Chapter 4 Flashcards
Gas
Compressible substance, with no specific volume, that tends to assume the shape of a container. Molecules move about most rapidly in this state
liquid
Incompressible substance woth a constant volume thats assumes the shape of its container; molecules flow freely, but substantial cohesion prevents them from expanding as a gas would
Solid
Substance that has a definite shape and size; the molecules of a solid generally have very little mobility
Incidents involving gases are potentially
the most dangerous for emergency responders
Compressed Gas
Gas that at normal temperature, exists solely as a gas when pressurized in a container as opposed to a gas that becomes a liquid when stored under pressure
Liguefied Gas
Confined gas that at normal temperatures exists in both liquid and gaseous states
Combustible Gase Detector
Device that detects the presence and or concentration of predefined combustible gases in a defined area. May require additional features to indicate the results to an operator
Be cautious and alert to vapors from liquids as they may be
Contact hazards Inhalation Hazards Flammable Corrosive Toxic
Micron
is the unit of measure typically used to express particle size. Unit of length equal to one millionth of a meter
Physical properties
Properties that do not involve a change in the chemical idntity of the substance, but affect the physical behavior of the material inside and outside the container, which involves the change of the state of the material. Exmples include boiling point, specific gravity, vapor density, and water solubility
Vapor Pressure
The pressure at which a vapor is in equilibrium with its liquid phases for a given temperature; liquids that have a greater tendency to evaporate have higher vapor pressuress for a given temperature
The lower the boiling point of a material
the highr the vapor pressure will be
Boiling point
Temperature of a substance when the vapor pressure equals atmospheric pressure. At this tempeature, the rate of evaporation exceeds the rate of condensation. At this point, more liquid is turning into gas then gas is turning back into a liquid
Sublimate
Change directly from a solid into a gas without going into a liquid state in between
Vapor density
Weight of pure vapor or gas compared to the weight of an equal volume of dry air at the same temperature and pressure. A vapor density less than one indicates a vapor lighter than air; a vapor density greater than one indicates a vapor havier than air
Material with a vapor density less than one included
helium, neon, acetylene and hydrogen.
Most gases have a vapo density
greater than one
Common materials with a vapor density greater than one
Propane Hydrogen sulfide Ethane Butan Chlorine Sulfur dioxide
Solubility
Degree to which a solid, liqud, or gas dissolves in a solvent
Hydrodcarbon
Gasoline, diesel fuel, pentane
Polar solvent
alcohol, methanol, methylethylketone MEK, combine with water, the two liquids mix.
irritant agents that are water soluble usually cause
early upper respiratory tract irritation, resulting in coughing and throat irritation.
Partially water soluble chemicals will
penetrate into the lower respiratory system and casus delayed (12 to 24 hours) symptoms that include breathing difficulties, pulmonary edema and coughing up blood
Misciblilty
Two or more liquids’ capability to mix together
Immiscible
Incapable of being mixed or blended with another substance
Specific Gravity
Mass weight of a substance compared to the weight of an equal volume of water at a given temperature. A specific gravity less than one indicates a substance lighter than water; a specific gravity greater than one indicates a substance heavier than water
Most flammable liquids have specific gravities
less than one and will float on water
Persistence
Length of time a chemical agent remains effective without dispersing
Dispersion
Act or process of being spread widely
Viscosity
Measure of a liquid’s internal friction at a given temperature. This concept is informally expressed as thickness, stickiness and ability to flow
Mercaptan
A sulfur containin organic compound often added to natural gas as an odorant. Natural gas is odorless; natural gas treated with mercaptan has a strong odor. Also known as a Thiol
Chemical properties
Relating to the way a substance is able to change into other substances. Chemical properties reflect the ability to burn, react, explode, or produce toxic substances hazardous to people or the environment
Flash point
Minimum temperature at which a liquid gives off enough vapors to form an ignitable mixture with air near the surface of the liquid
Fire point
Temperature at which a liquid fuel produces sufficient vapors to support combustion once the fuel is ignited. Fire point must exceed five seconds of burining duration during the test. The fire point is usually a few degrees above the flash point
Flmammable liquid
Any liquid having a flash point below 100F (37.8C) and a vapor pressure not exceeding 40 psi absolute
Combustible Liquid
Liquid having a flash point at or above 100f (37.8C) and below 200F (93.3C)
Nonflammable
incapable of combustion under normal circumstances; normally used when referring to liquids or gases
Autoignition Temperature
The lowest temperature at which a combustible material ignites in air without a spark or flame
Ignition Temperature
Minimum temperature to which a fuel (other that a liquid) in air must be heated in order to start self sustained combustion independent of the heating source
Lower Flammable (explosive) Limit (LFL
lower limit at which a fgammable gas or vapor will ignite and support combustion; below this limit the gas or vapor is too lean or thin to burn
Upper Flammable Limit (UFL)
Upper limit at which a flammable gas or vapor will ignite. Above this limit the gas or vapor is too rich to burn.
