Usage:
Diesel fuels combined with gasoline, naphtha, or other highly volatile fuels can be dangerous. BECAUSE OF THE SAFETY HAZARDS INVOLVED, CATERPILLAR DOES NOT RECOMMEND THE USE OF GASOLINE/DIESEL FUEL OR NAPHTHA/DIESEL FUEL BLENDS. Extreme caution must be exercised when these volatile fuel mixtures are present.
Gasoline and naphtha are light aromatic distillates of petroleum. When either of these fuels are combined with diesel fuel (No. 1 or No. 2) or kerosene, fuel blends of high volatility can result. The volatility of these blends could lie in a dangerous range even if a small percentage of gasoline or naphtha is added to the diesel fuel.
In a fuel tank, the vapor in the air space above pure diesel fuel is too lean to be a hazard at normal ambient temperatures. The vapor in a tank that contains pure gasoline or naphtha is too rich. However, when diesel fuel is mixed with gasoline or naphtha, the vapor-to-air ratios can be explosive. This vapor above the fuel in the fuel tank can be ignited by sparks, flames, electric arcing, and even static electric charges.
There are several reasons why such fuel blends are used. The most common is probably to combat fuel filter plugging problems (waxing) experienced in cold temperatures. Also in some areas, diesel fuel may be in short supply while gasoline or naphtha is readily available. Users may blend the fuels to extend the diesel fuel supply.
Mechanically, Caterpillar engines can accept certain proportions of gasoline or naphtha blended with diesel fuel without major effects on performance or engine life.
With this in mind, it is quite possible that hazardous fuel blends will be used by diesel equipment owners and operators-especially during periods of cold temperatures. It is for this reason, personnel who work with, on, or near diesel-powered equipment should be made aware of the safety hazards involved. SAFETY PRACTICES WHICH MAY HAVE WORKED WELL WHEN IN CONTACT WITH PURE DIESEL FUEL WILL NOT BE ADEQUATE WHEN DEALING WITH THESE BLENDS.
As it will be difficult at times to detect the usage of a fuel blend, we recommend that the following precautions be observed by personnel in contact with diesel fuels and diesel-powered equipment:
1. Do not smoke in areas where fuels are handled or used.
2. Keep heat sources, flames, sparks, electric arcing, etc. well away from storage or service tanks.
3. Prevent careless handling, fuel spillage, and tank leakage and exercise the above precautions if accidental spillage does occur.
4. Handle all fuels only in well ventilated areas.
5. Make sure that storage tanks are vented outside of buildings or enclosures and never into unventilated areas.
6. When transferring fuels from one tank to another, ensure that both tanks are grounded to a common ground or that they are electrically connected or bonded.
7. Always keep first aid and fire extinguishing equipment that is suitable for use on oil fires maintained and within easy access.
We recommend that this information be brought to the attention of all personnel who have contact with diesel fuels and diesel-powered equipment.
Refer to the articles, "Fuel Heaters Are Now Available For Field Installation", ENGINE NEWS January 9, 1980 and "General Information-Diesel Fuels In Cold Temperature Operation", ENGINE NEWS January 23, 1980 for practical and safe solutions to cold temperature operation problems.
THE USE OF FUEL HEATERS IN COMBINATION WITH HAZARDOUS FUEL BLENDS SHOULD BE AVOIDED. FUEL VOLATILITY INCREASES AS FUEL TEMPERATURE INCREASES.
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