This European Standard specifies performance criteria for off-gas systems with respect to the potential risks to the worker and the environment from microorganisms in use. This European Standard applies if the intended use of the off-gas system includes hazardous or potentiallly hazardous microorganisms used in biotechnological processes or if exposure of the worker or the environment to such microorganisms is restricted for reasons of safety. This European Standard does not apply to off-gas systems that use filter assemblies to remove microorganisms and to off-gas systems used to avoid contamination of processing areas or equipment.