Long-Term Performance of Rigid Plastic Foam Building Insulation

This article focuses on the characteristics of rigid plastic foam building insulation (RPFBI), one of several types of insulation available for new and retrofit applications. Most RPFBI currently in service incorporates a low thermal conductivity and low-flammability blowing agent within the cells of the foam matrix to enhance thermal and fire performance. Blowing agents diffuse out of the foam matrix with time, and environmental gases diffuse in, with concomitant changes in performance. To address the thermal performance issue, international standards organizations have developed standards that define thermal performance averaged over a specific time frame or assumed lifetime. These standards have several limitations that may result in inaccurate estimates of long-term performance, as well as confusion among stakeholders. None of the standards address possible changes in fire performance through time. This paper presents a review of the standards and literature regarding thermal and fire performance of RPFBI, and a call for harmonization and consistency across standards addressing thermal performance, fire behavior, durability, and service life.