The
flash point is the lowest temperature to which a lubricant
must be heated
before its vapor, when mixed with air, will ignite but not
continue to burn. The fire point is the temperature
at which lubricant combustion will be sustained. The flash
and fire points are useful in determining
a lubricant’s volatility and fire resistance. The flash
point can be used to determine the transportation
and storage temperature requirements for lubricants.
Lubricant producers can also use the flash
point to detect potential product contamination. A lubricant
exhibiting a flash point significantly lower
than normal will be suspected of contamination with a
volatile product. Products with a flash point less
than 38° C (100°F)
will usually require special precautions for safe handling.
The fire point for a lubricant
is usually 8 to 10 percent above the flash point. The flash
point and fire point should not be confused
with the auto-ignition temperature of a lubricant, which is
the temperature at which a lubricant will
ignite spontaneously without an external ignition source.
