Editing Explosive (section)

==Classification==

===By sensitivity===

====Primary====
A '''primary explosive''' is an explosive that is extremely sensitive to stimuli such as [[impact (mechanics)|impact]], [[friction]], [[heat]], [[electrostatic|static electricity]], or [[electromagnetic radiation]]. Some primary explosives are also known as [[contact explosive]]s. A relatively small amount of energy is required for [[initiation (chemistry)|initiation]]. As a very general rule, primary explosives are considered to be those compounds that are more sensitive than [[Pentaerythritol tetranitrate|PETN]]. As a practical measure, primary explosives are sufficiently sensitive that they can be reliably initiated with a blow from a hammer; however, PETN can also usually be initiated in this manner, so this is only a very broad guideline. Additionally, several compounds, such as [[nitrogen triiodide]], are so sensitive that they cannot even be handled without detonating. Nitrogen triiodide is so sensitive that it can be reliably detonated by exposure to [[Alpha particle|alpha radiation]].<ref>{{Citation |title=Nitrogen triiodide |date=2024-06-08 |work=Wikipedia |url=https://en.m.wikipedia.org/wiki/Nitrogen_triiodide |access-date=2024-09-02 |language=en}}</ref><ref>{{Cite web |last=UCL |date=2020-06-23 |title=Nitrogen Triiodide (NI3) |url=https://www.ucl.ac.uk/safety-services/policies/2021/jun/nitrogen-triiodide-ni3 |access-date=2024-09-02 |website=Safety Services |language=en}}</ref>  

Primary explosives are often used in [[detonator]]s or to [[trigger (firearms)|trigger]] larger charges of less sensitive [[secondary explosives]]. Primary explosives are commonly used in [[blasting cap]]s and [[percussion cap]]s to translate a physical shock signal. In other situations, different signals such as electrical or physical shock, or, in the case of laser detonation systems, light, are used to initiate an action, i.e., an explosion. A small quantity, usually milligrams, is sufficient to initiate a larger charge of explosive that is usually safer to handle.

Examples of primary high explosives are:
{{Div col|colwidth=17em}}
* [[Acetone peroxide]]
* Alkali metal [[ozonide]]s
* [[Ammonium permanganate]]
* [[Ammonium chlorate]]
* [[Azidotetrazolates]]
* Azoclathrates
* [[Benzoyl peroxide]]
* [[Benzvalene]]
* 3,5-Bis(trinitromethyl)tetrazole<ref>{{Cite web|url=https://www.science.org/content/blog-post/can-t-stop-nitro-groups|title=Can't Stop the Nitro Groups |work=Science.org |last=Lowe |first=Derek |date=15 August 2019 |access-date=22 August 2022}}</ref>
* [[Chlorine oxide]]s
* [[Copper(I) acetylide]]
* [[Copper(II) azide]]
* [[Cumene hydroperoxide]]
* Cycloprop(-2-)enyl nitrate (CXP or CPN)
* [[Cyanogen azide]]
* [[Cyanuric triazide]]
* [[Diacetyl peroxide]]
* [[1-Diazidocarbamoyl-5-azidotetrazole]]
* [[Diazodinitrophenol]]
* [[Diazomethane]]
* [[Diethyl ether peroxide]]
* [[4-Dimethylaminophenylpentazole]]
* [[Disulfur dinitride]]
* [[Ethyl azide]]
* [[Explosive antimony]]
* [[Fluorine perchlorate]]
* [[Fulminic acid]]
* Halogen azides:
** [[Fluorine azide]]
** [[Chlorine azide]]
** [[Bromine azide]]
** [[Iodine azide]]
* [[Hexamethylene triperoxide diamine]]
* [[Hydrazoic acid]]
* [[Hypofluorous acid]]
* [[Lead azide]]
* [[Lead styphnate]]
* [[Lead picrate]]<ref>{{cite web|url=http://www.powerlabs.org/chemlabs/lead_picrate.htm|title=PowerLabs Lead Picrate Synthesis|first=Sam |last=Barros |website=powerlabs.org|url-status=live|archive-url=http://arquivo.pt/wayback/20160522174456/http://www.powerlabs.org/chemlabs/lead_picrate.htm|archive-date=22 May 2016|df=dmy-all}}</ref>
* [[Manganese heptoxide]]
* [[Mercury(II) fulminate]]
* [[Mercury nitride]]
* [[Methyl ethyl ketone peroxide]]
* [[Nickel hydrazine nitrate]]<ref>{{cite book |first1=Robert |last1=Matyáš |first2=Jiří |last2=Pachman |title=Primary Explosives |publisher=Springer-Verlag Berlin Heidelberg |date=2013 |page=331}}</ref>
* Nickel hydrazine perchlorate
* Nitrogen trihalides:
** [[Nitrogen trichloride]]
** [[Nitrogen tribromide]]
** [[Nitrogen triiodide]]
* [[Nitroglycerin]]
* [[Nitronium perchlorate]]
* [[Nitrosyl perchlorate]]
* Nitrotetrazolate-''N''-oxides
* [[Pentazenium]] [[hexafluoroarsenate]]
* [[Peroxy acid]]s
* [[Peroxymonosulfuric acid]]
* [[Selenium tetraazide]]
* [[Silicon tetraazide]]
* [[Silver azide]]
* [[Silver acetylide]]
* [[Silver fulminate]]
* [[Silver nitride]]
* [[Tellurium tetraazide]]
* [[tert-Butyl hydroperoxide|''tert''-Butyl hydroperoxide]]
* Tetraamine copper complexes
* [[Tetraazidomethane]]
* [[Tetrazene explosive]]
* [[Tetrazole]]s
* [[Titanium tetraazide]]
* Triazidomethane
* Oxides of xenon:
** [[Xenon dioxide]]
** [[Xenon oxytetrafluoride]]
** [[Xenon tetroxide]]
** [[Xenon trioxide]]
{{div col end}}

