chapter 4 chemical properties and hazardous materials behavior
TRANSCRIPT
Hazardous Materials for First Responders
4th Edition
Chapter 4 — Chemical Properties and Hazardous Materials Behavior
Learning Objective 1
Discuss the three states of matter.
4–1
Gas, one state of matter, tends to expand indefinitely.
4–2
Independent shape
Volume
Fluid with
neither
Breathing/inhalation hazard
Contact hazard
May present potential
Liquid, one state of matter, may give off vapors.
4–3
NO independent shape
Specific volume
Fluid with
Gravity
Surface contours
Flow effected
by
Solid, one state of matter, often stays in place unless acted upon.
4–4
Specific shape
Specific volume
Substance with
When effected by exterior forces
Moves
Describe the three states of matter.
4–5
REVIEW QUESTION
Learning Objective 2
Discuss the flammability of various hazardous materials.
4–6
Flammability depends on three properties.
4–7
Flammability
Flammable/explosive/
combustible range
Autoignition temperature
Flash point
Flash point is the temperature at which there are sufficient vapors to ignite, but not sustain combustion.
4–8
What is fire point?
How is it different from flash point?
4–9
DISCUSSION QUESTION
Autoignition temperature is the level to which the fuel in air must be heated to initiate self-sustained combustion.
4–10
The flammable, explosive, or combustible range helps to establish the lower and upper explosive limits.
4–11
Define lower explosive limit (LEL) and upper explosive limit (UEL).
4–12
REVIEW QUESTION
Learning Objective 3
Describe vapor pressure.
4–13
Vapor pressure is the pressure exerted by a saturated vapor above its own liquid in a closed container.
4–14
Expressed in:
psi, kPa, bars, mmHg, or atm
Learning Objective 4
Explain boiling point.
4–15
• Temperature at which the vapor pressure of a liquid is equal to or greater than atmospheric pressure
• Usually expressed in degrees Fahrenheit (Celsius) at sea level air pressure
Boiling Point
4–16
Boiling liquid expanding vapor explosion (BLEVE) can occur when liquid in a container is heated.
4–17
What is a BLEVE?
4–18
REVIEW QUESTION
Learning Objective 5
Define melting point, freezing point, and sublimation.
4–19
Melting and freezing point definitions are based on normal atmospheric pressure.
4–20
• Temperature at which a solid substance changes to a liquid state
Melting point
• Temperature at which liquid becomes a solid
Freezing point
Sublimation is a change from solid to gas state without going into a liquid state.
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Learning Objective 6
Describe vapor density.
4–22
Vapor density is the weight of gases compared to the same volume of air at similar temperature and pressure.
4–23
What are some of the chemicals that have a vapor density lighter than air?
4–24
REVIEW QUESTION
DISCUSSION QUESTION
How does knowing the vapor density of a material help during a hazardous materials incident?
4–25
Learning Objective 7
Define solubility and miscibility.
4–26
Solubility is useful in determining spill clean up methods and extinguishing agents.
4–27
Percentage of a material that will dissolve in water
at ambient temperature
Affects if substances mixes
with water
Important contributor in
symptom development
What are some examples of hydrocarbons and polar solvents?
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DISCUSSION QUESTION
Miscibility impacts how two or more gases or liquids mix with or dissolve into each other.
4–29
Water and oil are immiscible, so they do not mix.
Courtesy of U.S. Coast Guard
Learning Objective 8
Discuss specific gravity.
4–30
Specific gravity is directly influenced by solubility.
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Learning Objective 9
Define persistence.
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Persistence is a chemical’s ability to remain in an environment.
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Learning Objective 10
Define reactivity and describe the reactivity triangle.
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Reactivity is the relative ability to undergo a chemical reaction with another material.
4–35
(Continued)
Substance 1
Substance 2
Results
• Pressure buildup
• Temperature increase
• Formation of noxious, toxic, or corrosive byproducts
The reactivity triangle explains the basic components of many chemical reactions.
4–36
(Continued)
Reactivity can be effected by polymerization and inhibitors.
4–37
Polymerization
• Simple molecules combine to form long chain molecules
• May be marked with a P in the ERG
Inhibitors
• Materials added to products that easily polymerize to control or prevent undesired reaction
• May be time sensitive
Describe the General Hazardous Materials Behavior Model (GEBMO).
Learning Objective 11
4–38
GEBMO defines hazardous materials and explains common elements of haz mat incidents.
4–39
Common elements
Material(s) presenting
hazards to people, environment,
property
Container(s) that have failed or
have the potential to fail
Exposure or potential exposure
to people, environment,
property
GEBMO describes the general sequence of events for hazardous materials incidents.
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Stress Breach Release
Dispersion/Engulf
Exposure/Contact
Harm
Stress is stimulus causing strain, pressure, or deformity.
Haz Mat for First Responders
4–41
Thermal Chemical Mechanical
Breach occurs when a container is stressed beyond limits of recovery.
4–42
What are the six portions of the GEBMO?
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REVIEW QUESTION
• Disintegration
• Runaway cracking
• Attachments open or break
• Puncture
• Split or tear
• Metal reduction
Types of Breaches
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Courtesy of Phil Linder
Describe several types of breaches.
4–45
REVIEW QUESTION
Release can be product, energy, or parts of the container.
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DetonationViolent rupture
Rapid relief
Spill/Leak
Courtesy of U.S. U.S. Army, photo by Sgt. Jabob H.Smith
The dispersion/engulf distribution occurs according to five factors.
4–47
Physical/chemical properties
Prevailing weather
conditions
Local topography
Duration of release
Control efforts of
responders
What are the classifications of releases?
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REVIEW QUESTION
A hemispheric dispersion pattern generally results from a rapid release.
4–49
(Continued)
A cloud dispersion pattern occurs when the material has collectively risen above the ground or water.
4–50
(Continued)
The plume dispersion pattern is affected by vapor density, terrain, and wind speed/direction.
4–51
(Continued)
The cone dispersion pattern has a wide base downrange of the breach.
4–52
(Continued)
The stream dispersion pattern is affected by gravity and topographical contours.
4–53
(Continued)
The pool dispersion pattern is created by a three-dimensional, slow flowing liquid.
4–54
(Continued)
Irregular dispersion patterns can result from contaminated vehicles or responders.
4–55
Describe each of the dispersion patterns.
4–56
REVIEW QUESTION
Exposure/contact can effect people, environment, and property in a variety of timeframes.
4–57
Immediate
• Deflagration, explosion, detonation
Short-term
• Gas or vapor cloud
Medium-term
• Lingering pesticide
Long-term
• Permanent radioactive source
Harm can be generated by a variety of health and physical hazards.
Thermal
Mechanical
Poisonous
CorrosiveAsphyxiation
Radiation
Biological
What types of exposures should be considered in hazard and risk assessment?
4–59
REVIEW QUESTION
Summary
• First responders need the ability to predict how a hazardous material will behave when it escapes its container.
• The behavior is often determined by the material’s physical properties.
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