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OCR for page 13
Permissible Exposure Levels for Selected Military Fuel Vapors 2 Physical and Chemical Properties of Military Fuels Jet fuels and diesel fuel marine (DFM) are complex mixtures of hydrocarbons produced by distillation of crude oil. They contain hundreds of hydrocarbons as well as many additives. The actual composition of any given fuel varies depending upon source of the crude oil, refinery processes, and product specifications. The hydrocarbons in jet and diesel fuels are less volatile than those in gasoline. JP-5 is a high-flash-point jet fuel developed by the Navy. JP-5 is a specifically refined type of kerosene consisting of C9-C16 paraffins (53%), cycloparaffins (31%), aromatics (16%), and olefins (0.5%). The aromatic content of JP-5 might vary from less than 2.5% to greater than 22% by volume. The benzene content of JP-5 is typically less than 0.02% (Dollarhide, 1992), and a small amount of polycyclic aromatic hydrocarbons might be present in JP-5. Because water contamination in aviation fuels is a serious problem, a fuel-system icing inhibitor is added to the fuel to eliminate the formation of ice in
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Permissible Exposure Levels for Selected Military Fuel Vapors aircraft systems. JP-8 is similar to commercial jet A-1 fuel. JP-8 was developed for the Air Force to provide a safe kerosene-based jet fuel that would still have adequate reliability and an acceptable freezing point. DFM is a blend of diesel fuel that is basically the same as kerosene to which high-boiling-point fractions and high-boiling-point residual oils have been added. Diesel fuels consist primarily of C9-C20 hydrocarbons. For DFM, these are roughly 13% paraffins, 44% aromatics, and 44% naphthalenes. DFM might also contain less than 10% polycyclic aromatic hydrocarbons. In considering the potential toxicity of the fuel vapors, it is important to note that many compounds in the fuel do not exist in the vapors (Bishop, 1982). The toxicity of the more-volatile fractions of the fuel is considered in this report and not the toxicity of the total fuel. The composition of the vapors from the three fuels under consideration are expected to be similar since the fuels are made by mixing kerosene with different amounts of low-boiling-point distillates. The physical and chemical properties of military fuels JP-5, JP-8, and DFM are described below.
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Permissible Exposure Levels for Selected Military Fuel Vapors JET-PROPULSION FUEL 5 Molecular weight: ≈185 Synonyms: Jet fuel JP-5, MIL-T-5624M, AVCAT Freezing point, maximum: -46°C Boiling point: 156-293°C Initial point: 182°C (156-191°C) 10% evaporated: 199°C ( 180-211°C) 20% evaporated: 207°C (199-213°C) 50% evaporated: 220°C (212-229°C) 90% evaporated: 246°C (236-275°C) End point: 166°C (248-293°C) Flash point, minimum: 60°C Vapor pressure: 0.52 mm Hg (10°C) 1.8 mm Hg (28°C) Specific gravity, kg/L, 15°C, Minimum: 0.788 Maximum: 0.834 Heating value, Btu/lb, minimum: 18,300 Autoignition temperature: 246°C Viscosity, maximum at -20°C: 8.5 Composition: C9–C16 paraffins, vol % ≈ 53%; cycloparaffins, vol % ≈ 31%; aromatics, vol % ≈ 16%; olefins, vol % ≈ 0.5%. Aromatics typical of cracked gasoline and kerosene include benzene, alkyl benzenes, toluene, xylene, indenes, naphthalenes. Benzene content = 0.02%. Conversion factors at standard temperature and pressure: 1 ppm = 8.3 mg/m3 1 mg/m3 = 0.12 ppm
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Permissible Exposure Levels for Selected Military Fuel Vapors JET-PROPULSION FUEL 8 Molecular weight: ≈180 Synonyms: Jet fuel JP-8, MIL-T-83133B, AVTUR Freezing point, maximum: -47°C Boiling point: 175-300°C 10% recovered, maximum: 205°C End point, maximum: 300°C Flash point, minimum: 38°C Vapor pressure: 0.52 mm Hg (10°C) 1.8 mm Hg (28°C) Specific gravity, kg/L, 15°C, Minimum: 0.775 Maximum: 0.840 Heating value, Btu/lb, minimum: 18,400 Viscosity, maximum at -20°C: 8 Composition: C8–C9 aliphatic hydrocarbons, vol % ≈ 9% C10–C14 aliphatic hydrocarbons, vol % ≈ 65%; C15–C17 aliphatic hydrocarbons, vol % ≈ 7%; aromatics, vol % ≈ 18%. Aromatics typical of cracked gasoline and kerosene include benzene, alkyl benzenes, toluene, xylene, indenes, naphthalenes. Conversion factors at standard temperature and pressure: 1 ppm = 8.0 mg/m3 1 mg/m3 = 0.12 ppm
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Permissible Exposure Levels for Selected Military Fuel Vapors DIESEL FUEL MARINE Molecular weight: 198-202 Synonyms: DMF, diesel, petroleum, diesel fuel no. 4, distillate Freezing point, maximum: NA Boiling point, 760 mm Hg: 220-400°C 90% recovery, Minimum: 282°C Maximum: 338°C Specific gravity, kg/L, 15°C: 0.87 Viscosity, 40°C: 1.9-4.1 Vapor density (air = 1): 8 % volatile by volume at 38°C: Negligible Flash point: 52°C Autoignition temperature: 257°C Composition: C9–C20 paraffins, vol % ≈ 13%; aromatics, vol % ≈ 44%; naphthalenes, vol % ≈ 44%; may contain some (< 10%) polycyclic aromatic hydrocarbon. Conversion factors at standard temperature and pressure: 1 ppm = 8.9 mg/m3 1 mg/m3 = 0.11 ppm
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