JP-8 Jet Fuel: An Overview
JP-8 jet fuel was developed as a jet fuel in response to problems encountered in use of JP-4 jet fuel. By the fall of 1996, JP-8 completely replaced JP-4 in the United States Air Force. Compared to JP-4, JP-8 has a higher flash point and lower vapor pressure, making it less volatile; contains less benzene, a known carcinogen; and contains less n-hexane, a known neurotoxicant. However, as a kerosene-based fuel, JP-8 has a strong odor and is oily to the touch, while JP-4, a kerosene-gasoline mix, is less pungent and has a non-oily, solvent-like feel.
It has been estimated that approximately 60 billion gallons are used worldwide each year, with 4.5 billion used by the US Air Force, the US Army, and NATO. The US Navy uses JP-5, which is very similar to JP-8. JP-8 is also used to fuel heaters, stoves, tanks, and other vehicles in military service; and used as coolant for engines and other aircraft components. JP-8 is planned on being used at least until the year 2025 as the battlefield fuel for all U.S. military operations. The Department of Defense has recognized JP-8 as the single largest chemical exposure for its personnel. JP-8 without several additives is Jet A or commercial fuel.
As a newer type of fuel, the hazards of the use of JP-8 are less fully known. OSHA & ACGIH have no promulgated exposure standards set for the use of JP-8. The Navy has a standard of 8 hours of PEL of 350 mg/m3 and 15 min STEL of 1800 mg/m3. The higher flash pt of JP-8, along with its low volatility cause cold starts and engine coking. Cold starts result in exposure to unburned aerosolized fuel, and the low volatility makes it easier for fuel to remain on surfaces such as skin and clothes. Workers have complained of smelling and tasting JP-8 many hours after cessation of the exposure. They have also reported dizziness, lightheadedness and skin problems.
The bottom line is that JP-8 aerosols are easily produced and less likely to evaporate. This has increased contact/residence time of jet fuel on surfaces, which increases the risk of toxic response.
HTH :mrgreen:


Reply With Quote

