Reduced Energy and Maintenance Costs Using Polyurethane as a Replacement Roof System

摘要

Reduction in maintenance and allied costs was the number one priority when Texas A&M University first considered polyurethane foam as a replacement roof for existing buildings. An investigation revealedthat when properly applied, this system would solve most of the maintenance problems associated with built-up roofs. Standard specifications for thisreplacement roof were developed, requiring the application of 2 inches of polyurethane foam and 45 mils of a urethane coating. The result being a monolithic weatherproof cover for the roof. Additionly, with the application of polyurethane foam, a reduction in the energy used to air condition the building was noted. A method was developed for estimating maximum roof temperatures. Using the Heat Transfer Equation, Q = U x A x dT, roof loads before and after the application of the foam were calculated. With these loads, annual energy used was calculated and the savings resultingfrom the use of the foam were determined. 27 buildings were reroofed using polyurethane foam, totalling some 593,000 square feet at a total cost of $1,694,000. Annual energy savings were $327,500, for a payback of 5 years, 2 months, using the Simple Payback Method.