Rigid polyurethane foam is the most efficient insulating material, formed by two chemicals component reaction. The material expands in a matter of second and within few moments letter becomes a CLOSED CELL RIGID INSULATING MATERIAL. The superior insulating ability of PU FOAM is due to the presence of an inert gas trapped in micro of tiny cells. These cells inhibit heat transfer. Rigid polyurethane foam is the most efficient insulating material, formed by two chemicals component reaction. The material expands in a matter of second and within few moments letter becomes a CLOSED CELL RIGID INSULATING MATERIAL. The superior insulating ability of PU FOAM is due to the presence of an inert gas trapped in micro of tiny cells. These cells inhibit heat transfer.The material expands in a matter of second and within few moments letter becomes a CLOSED CELL RIGID INSULATING MATERIAL. The superior insulating ability of PU FOAM is due to the presence of an inert gas trapped in micro of tiny cells. These cells inhibit heat transfer.