Investigation of the entry characteristics of dust samplers of a type used in the British nuclear industry

Experiments have been carried out in a large wind tunnel to investigate the entry characteristics of dust samplers—both static and personal—of the type used to monitor ‘total’ airborne radioactive paniculate in the British nuclear industry. These samplers were exposed to test dusts of closely-graded fused alumina under experimental conditions relevant to the environmental conditions found in nuclear industry workplaces. For the static samplers (60-mm open face filter holders), performance was determined by reference to a 10-mm isokinetic probe. The resultant aspiration efficiency (A) was found to be close to unity for the range of environmental conditions found in the nuclear industry workplace and for particles with aerodynamic diameter up to about 30 μm. Also it is unaffected by mounting the sampler itself on the large bluff body of the sampling pump. The performances of the personal samplers (of the 25-mm filter holder type) were assessed in terms of the ratio (R) between the mass of dust entering each personal sampler when worn on the body of a mannequin and that entering the mouth of the mannequin under simulated breathing. The results show that, for nuclear industry workplace conditions, the personal samplers reflect satisfactorily the health-related ‘total’ dust exposure of the wearer