More rigorous energy codes and requirements for energy-efficient construction are spurring interest in new insulation products, specifically those that provide continuous exterior insulation. New exterior insulation products, especially those that have nontraditional forms, need to be evaluated not only for basic material properties such as R-value, but also for their installed assembly performance and compatibility with other system components. This paper discusses several methods that can be used for system-level product evaluation and demonstrates the value of this approach. Full-scale laboratory testing was conducted on wall assemblies constructed using two different types of exterior insulation. The exterior insulation products compared were a low vapor permeance XPS insulation and a high vapor permeance fibrous exterior insulation relatively new to the market. Evaluation methods included thermal imaging analysis using a climate simulator and structural performance testing of cladding attached to strapping that was fastened to the structure through the continuous exterior insulation. The thermal imaging analysis included side-by-side wall construction in the climate simulator and infrared thermal images taken of both the interior drywall and exterior insulation or cladding while operating the simulator in a winter climate condition. The structural assembly testing consisted of deflection measurement of both short- and long-term loading of various simulated cladding weights to the strapping, which was fastened to the structure through the exterior insulation. Conducting these laboratory tests and analysis produced a more realistic in-service performance prediction of exterior insulated wall assemblies that accounts for the interaction of the various assembly components.
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