What is Polyisocyanurate Foam?
Polyisocyanurate foam (polyiso foam) is a cellular, thermoset plastic formed when two basic liquid chemicals, isocyanurate and polyol, are combined in the presence of a catalyst that helps the molecules to rearrange and join, a blowing agent to create closed cells in the structure, flame retardents, and possibly other agents. If the "art" of the process is correct, the result is an inert, non-nutritive, highly stable polyiso rigid foam that has the highest thermal insulating values of any conventional foam insulation commercially available today. Some inappropriately refer to polyiso as polyurethane (PUR), and they should not since polyiso's physical properties are much better, including k-factor, flame/smoke performance, and dimensional stability.
Polyisocyanurate foam insulation (often referred to as PIR foam) has been used successfully as foundation, wall, and roof insulation in both commercial and residential environments.
Polyisocyanurate foam insulation in these applications is shaped as an insulated panel, typically consisting of a polyisocyanurate board that forms a rigid foam core, laminated on one or two sides with foil, fiber-reinforced felt, or coated-glass facers.
Due to its excellent thermal insulating efficiency at service temperatures ranging from -297°F to +300°F, polyiso foam has become the standard for low temperature insulation applications such as:
- unfaced polyisocyanurate sheet (cut from polyiso bunstock) for commercial refrigeration insulation and freezer insulation
- polyiso sheet insulation for transportation vessels and containers such as railcars
- polyiso foam shape (fabricated from polyisocyanurate foam bunstock) to serve mechanical insulation for pipe insulation, equipment insulation, and other commercial and industrial applications, including cryogenic insulation, chilled water insulation, and HVAC duct insulation