Titanium and its alloys are widely used in aerospace industry where the metal's low density, high-specific strength, and corrosion resistance properties are required. Examples where titanium and its alloys are used is in turbine engines and airframes, and in oxidizing sulfuric acid environments present in sulfide pressure-leaching operations (pressure oxidation autoclaves). Titanium has been considered for use in oxygen-enriched environments such as space suit applications. However, like most metals and alloys, titanium will burn in oxygen-enriched environments. This paper describes the ignition and combustion of titanium and its alloys. The ignition propensity of titanium was determined by frictional ignition testing and the combustibility determined by promoted combustion testing. Results indicate that the Pv products required for ignition by friction are 0.0035×108 W/m2 (0.01×106 psi ft/min) and in 100 percent oxygen titanium is combustible at pressures as low as 13.8 kPa (2 psia).