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.

4–21

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?

4–28

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.

4–31

Learning Objective 9

Define persistence.

4–32

Persistence is a chemical’s ability to remain in an environment.

4–33

Learning Objective 10

Define reactivity and describe the reactivity triangle.

4–34

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.

4–40

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?

4–43

REVIEW QUESTION

• Disintegration

• Runaway cracking

• Attachments open or break

• Puncture

• Split or tear

• Metal reduction

Types of Breaches

4–44

Courtesy of Phil Linder

Describe several types of breaches.

4–45

REVIEW QUESTION

Release can be product, energy, or parts of the container.

4–46

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?

4–48

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.

4–60