This part of IEC60794 , which is a sectional specification, specifies the requirements of microduct optical fibre cables, microduct fibre units, microducts and protected microducts for installation by blowing for outdoor and/or indoor use. The microduct optical fibre cables and microduct fibre units utilize the structure of the microduct or protected microducts to support installation and to provide protection over the design lifetime. These products may be used for applications such as communication and transmission networks, transmission, telephone and data processing equipment, control and monitoring applications. The cabling structures described in this sectional specification are uniquely designed to facilitate and take advantage of installation by blowing into microducts. IECTR62839‑1 gives rules to build an environmental declaration, if needed.