Domain III: Store Materials with Hazards Flashcards
What is combustion?
Combustion can be defined as the rapid chemical reaction of oxygen with a fuel. when a fuel has burned the carbon in the fuel reacts with oxygen to form either carbon dioxide or carbon monoxide.
There are four elements required for combustion. These are oxygen, fuel, source of ignition or sufficient heat, and chemical chain reaction.
Fuel is a necessary component of all combustion reactions. The fuel can be present in solid, liquid, vapor, or gaseous form. Examples of solid fuels that can support combustion are wood, coal, textiles, paper, plastics, and some metals such as magnesium and cesium.
What is BLEVE?
Boiling Liquid-Expanding Vapor Explosion
BLEVE refers to the failure of a container at atmospheric pressure holding a liquid above its boiling point.
What are some of the common gases generated from fires and what are their dangers?
Carbon monoxide - As a result of the incomplete combustion of carbon-containing compounds, CO is produced in large amounts during a fire. Although CO is not the most toxic fire gases, it is 210 times more reactive with blood than oxygen. Thus, CO poisons humans by a form of asphyxiation.
Carbon Dioxide - Fires produce large amounts of CO2. CO2 itself is not a toxic gas. Its major contribution to death and injury results from its reducing the relative concentration of oxygen in the air.
Hydrogen Cyanide - Hydrogen cyanide, a deadly gas, can be produced from the combustion of wool, silk, acrylonitrile, acrylates, agricultural chemicals, rodenticides, and polyurethane.
Sulfur Dioxide - This gas can be produced from fires from the combustion of sulfur-containing materials. A strong irritant, it is intolerable well below lethal concentrations.
Ammonia - During fires, ammonia can be generated from the combustion of materials such as wool, silk, fertilizers, explosives, acrylonitrile, and nylon.
Hydrogen Chloride - This gas can be generated by the combustion of materials such as PVC, dyes, perfumes, agricultural chemicals, and some fire-retardant materials.
Hydrogen Sulfide - During fires, hydrogen sulfide can be generated as a result of the incomplete combustion of sulfur-containing compounds such as wool and rubber.
Nitrogen dioxide - This gas can be generated from the combustion of nitrogen-containing compounds such as fabrics, cellulose nitrate, celluloid, catalysts, and polymerization inhibitors.
What is an exothermic and endothermic reaction?
Exothermic reactions release energy to their surroundings.
Give off heat
combustion is an exothermic reaction
Endothermic reactions absorb energy from their surroundings
What is the NFPA 704?
National Fire Protection Association
704
Standard System for the Identification of the Hazards of Materials for Emergency Response
This standard presents a simple, readily recognized, and easily understood system of markings (commonly referred to as the “NFPA hazard diamond”) that provides an immediate general sense of the hazards of a material and the severity of these hazards as they relate to emergency response.
This uses the standard NFPA Diamond.
What does each section of the NFPA Diamond represent?
Blue - Health Hazard
Red - Fire Hazard
Yellow - Reactivity
White - Specific Hazard
What are grounding and bonding?
Why are grounding and bonding important for flammable liquids?
Bonding is the mechanism of connecting two conducting bodies by means of a conductor.
Grounding provides a conducting path between the charged object and the earth.
Many flammable liquids can build up electrostatic charges when agitated or during transfer; so it is imperative to ensure that proper bonding and grounding procedures have been followed before any attempt is made to transfer a flammable liquid.
What is the NFPA definition of a flammable liquid?
The NFPA defines a flammable liquid as any liquid that has a closed cup flash point below 100°F and a vapor pressure not exceeding 40 psia (pounds per square inch absolute) at 100°F.
What is the NFPA definition of a combustible liquid?
A combustible liquid is one whose flash point is 100°F or higher.
What is the definition of a flashpoint?
Flash point is defined as the lowest temperature at which a liquid can generate enough vapor above its surface to support combustion in the presence of a source of ignition.
What is vapor pressure?
The pressure exerted by vapor on its liquid at equilibrium is called the vapor pressure of the liquid at the temperature of the system.
Vapor pressure of a liquid always increases with an increase in temperature.
What is a fire point?
The fire point is the lowest temperature at which a flammable liquid in an open container gives off vapors to continue to burn once it has been ignited. The fire point usually is higher than the flash point.
What is explosive or flammable range?
The explosive or flammable range encompasses those concentrations of flammable vapor or gas in air that can ignite in the presence of a source of ignition.
The term Lower Flammability Limit (LFL) is used to describe the minimum concentration of vapor in air below which a flame will not propagate through the mixture.
The term Upper Flammability Limit (UFL) is used to describe the maximum concentration of flammable vapor in air above which a flame will not propagate.
What is autoignition temperature?
Autoignition temperature is the lowest temperature that will produce combustion in the absence of an ignition source.
What is specific gravity?
Specific gravity describes the density of a liquid relative to the density of water. Most flammable liquids have a specific gravity less than water and will float on top. There are a few that are heavier and will sink.