Economic Analysis of Insulation Materials Used in Low-Slope, Built-Up Roof Systems

摘要

A wide variety of rigid-board types of insulations are currently manufactured for use under membranes of built-up roof (BUR) systems on buildings with low slope roofs. The US Air Force currently specifies one type of BUR insulation in reroofing its facilities within the continental US. The primary goal of this study was to develop an evaluation method for future Air Force use in selecting rigid-board insulations. The method was to include roof performance requirements for a long-lived system with life cycle costs (LCC) comparable with the currently specified insulation - fibrous glass. Insulation thermal resistance values up to R-33 (ft exp 2 .h. exp 0 F/Btu) were included in the range of investigation. This report describes the development of an LCC-based evaluation method for long-lived BUR insulations. The study emphasizes general performance requirements for a long-lived BUR system, and presents the results of 20-year energy costs and general recommendations for insulations on a comparable economic (LCC) basis over a range of R-10 to R-33. The economic justification of very high (up to R-33) insulation levels under BUR membranes is also evaluated on the basis of optimum economic levels and is found to have little or no justification above an R-25 level. (ERA citation 09:035684)