Thermal Performance of an Interlocking Fiber-Reinforced Plastic Building Envelope System

Abstract

Fiber-reinforced plastic (FRP) materials are being more frequently used in building construction. Recently, a newly developed concept consisting of a tongue-and-groove fiberglass composite panel system has been developed for use in the construction of building envelope systems. Since little information is available on the thermal characteristics of such panel systems, a testing program was developed to investigate the thermal characteristics of panels that are commercially available at the present. Two full-scale 1.22 m × 1.22 m (4 ft × 4 ft) FRP panels were tested. Two panel thicknesses were considered: 25 mm (1 in.) and 76 mm (3 in.). A calibrated temperature-controlled test plate was used with heat-flow sensors to determine the thermal resistance of the FRP panels at the midsections of panels and at the interfaces (i.e., joints) between two adjoining panels. Two conditions were simulated: “dry joint,” which includes only mechanical interlocking at the joints, and “sealed joint,” in which the joints were sealed with a commercially available sealant. The R-values of the tested panels were approximately 5–46% higher in the sealed-joint condition. Sealed joints decrease heat exchange across the envelope system, thereby increasing the thermal resistance values of the panel system. The relatively high R-value of the 76 mm (3 in.) panel system {2.0 (m² K)/W [11.36 (h ft²°F)/Btu]} is encouraging, and the possibilities of using the panels in building construction should further be explored.