FLAMMABLES

1. PROPERTIES OF FLAMMABLES

Combustion (redox) reactions

Solids, gases, most commonly liquids

Fire Tetrahedron

Ignition sources

External-

Internal – spontaneous comb.

2. DEFINITIONS / HAZARDS

a. Flash Point

Lowest temp. at which liquid gives off sufficient vapor to form ignitable

mixture with air at or near surface of liquid when exposed to a spark.

Examples – see handout

Significance

b. Auto-ignition Temperature

Temperature of flammable liquid at which self-sustained combustion occurs in absence of external ignition source. (internal ignition source – heat)

Example

Ether – 1600C

c. Limits of Flammability

LEL (Lower Explosion Limit)

Minimum conc. of vapor in air below which a flame is not propegated when ignited.

UEL (Upper Explosion Limit)

Maximum conc. of vapor in air above which flame is not propegated when ignited.

** Significance of limits

3. CLASSIFICATION OF FLAMMABLES

Class I A Class I B Class I C

730F 730F 73-1000F

1000F > 1000F

Pentane

Ether

Acetaldehyde

Ethanol

Acetone

Benzene

p-Xylene

Flash Point

Boiling Point

Examples

4. PECAUTIONARY MEASURES

a. Reduce Possible Ignition Source

No flames

Sparking from electrical motors

Ground and bond metal containers

b. Reduce Concentrating Vapors

Minimize organic solvents poured down drain

Proper ventilation

Possibility of “Flashback”

c. Proper Storage Containers

Minimal size / type in lab

Flammable Safety Cans

Flammable Storage Cabinets

5. EMERGENCY SYSTEMS AND PRODEDURES

Appropriate # and type extinguishers

Fire Blanket

Fire Drills

Proper clean-up for spills

Spill pillows

Stop, drop, and roll method