These requirements cover the following types of optical fiber and communication cable raceways and fittings designed for use with optical fiber and communication cables in accordance with the National Electrical Code: a) Plenum ?C Evaluated for installation in ducts@ plenums@ or other spaces used for environmental air in accordance with the National Electrical Code as well as general purpose applications. b) Riser ?C Evaluated for installation in risers in accordance with the National Electrical Code as well as general purpose applications. c) General Use ?C Evaluated for general purpose applications only.