Exposition professionnelle aux vapeurs de solvants : étude d'un modèle deux zones par comparaison numérique et expérimentale

Abstract

The Industrial Hygiene Modeling (IH MOD) software, developed by the AIHA (American Industrial Hygiene Association), constitutes the main mathematical tool for modeling the occupational exposure to chemicals. However, the assessment of the exposition to vapors solvents is realized by models based on many simplified assumptions that take in consideration a limited number of parameters such as of a well-mixed air in the modeled field which is rarely the case in reality. The aim of this memoir is to compare the expositions to vapor predicted by IH MOD with the results obtained from a computational fluid dynamic software called Fire Dynamics Simulator (FDS) and with experimental measurements collected inside a model room located in the Centre de Technologie Thermique (CTT) at the École de Technologie Supérieure (ÉTS). The two zones model of IH MOD with a constant generation rate was chosen for this study. The time-dependent concentration in the near field resulting from acetone evaporation was predicted with this model and compared, for many generation rates and different ventilation scenarios, with the numerical results from FDS and the measurements done inside the model room. Three ventilation scenarios and many air exchange rates (1 to 8 CAH) were made to allow studying the impact of the displacement of the supply and exhaust air grilles on the dispersion of contaminants in the room model. The air exchange ratio between the near field and the far field was determined by two different expressions and its influence on the concentrations predicted by IH MOD was quantified. The results show that the air exchange ratio is an important parameter for estimating concentrations in the near field. A 5% difference between IH MOD and FDS values in scenario 1 and a 40% difference in scenario 2 was found. Acetone concentrations predicted by IH MOD and FDS in the near field were compared to the experimental measurements taken by a photo-ionization device in a third ventilation scenario. The results obtained from this third scenario show that both FDS and IH MOD underestimate concentrations in the near field by around 20%, regardless of the air exchange rate.

Date	15 Nov 2016
Original language	French
Awarding Institution	École de technologie supérieure
Supervisor	Stéphane Hallé (Supervisor) & Ali Bahloul (Co-supervisor)