higher. The presence of water and/or sediment can lead to improper motor operation and thus excess emissions of pollutants.

Jet Fuel

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.

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.

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.

Density

The relative density of jet fuel can be used as a production control test, or in the field, as an indication of possible contamination.