Related Rule
South Africa
Practice Relating to Rule 84. The Protection of Civilians and Civilian Objects from the Effects of Incendiary Weapons
South Africa’s Revised Civic Education Manual (2004) provides that incendiary weapons “may be used only against military targets, which are clearly separated from concentrations of civilians”. 
South Africa, Revised Civic Education Manual, South African National Defence Force, 2004, Chapter 4, § 56(f)(ii); see also § 56(f)(iv)(3) (on the Convention on Certain Conventional Weapons).
South Africa’s LOAC Teaching Manual (2008) states:
3. Means and Methods of Warfare
Several specific weapons are governed by specific treaties. These treaties establish two categories of weapons, to wit[:]
- Weapons of which the use is totally prohibited; and
- Weapons of which the use is permitted under certain conditions.
Weapons of which the use is Permitted under Certain Conditions:
- Incendiary Weapons (Geneva Protocol III on Prohibitions or Restrictions on the Use of Incendiary Weapons dated 10 October 1980)
Definition.
“Incendiary weapon” means any weapon or munition which is primarily designed to set fire to objects or to cause burn injury to persons through the action of flame, heat or a combination thereof, produced by a chemical reaction of a substance delivered on the target.
- Examples. Incendiary weapons can take the form of flamethrowers, shells, rockets, grenades, mines, bombs or other containers of incendiary substances (also Napalm, phosphorous bombs).
- The following are not considered to be incendiary weapons:
- Munitions which may have incidental incendiary effects, such as illuminants[,] tracers, smoke or signalling systems; or
- Munitions designed to combine penetration, blast or fragmentation effects with an additional incendiary effect, such as armour[-]piercing projectiles, fragmentation shells, explosive bombs and similar combined effects munitions in which the incendiary effect is not specifically designed to cause burn injury to persons, but to be used against military objectives such as armoured vehicles, aircraft and installations or facilities.
- Conditions for Permitted Use (Geneva Protocol III Article 2):
[-] Incendiary weapons which are not air delivered may be used[:]
- When the military objective is clearly separated from any concentration of civilian persons; and
- Subject to precautions to limit incendiary effects to the military objective when the tactical situation permits.
[-] Air delivered incendiary weapons may only be used in attack against a military objective located outside any concentrations of civilian persons. 
South Africa, Advanced Law of Armed Conflict Teaching Manual, School of Military Justice, 1 April 2008, as amended to 25 October 2013, Learning Unit 3, pp. 174, 176 and 178–179.
[emphasis in original]
South Africa’s Prohibition or Restriction of Certain Conventional Weapons Act (2008) states:
Incendiary weapons
7. No person may –
(a) make the civilian population, individual civilians or civilian objects the object of attack by incendiary weapons;
(b) make any military objective located within a concentration of civilians the object of attack by air-delivered incendiary weapons;
(c) make any military objective located within a concentration of civilians the object of attack by means of incendiary weapons except when such military objective is clearly separated from the concentration of civilians and all feasible precautions are taken with a view to limiting the incendiary effects to the military objective and to avoiding, and in any event to minimising the incidental loss of civilian life, injury to civilians and damage to civilian objects; or
(d) make forests or other kinds of plant cover the object of attack by incendiary weapons except when such natural elements are used to cover, conceal or camouflage combatants or other military objectives, or are themselves military objectives. 
South Africa, Prohibition or Restriction of Certain Conventional Weapons Act, 2008, Section 7.
The Act defines an “incendiary weapon” as “any weapon or munition which is primarily designed to set fire to objects or to cause burn injury to persons through the action of flame, heat, or combination thereof, produced by a chemical reaction of a substance delivered on the target”. 
South Africa, Prohibition or Restriction of Certain Conventional Weapons Act, 2008, Section 1.