chapter 2 hazardous materials properties and hazards

City of P igeon Forge F i re DepartmentD i v i s i o n o f Tr a i n i n g a n d C o n ti n u i n g E d u c a ti o n

Chapter 2

Hazardous Materials Properties and Hazards

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Hazardous MaterialsProperties and Hazards

• Introduction– Hazardous materials may be• Elements• Compounds• Mixtures

– Gaseous– Liquid– Solids



• Introduction– They may present a direct threat to health• Poison

– Carcinogens– Toxic or highly toxic– Irritants– Corrosives – Sensitizers



• Introduction– They may be considered dangerous because of

their physical hazards• Flammable• Compressed gases• Explosives• Organic peroxides• Oxidizers• Pyrophoric chemicals• Cryogenic materials• Radioactive materials• Water-reactive materials



• Introduction– The severity of hazards these materials

present range from• Insignificant • Catastrophic

– Depends on material and quantity involved



• Introduction– Exposures to hazardous materials• Acute

– Single occurrence• Chronic

– Long-term– Reoccurring



• Introduction– Health effects from exposure• Acute

– Short-term effects– Appear within hours or days

» Vomiting» Diarrhea

• Chronic– May take years to appear

» Cancer



• Hazardous Materials Properties – Awareness level• Need to understand

– Basic hazards associated with different classes of hazardous materials» Flammables» Corrosives» Reactives

– Operations level• Need to know how hazardous materials behave• Signs and symptoms of an exposure



• Hazardous Materials Properties – Matter• Substances that make up everything in the world

– Gas» Fluid that has neither independent shape nor volume» Tend to expand indefinitely

– Liquid» Fluid that has no independent shape but does have a specific volume» Flow in accordance with the laws of gravity

– Solid» Substance that has both a specific shape and volume (without a container)



• Hazardous Materials Properties – Matter



• Hazardous Materials Properties – Flammability• Majority of hazardous materials incidents involve

materials that are flammable– Burn– Explode

• Flammable hazards depend on – Flash point– Autoignition temperature – Explosive or combustible range



• Hazardous Materials Properties – Flash Point• Minimum temperature at which a liquid or

volatile solid gives off sufficient vapors to form an ignitable mixture with air near its surface– Vapors will flash– Will NOT continue to burn

• DO NOT confuse with Fire Point



• Hazardous Materials Properties – Fire Point• Temperature at which enough vapors are given off

to support continuous burning– Temperature is usually only slightly higher than the

flash point

• Liquids and solids themselves do not burn– Vapors they produce burn

» As temperature increases, more vapors are produced

• Flammable gases have no flash point



• Hazardous Materials Properties – Autoignition Temperature/Autoignition Point• Minimum temperature to which the fuel in air

must be heated to initiate self-sustained combustion– No independent ignition source– Spontaneously ignites– Considerably higher than the flash and fire points

• Ignition temperature is often used synonymously



• Hazardous Materials Properties – Flammable, Explosive or Combustible Range• Percentage of the gas or vapor concentration in

air that will burn or explode if ignited



• Hazardous Materials Properties – Flammable, Explosive or Combustible Range• Lower explosive limit / lower flammable limit

– LEL / LFL» Lowest concentration of a vapor/gas that will

produce a flash of fire» Concentrations lower than the LEL

• Mixture is too lean to burn



• Hazardous Materials Properties – Flammable, Explosive or Combustible Range• Upper explosive limit / upper flammable limit

– UEL / UFL» Highest concentration of a vapor / gas that will

produce a flash of fire» Concentrations higher than the UEL

• Mixture is too rich to burn



• Hazardous Materials Properties – Vapor Pressure• Pressure exerted by a saturated vapor above its

own liquid in a closed container– Pressure produced or exerted by the vapors released by

a liquid» Can be expressed in terms of

• Pounds Per Square Inch (PSI)• Kilopascals (kPa)• Bars• Millmeters of mercury (mmHg)

• Usually found on MSDS• Atmospheres (atm)



• Hazardous Materials Properties – Vapor Pressure• The higher the temperature of a substance, the

higher the vapor pressure will be– Higher temperature provide more energy to a liquid

» Allows liquid to escape into a gas form

– The lower the boiling point of a substance, the higher its vapor pressure will be

– Used as a general gauge to tell how fast a product will evaporate under normal circumstances



