Lessons Learned from a Low-Slope Roof System LCA Project Dr. James L. Hoff, DBA TEGNOS Research, Inc. Prepared for ASTM E-60 Workshop on Life Cycle Assessment: Methodology, Current Development and Application in Standards Atlanta, Georgia October 18-19, 2009

Low-Slope Roof System LCA Project Background Project commissioned by a roofing industry trade association –Interested in correcting apparent discrepancies and omissions in existing LCI databases –Provided updated material and process information Calculations performed by an experienced LCA practitioner –Using best of current LCI data –Calculated using Simapro 7.1 Study data will be released in the near future –Input / output data to LCI databases –Public report summary

Low-Slope Roof System LCA Project Lessons Learned Impacts –Prioritization / Weighting –Comparative v. Actual Values Energy –Embodied v. Operating –Offsetting Life Cycle Management –Service Life Strategies –Managing Assumptions

Prioritization / Weighting –Whats really important? –The energy / atmosphere complex –Other impacts Comparative v. Actual Values –Comparative values may promote improvement –Actual values provide important order-of- magnitude information Low-Slope Roof System LCA Impacts

Impacts Comparative v. Actual Values Comparative Values (100 = Highest) Actual Values (kg CFC-11 eq.) Source: TENGOS Research, Inc.

Embodied v. Operating Energy –Embodied energy of buildings is 15% or less over service life –Operating energy of buildings is 85% or more over service life Other Energy-Related Offsets –Reflective and other cool roof systems –Rooftop solar Low-Slope Roof System LCA Energy

Kg / Sq. Ft. Initial Embodied GWPAnnual Operating GWP* *Typical GWP from roof-related heating and cooling loads Embodied v Operating Energy Annual Global Warming Potential : Typical Commercial Roofing System Source: TENGOS Research, Inc.

Operating energy accounts for over 85% of total energy usage in buildings O Energy (GJ/m 2 ) Building Life (Years) Operating Energy Recurring Embodied Energy Total Energy Initial Embodied Energy Embodied v. Operating Energy: Contribution over Building Life Cycle Source: New Solutions, Vol. 11, January, 2007.

Embodied v. Operating Energy Other Energy-Related Offsets Cool Roofing –Roof surface may reduce Urban Heat Island Effect –Roof surface reflectivity may offset other global warming impacts Rooftop Solar –Roof surface may serve as an integrated platform for renewable energy offsets

Service Life Strategies –Periodic maintenance & minor repairs –Planned & scheduled major renovations Managing Assumptions –At beginning of use: Commissioning –Throughout life cycle: Continuous Commissioning Low-Slope Roof System LCA Life Cycle Management

Time Raw MaterialsManufactureTransportInstallation Use Removal Disposal Raw MaterialsManufacture TransportInstallation Use Removal Disposal Impact Service Life Strategies Common Roof Service Life Scenario

Time Raw MaterialsManufactureTransportInstallation Expanded Use Repair / Renovation Removal Disposal Extended Use Maintenance Service Life Strategies Extended Roof Service Life Scenario Impact