Flash point is an indication of the combustibility of the vapors of a mineral oil, and is defined as the lowest temperature at which the vapor of an oil can be ignited under specified conditions. Flash point is clearly related to safety. Flash point of lubricating oils is measured using ASTM D 92. An open cup of oil is heated at a specific rate while periodically passing a small flame over its surface. The flash point is considered to be the lowest temperature at which the oil vapors will ignite, but not sustain a flame. |
For example, the flash point of an ISOVG 32 turbine oil might be 222 degree C. If one continues to heat the oil and continues to pass the small flame across the surface, the vapors will eventually sustain a flame and this is the fire point. The fire point of the same turbine oil would approach 252 degree C. |
