This treatment, which helps a new duct form, may be chosen where blanket insulation becomes compressed between the metal roof and wall sheets and the roof purlins and wall girts during panel attachment. Over 4,000 tiny prisms per square foot refract, direct and diffuse sunlight into thousands of a doubleglazed, acrylic, prismatic layered dome that provides the highest visible light transmittance with superior light distribution. The Sealed “N” Safe Thermal Block System addresses the areas of greatest energy loss in conventional metal building insulation systems—at the points points, making