The purpose of sports lighting is to provide lighting that allows a sport to take place safely (i.e. designed to suit the speed of play and size of any objects used in the sport) and provide good viewing conditions, both in visibility of the sports action and comfort of the audience. Lighting requirements are defined by EN 12193. Additional requirements may be defined by sports governing bodies such as FIFA, Olympic Delivery Authorities, etc. and by television authorities, such as Sky. EN 12193 defines requirements based on the lighting class (I, II, or III). This is derived from the level of competition, international and national, regional, local, training and recreational. At the lower standard of play there is flexibility with the light source options (i.e. LED, high pressure sodium, metal halide) but at class II and III metal halide light sources with high colour rendering abilities are required. When lighting exterior sports facilities to achieve good uniformity lighting equipment must be mounted on masts of sufficient height to ensure floodlight aiming angles are no greater than 70°. This will ensure a high utilisation of lamp lux, minimum electrical load, and lower installed costs.