DIN Standards Committee Materials Testing
DIN ISO 2889 Beiblatt 2
Sampling airborne radioactive materials from the stacks and ducts of nuclear facilities - Supplement 2: Assessment of the changes in the concentration of aerosol particles due to non-isokinetic sampling
Probenentnahme von luftgetragenen radioaktiven Stoffen aus Kanälen und Kaminen kerntechnischer Anlagen - Beiblatt 2: Abschätzung der Änderungen der Konzentration der Aerosolpartikel infolge nicht-isokinetischer Probenentnahme
Overview
Non-isokinetic sampling can lead to a change in the aerosol particle size distribution and as a result to a non-representative sample. These modifications of the particle size concentration depend on the diameter and density of aerosol particles, stream velocity and nozzle shape. This supplement to DIN ISO 2889 deals with the following two cases: - same stream direction of the bulk and partial air stream; - different stream direction of the bulk and partial air stream. For aerosol particles with an aerosol particle diameter lower than 1 µm, the modifications of the aerosol particle concentrations can be generally neglected. For a usual aerosol particle collective the change of the concentration for each aerosol particle diameter and thus for the aerosol particle collective should be calculated. The results also provide information on the change of the particle size distribution leading to a change of the distribution of activity via the diameter of aerosol particles. The responsible committee is Joint Subcommittee GUK 967.2 "Aktivitätsmessgeräte für den Strahlenschutz" ("Activity meters for radiation protection") of the DKE (German Commission for Electrical, Electronic and Information Technologies) at DIN and VDE, Joint Committee with the Radiology Standards Committee (NAR).
