Haz Mat chemical properties and hazardous materials behavior

(BLEVE) boiling liquid expansion vapor explosion

(Also called violent rupture) can occur when a liquid within a container is heated, causing the material inside to boil or vaporize (such as in the case of a liquefied petroleum gas tank exposed to a fire.)

Gasoline fire point

-40to-35 degrees F (-40to-37 degrees C)

Gasoline (flash point)

-45 degrees F (-43Degrees C)

5 factors determining distribution over a surrounding area

1. Physical/chemical properties 2. Prevailing weather conditions 3. Local topography 4. Duration of the release 5. Control efforts of responders.

Gasoline Boiling point

100-104 degrees F 38-40 degrees C

Diesel Flash point

100-160 degrees F 38-71 degrees C

Chlorine Vapor pressure

4,800 mm Hg at 68 degrees because of this, if it's released from it container it will escape as a gas.

Gasoline ignition temp

536 degrees F 280 degrees C

Autoignition temperature

A substance is the minimum temperature to which the fuel in air must be heated to initiate self-sustained combustion with out initiation from and independent ignition source.

Water solubility

Ability of liquid or solid to mix with or dissolve in water

Dispersion

Act or process of being spread widely

Activation energy

Amount of energy that must be added to an atomic or molecular system to begin a reaction.

Flash point temperature

At this temperature the vapors will flash but not continue to burn

Attachments (closures) open or break breach

Attachments ( such as pressure relief devices, discharge valves, or other related equipment) fail. Open, or break off when subjected to stress, leading a total failure of a container.

Release is classified

Based on how fast they occur

Dry ice and moth balls

Both sublime rather than melt

Heat (thermal stress)

Can initiate or speed up a chemical reaction while weakening a container and increasing pressure

Dry ice

Carbon dioxide

Sublime

Change directly from a solid into a gas without going into a liquid state in-between.

Carbon Monoxide (CO)

Colorless odorless dangerousness has formed by the incomplete combustion of carbon.it forms more than 200 times as quickly with hemoglobin as oxygen, thus decrease the bloods ability to carry oxygen.

Carbon Dioxide (CO2)

Colorless odorless, heavier than air gas that neither supports combustion nor burns CO2, is used in portable fire extinguishers as an extinguishing agent to extinguish Class B or C fires by smothering or dip lacing oxygen

Hydrogen Cyanide (HCN)

Colorless, toxic gas with a faint Oder similar to bitter almonds; produced by the combustion of nitrogen bearing substances.

Disintegration Breach

Container suffers a general loss of integrity such as a glass bottle shattering or a Granada exploding.occurs in containers what contain brittle material

Puff

Continuous plume, or a sporadic fluctuation

Runaway cracking breach

Crack develops in a container as a result of some type of damage, which continues to grow rapidly, breaking the container into 2 or more large pieces. Usually associated with BLEVE's

Flammable hazards

Depend on properties such as flash point, auto ignition temperatures, and flammable range.

Thermal stressor

Excessive heat or cold causing intolerable expansion, contraction, weakening (loss of temper), or consumption or consumption of the container and its parts.

Rapid relief release

Fast release of a pressurized hazardous material through properly operating safety devices caused by damaged valves, piping, or attachments or holes in the container. May occur in several seconds or several min.

Mist

Finely divided liquid suspended in the atmosphere.

NFPA Flammable and Combustable temps

Flammable Liquid Less than 100degrees Combustable Liquids 100 degrees or greater

OSHA Flammable and combustible temp

Flammable Liquid Less than 100 degrees Combustible liquid 100 degrees or greater

DOT Flammable and combustible temp

Flammable liquid 141 degrees or less Combustible liquid Greater than 141 degrees and below 200 degrees

Polar solvant

Flammable liquids that have an attraction for water, much like a positive magnetic pole attracts a negative pole; ex. Alcohols, esters, ketones, amines

Gas

Fluid that has neither independent shape nor volume; gases tend to expand indefinitely.

Liquid

Fluid that has no independent shape but does have a specific volume; liquids flow in accordance with the laws of gravity.

Aerosol

Form of most characterized by highly restorable, minute liquid particles.

Matter

Found in three stages: gas, liquid, and solid

Flammability

Fuels susceptibility to ignition

Vapor

Gaseous form of a substance that is normally in a solid or liquid state at room temperature and pressure.

Vapor density greater than 1

Heavier than air.

Chemicals less than 1

Helium, neon, acetylene, and hydrogen

Dispersion patterns

Hemispheric Cloud Plume Cone Stream Pool irregular

Violent rupture release

Immediate release of chemical or mechanical energy caused by runaway cracks.

Non flammable

Incapable of combustion under normal circumstances; normally used when referring to liquids or gases.

Detonation release

Instantaneously and explosive release of stored chemical energy of a hazardous material.

