Physics Van 3-site Navigational Menu

Physics Van Navigational Menu

Q & A: Oil on Fire - Flash Point, Fire Point

Learn more physics!

Most recent answer: 10/22/2007
Q:
What’s the boiling point of oil?,what’s depend by the viscosity?so what’s flsh point? its depend whit fire point
- isis (age 22)
ub university, indonesia
A:

Isis -

The first part of your question has . You may also want to look at  to find out why oil often smokes before it boils. On to your other questions:

What’s the flash point?

According to , an oil’s flash point is the temperature at which "a flame appears and instantaneously propagates itself over the entire surface. The oil flashes because a flammable mixture results when it is heated sufficiently, causing vapors to emerge and mix with oxygen in the air. The flash point temperature of an oil corresponds roughly to a vapor pressure of 3-5 mm Hg. When a small flame (ignition source) is applied to the oil’s surface this vaporous mixture will burn momentarily and then extinguish if the critical temperature has been reached." Naturally, the exact flash point will vary depending on the type and composition of the oil. Follow the link above for some great information on how the flash point can be useful.

Another example of how it can be useful is in candle-making. When you make a candle, you want to be able to burn the wick without the whole surface of the candle catching fire. Commercial sites like often list the flash points for the oils they sell.

What’s the fire point?

To quote again, "Continued heating of the oil (typically 50-75° F above the flash point temperature) will cause the fire point to be reached. As the name implies, the fire point is the temperature at which a sustained flame results (longer than four seconds)." Naturally, the fire point is always going to be higher than the flash point.

-Tamara


(published on 10/22/2007)

Follow-up on this answer.