These tests are designed to test and evaluate the waste material in question to determine if one or more of the characteristics of reactivity exist for that material. Not all of the tests are always required for a given substance. The list below is a partial listing only. Some of the tests are discussed in other sections.

Explosive Cap (No. 8) Testing

The No. 8 cap test is used to determine susceptibility of explosives to detonation from the energy delivered by a No. 8 electric blasting cap. The test consists of a sample approximately 60 cubic inches in size placed in a cardboard tube. (Liquid samples are placed in a polypropylene bottle.) The tube is placed on top of a steel witness plate with a No. 8 cap inserted at the top of the cardboard tube. Sample detonation is determined by examining the witness plate the criteria for detonation is that the witness plate is torn or penetrated. This test is part of the series conducted to establish propellant hazard classification for shipping and for quantity-distance siting. This test can also be completed by using a lead cylinder as a witness device by placing a cardboard tube 80 mm in diameter by 160 mm long on top of a common (soft) lead cylinder (51-mm O.D. x 102-mm). Sample detonation is determined by examining the lead cylinder; compression from its initial length by 3.2 mm or more indicates a detonation.

Hazardous When Wet

This is a series of four tests beginning with a very small sample and gradually increasing in size up to 25 grams. The sample material is exposed to varying degrees of moisture and the reaction or gas evolution is observed and measured. Wetted materials that do not spontaneously ignite nor release more than 1 liter of flammable or toxic gas per hour per kilogram of material are not considered Dangerous When Wet.

Ignition and Unconfined Burn

This test is used to determine if samples, once ignited continue burning or transit to an explosion or detonation and helps establish the unconfined burning properties of explosives. A 125 gram sample is placed on a bed of sawdust soaked with kerosene or diesel fuel approximately 30 cm square and 1.3-2.5 cm thick. The sawdust is ignited with an electric match or similar device and the burn time is measured. The test is performed three times unless an explosion or detonation occurs.

This test is also conducted using four 2-inch cubed samples end-to-end in a single row as part of the series of tests conducted to establish hazard classification for shipping and quantity-distance siting.

Internal Ignition

This test is designed to determine the response of an explosive to rapidly rising temperatures and pressures. The sample, with an initial temperature of 25°C, is loaded into a schedule 80 pipe with forged steel end caps. A black powder bag igniter is inserted into the center of the pipe and the leads are sealed with epoxy resin. The igniter is fired and the results are assessed. Either the pipe or at least one of the end caps must be fragmented into at least two distinct pieces for a positive result.

The test is considered negative (the material passes) if the pipe is merely split open or the caps are blown off in one piece. Three trials are performed unless a positive result occurs earlier. The test determines if a material will explode or detonate when ignited under confinement.
Reference: Transport of Dangerous Goods – Tests and Criteria

Modified Unconfined Burn (Oxidizers)

Dry sawdust is mixed with a specified, known oxidizer and ignited under specified temperature and humidity criteria. The time to consume the sawdust mixture is recorded. The sample material is then mixed with the sawdust in two specified ratios. Each ratio is tested three times by igniting the mixture and timing the burn duration. If the average burn times of both mix ratios are greater than that observed with the known oxidizer, the material is not classed as an oxidizer. This test is also used for DOT classification of materials as oxidizers.

Single Package

This test determines if there is a mass explosion hazard of the contents of a single package. The package is placed on a steel witness plate on the ground, and confined using containers that are similar in shape and size to the test package and completely filled with earth or sand. The substance or article is initiated and the following observations are made: evidence of thermal effects, projection effects, detonation, deflagration or explosion of the total package contents. This test is performed three times unless a decisive result occurs earlier (e.g. explosion of the total contents, damage to witness plate beneath the package, etc.).

Zero Gap, Card Gap

The sample is loaded into the specified steel tubes and placed facing a steel witness plate. A pentolite booster is used to provide a known shock source. The damage to the tube and witness plate is the criteria for a “go” or a “no-go” reaction.