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Flammables


A flammable chemical is any solid, liquid, vapor, or gas that ignites easily and burns rapidly in air. Consult the appropriate MSDSs before beginning work with flammables.

Flashpoint, Boiling Point, Ignition Temperature, and Class

Flammable chemicals are classified according to flashpoint, boiling point, and ignition temperature. Flashpoint (FP) is the lowest temperature at which a flammable liquid gives off sufficient vapor to ignite. Boiling point (BP) is the temperature at which the vapor pressure of a liquid is equal to the atmospheric pressure under which the liquid vaporizes. Flammable liquids with low BPs generally present special fire hazards. The FPs and BPs of certain chemicals are closely linked to their ignition temperature — the lowest temperature at which a chemical will ignite and burn independently of its heat source.

The following table illustrates flammable class characteristics: (OSHA Std 29 CFR1910.106 and NFPA 30)

CLASS

FLASHPOINT
(°F)

BOILING POINT
(°F)

EXAMPLES
1A
< 73
< 100
Ethyl ether
"Flammable" aerosols
1B
< 73
> 100
Acetone
Gasoline
Toluene
1C
> 73
< 100
Butyl alcohol
Methyl isobutyl ketone
Turpentine
2
100 - 140
---
Cyclohexane
Kerosene
Mineral spirits
3A
140 - 199
---
Butyl cellosolve
3B
> 200
---
Cellosolve
Ethylene glycol
Hexylene glycol

The following table provides examples of common flammables and their flashpoint and class.

CHEMICAL FLASHPOINT (°F) CLASS
Acetone
0
1B
Benzene
12
1B
Butyl Acetate
>72
1C
Carbon Disulfide
-22
1B
Cyclohexane
-4
1B
Diethylene Glycol
225
3B
Diethyl Ether
-49
1A
Ethanol
55
1B
Heptane
25
1B
Isopropyl Alcohol
53
1B
Methanol
52
1B
Pentane
<-40
1A
Toulene
40
1B

Conditions for a Fire

Improper use of flammable liquids can cause a fire. The following conditions must exist for a fire to occur:

  • Flammable material must be present in sufficient concentration to support a fire (i.e., fuel).
  • Oxygen or another oxidizer must be present.
  • An ignition source must be present (i.e., heat, spark, etc.).

When working with flammables, always take care to minimize vapors which act as fuel.

Safe Handling Guidelines for Flammables

Follow these guidelines when working with flammable chemicals:

  • Handle flammable chemicals in areas free from ignition sources.
  • Never heat flammable chemicals with an open flame. Use a water bath, oil bath, heating mantle, hot air bath, etc.
  • Use ground straps when transferring flammable chemicals between metal containers to avoid generating static sparks.
  • Use a fume hood when there is a possibility of dangerous vapors. (Ventilation will help reduce dangerous vapor concentrations.)
  • Restrict the amount of stored flammables, and minimize the amount of flammables present in a work area.
  • Remove from storage only the amount of chemical needed for a particular experiment or task.

 June 2011
Revised November 2014