Editing Smoke screen (section)

==Technology==
===Smoke grenades===
{{Main|Smoke grenade}}
[[File:171029-M-MN519-0191 (37534718814).jpg|thumb|A [[French Foreign Legion|French Legionnaire]] moving through a smoke screen generated using a smoke grenade]]
These are canister-type [[grenades]] used as a ground-to-ground or ground-to-air signalling device. The body consists of a steel sheet metal cylinder with a few emission holes on the top and/or bottom to allow smoke release when the [[smoke composition]] inside the grenade is ignited. In those that produce [[colored smoke]], the filler consists of 250 to 350&nbsp;grams of colored (red, green, yellow or violet) smoke mixture (mostly [[potassium chlorate]], [[sodium bicarbonate]], [[lactose]] and a [[dye]]). In those that produce screening smoke, the filler usually consists of HC smoke mixture (hexachloroethane/zinc) or TA smoke mixture (terephthalic acid). Another type of smoke grenade is filled with [[white phosphorus incendiary|white phosphorus]] (WP), which is spread by explosive action. The phosphorus catches fire in the presence of air, and burns with a brilliant yellow flame, while producing copious amounts of white smoke (phosphorus pentoxide). WP grenades double as [[incendiary grenade]]s.

===Smoke shell===
{{See also|Shell (projectile)#Smoke}}
[[Artillery]] and [[mortar (weapon)|mortar]]s can also fire smoke generating munitions, and are the main means of generating tactical smokescreens on land. As with grenades, artillery shells are available as both emission type smoke shell, and bursting smoke shell. Mortars nearly always use bursting smoke rounds because of the smaller size of mortar bombs and the greater efficiency of bursting rounds.

===Smoke generators===
[[File:Challenger 2 Tank MOD 45154622.jpg|thumb|A [[British Army]] [[Challenger 2]] deploying a smoke screen using a smoke generator installed in its rear]]
[[File:JGSDF Smoke generator equipment(High Mobility Vehicle,Right Rear View) at Camp Shinodayama April 24, 2016.JPG|thumb|A [[Japan Ground Self-Defense Force|JGSDF]] [[Toyota Mega Cruiser]] with a smoke generator installed in its rear compartment]]
Very large or sustained smoke screens are produced by a smoke generator. This machine heats a volatile material (typically oil or an oil based mixture) to evaporate it, then mixes the vapor with cool external air at a controlled rate so it condenses to a mist with a controlled droplet size. Cruder designs simply boiled waste oil over a heater, while more sophisticated ones sprayed a specially formulated oily composition ("fog oil") through nozzles onto a heated plate. Choice of a suitable oil, and careful control of cooling rate, can produce droplet sizes close to the ideal size for [[Mie theory|Mie scattering]] of [[visible light]]. This produces a very effective obscuration per weight of material used. This screen can then be sustained as long as the generator is supplied with oil, and&mdash;especially if a number of generators are used&mdash;the screen can build up to a considerable size. One 50 gallon drum of fog oil can obscure {{convert|60|mi|km}} of land in 15 minutes.

Whilst producing very large amounts of smoke relatively cheaply, these generators have a number of disadvantages. They are much slower to respond than pyrotechnic sources, and require a valuable piece of equipment to be sited at the point of emission of the smoke. They are also relatively heavy and not readily portable, which is a significant problem if the wind shifts. To overcome this latter problem, they may be used in fixed posts widely dispersed over the battlefield, or else mounted on specially adapted vehicles. An example of the latter is the [[M56 Coyote]] generator.

Many [[armoured fighting vehicle]]s can create smoke screens in a similar way, generally by injecting [[diesel fuel]] onto the hot [[exhaust system|exhaust]].

===Naval methods===
[[File:US Navy 090425-N-4879G-393 A group of multinational amphibious assault vehicles from the amphibious dock landing ship USS Ashland (LSD 48) deploy smoke to cover their landing during a simulated amphibious landing demonstration.jpg|thumb|[[Assault Amphibious Vehicle]]s deploying smoke to cover their landing]]
Warships have sometimes used a simple variation of the smoke generator, by injecting fuel oil directly into the funnel, where it evaporates into a white cloud. An even simpler method that was used in the days of steam-propelled warships was to restrict the supply of air to the boiler. This resulted in incomplete combustion of the coal or oil, which produced a thick black smoke. Because the smoke was black, it absorbed heat from the sun and tended to rise above the water. Therefore, navies turned to various chemicals, such as [[titanium tetrachloride]], that produce a white, low-lying cloud.<ref>{{cite video
 | title = The Royal Navy at War
 | medium =DVD
 | publisher =[[Imperial War Museum]]
 | location =London
 | date =2005}}</ref><ref>{{Cite web
  | title = Smoke
  | work = Treatment of Chemical Agent Casualties and Conventional Military Chemical Injuries
  | publisher = Department of Defense, Washington DC
  | date = 22 December 1995
  | url = http://www.globalsecurity.org/wmd/library/policy/army/fm/8-285/ch8.pdf
  | access-date = 27 May 2011}}</ref>