====Secondary====
A '''secondary explosive''' is less sensitive than a primary explosive and requires substantially more energy to be initiated. Because they are less sensitive, they are usable in a wider variety of applications and are safer to handle and store. Secondary explosives are used in larger quantities in an explosive train and are usually initiated by a smaller quantity of a primary explosive.

Examples of secondary explosives include [[TNT]] and [[RDX]].

====Tertiary====
'''Tertiary explosives''', also called '''blasting agents''', are so insensitive to shock that they cannot be reliably detonated by practical quantities of [[primary explosive]], and instead require an intermediate [[explosive booster]] of [[secondary explosive]]. These are often used for safety and the typically lower costs of material and handling. The largest consumers are large-scale [[mining]] and [[construction]] operations.

Most tertiaries include a fuel and an oxidizer. [[ANFO]] can be a tertiary explosive if its reaction rate is slow.

===By velocity===

====Low====
Low explosives (or low-order explosives) are compounds wherein the rate of decomposition proceeds through the material at less than the [[speed of sound]]. The decomposition is propagated by a flame front ([[deflagration]]) that travels much more slowly through the explosive material than the [[shock wave]] of a high explosive. [[Standard temperature and pressure|Under normal conditions]], low explosives undergo deflagration at rates that vary from a few centimetres per second to approximately {{Convert|0.4|km/s|ft/s}}. It is possible for them to deflagrate very quickly, producing an effect similar to a [[detonation]]. This can happen under higher [[pressure]] (such as when [[gunpowder]] deflagrates inside the confined space of a bullet casing, accelerating the bullet to well beyond the speed of sound) or [[temperature]].

A low explosive is usually a mixture of a [[combustible]] substance and an [[oxidant]] that decomposes rapidly (deflagration); however, they burn more slowly than a high explosive, which has an extremely fast burn rate.<ref>{{Cite book |url=https://nap.nationalacademies.org/read/5966/chapter/22 |title=Read "Containing the Threat from Illegal Bombings: An Integrated National Strategy for Marking, Tagging, Rendering Inert, and Licensing Explosives and Their Precursors" at NAP.edu |date=1998 |doi=10.17226/5966 |isbn=978-0-309-06126-1 |language=en}}</ref>

Low explosives are normally employed as [[propellant]]s. Included in this group are petroleum products such as [[propane]] and [[gasoline]], [[gunpowder]] (including [[smokeless powder]]), and light [[pyrotechnics]] such as [[flare]]s and [[fireworks]], but they can replace high explosives in certain applications, including gas pressure blasting.<ref>{{Cite journal |date=1958-07-29 |title=The initiation of explosion by neutrons, α -particles and fission products |url=https://royalsocietypublishing.org/doi/10.1098/rspa.1958.0123 |journal=Proceedings of the Royal Society of London. Series A. Mathematical and Physical Sciences |language=en |volume=246 |issue=1245 |pages=216–219 |doi=10.1098/rspa.1958.0123 |bibcode=1958RSPSA.246..216B |s2cid=137728239 |issn=0080-4630|last1=Bowden |first1=F. P. |url-access=subscription }}</ref>

