Yes, the flash point does sound low, but what it actually is telling us
is that we could put a match directly into the solvent if the
temperature of the solvent is less than 110 degrees, the match would go
out. Many solvents are rated at 105 F or less. Gasoline and acetone's
flash points are less than 73 F (I have some of both out in the garage).
Even in the South, chances are the actual temperature of the solvent
would not reach 110 F (should take several days when the average 24 hour
temperature is well above 110 F). At a solvent temperature of 109 F, we
still should be able to put out cigars in the parts washer. Agitene at
110 F is not considered "flammable," only "combustable," like heating
oil or diesel.
In comparison, the flash point for ethyl alcohol (Scotch) is 55 F---be
careful smoking that cigar with your scotch! I'm attaching a summary I
grabbed from the web.
doug
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Flash Point
A fire will not occur until a flammable liquid is
heated above a certain temperature called the
flash point. Put more scientifically, flash point is
the lowest temperature at which a liquid gives off
enough vapor to cause a momentary flame in the
presence of an ignition source.
In general, the lower the flash point, the greater
the hazard. If the liquid's temperature is below the
flash point, it simply will not give off enough
vapor to burn. For example, the flash point of one
of my favorite compounds, ethyl alcohol, is 55 F.
If we put a lighted match into an ice-cold glass of
Scotch or Brandy, the match would go out.
However, when the glass warms up to a little over
55 F, the vapors formed at the mouth of the glass
would ignite if the match is brought close to the
edge.
Liquid Classes
Flash point and boiling point are important to
know because they are used as the basis for
identifying liquids that present a similar degree of
hazard. Those chemicals with flash points less
than 100 F are referred to as flammable liquids,
while those with flash points greater than, or
equal to 100 F, are called combustible liquids.
Flammable and combustible liquids can be further
divided into classes. Class I-A flammable liquids
are those with flash points less than 73 F, and
boiling points less than 100 F. Ethyl ether,
pentane, and ethylene oxide are examples of Class
I-A materials.
Class I-B flammable liquids include materials like
acetone, cyclohexane, and gasoline that have flash
points less than 73 F and boiling points at or above
100 F. Class I-C flammable liquids are solvents
like butyl alcohol, turpentine, and xylene with
flash points between 73 F and 100F.
Class II combustible liquids are those with a flash
point above 100 F but below 140 F. Kerosene,
diesel fuel, and No. 2 heating oil are familiar
examples. Class III-A combustible liquids have a
flash point between 140 F and 200 F and include
acetophenone, diethyl benzene, and isopherone.
Class III-B are those with a flash point greater
than 200 F and include many natural oils like
castor oil, olive oil, and peanut oil.
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