Chemistry & Toxicology Definitions and terminology
Objectives To understand basic chemistry and toxicology terms (29 CFR 1910.120 (q) (6) (iii)) To understand the 8 UN hazard classes To demonstrate understanding by relating terms to decisions made on scene
Properties of Flammable Materials Flash point - the temperature at which a fuel will give off enough vapors to flash near the surface but not continue to burn Fire point - the temperature at which a fuel will give off enough vapors to support combustion
More Definitions... AgencyFlammableCombustible DOT<141°F141-200°F OSHA<100°F>100°F NFPA<100°F>100°F EPA<140°F
Auto-ignition Temperature The minimum temperature to which a fuel in air must be heated to start self-sustained combustion without a separate ignition source. Gasoline? 800 o F Diesel? 400 o F
Flammable Range LEL UEL GAS } Too Rich Too Lean } The concentration of fuel in air required to burn. It falls between the LEL and UEL. The wider the flammable range the more dangerous the fuel.
Vapor Pressure Gasoline The pressure molecules apply towards the atmosphere while trying to escape a liquid surface (evaporate). Vapor molecules are always over a liquid, if the Vp is higher than the atmospheric pressure, the liquid will evaporate. Boiling point is when a liquids Vp is equal to the atmospheric pressure.
Specific Gravity The specific gravity of a product is the weight of the product compared to the weight of water (Water = 1) Examples: Gasoline.68 Parathion1.27
Vapor Density Vapor density is the weight of the product compared to air (Air = 1) Examples: Gasoline3.5 Methane0.55
Crossing state lines Melting point Boiling point Sublimation
Mixing substances Miscibility: The ability for two substances to mix so that they will not separate into phases. Alcohol into water, acid into water Solubility : A measure of how much solute will dissolve into a solvent. Usually refers to water when possible, but obviously not everything dissolves in water.
UN Hazard Classes Classes 1 – 9 UN hazard class Symbol of the hazard Color indicates hazard Center may have words or UN ID number
Explosives What is the difference between an explosion and rust? Rate Detonation exceeds the sound barrier and deflagration is slower than the sound barrier.
Gases Burning state for all matter May be kept under high pressure Can be liquefied by pressure or temperature
Flammable Liquids One of the most common commodities transported If gasoline and diesel are carried together, it can be placarded with the worst hazard Carried in MC-306 and MC-307 Toxicity is also a hazard
Flammable Solids Some are water reactive such as sodium or calcium carbide. Some are pyrophoric (reacts with air) such as phosphorus.
Oxidizers Bring their own oxygen to the table Make ordinary combustible highly flammable Organic peroxides can breakdown into explosive crystals MSST: Maximum safe storage temperature SADT: Self accelerating decomposition temperature
Poisons These are toxic to life May be marked: Marine pollutant Keep from food stuffs Inhalation hazard Table II (49 CFR) commodity, meaning it is placarded for any amount being transported
Radioactive Alpha radiation ( α ): About the size of a proton, its heavy and doesnt travel far. Can be stopped by paper. Beta radiation ( β ): About the size of an electron, travels farther than α but is still stopped by skin Gamma ( γ ): Not a particle, its a wave. Travels through the body. Thick concrete, lead, or water can stop it. TDS: Time, Distance, Shielding are your only protections from radiation.
Corrosives 1714 pH is a measure of the H + ion concentration. A pH of 7 is 10,000,000 times weaker an acid that a pH of 1. wateracid base Neutralization is an option for mitigation and decon for incidents involving corrosives.
Miscellaneous Whatever didnt fit in the other drawers. Often these are dusts, ores, or hazardous wastes (n.o.s. – not otherwise specified)
Toxicity Dose response: The relationship between the amount of a substance taken in over time and its effect. BAC Time BAC Which type of consumption will have the worst acute effect? How does this work with chronic effects?
Effects Carcinogen: Cancer causing. 100% chance that being a lab rat causes cancer. –unknown Mutagen: DNA changing, will effect future offspring. Teratogen: Effects a fetus.
MSDS (a) Physical and chemical characteristics (b) Physical hazards of the material (c) Health hazards of the material (d) Signs and symptoms of exposure (e) Routes of entry (f) Permissible exposure limits (g) Responsible party contact (h) Precautions for safe handling (including hygiene practices, protective measures, procedures for cleanup of spills or leaks) (i) Applicable control measures including personal protective equipment (j) Emergency and first aid procedures
Pesticides (a) Name of pesticide (b) Signal word Caution Warning Danger (c) Precautionary statement (d) Hazard statement (e) Active ingredient