Lighting is of critical importance in all types of buildings. An adequate level and distribution of light is vital if visual tasks are to be carried out safely and effectively. Good lighting will also improve the internal environment and appearance of a building. The use of efficient lamps, ballasts and luminaires, with appropriate lighting controls, can provide the right visual environment, be energy efficient and cost effective. Part 3 of this Good Building Guide describes how to fulfill the lighting requirements of Part L2 in non-domestic buildings and how to follow good practice in energy efficient lighting for specific applications. Exterior lighting is covered in Part 2. General principles of energy efficiency such as lighting controls are covered and certain types of buildings are considered specifically: offices and warehouses, public houses, hotels, shops and other retail buildings. 8 pages.