Is ‘PUR’ or ‘PIR’ better for cryogenic supports for LNG terminals?

PUR (polyurethane) and PIR (polyisocyanurate) are both cellular insulation materials produced from a catalytic self-polymeric reaction of isocyanate. They are widely used in chemical, alkene cracking plants and LNG storage and transportation where excellent cold insulation capability is required.

The difference between PUR & PIR is that PUR is a much stronger material able to absorb impact. PIR is a very brittle material that is normally used as low density line insulation but it is not suitable for use at pipe support locations where high loading has to be absorbed.

PUR is moulded by Bergen Pipes Supports to the required shape & so has no residual stress. PIR is generally cut from bun stock which can have high residual stress & can cause cut pieces to distort. Their operating temperatures are similar (PUR’s range is -196 ~ 140oC and PIR’s is -196 ~ 160oC).

PIR has better fire resistance than PUR, but PUR is acceptable for LNG applications.