An experimental protocol for measuring aerosol deposition in industrial-sized ventilation ducts

In the literature, studies on aerosol deposition in ventilation ducts mainly focus on ventilation ducts with a hydraulic diameter (D-h) of around 15-25 cm and with circular or square cross-sections. However, to the best of our knowledge, common industrial-sized ventilation ducts (D-h similar to 50 cm) with rectangular cross-sections have not been studied. As a result, experimental aerosol deposition measurement protocols relative to smaller ventilation ducts are not suitable for measurements in industrial-sized ducts. Therefore, a new experimental protocol is proposed here, which can be used without destruction of the surface or addition of a substrate onto the duct surface and which could be applied in industrial ventilation networks if certain conditions are met. In this paper, we present an experimental protocol developed to measure aerosol deposition in large-scale ventilation ducts. First, the collection and measurement technique, the type of aerosol and the injection method are chosen. Second, an experimental protocol relative to the collection of aerosols deposited on duct surfaces is developed, based on a so-called 'wiping' technique. Many verifications are presented to ensure repeatable and reproducible measurements. Third, a repeatability study is conducted as well as a validation process. In the last section of this paper, we present some results on aerosol deposition obtained at a test facility compared to two other studies.