Editing Explosive train

{{Short description|Sequence of events that results in the detonation of explosives}}
{{More citations needed|date=April 2022}}
A '''triggering sequence''', also called an '''explosive train''' or a '''firing train''', is a sequence of events that culminates in the [[detonator|detonation]] of [[explosives]].<ref>{{Cite book |url=https://www.ojp.gov/pdffiles1/Digitization/60135NCJRS.pdf |title=Modular Explosives Training Program |publisher=United States Bureau of Alcohol, Tobacco and Firearms |pages=8–9 |language=en}}</ref> For safety reasons, most widely used high explosives are difficult to detonate. A [[primary explosive]] of higher sensitivity is used to trigger a uniform and predictable detonation of the main body of the explosive. Although the primary explosive itself is generally a more sensitive and expensive compound, it is only used in small quantities and in relatively safely packaged forms. By design there are low explosives and [[high explosive]]s made such that the low explosives are highly sensitive (i.e. their [[Figure of Insensitivity]] is low) and high explosives are comparatively insensitive. This not only affords inherent safety to the usage of explosives during handling and transport, but also necessitates an explosive triggering sequence or explosive train. The explosive triggering sequence or the explosive train essentially consists of an 'initiator', an 'intermediary' and the 'high explosive'.

For example, a [[match]] will not cause [[plastic explosive]] to explode, but it will light a fuse coupled with a blasting cap which will detonate a primary explosive that will shock a secondary high explosive and cause it to detonate. In this way, even very insensitive explosives may be used; the primary detonates a "booster" charge that then detonates the main charge. Triggering sequences are used in the [[mining]] industry for the detonation of [[ANFO]] and other cheap, bulk, and insensitive explosives that cannot be fired by only a [[blasting cap]] or similar item.

== Low explosive train ==
An example of a low-explosive train is a rifle cartridge, which consists of 
# a [[Explosive primer|primer]] consisting of a small amount of [[primary explosive|primary]] [[high explosive]] which initiates the explosive train
# an [[igniter]] which is initiated by the primer and creates a flame that ignites the propellant
# a [[propellant]] consisting of a [[secondary explosive|secondary]] [[low explosive]] that emits a large amount of gas as it [[deflagration|deflagrates]].

== High explosive train ==
High-explosives trains can be either two-step (e.g., [[detonator]], [containing primary explosive] and [[dynamite]] / other sensitive secondary) or three-step configuration (e.g., [[detonator|initiator]], [detonator, compound cap or NPED] [[explosive booster|booster]] of intermediate explosive, and main charge of insensitive [[secondary explosive]]).

=== Primary components ===
A high explosive train includes three primary high explosive components which are used to initiate explosives:
# [[Fuse (explosives)|Fuse]] or [[fuze]]
# [[Explosive primer|Primer]]
# [[Detonator]]

Detonators are conventionally made from [[tetryl]] and [[fulminate]]s, but can be made of other initiating explosive materials.

=== Secondary components ===
In an explosive train there are two secondary high explosive components:
# [[explosive booster|Booster]]s
# [[Bursting charge]]s, also known as the [[main charge]]

Examples of explosives used in bursting charges are
* [[Trinitrotoluene|TNT]]
* [[Composition B]]
* [[Ammonal]]
* [[Semtex]]
* [[RDX]]
* [[HMX]]
* [[Erythritol tetranitrate|ETN]]
* [[PETN]]
* [[C-4 (explosive)|C-4]]
* Other suitable [[Binary explosives]]

=== Tertiary components ===
#[[main charge]]

Examples of main charges are
* [[Trinitrotoluene|TNT]]
* [[Composition B]]
* [[Pentolite]]
* [[Baratol]]
* [[Amatol]]
* [[PLX]]
* [[HMX]]
* [[Erythritol tetranitrate|ETN]]
* [[PETN]]
* Other suitable [[binary explosives]]

In some cases, the main charge is so insensitive that using typical primary materials becomes impractical due to large amount required. Thus, an explosive booster is used to deliver a sufficient shockwave to successfully initiate the main charge, as so full detonation occurs.

The most significant tertiary material in widespread general usage is [[ANFO]], an [[binary explosive|explosive binary]] made from [[Ammonium nitrate]] and [[Fuel oil]].

== References ==
{{reflist}}

{{DEFAULTSORT:Triggering Sequence}}
[[Category:Explosives]]