ISO 18852:2012 specifes a method for the determination of the nitrogen surface area (NSA) of carbon blacks and other rubber compounding ingredients, like silicas and zinc oxides, based on the Brunauer,Emmett and Teller (BET) theory of gas adsorption using a multipoint determination. This test method specifes the sample preparation and treatment, instrument calibration, required accuracy and precision of the experimental data, and calculation of the surface area results from the data obtained. Also given is a procedure for calculating the statistical thickness surface area (STSA), otherwise known as the external surface area. The test method specifed uses an automatic static-volume vacuum apparatus, the surface area being calculated using the BET theory based on monolayer measurements.
