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1 Flammable and Combustible Liquids INSY 3020 Spring 2006

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2 Where do you encounter Flammable Liquids Gasoline Car/Truck BBQ Deodorant Sprays/Perfumes

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3 Flammable and Combustible Liquids 29CFR 1910.106 Based on National Fire Protection Association-NFPA 30 Code The standard applies to handling, storage and use of flammable and combustible liquids with flash point below 200F

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4 Definitions Boiling Point It is the temperature at which the liquid and vapor (gas) phases of a substance can exist in equilibrium Temp at which vapor pressure = 1 atm

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5 Definitions Vapor Pressure Partial pressure of the vapors produced at the surface of a liquid at a given temperature (i.e. 100 F) Remember, its the vapor which burns, not the liquid. How will you find the vapor pressure of a liquid?

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6 Definitions Vapor Density The weight of a flammable vapor compared to air. (Air = 1) Vapor with high density are more dangerous than vapors with low density.

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7 Definitions Relationship between Boiling Point and Vapor Pressure The boiling point is the temperature at which the vapor pressure of the liquid equals the external pressure

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8 Definitions Flash Point The minimum temperature at which a liquid gives off enough vapor within a test vessel in sufficient concentration to form an ignitable mixture with air near the surface of the liquid.

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9 How to Determine Flash Point? It is determined by heating the liquid in test equipment and measuring the temperature at which a flash will be obtained when a small flame is introduced above the surface of the liquid.

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10 How will you differentiate between a flammable liquid & a combustible liquid? Depends on flash point and vapor pressure/boiling point Both are properties of materials

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11 Classes of Flammable and Combustible Liquids 200 140 100 73 IIIA II IC IAIB 100 COMBUSTIBLE (Flash Point >100 F) FLAMMABLE (Flash Point < 100 F) Boiling Point (F) Flashpoint (F o )

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12 Flammable and Combustible Liquids Flammable Liquids Any liquid having a flashpoint below 100 o F (37.8 o C) or lower. NFPA Classes IA, IB, & IC Combustible Liquids Any liquid having a flashpoint at or above 100 o F (37.8 o C). NFPA Classes II & IIIA & B

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13 Flammable Liquid Classification Flammable liquids are also called as Class I liquids Class IA - flashpoints