Refers to general contaminants / impurities. In relation to the heat exchanger, fouling may occur in the jacket area (heating medium) and in the product tubing. Particularly when tempering viscous media (e.g. cooling silicon), fouling may occur as the dynamic viscosity (flowability) of the medium to be tempered increases exponentially as the temperature drops. Fouling inside the product tubing of heat exchangers can be counteracted by using the patented STRIKO S-Helical technology. Fouling reduces the heat transfer and in turn the efficiency of heat exchangers.