In the earlier 70′s, when PEX tubing have been widely used in housing construction, the Nordic countries, professionals are faced with annoying regularity. PEX plumbing in some apartments, started, for whatever reasons, leak. Each of us can imagine the trials endured by the residents of these apartments. The situation surrounding these accidents, exacerbated by the fact that the owners have to seek redress through the courts. In short order, manufacturers of pipes studies were conducted.
While most popular in the sewage systems have been PVC-pipe with an outer diameter of 110 mm and wall thickness of 2,2 mm. As a result, studies found that the apartment in which is automatic washing machines, dishwashers and other appliances to the drain hot water into the sewer above the pipe, due to the small thickness of the walls, could not withstand the heat load.
Soon introduced a new standard, which classified the two types of PEX tubing: Type A – for primary and secondary ventilation, as well as internal storm water pipeline and Type B – for the distribution system and waste water treatment. In the first case used the previously applied to the pipe wall thickness of 2.2 mm, while the second, this thickness was increased to 3.2 mm (diameter 110 mm).