Ph
measure of the acidity or alkalinity of a solution
Acid
Compound containing hydrogen that reacts with water to produce hydrogen ions; a proton donor; a liquid compound with a ph les that 7. acidic chemicals ar corresive
Ion
Atom that has lost or gained an electron thus giving it apositive or negative charge
Base
Any alkaline or caustic substance; corrosive water soluble compound or substance containing group forming hydroxide ions in water solution that reacts with an acid to form a salt
Disssociation (chemical)
Process of splitting a molecule or ionic compounds into smaller particles especially if the process is reversible
Saponification
Reaction between an alkaline and a fatty acid that produces soap
Base Solution
Solution that has a ph between 7 and 14
Reactivity
Ability of a substance to chemically react with other materials, and the speed with which that reaction takes place
Reaction material
Substance capable of chemically reacting with other substances; for example, material that reacts violently when combined with air or water
Activation Energy
Minimum energy that starts a chemical reaction when added to an atomic or molecular system
Strong Oxidizer
Substance that readily gives off larges quantities of oxygen, thereby stimulating combustion; produces a strong reaction by readily accepting electrons from a reducing agents (Fuel).
Reducing agent
Fuel that is being oxidized or burned during combustion
Inhibitor
Material that is added to products that easily polymerize in order to control or prevent an undersired reaction Also known as Stabilizer
Nonionizing radiation
Series of energy waves composed of oscillating electric and magnetic fields traveling at the speed of light.
Ionizing radiation
Radiation that causes a chemical change in atoms by removing their electrons.
Electron
Subatomic particle with a physical mass and a negative electric charge
Photon
Weightless packet of electromagnetic energy, such as x-rays or visible light
Radioactive Material (RAM)
Material with an atomic nucleus that spontaneously decays or disintegrates, emitting radiation as particles or electromagnetic waves at a rate of greater that 0.002 microcuries per gram
Exposure
(1) Contact with a hazardous material, causing biological damage, typically by swallowing, breathing, or touching (skin or eyes). Exposure may be short-term (acute exposure), or intermediate duration, or long-term (chronic exposure). (2) People, property, systems, or natural features that are or may be exposed to the harmful effects of a hazardous materials emergency.
Dose
Quantity of a chemical material ingested or absorbed through skin contact for purposes of measuring toxicity.
Contamination
Impurity resulting from mixture of contact with a foreign substance.
Contaminant
Foreign substance that compromises the purity of a given substance.
Inverse Square Law
Physical law that states that the amount of radiation present is inversely proportional to the square of the distance from the source of radiation.
Toxicity
Degree to which a substance ( toxin or poison) can harm humans or animals. Ability of a substance to do harm within the body.
Systemic Effect
Damage spread through an entire system; opposite of a local effect, which is limited to a single location.
Asphyxiant
Any substance that prevents oxygen from combining sin sufficient quantities with the blood or from being used by body tissues.
Irritant
Liquid or solid that, upon contact with fire or exposure to air, gives off dangerous or intensely irritating fumes. Also known as Irritating Material.
Convulsant
Poison that causes convulsions
Carcinogen
Cancer producing substance
Allergen
Material that can cause an allergic reaction of the skin or respiratory system.
Carbon Monoxide (CO)
Colorless, odorless, dangerous gas (both toxic and flammable) formed by the incomplete combustion of carbon. It combines with hemoglobin more than 200 times faster than oxygen does, decreasing the blood’s ability to carry oxygen.
Hydrogen Cyanide (HCN)
Colorless, toxic, and flammable liquid until it reaches 79 degrees F (29 degrees C). Above that temperature, it becomes a gas with a faint odor similar to bitter almonds; produced by the combustion of nitrogen-bearing substances.
Carbon Dioxide (CO2)
Colorless, odorless, heavier than air gas that neither supports combustion nor burns; used in portable fire extinguishers as an extinguishing agent to extinguish Class B or C fires by smothering or displacing the oxygen. CO2 is a waste product of aerobic metabolism.
Infectious
Transmittable; able to infect people.
Pathogen
Biological agent that causes disease or illness.
Contagious
Capable of transmissions from one person to another through contact or close proximity.
Infectious Substance
Substance that is known, or reasonably expected, to contain pathogens.
Explosive
Any material or mixture that will undergo an extremely fast self-propagation reaction when subjected to some form of energy.
Division Number
Subset of a class within an explosives placard that assigns the product’s level of explosion hazard.
Compatibility Group Letter
Indication on an explosives placard expressed as a letter that categorizes different types of explosive substances and articles for purposes of stowage and segregation.
Binary Explosive
A type of explosive device or material with two components that are explosive when combined but not separately.