• Hazardous Materials Properties – Boiling Point• The temperature at which the vapor pressure of a

liquid is equal to or greater than atmospheric pressure– The temperature at which a liquid changes to a gas

– 760 mmHg = 14.7 psi or 1 atmosphere



• Hazardous Materials Properties – Boiling Liquid Expanding Vapor Explosion • BLEVE

– Also called Violent Rupture• Can occur when a liquid within a container is

heated– Causes material inside to boil / vaporize– Increases vapor pressure– Exceeds the vessel’s ability to relieve the excess

pressure» Most commonly occur when flames contact a tank shell above the liquid level



• Hazardous Materials Properties – Melting Point

• Temperature at which a solid substance changes to a liquid state

– Freezing Point• Temperature at which a liquid becomes a solid

– Sublimation• Substances changes from a solid directly Into a gas

– Carbon dioxide (dry ice)– Mothballs



• Hazardous Materials Properties – Vapor Density• Weight of a given volume of pure gas• Gas compared to the weight of an equal volume of

dry air– Air has a value of 1

» Vapor density <1• Vapor is lighter than air

» Vapor density >1• Vapor is heavier than air

– All vapors / gases will mix with air– Spread can not be predicted exactly from vapor density



• Hazardous Materials Properties – Solubility• Term expressing the percentage of a material (by

weight) that will dissolve in water at ambient temperature – Used for spill clean up methods– Extinguishing agents

» Non-water soluble• Liquids remain separate from water

» Polar solvent• Liquids mix easily with water



• Hazardous Materials Properties – Solubility

• Health effects– Water-soluble agents

» Cause early upper respiratory tract irritation

– Partially water-soluble agents» Penetrate into the lower respiratory system» Delayed symptoms

• 12-24 hours» Causes breathing difficulties

• Pulmonary edema• Coughing up blood



• Hazardous Materials Properties – Miscibility / Immiscibility• The degree or readiness to which two or more

gases or liquids are able to mix with or dissolve into each other

– Miscible» Two liquids that dissolve into each other in any

proportion – Immiscible

» Two materials that do not readily dissolve into each other



• Hazardous Materials Properties – Specific Gravity• Ratio of the density of a material to the density of

some standard material – Heaviness of a material

– Water has a value of 1» Specific gravity <1

• Liquid is lighter than water and will float

» Specific gravity >1• Liquid is heavier than water and will sink



• Hazardous Materials Properties – Reactivity• Relative ability to undergo a chemical reaction

with another material – The fire tetrahedron

» Reactive triangle• Fuel (Reducing Agent)• Heat• Oxygen (Oxidizer)

– Activation energy» Required energy to get them started

• Starting a fire with a match



• Hazardous Materials Properties – Reactivity• Examples

– Light-sensitive– Heat-sensitive– Shock-sensitive

• Polymerization– Often results in a tremendous release of energy

» Designated with a “P” in the ERG– Inhibitors are added in order to control or prevent an undesired reaction



• Hazardous Materials Hazards– Health hazards• Directly effect an individual’s health

– Poisons – Corrosives

– Physical hazards• Present a threat because of the material’s physical

properties – Temperature– Radioactivity



• Hazardous Materials Hazards– U.S. National Fire Academy (NFA)• Uses a simple classification system

– TRACEMP» T Thermal» R Radiological » A Asphyxiation» C Chemical» E Etiological » M Mechanical» P Psychological




– TRACEMP» T Thermal

• Thermal harm is the result of exposure to extremes of heat and cold

» R Radiological • Refers to nuclear radiation

• Alpha• Beta• Gamma




– TRACEMP» A Asphyxiation

• Interfere with oxygen flow during normal breathing• Simple asphyxiants

• Inert gases that displace or dilute oxygen

• Chemical asphyxiants• Blood poisons




– TRACEMP» C Chemical

• Toxic• Harm depends on concentration and

length of exposure• Corrosive

• Harm causes visible destruction




– TRACEMP» E Etiological

• Harm involves exposure to a living microorganism

» M Mechanical• Causes trauma

• Shrapnel during an explosion» P Psychological

• Causes strong emotional reaction



• Hazardous Materials Hazards– Cryogenics• Refrigerated liquefied gas• Gases that turn into a liquid at or below -130o F• Vaporize rapidly when released from container

– Liquid oxygen (LOX)– Liquefied natural gas (LNG)– Nitrogen– Helium– Hydrogen– Argon



