SYMPOSIA PAPER Published: 30 August 2014
STP158620140035

Economic Impact of Improved Service-Life Prediction for Seams in Low-Slope EPDM Roofing

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In the early part of the 1970s, built-up roofing dominated the U.S. membrane roofing industry. It was estimated that 10 % to 15 % of these roofs failed prematurely, but by the early 1980s new membranes were being rapidly adopted. Among them, ethylene-propylene-diene terpolymer (EPDM) rubber, manufactured as preformed single-ply sheets ready for field installation, experienced the most rapid growth. Although performance was generally satisfactory, far too often, disbonding of seams occurred. National Institute of Standards and Technology (NIST) researchers developed a creep-rupture methodology to study the factors affecting seam performance including mechanical loading of the seam, thickness of the adhesive used to form the seam, and rubber surface cleanness of the rubber before the adhesive was applied. This research had a noteworthy impact on the EPDM roofing industry in that it accelerated changes to seam technology and increased users’ confidence that EPDM would provide satisfactory long-term performance. This paper examines the economic impact of the research conducted by NIST’s Service Life Prediction (SLP) Program for EPDM roofing. Three ASTM standards are used to calculate the value of NIST’s research investment: (1) present value of net savings (PVNS) [ASTM E1074-09: Practice for Measuring Net Benefits and Net Savings for Investments in Buildings and Building Systems, Annual Book of ASTM Standards, ASTM International, West Conshohocken, PA, 2012], (2) savings-to-investment ratio (SIR) [ASTM E964-06: Practice for Measuring Benefit-to-Cost and Savings-to-Investment Ratios for Buildings and Building Systems, Annual Book of ASTM Standards, ASTM International, West Conshohocken, PA, 2012], and (3) adjusted internal rate of return (AIRR) [ASTM E1057-06: Standard Practice for Measuring Internal Rate of Return and Adjusted Internal Rate of Return for Investments in Buildings and Building Systems, Annual Book of ASTM Standards, ASTM International, West Conshohocken, PA, 2012]. The results show that the PVNS attributable to NIST is $26.7 × 106 with an SIR of 2.5 and an AIRR of 13.7 %. Stated in present-value terms, every public dollar invested in NIST’s SLP-related research, development, and deployment effort generated $2.5 in cost savings to the public.

Author Information

Thomas, Douglas, S.
Applied Economics Office, Engineering Laboratory, National Institute of Standards and Technology, Gaithersburg, MD, US
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Developed by Committee: E06
Pages: 1–22
DOI: 10.1520/STP158620140035
ISBN-EB: 978-0-8031-7618-8
ISBN-13: 978-0-8031-7617-1