====High====
High explosives (HE, or high-order explosives) are explosive materials that [[Detonation|detonate]], meaning that the [[explosion|explosive]] [[shock front]] passes through the material at a [[supersonic]] speed. High explosives detonate with [[explosive velocity]] of about {{Convert|3|-|9|km/s|ft/s}}. For instance, TNT has a detonation (burn) rate of approximately 6.9&nbsp;km/s (22,600 feet per second), detonating cord of 6.7&nbsp;km/s (22,000 feet per second), and C-4 about 8.0&nbsp;km/s (26,000 feet per second). They are normally employed in mining, demolition, and military applications. The term ''high explosive'' is in contrast with the term ''low explosive'', which explodes ([[Deflagration|deflagrates]]) at a lower rate.

High explosives can be divided into two explosives classes differentiated by [[sensitivity (explosives)|sensitivity]]: [[#Primary|primary explosive]] and [[#Secondary|secondary explosive]]. Although tertiary explosives (such as ANFO at 3,200&nbsp;m/s) can technically meet the explosive velocity definition, they are not considered high explosives in regulatory contexts.

Countless high-explosive compounds are chemically possible, but commercially and militarily important ones have included [[nitroglycerin|NG]], [[TNT]], [[Trinitrophenol|TNP]], TNX, [[RDX]], [[HMX]], [[pentaerythritol tetranitrate|PETN]], [[TATP]], [[TATB]], and [[hexanitrostilbene|HNS]].

===By physical form===
{{Main|Use forms of explosives}}
Explosives are often characterized by the physical form that the explosives are produced or used in. These use forms are commonly categorized as:<ref name="Cooper">{{cite book
|last=Cooper
|first=Paul W.
|title=Explosives Engineering
|year=1996
|publisher=Wiley-VCH
|pages=51–66
|chapter=Chapter 4: Use forms of explosives
|isbn=978-0-471-18636-6}}</ref>
* Pressings
* Castings
* [[Polymer-bonded explosive|Plastic or polymer bonded]]
* [[Plastic explosive]]s, a.k.a. putties
* Rubberized
* Extrudable
* [[Binary explosive|Binary]]
* Blasting agents
* Slurries and gels
* Dynamites

===Shipping label classifications===
Shipping labels and tags may include both [[United Nations]] and national markings.

United Nations markings include numbered Hazard Class and Division (HC/D) codes and alphabetic Compatibility Group codes. Though the two are related, they are separate and distinct. Any Compatibility Group designator can be assigned to any Hazard Class and Division. An example of this hybrid marking would be a consumer [[firework]], which is labeled as 1.4G or 1.4S.

Examples of national markings would include [[United States Department of Transportation]] (U.S. DOT) codes.

====United Nations (UN) GHS Hazard Class and Division====
[[File:UN transport pictogram - 1.svg|thumb|GHS Explosives transport pictogram]]
{{See also|HAZMAT Class 1 Explosives}}

The UN [[Globally Harmonized System of Classification and Labelling of Chemicals|GHS]] Hazard Class and Division (HC/D) is a numeric designator within a hazard class indicating the character, predominance of associated hazards, and potential for causing personnel casualties and property damage. It is an internationally accepted system that communicates using the minimum amount of markings the primary hazard associated with a substance.<ref>[http://www.tpub.com/content/aviation/14313/css/14313_288.htm Table 12-4. – United Nations Organization Hazard Classes] {{webarchive|url=https://web.archive.org/web/20100605034021/http://www.tpub.com/content/aviation/14313/css/14313_288.htm |date=5 June 2010}}. Tpub.com. Retrieved on 2010-02-11.</ref>

