Abbas Salehi - Head of Eng. Material Dept., At Standadization Div.,
Masoud Motevallian Naini - Research and Technology Management of National Iranian Gas Company, Tehran, Iran

Field weld joints protection of transmission oil/gas pipeline has been one of the most discussed problem in the pipeline industry .The challenge to develop a joint coating that help mitigate this problem has been pursued by many field weld joint coating manufacturers and applicators/end users. Despite the fact that ,there are few alternative for pipe weld joint coating ,such as liquid epoxy,polyurathane,3 ply co-extruded cold applied plastic tape ,heat shrinkable sleeve ,and etc ,which end user may select one of them with regards to environmental consideration ,performance ,ease of operation and cost. This article has only focused on heat-shrinkable sleeve, which may classifies as follows: - Two layer system with mastic type adhesive (primerless) - Three layer system with hot- melt type adhesive (with primer) For protection of weld joint of transmission oil/gas pipeline when the main coating is three layer polyethylene.

Shrinkable seleeve nastic hot-melt