This document describes the generic requirements of metal free optical fibre cable (multi loose tube construction design) for underground installation in ducts. Recent years have seen rapid development of optical fiber networks and implementation of fiber-to-the-home (FTTH) in common homes, along with the increased demand for optical communications to support the proliferation of Internet as well as delivery of moving pictures. Conventional method of. This Engineering Instruction (EI) deals with the guidelines and the installation practice for installing self-supporting metal free aerial optical Fiber cable. BHAWAN, JANPATH, NEW DELHI-110001. Aerial installation is generally much less costly than underground construction also. Fiber in a duct solutions. The Fiber Optic Association, Inc.