thermo-sensitive pigments. PB-1 disperses easily in other polyolefins, and at low concentration, acts as processing aid reducing torque and/or increasing throughput. Thermal insulation PB-1 can be foamed. The use of PB-1 foam as thermal insulation is of great advantage for district heating pipes, since the number of materials in the sandwich structure is reduced to one, facilitating its recycling. Other applications Other applications include domestic water heaters, electrical insulation, compression packaging, wire and cable, shoe soles, and polyolefin modification (thermal bonding, enhancing softness and flexibility of rigid compounds, increasing temperature resistance and compression set of soft compounds). Environmental longevity Plumbing and heating systems made from PB-1 have been used in Europe and Asia for more than 30 years. First reference projects in district heating and floor heating systems in Germany and Austria from the early 1970s are still in operation today. One example is the installation of PB-1 pipes in the Vienna Geothermal Project (1974) where aggressive geothermal water is distributed at a service temperature of 54 °C and 10 bar pressure. Other pipe materials in the same installation failed or corroded and had been replaced in the meantime. International standards set minimum performance requirements for pipes made from PB-1 used in hot water applications. Standardized extrapolation methods predict lifetimes in excess of 50 years at 70 °C and 10 bar. Class action lawsuits and removal from building code approved usage Polybutylene plumbing was used in several million homes built in the United States from around 1978 to 1997. Problems with leaks and broken pipes led to a class action lawsuit, Cox v. Shell Oil, that was settled for $1 billion. The leaks were associated with degradation of polybutylene exposed to chlorinated water. Polybutylene water pipes are no longer accepted by the United States building codes and have been the subject of class action lawsuits in both Canada and the U.S. The National Plumbing Code of Canada 1995 listed polybutylene piping as acceptable for use with the exception of recirculation plumbing. The piping was removed from the acceptable for use list in the 2005 issue of the standard. There is evidence to suggest that the presence of chlorine and chloramine compounds in municipal water (often deliberately added to retard bacterial growth) will cause deterioration of the internal chemical structure of polybutylene piping and the associated acetal fittings. The reaction with chlorinated water appears to be greatly accelerated by tensile stress,