Vapor Explosion
Occurrence when a hot liquid fuel transfers heat energy to a colder, more volatile liquid fuel. As the colder fuel vaporizes, pressure builds in a container and can create shock waves of kinetic energy.
Organic Peroxide
Any of several organic derivatives of the inorganic compound hydrogen peroxide.
Maximum Safe Storage Temperature (MSST)
Temperature below which the product can be stored safely. This is usually 20-30 degrees cooler than the SADT temperature, but may be much cooler depending on the material.
Self-Accelerating Decomposition Temperature (SADT)
Lowest temperature at which product in a typical package will undergo a self-accelerating decomposition. The reaction can be violent, usually rupturing the package, dispersing original material, liquid and/or gaseous decomposition products considerable distances.
Poison
Any material, excluding gases, that when taken into the body is injurious to health.
Inhalation Hazard
Any material that may cause harm via inhalation.
Isotope
Atoms of a chemical element with the usual number of protons in the nucleus, but an unusual number of neutrons; has the same atomic number but a different atomic mass from normal chemical elements.
Incident involving gases are
Potentially the most dangerous for emergency responders
Incidents involving gas require
Complex and difficult actions to protect responders and the public
Viruses
Are the simplest types of microorganisms that can only replicate themselves in the living cells of their hosts. Viruses do not respond to antibiotics
Bacteria
Are microscopic, single called organisms. Bacteria may cause disease in people either by invading the tissues or producing toxins
Diseases associated with biological hazards or threats are
Malaria Tuberculosis Hep B Measles Ebola Influenzas Typhiod
Potential biological weapons include
Smallpox (virus)
Anthrax
Botulism (toxin from the bacteria clostridium botulinum)
Product’s hazard class is assigned based on
It’s most dangerous chemical and or physical properties
Class 1
Explosives
Class 2
Gases
Class 3
Flammable liquids (and combustible liquids in the US)
Class 4
Flammable solids, spontaneously combustible, and dangerous when wet
Class 5
Oxidizes and organic peroxide’s
Class 6
Poisons, poisons inhalation hazards, and infectious substance
Class 7
Radioactive
Class 8
Corrosive
Class 9
Miscellaneous hazards materials
The primary hazards of explosives are
Thermal and mechanical
The blast pressure was is the
Primary reason for injuries and damage
The potential hazards of gas include
Energy
Toxicity (including asphyxiation)
Corrosivity
Class 2 gas
Heat hazards
Fire, particularly associated with Division 2.1 and oxygen, gases can travel great distances to an ignition source
Class 2 gas
Asphyxiation hazards
Leaking or released gases displacing oxygen in a confined space
Class 2 gas
Cold hazards
Exposure to Division 2.2 cryogens
Class 2 gas
Mechanical hazards
A BLEVE for container exposed to heat or flame;a ruptured cylinder rocketing after exposure to heat or flame
Class 2 gas
Chemical hazards
Toxic and or corrosive gases and vapors particularly associated with Divsion 2.3
The primary hazards of flammable and combustible liquids are
Energy
Corrosivity
Toxicity
Class 3 flammable liquids
Thermal hazards
Fires and vapor explosions
Class 3 flammable liquids
Asphyxiation
Heavier than air vapors displacing oxygen and low lying and or confined spaces
Class 3 flammable liquids
Chemical hazards
Toxic and/or corrosive gases and vapors; these may be produce by fires
Class 3 flammable liquids
Mechanical hazards
A BLEVE, for containers exposed to heat or flame; caused by a vapor explosion
Class 3 flammable liquids
Vapors
Can mix with air and travel great distances to an ignition source
Class 3 flammable liquids
Environmental hazards
Caused by runoff from fire control
4.1
Flammable solids
4.2
Spontaneously combustible materials
4.3
Dangerous when wet
The primary hazards of class 4 materials are
Chemical energy
Mechanical energy
Corrosivity
Toxicity
5.1
Oxidizer - Typically Solids or aqueous solutions
5.2
Organic peroxide’s - liquid or solids
The primary hazards of class 5 are
Thermal
Mechanical
Chemical
At night winds tend to be
Lighter, so gases and vapors will not typically travel as far
Many hazmat related injuries are due to
The inhalation of vapors or gases
Be cautious and alert to vapors from liquids as they may be
Contact hazards Inhalation hazards Flammable Corrosive Toxic
BLEVE most commonly occur when
Flames contacts tank shell above the liquid level or when insufficient water is applied to keep a tank shell cool
Many organic materials ignite
Spontaneously when they come into contact with a strong oxidizer
Many times the SADT is written into
The SDS as decomposition temperature
The following actions can ignite flammable/explosive atmosphere
Opening or closing a switch or electrical circuit such as a light switch
Turning on a flash-light
Operating a radio
Activating a cell phone
Viscous materials tend to be
More persistent and may have a lower vapor pressure.
Inhalation hazards are
Toxic vapor hat can be lethal if inhaled
