When deploying a burning or pyrotechnic chemical agent grenade into a structure, major concerns are fire and oxygen depletion from the resulting fire. Each of these elements may kill persons who are
inside a building. Oxygen depletion, caused by fire, can be overcome by ventilating the structure or by wearing a SCBA (self contained breathing apparatus). The ventilation may increase the rate of fire. Smoke from a smoke canister or a burning chemical agent grenade by itself will not deplete the oxygen in a structure.
All police officers are familiar with the fire triangle and the three elements that fire requires: heat, fuel and oxygen. When deploying 
a hot, burning agent inside a structure, heat is introduced into an environment where oxygen and fuel are already present. In order to prevent a burning grenade from starting a fire, removal of one of the elements of the fire triangle is essential.
Many agencies have discovered or invented clever deployment devices that remove the heat element from the fire triangle equation. These devices are commonly referred to as Burn Boxes, Tomahawks, Gas Axes or Rams, and Burn Safes. All these devices contain a burning grenade inside a heavy metal device that allows the heat from the combustion of the burning grenade to dissipate, or the device contains the heat, preventing the ignition of any combustible materials.
A commonly accepted temperature when wood or paper starts to pyrolyze to form burnable gases is 246°C. If you light those gases with a flame they will burn. But if you heat wood up in a closed container with no flame to start it, it may require a temperature of 450°C before it spontaneously bursts into flame.
Each of these devices is unique in the way they are deployed. If not properly constructed and maintained, they have injured and killed the operator. Do not construct or use these devices without proper knowledge and training. Containing a burning device that creates a great amount of pressure in a sealed container is the same as making a pipe bomb. Your homemade device may explode.
Burn Box/Burn Safe/Tomahawk
A burn box holds a burning grenade in the middle of a ventilated ammunition can. The burning grenade is ignited and the burn box can then be thrown into a structure. Because the grenade is in the middle of the can, the stand-off distance from combustible materials may decrease the liklihood of starting a fire.
A burn safe works on the same principle as the burn box, but is usually constructed of heavy gauge steel. The additional weight enables it to be thrown through a window onto the floor surface to allow the grenade to dispense its contents. Commercially made BurnSafes have not started a fire when applied to gasoline soaked rags.
A tomahawk works on the same principal and is made for a smaller burning grenade like a pocket grenade. It is shaped to be easily tossed by one hand and will sometimes penetrate a single pane window.
Gas Axe/Gas Ram
Gas axes have been used by some police agencies for years. It is a heavy-gauged metal tube attached to a axe handle. The handle is attached to a metal tube that contains a compartment for a burning grenade. The tube has a hollow spike attached to the front. The device is made to drive through a heavy wall and expel its contents into a structure. It generally will not start a fire. If necessary, the device can be thrown through a window and deployed much like a burn safe. A homemade Gas Axe exploded during training in Gilbert, Arizona killing one officer and injuring several others.
Gas rams are similar to the gas axe, but are configured and deployed differently. Basically, they are door rams with a probe and a containment space for a burning grenade. Small gas rams can be operated by one officer, while larger gas rams need two operators because of increased size and weight. The gas ram can also be mounted to the front of an armoured car and driven through a wall letting the operators stay inside the srmored vehicle. These devices are available commercially. Plans for constructing these devices are available from many police agency SWAT Teams. However, do not construct or use these devices without the proper knowledge and training. Containing a burning device that creates a great amount of pressure in a sealed container is the same as making a pipe bomb. Your homemade device may explode.
