Permanently elastic sealants

Permanently elastic sealants that were used between 1955 and 1975 in buildings often contain polychlorinated biphenyls (PCBs) as plasticisers. An estimated total of 100 to 300 tonnes of PCBs were used in Switzerland in sealants. A significant proportion of these are still found to this day in buildings from the period in question. Most commonly affected are large concrete buildings.

A study carried out from 1999 to 2002 of more than 1300 sealant putty tests in around 450 buildings constructed between 1950 and 1980 throughout Switzerland revealed that around a quarter of the tests disclosed the presence of a percentage level of PCBs. Where renovation work is not carried out to a professional standard, PCBs can enter the environment and become a danger to tradesmen and the public.

Buildings that were constructed between 1955 and 1975 must therefore be checked in advance of any renovation work for sealants containing PCBs. If such sealants are present, a removal and disposal plan must be drawn up. During the renovation work, special safety measures for the protection of workers and the environment are required.

Immediate renovation work is required where the annual average value in the ambient air amounts to more than 6 micrograms per m³. This value applies to buildings occupied by people during working hours, such as schools and office buildings. For buildings that are constantly occupied, such as private housing and residential homes, a value of 2 micrograms per m³ of ambient air applies.