Why does ICS use polyurethane rather than polystyrene?
ICS chose to use polyurethane foam insulation instead of expanded polystyrene (EPS) for several reasons. First, polyurethane is a far better insulator. ICS polyurethane foam has a stable R-value of R-7 per inch of thickness, versus R-4 for EPS. This means that you can achieve R-28 with 4.5-inch walls. EPS-insulated walls would have to be nearly twice as thick to achieve the same R-value. Second, when polyurethane foam is injected into panels, the panels are stronger than EPS panels. While the EPS is simply glued onto the substrates, injected polyurethane foam adheres and bonds to every surface (substrates, top-plates, splines, cam-locks, electrical boxes, etc.), and then becomes rigid. Polyurethane panels can withstand higher compression (or axial), transverse (or flexural), and racking loads. Third, polyurethane has better fire, flame, and smoke characteristics. Polyurethane does not melt at any temperature. It will withstand constant service temperatures up to 180-degrees Fahrenheit
