definition
strict definition
polyisocyanurate foam
Insulating foam made from polyisocyanurate, a plastic similar to polyurethane.
Polyisocyanurate foam is a plastic material which is sprayed into cavities or layers in walls and roofs for thermal insulation. It is similar to polyurethane, and usually has somewhat better insulating properties.
The plastic is applied as foam within wall or roof spaces. A rigid polyisocyanurate panel has a separate insulation form.
Its polymer composition is related to polyurethane without making the two materials identical. Thermal performance depends on the particular product and its installed condition.