This document gives specific requirements for polyethylene sheathing compounds, as given in Table 1, for use in inner and outer sheathing of communication cables including fibre optic cables. It is expected to be read in conjunction with EN50290-2-20, the product standards EN50407 series, EN50117 series, EN60794 series and other applicable product standards. Using raw material and type test data as outlined in this document, the raw material supplier will have sufficient data to demonstrate compliance and warrant that the material is suitable for the specified application. There are several routes used for manufacture of polyethylene and as a consequence a number of different types of polyethylene are defined as given in Table 1. Table1 — Polyethylene materials (informative) Abbreviation Material type Reactor process Polymer structure Maximum operating temperaturea °C LDPEb Low density polyethylene High pressure/ temperature radical reaction Long chain branched +70 LLDPE Linear low density polyethylene Low pressure/ temperature catalytic reaction Significant short chain branching +80 MDPE Medium density polyethylene Low pressure/ temperature catalytic reaction Short chain branched +80 HDPE High density polyethylene Low pressure/ temperature catalytic reaction Limited short chain branching +80 aFurther guidance on operating temperature is contained in EN50290-2-20 bUpper process capability for density 0,930g/ml. Normally density range 0,917–0,925g/ml