Specific Gravity

Is the ratio of the density (heaviness) of a material to the density of some standard material at standard conditions of pressure and temperature

Reactivity of a substance

It's relative ability to undergo a chemical reaction with another material

Fuel Oil No. 1 Flammable range percentage

LFL 0.7 UFL 5.0

Gasoline Flammable range percentage

LFL 1.4 UFL 7.6

Carbon Monoxide Flammable Range percentage

LFL 12.5 UFL 74.0

Propane flammable range percentage

LFL 2.1 UFL 9.5

Acetylene Flammable range

LFL 2.5 UFL 100.0

Ethyl Alcohol Flammable Range percentage

LFL 3.3 UFL 19.0

Methane Flammable range percentage

LFL 5.0 UFL 15.0

Persistence

Length of time a chemical agent remains effective without dispersing.

EPA Flammable and Combustable temps

Less than 140 degrees (Ignitable waste)

Vapor density less than 1

Lighter than air

Flammable liquids

Liquids that have low flash points and burn easily

Combustible liquids

Liquids with higher flash points which do not burn as easily

Lower Explosive limit

Lowest percentage of fuel/oxygen mixture required to support combustion.

Strong oxidizer

Material that encounters a strong reaction (by readily accepting electrons) from a reducing agent (fuel)

Inhibitors

Material that is added to products that easily polymerize in order to control or prevent an undesired reaction. Also called a stabilizer.

Upper Explosive Limit

Maximum concentration of vapor or gas in air that will allow combustion to occur.

Liquid Hazards

May give off vapors that become inhalation hazards, the liquid itself is primarily a splash or contact hazard.

Puncture breach

Mechanical stress coming into contact with a container causes a puncture. Examples forklifts puncturing drums and couplers puncturing rail tank cars

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.

GEBMO General Emergency Behavior Model

Model used to describe how hazardous materials are accidentally released from their containers and how they behave after the release.

Flammable gases have flash points?

No because they are already in a gaseous state

Solids hazards

Partial size of solids such as dust, fumes, or powders may influence their behavior, for example how long partials may remain suspended in air. Large particles will settle out more quickly.

Mechanical stressor

Physical application of energy resulting in container/attachment damage; mechanical application may change the shape of the container (crushing), reduce the thickness of the container surface (abrading or scoring), crack or produce gouges, unfasten or disengage valves and include collision, impact, or internal over-pressure.

Chemicals greater than 1

Propane, hydrogen sulfide, ethane, butane, chlorine, and sulfur dioxide

Preventing container failure my require,

Reducing or eliminating stress

Autoignition temperature

Same as ignition temperature except that no external ignition source is required for ignition because the material itself has be heated to ignition temperature;

Hemispheric release (Dispersion)

Semicircular or dome shaped pattern of airborne hazardous material that is still partially in contact with the ground or water.

Spill/leak release

Slow release of a hazardous material under atmospheric or head pressure through holes, rips, tears, or usual openings/ attachments van occur in a period of several minutes or days.

Dust

Solid particle that is formed or generated from solid organic or inorganic materials by reducing its size through mechanical processes such as crushing, grinding, drilling, abrading, or blasting

Fiber

Solid particle whose length is several times greater than its diameter

Engulf

Sometimes referred to as dispersion of materials according to (GEBMO)

In hazardous materials incidents the following sequence usually occur...

Stress Breach Release Dispersion/Engulf Exposure/Contact Harm

Reactive material

Substance capable of or tending to react chemically with other substances; materials that react violently and release energy when combined with air or water

Solid

Substance that has both specific shape (without a container) and volume.

Fume

Suspension of particles that form when material from a volatilized (vapor state) solid condenses in cool air

Fire point

Temperature at which enough vapors are given off to support continuous burning. Fire point temps are usually a few degrees higher than flash point temps.

Boiling point

Temperature at which the vapor pressure of a liquid is equal to or greater than atmospheric pressure.

NFPA defines Autoignition temp as

The minimum temperature required to initiate or cause self-sustained combustion, independent of the heating or heated element.

The Flammable, explosive, or Combustable range

The percentage of the gas or vapor concentration in the air that will burn or explode if ignited

Vapor pressure

The pressure exerted by a saturated vapor above its own liquid in a closed container, or more simply, it is the pressure produced or exerted by the vapors released by a liquid.

Freezing Point

The temperature at which a liquid becomes a a solid at normal atmospheric pressure.

Melting Point

The temperature at which a solid substance changes to a liquid state at normal atmospheric pressure.

Vapor density

The weight of a given volume of pure vapor or gas compared to the weight of and equal volume of dry air at the same temperature and pressure.

Common Stressors

Thermal, chemical, mechanical

Miscibility

Two or more liquids capability to mix together.

Chemical stressor

Uncontrolled reactions/interactions of contents in the container and the container itself, resulting in a sudden or long term deterioration of the container.

Reactivity Triangle

Used to explain the basic components of many (through not all) chemical reactions: oxidizing agents (oxygen), a reducing agent (fuel), and an activation energy source (often heat, but not always so)

What burns

Vapors not liquids.

Split or tear breach

Welded seam on a tank or drum fails or a seam on a bag of fertilizer rips.

Breach

When a container is stressed beyond its limits of recovery.

Release

When a containers fails 3 things may release: the product, energy, and the container ( whole or in pieces)

Gas hazards

Will be present in the air presenting a breathing or inhalation hazard. Some may present a contact hazard.

Compressed gases

Will expand rapidly when released, potentially threatening large areas.