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
Mineral industry of Seychelles Mineral industry of Seychelles The mineral industry of Seychelles consists mostly of production of such materials as clay, coral, sand, and stone. Seychelles is not a globally significant mineral producer or consumer. In 2006, imports of mineral fuels accounted for about 27% of the value of total imports. That same year, Seychelles was estimated to produce about 210,000 metric tons per year (t/yr) of gravel and crushed stone, 93,000 t/yr of granite, and 8,100 t/yr of sand. The main commercial producers of these construction materials are Civil Construction Company Ltd., Gondwana Granite, and United Concrete Products (Seychelles) Ltd.; which are