flammables. 1. properties of flammables combustion (redox) reactions solids, gases, most commonly...
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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
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