This part of IEC 60684 gives the requirements for two types of heat-shrinkable, polyolefin sleeving, dual wall, not flame retarded with a nominal shrink ratio of 3:1.  
This sleeving has been found suitable for use at temperatures of up to 100 °C. 
Type  A : Medium wall, internal diameter up to 200,0 mm typically 
Type  B : Thick wall, internal diameter up to 200,0 mm  typically 
These sleevings are normally supplied in colour black. 
Since these types of sleevings cover a significantly large range of sizes and wall thicknesses, Tables A.1 and A.2 provide a guide to the range of sizes available. The actual size shall be agreed between the user and supplier. 
Materials which conform to this specification meet established levels of performance. However, the selection of a material by a user for a specific application should be based on the actual requirements necessary for adequate performance in that application and not based on this specification alone.dition 1.1 2016-12 CONSOLIDATED VERSION VERSION CONSOLIDéE colour inside Flexible insulating sleeving – Part 3: Specifications for individual types of sleeving – Sheet 247: Heatshrinkable, polyolefin sleeving, dual wall, not flame retarded, thick and medium wall Gaines isolantes souples – Partie 3: Spécifications pour types particuliers de gaines – Feuille 247: Gaines thermorétractables en polyoléfine, à double paroi (épaisse et moyenne), non retardées à la flamme IEC 6068