Internal Ignition Test Description
Test Purpose
The internal ignition test determines if the test material will transition from a deflagration to an explosion under high confinement. If this test result in a positive result then the material should be classified as an explosive in a manufacturing operation.
Equivalence
This test is equivalent to UN Test 1 or 2 (c) (ii) in the UN Manual of Tests and Criteria.
Test variations
A 20-gram or 10-gram black powder bag igniter is used for IP Series 2 or 4 respectively.
Key Parameters
| Key Parameter | Objectives | Origin | Specs |
|---|---|---|---|
| Confining medium (steel pipe with end caps) | Confined vessel that can be used as evidence of sample reactivity should the material be capable of sustaining the reaction | 3-inch Schedule 80 carbon steel (A53 Grade B) pipe, 74mm ID, 7.6mm wall, 45.7 cm (18-in) long, capped at both ends with 3,000-pound forged steel end caps | |
| Ignition stimulus (igniter size and type) | Ensure a sufficient amount of the material is ignited | 20-gram black powder igniter with lead wires sealed | |
| Ignition position | Provide an ignition in the center of the confined substance | Center of the sample | |
| Substance density | Determine whether the substance in its in-process form has explosive properties | Substance to be tested as near as possible to the in-process density | |
| Pipe position | Allow the weight of the substance to provide additional confinement | The tube is fired in a vertical position | |
| Number of trials | Obtain an accurate characterization of the sample | 3 trials |
Indicators
| Indicators | Detection Method | Assessment* |
|---|---|---|
| Damage to the steel pipe | Visual post-test inspection | Fragmentation of pipe into at least two distinct pieces (pipe rupture by splitting open is not a failure): Class 1 |
| Damage to the end cap | Visual post-test inspection | Fragmentation of either cap into at least two distinct pieces: Class 1 |
*OR relationship
Setup Example
Example Photo of Pipe and Caps Not Fragmented (-)
