Jul 26 2005
Sarnafil Inc., a leading manufacturer of high quality thermoplastic roofing and waterproofing systems, received the highest eco-efficiency ratings for its vinyl roofing membrane in a recent analysis of low slope roofing systems.
The study, conducted by an independent environmental consultant, ranks Sarnafil’s S327 membrane as the most eco-efficient, a ratio of a roofing system’s total life cycle costs to its total life cycle environmental impacts. Conducted by Carbotech AG of Basel, Switzerland, the study analyzed the environmental impact and operational costs of commonly used North American low slope roof systems, with a particular focus on the selection of the optimal membrane due to its impact on service life and energy consumption.
Tested membrane/insulation combinations included Sarnafil S327 membrane with both polyisocyanurate and expanded polystyrene insulation; and US manufactured TPO, EPDM, modified bitumen, and 4-ply BUR membranes, each with polyisocyanurate insulation.
“We are extremely pleased to have this independent confirmation of both the cost effectiveness and environmental effectiveness of our vinyl roofing membrane,” said Stanley Graveline, vice president of technical services, Sarnafil Inc. “Eco-efficiency captures the total picture of the impact of a particular building component so that a specifier or building owner can make an informed decision in his or her selection. This methodology is at the leading edge of life cycle analysis evaluation”
According to Dr. Fredy Dinkel, project leader, and Cornelia Stettler, consulting expert, the two key components of eco-efficiency are environmental impact (total life cycle impact) and cost (total life cycle costs), both of which include life cycle and operational components. This study used a life cycle analysis (LCA) methodology to calculate life cycle environmental impacts. They were aggregated for all the components into various impact categories (global warming, non-renewable primary energy, photochemical smog, acidification) using the U.S. Environmental Protection Agency’s TRACI model. The life cycle costs include the average installed roof price, maintenance and disposal costs. Operational costs include roof related energy costs for heating and cooling. Study results demonstrate that low slope roof systems with lightweight thermoplastic membranes and a long service life impose the lowest global warming impacts. Systems incorporating EPDM and modified bitumen membranes, with a shorter service life and/or 4- ply BUR low slope roof systems, with high material usage and short service life impose the greatest impacts.
Based on an assessment of the eco-efficiency of the chosen systems, the study concludes that low slope roof systems should be selected according to the following criteria, in order of priority:
- Long service life
- White reflective surface (less relevant for moderate and cold climates)
- Light weight, low material consumption
- Low maintenance requirements
Using these criteria, white single ply, heat-weldable, thermoplastic membranes are the best choice of the analyzed low slope roof systems, with Sarnafil’s S327 vinyl membrane performing best overall in this evaluation. Selection of a low slope roof system using these criteria can reduce the total impacts and costs to the building owner and the environment.
A high eco-efficiency rating was found for the Sarnafil S327 vinyl systems in all climatic regions. The eco-efficiency rating for TPO was average while it was low for the EPDM, 4-ply BUR and modified bitumen.