These doors can be operated by hand, however, electric motorisation is recommended. Standard designs are available up to 3000mm high by 7500mm wide, should opening exceed these sizes the manufacturer should be consulted. The aluminium Sectional Overhead Door shall be divided into panels of approximately 500mm in depths and constructed using aluminium box type frames. The door panel sections are divided into equal parts of approximately 1200mm in width using intermediate bracing members and infilled using expanded aluminium choice of decorative pressed metals.