Listed below are the Divisions for Class 1 (Explosives):
* '''1.1''' Mass Detonation Hazard. With HC/D 1.1, it is expected that if one item in a container or pallet inadvertently detonates, the explosion will [[sympathetic detonation|sympathetically detonate]] the surrounding items. The explosion could propagate to all or the majority of the items stored together, causing a mass detonation. There will also be fragments from the item's casing and/or structures in the blast area.
* '''1.2''' Non-mass explosion, fragment-producing. HC/D 1.2 is further divided into three subdivisions, HC/D 1.2.1, 1.2.2 and 1.2.3, to account for the magnitude of the effects of an explosion.
* '''1.3''' Mass fire, minor blast or fragment hazard. Propellants and many pyrotechnic items fall into this category. If one item in a package or stack initiates, it will usually propagate to the other items, creating a mass fire.
* '''1.4''' Moderate fire, no blast or fragment. HC/D 1.4 items are listed in the table as explosives with no significant hazard. Most small arms ammunition (including loaded weapons) and some pyrotechnic items fall into this category. If the energetic material in these items inadvertently initiates, most of the energy and fragments will be contained within the storage structure or the item containers themselves.
* '''1.5''' mass detonation hazard, very insensitive.
* '''1.6''' [[detonation]] hazard without mass detonation hazard, extremely insensitive.

To see an entire UNO Table, browse Paragraphs 3–8 and 3–9 of NAVSEA OP 5, Vol. 1, Chapter 3.

====Class 1 Compatibility Group====
Compatibility Group codes are used to indicate storage compatibility for HC/D Class 1 (explosive) materials. Letters are used to designate 13 compatibility groups as follows.
* '''A''': Primary explosive substance (1.1A).
* '''B''': An article containing a primary explosive substance and not containing two or more effective protective features. Some articles, such as detonator assemblies for blasting and primers, cap-type, are included. (1.1B, 1.2B, 1.4B).
* '''C''': Propellant explosive substance or other deflagrating explosive substance or article containing such explosive substance (1.1C, 1.2C, 1.3C, 1.4C). These are bulk [[propellant]]s, propelling charges, and devices containing propellants with or without means of ignition. Examples include single-based propellant, double-based propellant, triple-based propellant, and [[composite propellant]]s, [[solid propellant]] [[rocket motor]]s and ammunition with inert projectiles.
* '''D''': Secondary detonating explosive substance or black powder or article containing a secondary detonating explosive substance, in each case without means of initiation and without a propelling charge, or article containing a primary explosive substance and containing two or more effective protective features. (1.1D, 1.2D, 1.4D, 1.5D).
* '''E''': Article containing a secondary detonating explosive substance without means of initiation, with a propelling charge (other than one containing flammable liquid, gel or [[hypergolic]] liquid) (1.1E, 1.2E, 1.4E).
* '''F''' containing a [[secondary explosive|secondary]] [[detonating explosive]] substance with its means of initiation, with a propelling charge (other than one containing flammable liquid, gel or hypergolic liquid) or without a propelling charge (1.1F, 1.2F, 1.3F, 1.4F).
* '''G''': Pyrotechnic substance or article containing a pyrotechnic substance, or article containing both an explosive substance and an illuminating, incendiary, tear-producing or smoke-producing substance (other than a water-activated article or one containing white phosphorus, phosphide or flammable liquid or gel or hypergolic liquid) (1.1G, 1.2G, 1.3G, 1.4G). Examples include Flares, signals, incendiary or illuminating ammunition and other smoke and tear producing devices.
* '''H''': Article containing both an explosive substance and white phosphorus (1.2H, 1.3H). These articles will spontaneously combust when exposed to the atmosphere.
* '''J''': Article containing both an explosive substance and flammable liquid or gel (1.1J, 1.2J, 1.3J). This excludes liquids or gels which are spontaneously flammable when exposed to water or the atmosphere, which belong in group H. Examples include liquid or gel filled incendiary ammunition, fuel-air explosive (FAE) devices, and flammable liquid fueled missiles.
* '''K''': Article containing both an explosive substance and a toxic chemical agent (1.2K, 1.3K)
* '''L''' Explosive substance or article containing an explosive substance and presenting a special risk (e.g., due to water-activation or presence of hypergolic liquids, phosphides, or [[pyrophoricity|pyrophoric]] substances) needing isolation of each type (1.1L, 1.2L, 1.3L). Damaged or suspect ammunition of any group belongs in this group.
* '''N''': Articles containing only extremely insensitive detonating substances (1.6N).
* '''S''': Substance or article so packed or designed that any hazardous effects arising from accidental functioning are limited to the extent that they do not significantly hinder or prohibit fire fighting or other emergency response efforts in the immediate vicinity of the package (1.4S).