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

Abstract

In the literature, studies on aerosol deposition in ventilation ducts mainly focus on ventilation ducts with a hydraulic diameter (Dh) of around 15 to 25 cm and with circular or square cross-sections. However, to our knowledge, common industrial-sized ventilation ducts (Dh ~ 50 cm) with rectangular cross-sections have not been studied. As a result, experimental aerosol deposition measurement protocols relative to ventilation ducts of smaller sizes are not suitable for measurement 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 on the duct surface and could be applied in industrial ventilation networks as soon as certain conditions are met. In this paper, we present an experimental protocol developed to measure aerosol deposition adapted for large-scale ventilation ducts. First, the collection and measurement technique, the type of aerosol and the injection method are chosen. Second, the 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 here 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 on a test facility compared to two other studies.