Piping systems - Import export

Pre-insulated pipes are incresingly popular for centralised and energy efficient district heating and cooling systems. Â A central service pipe is surrounded by PUR foam insulation and a durable HDPE outer cladding. Adding an EVALâ„¢ layer to the pipe structure helps extend system service life, by maintaining insulation efficiency and structural integrity. Â EVALâ„¢ helps make sure pre-insulated pipe systems performs not only longer, but more efficiently as well.

Many pre-insulated pipes use rigid polyurethane foam and a HDPE casing. Over time, the insulation efficiency of the pipe structure decreases, caused by the permeation of air (oxygen, nitrogen) into the foam cells and the diffusion of cell gases (blowing agent, carbondioxide) out of the foam cells. The insulation efficiency of PUR foam decreases as air permeates in and cell gasses permeate out of the pipe structure, increasing thermal conductivity. Oxygen permeation can also lead to oxidative degradation of the PUR-foam insulation itself. This reduces the adhesion between the PUR-foam and inner pipe, weakening the structure and compromising the mechanical integrity of the entire pipe system.