• Hazardous Materials Hazards– Radiological• Nonionizing radiation

– Has enough energy to move atoms around but not change them chemically» Radio waves» Infrared radiation» Microwaves

• Ionizing radiation– The most energetic form of radiation



• Hazardous Materials Hazards– Radiological• Ionizing radiation

– Has sufficient energy to remove electrons from atoms» Disrupts chemical bonds» Called “Ionization”

– Causes damage to the human body



• Hazardous Materials Hazards– Radiological• Alpha Particles

– Lose energy rapidly in matter– Do not penetrate very far– Blocked by paper

• Beta Particles– Fast moving– Blocked by aluminum



• Hazardous Materials Hazards– Radiological

• Gamma Rays– Similar to X-rays– Completely pass through the human body

» Radiation hazard– Stopped by a few inches of lead or several feet of

concrete

• X-rays– Lower energy then gamma rays– Stopped by a few inches of lead or several feet of

concrete



• Hazardous Materials Hazards– Radiological• Neutrons

– Ultrahigh energy particles– Highly penetrating



• Hazardous Materials Hazards– Radiological• Exposure pathways

– Inhalation» Breathe radioactive materials into the lungs» Can remain in the lungs for a long time

– Ingestion» Swallowing radioactive materials » Expose entire digestive system

– Direct Exposure» Skin contact



• Hazardous Materials Hazards– Radiological• Protection Strategies

– Time» Limit exposure time to radiation source

– Distance » Increase distance from source

• Doubling distance reduces the exposure by a factor of four

– Shielding» Lead» Concrete



• Hazardous Materials Hazards– Toxic Materials• Nephrotoxic agents

– Affect the kidneys• Hematotoxic agents

– Affect the blood• Neurotoxic agents

– Affect the nervous system• Hepatotoxic agents

– Affect the liver



• Hazardous Materials Hazards– Toxic Materials

• Lethal dose (LD)– The minimum amount of a solid or liquid that will cause death

• Median lethal dose (LD50)– Single dose of a substance that can be expected to cause death in

50% of animals» Administered orally » The other half isn’t completely well

• They just didn’t die

• Lethal dose low (LDLO or LDL)– Lowest administered dose of a material capable of killing a specific test species



• Hazardous Materials Hazards– Toxic Materials• Lethal concentration (LC)

– Minimum concentration of an inhaled substance in the gaseous state that will be fatal» Usually within 1-4 hours » May be expressed in LC50

• Lethal concentration low (LCLO or LCL)– Lowest concentration of a gas or vapor capable of

killing a specified species over time



• Hazardous Materials Hazards– Toxic Materials• Immediately Dangerous to Life or Health (IDLH)

– An atmospheric concentration of a substance that poses an immediate threat to life

• Permissible Exposure Limit (PEL)– Maximum concentration to which the majority of

healthy adults can be exposed over a 40-hour workweek» Time-Weighted Average (TWA)

• 8-hour period



• Hazardous Materials Hazards– Toxic Materials• Permissible Exposure Limit Ceiling Limit (PEL) (C)

– The maximum concentration to which an employee may be exposed at any time» Instantaneous

• Short-term Exposure Limit (STEL)– The maximum concentration allowed for a 15-minute

exposure



• Hazardous Materials Hazards– Toxic Materials• Irritants

– Toxins that cause temporary but sometimes severe inflammation to the eyes, skin or respiratory system» Attack the mucous membranes of the body

• Convulsants– Toxic materials that can cause convulsions

» Sensation of difficulty breathing» Painful muscle spasms

• 3-30 minutes




• Corrosives– Chemicals that destroy or burn living tissues and have

destructive effects – With the exception of liquid and gas fuels

» Corrosives comprise the largest usage class in industry

– Acids» pH <6

– Bases (Alkalis)» pH 8-14



• Hazardous Materials Hazards– Toxic Materials• Carcinogens

– Cancer-causing agents

• Mutagens– Substances or agents that are capable of altering the

genetic material in a living cell




• Teratogens– Substances or agents that are capable of causing

developmental abnormalities in utero » Malformation in the fetus of a pregnant female

• Sensitizers– Chemicals that cause the development of allergic reactions in

people with repeated exposures

• Allergens– Substances that cause allergic reactions


Hazardous Materials Properties and Hazards

Works Cited“Hazardous Materials for First Responders” International Fire Service Training Association

3rd Edition 2004 Print

chapter 2 hazardous materials properties and hazards

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