156 describes air-assisted methods for installation of optical fibre cables in ducts. Installing conditions and equipment required should be different in. Recommendation ITU-T L. Installing long. Fiber blowing and fiber pulling are two primary methods used in ODN, metro, and backbone fiber installation. While both techniques achieve the same goal—placing fiber cables inside ducts—their engineering mechanics, tension characteristics, duct preparation requirements, and environmental. ing and blowing a cable in a duct and the impact on the cable designs. Generally, the duct is available in plastic, concrete, steel, iron and so on.