R-value (insulation) contain no trapped CFCs or HFCs (e.g., half-pound low density foams). On certain brands, twenty-year tests have shown no shrinkage or reduction in insulating value. This has led to controversy as how to rate the insulation of these products. Many manufacturers will rate the R-value at the time of manufacture; critics argue that a more fair assessment would be its settled value. The foam industry adopted the LTTR (Long-Term Thermal Resistance) method, which rates the R-value based on a 15-year weighted average. However, the LTTR effectively provides only an eight-year aged R-value, short in the scale of a building that
Building Design+Construction Building Design+Construction Building Design+Construction (BD+C) is a trade publication and web site serving the information needs of designing, building, and owning firms in the non-residential construction industry. Established in 1950, "Building Design+Construction" is published 12 times per year. In 2010, former owner Reed Business Information sold the magazine to MB Media, who was acquired by SGC Horizon, LLC. "BD+C"'s editorial focus is on the Building Team—architects, engineers, contractors, and building owners/developers. Each issue provideS the industry story on the process of how significant projects get built, from how Building Teams solve problems and deliver a project on time and on