Page 462 - Materials Chemistry, Second Edition

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Division 1.3 — explosives that have a fire hazard and either a minor blast hazard or a minor
projection hazard, or both.
Division 1.4 — explosives that present a minor explosion hazard. The explosive effects are
largely confined to the package and no projection of fragments is expected.
Division 1.5 — very insensitive explosives. This division includes substances that have a mass
explosion hazard but are so insensitive that there is very little probability of initiation under routine
transport. This division includes blasting agents. The material is capable of exploding under very
specialized conditions.
Division 1.6 — extremely insensitive articles.
Class 2 — Gases. Gases are products that are cooled and compressed for ease in transportation.
Gases pose dangers because they are stored under pressure. A compressed gas is defined as any
material or mixture with an absolute pressure in a container of:

● More than 40 psa at 70°F
● More than 140 psa at 130°F

Divisions of Class 2 are as follows:
Division 2.1 — Flammable gas. A flammable compressed gas has a lower flammable limit
(LFL) concentration of 13% or less by volume in air, or which has a flammable range (i.e., the dif-
ference between the LFL and UFL) of greater than 12%.
Division 2.2 — Nonflammable, nonpoisonous, compressed gas. Includes compressed gas,
liquefied gas, pressurized cryogenic gas, compressed gas in solution, asphyxiant gas, and oxi-
dizing gas.
Division 2.3 — Gas poisonous by inhalation.
Division 2.4 — Toxic gas. The term “toxic gas” may be used in place of “poison gas” for
domestic shipments. The term “toxic gas” must be used for international shipments.
Class 3 — Flammable liquids. A flammable liquid refers to any liquid that has a closed-cup flash
point below 37.8°C (100°F). The closed-cup test procedures are outlined in 40 CFR Part 261.21 and
in EPA Method 1020B (U.S. EPA, 1986). The term “flash point” refers to a temperature at which a
substance produces sufficient vapors to sustain combustion. A combustible liquid is one with flash
point between 37.8 and 75.6°C (100 and 200°F).
Class 4 — Flammable solids. Flammable solids include: any solid material, other than one clas-
sified as an explosive, which, under conditions normally incident to transportation is liable to cause
fires through friction, retain heat from manufacturing or processing, or which can be ignited read-
ily and when ignited burn so vigorously and persistently as to create a serious transportation haz-
ard. Spontaneously combustible and water-reactive materials are included in this class.
An example of a flammable solid is aluminum hydride.
Division 4.1 — Materials that ignite easily and burn vigorously.
Division 4.2 — Spontaneously combustible material. This could include pyrophoric materials.
A pyrophoric material is a liquid or solid that, without an external ignition source, can ignite after
coming in contact with air.
Division 4.3 — Dangerous in the form of wet material. A material that, by contact with water,
is liable to become spontaneously flammable or releases flammable or toxic gas.
Class 5 — Oxidizers and organic peroxides. An oxidizer “is a substance such as a chlorate per-
manganate, inorganic peroxide, or a nitrate, that yields oxygen readily to stimulate the combustion
of organic matter.” The main hazard with oxidizing agents is that contact with a combustible sub-
stance, for example organic materials (even dust) may cause the substance to ignite or explode.
Division 5.1. Releases oxygen. These will therefore promote vigorous combustion of a substance.
Division 5.2. Organic peroxides. An organic peroxide is derived from hydrogen peroxide (H O ).
2
2
One or more hydrocarbon groups have replaced one of the hydrogen atoms. These substances may
explode under certain conditions.