Reactive and Explosive MaterialsAn Introduction

Reactive and Explosive MaterialsWhat are explosive materials?DefinitionsHazard CategoriesReactivityVideo

What are reactive and explosive materials?Any material capable of violent or explosive decomposition when subjected to shock, heat, friction, flame, static discharge, elevated temperature, or exposure to air or water.Resulting decomposition may produce a lethal shock front, extreme heat, flame or a gaseous atmosphere that may explode or ignite.

Reactive and explosive materialsThese materials may be reactive by nature or may become reactive due to age, exposure to air, to a contaminant, exhausted inhibitors, elevated temperatures, or separation of product while under bad storage conditions.

Reactive and explosive materialsAny materials that fit this description, and whose condition is not known, should be considered extremely dangerous and should only be handled by qualified personnel who are properly equipped to do so.All these materials can be safely handled and disposed of if you maintain the proper attitude, respect, procedures and technical expertise.

Reactive and Explosive MaterialsWhat are explosive materials?DefinitionsHazard CategoriesReactivityVideo

DefinitionsDecomposition: A breakdown of a substance into a group of different substances. In the case of highly reactive or explosive materials, large amounts of energy will be released

DefinitionsExplosion: A chemical reaction that generates high temperatures and large amounts of gas at a very fast rate. If under confinement, an explosion may produce a shock front and a missile hazard. This may be a rapid gas expansion (deflagration) in a confined area or a detonation.

DefinitionsDeflagration: A rapid or violent decomposition with flame and large amounts of heat. The speed of the decomposition (the reaction front as it moves through the material) is subsonic, i.e.: slower than ~1250 ft/sec. A characteristic of propellant explosives such as smokeless powder or a match.

DefinitionsDetonation: An extremely rapid and violent decomposition producing a lethal shock front, heat and flame. The speed of the decomposition is supersonic, i.e.: 1250 to 30,000 ft/sec. Picric acid, for example, detonates at 24,000 ft/sec or 16,344 mph!

DefinitionsShock wave: A high pressure wave that radiates from the surface of an explosion that has detonated.

Overpressure: The pressure, over atmospheric pressure, that is present at the leading end of a shock wave.

Over PressureExample for 1 lbm of TNTDistance Over PressureEffect 10 ft 5 psilethal, wooden utility poles snapped16 ft3 psistructural damage, steel framed buildings pulled from foundation40 ft1 psiwindows break, partial demolition of houses250 ft 0.1 psisome windows break

DefinitionsSADT: Self Accelerating Decomposition Temperature.

MSST: Maximum Safe Storage Temperature

DefinitionsCompressed gas (DOT): Any substance having an absolute pressure exceeding 40 psi at 70F, or, regardless of pressure at 70F, having an absolute pressure exceeding 104 psi at 130F, or any flammable liquid having a vapor pressure exceeding 40 psi at 100F. Any compressed gas may have a high pressure hazard regardless of other hazards specific to the material, and must be protected against an uncontrolled release

Reactive and Explosive MaterialsWhat are explosive materials?DefinitionsHazard CategoriesReactivityVideo

Hazard CategoriesExplosive A: A chemical compound capable of detonating when unconfined and subjected to shock or heat. The degree of sensitivity varies greatly. Some materials which deflagrate but do not detonate are also considered class A explosive by DOT. Black powder is one such example.

Hazard CategoriesExplosive B: A chemical compound that generally deflagrates rather than detonates. Examples are propellants and pyrotechnic powders.

Hazard CategoriesExplosive C: Any manufactured article that may contain a small quantity of a class A or B explosive. Examples are certain types of fireworks.

Hazard CategoriesFlammable Liquid: Any liquid material that will ignite easily and burn rapidly with a flash point below 100F, and a vapor pressure not over 40 psia at 100F.

Hazard CategoriesPyrophoric Liquid: Any liquid material that will spontaneously ignite and burn rapidly when exposed to air that is below 130F.

Pyrophoric Solid: Any solid material that will spontaneously ignite and burn rapidly when exposed to air that is below 130F

Hazard CategoriesOxidizer, Solid or Liquid: Any solid or liquid material that spontaneously evolves oxygen either at room temperature or when under slight heat.

Hazard CategoriesOrganic Peroxide, Solid or Liquid: Any solid or liquid organic compound containing the bivalent O-O in its structure. Such compounds release oxygen readily, are capable of violent or explosive decomposition, and are generally unstable at elevated temperatures.

Hazard CategoriesFlammable Solid: Any solid material that will ignite easily and burn rapidly.

Flammable Solid DWW: Basically the same as a flammable solid, these materials, when in contact with water, will ignite, explode, or liberate a flammable gas that itself may ignite or explode

Hazard CategoriesFlammable Gas: Any gas that will ignite easily and burn rapidly. The flame and heat propagation rate is so great as to resemble an explosion, especially if confined.Non-Flammable Gas: Any gas that doesnt meet the definition above. Although a gas may be nonflammable, it may be a strong oxidizer, very corrosive, or toxic. The high pressure in many cylinders is a hazard in itself

Reactive and Explosive MaterialsWhat are explosive materials?DefinitionsHazard CategoriesReactivityVideo

ReactivityInitiating Stimuli:Temperature, elevated above SADTAir, exposure to airWater, contact with water or moistureShock (heat, friction, static), exposure to high temperatures, flame, grinding friction, or electrical discharge.Contamination, contact with an incompatible material

ReactivitySensitizing StimuliContamination, introduction of another materialAge, loss of desensitizer, inhibitor, or a slow, long-term degradationElevated temperature, temperatures high enough to cause degradation or separation of productLight, initiates a slow or violent decompositionMoisture, separation of a productFreezing, separation of a product

ReactivityDegrees of Initiating StimuliLow sensitivity, must be subjected to a strong shock or heat source to initiate decompositionModerate, any moderate stimuli found in normal handling, transportation, or disposal.High, a very sensitive or spontaneous material that, for no apparent reason, will generate a gas, ignite, decompose violently, explode, or detonate. Usually the result of age, exposure, contamination, etc.

ReactivityDegree of DecompositionMild, ignition of a material that burns at a moderate rate and may ignite adjacent materials.Severe, ignition of a material that will decompose with a rapid deflagration and may produce very high temperatures or large amounts of gas.Violent, ignition or initiation of a material that will detonate, produce a lethal shock and missile hazard.

VideoAlthough filmed in 1988, the message is timeless: what precautions must be made when working with explosive and reactive chemicals.