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
Construction industry of the United Kingdom Construction industry of the United Kingdom The construction industry of the United Kingdom contributed gross value of £64,747 million to the UK economy in 2004. The industry employed around 2.2 million people in the fourth quarter of 2009. There were around 194,000 construction firms in Great Britain in 2009, of which around 75,400 employed just one person and 62 employed over 1,200 people. In 2009 the construction industry in Great Britain received total orders of around £18.7 billion from the private sector and £15.1 billion from the public sector. While manufacturing in the United Kingdom shrank as a proportion of