Limits of Flammability of Solvents

Limits of Flammability of Solvents 

• The limits of flammability is the range that a mixture of air and a solvent vapor is flammable.
• Mixtures can be too lean (not enough vapor) or too rich (too much vapor) to ignite and burn.
• An example is an automobile engine. Even though gasoline is very flammable, the car won’t run if the mixture is too rich (too much gasoline vapor) or too lean in the carburetor or fuel injection system.
• In most work situations, the “lower flammable limit” (LFL) is the main concern.
• Vapors from flammable liquids in the workplace are often too diluted to catch fire or explode.
• In a small room or confined space like a tank, the vapor levels can quickly go above the LFL.
• OSHA regulations prohibit anyone entering a confined space if flammable vapor levels are above 10% of the LFL. LFL is also called “LEL” or “lower explosive limit”.