There are several ways to break the bridge across a steel framing member. This can be done by insulated sheathing, designing and installing distance spacers (This will place an air barrier between the framing and the exterior sheathing), adding a reflective surface to the space and this way the air barrier has an increased R-Value and alternate framing members. In order to ensure the best results, this requires the full involvement of the design team. Insulation to extreme levels can be achieved with any building, however the return on investment can be reached relatively quickly.
The different types of foam insulation are: expanded polystyrene (EPS), extruded polystyrene (XPS) and polyisocyanurate (Polyiso). The way EPS is manufactured is by expanding polystyrene beads to fill a form. Depending on the density of the beads, vapor resistance, thermal resistance and structural strength can be varied. The way XPS is created is by extruding a mixture called molten polysterene and then using a blowing agent through a die at high temperatures. You can find polyiso anywhere, it is commercially available and it is made up by polyurethane foam modified with polyisocaynurate. This mix together, will increase the fire resistance while maintaining R-values and strength.