Multi-stage downscaling procedure to analyse the impact of exposure concentration in a factory on a specific worker through computational fluid dynamics modelling

2016 ◽  
Vol 27 (4) ◽  
pp. 486-498 ◽  
Author(s):  
Alicia Murga ◽  
Sung-Jun Yoo ◽  
Kazuhide Ito
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Air Quality ◽  
Indoor Air Quality ◽  
Indoor Air ◽  
Human Body ◽  
Industrial Hygiene ◽  
Exposure Concentration ◽  
Multi Stage ◽  
The Impact

Indoor air quality plays a significant role in human health, especially for those who spend the majority of their time indoors, as is the case of workers in the industrial field. The control of contaminants inside the occupational indoor environment becomes critically important for promoting health. In terms of Health Impact Assessment, indoor air quality inside a factory becomes an essential factor of industrial hygiene. Here, computational fluid dynamics-based indoor environmental design was applied to potentially evaluate the environmental quality in a factory and to improve industrial hygiene. In particular, this study proposes an integrated simulation procedure to predict the inhalation exposure concentration of a hazardous chemical compound (here, cyclohexanone) by using a multi-stage, one-way nesting method. This procedure connects a factory building space, a micro-climate around the human body, and a respiratory tract in the human body. This research provides quantitative and qualitative detailed information of contaminant dosing in workers. The exact inhalation dose of contaminants in the human airways can be estimated based on factory-environment conditions through this procedure. Subsequently, the average contaminant concentration in the work place and inside the human body can be calculated.

scholarly journals Effect of Bench Hood Exhaust Usage on Indoor Air Quality in a Chemical Laboratory

2014 ◽  
Vol 1 ◽  
pp. 14-22
Author(s):  
Ayman A. Shaaban ◽  
Samy M. Morcos ◽  
Essam Eldin Khalil ◽  
Mahmoud A. Fouad
Keyword(s):  
Fluid Dynamics ◽  
Experimental Data ◽  
Computational Fluid Dynamics ◽  
Air Quality ◽  
Indoor Air Quality ◽  
Mole Fraction ◽  
Indoor Air ◽  
Cfd Model ◽  
Ansys Fluent ◽  
Computational Fluid Dynamics Cfd

Indoor air quality inside chemical laboratories subjected to gaseous contaminants was investigated numerically throughout the current research using Ansys Fluent 13. The lab is 4.8 m (L) * 4.3 m (W) * 2.73 m (H). The model was built and mesh was generated using Gambit 2.2.30 yielding around 1.4 million cells. To ensure the reliability of the Computational Fluid Dynamics (CFD) model validation was done against experimental data of three cases done by Jin et al. [1]. The model could simulate accurately contaminant mole fraction to the order of 10 Indoor air quality inside chemical laboratories subjected to gaseous contaminants was investigated numerically throughout the current research using Ansys Fluent 13. The lab is 4.8 m (L) * 4.3 m (W) * 2.73 m (H). The model was built and mesh was generated using Gambit 2.2.30 yielding around 1.4 million cells. To ensure the reliability of the Computational Fluid Dynamics (CFD) model validation was done against experimental data of three cases done by Jin et al. [1]. The model could simulate accurately contaminant mole fraction to the order of 10.

scholarly journals Effects of Climatic Conditions, Season and Environmental Factors on CO2 Concentrations in Naturally Ventilated Primary Schools in Chile

2021 ◽  
Vol 13 (8) ◽  
pp. 4139
Author(s):  
Muriel Diaz ◽  
Mario Cools ◽  
Maureen Trebilcock ◽  
Beatriz Piderit-Moreno ◽  
Shady Attia
Keyword(s):  
Air Quality ◽  
Indoor Air Quality ◽  
Indoor Air ◽  
Primary Schools ◽  
Co2 Concentration ◽  
Building Design ◽  
Climatic Conditions ◽  
Indoor Environmental Quality ◽  
Co2 Concentrations ◽  
The Impact

Between the ages of 6 and 18, children spend between 30 and 42 h a week at school, mostly indoors, where indoor environmental quality is usually deficient and does not favor learning. The difficulty of delivering indoor air quality (IAQ) in learning facilities is related to high occupancy rates and low interaction levels with windows. In non-industrialized countries, as in the cases presented, most classrooms have no mechanical ventilation, due to energy poverty and lack of normative requirements. This fact heavily impacts the indoor air quality and students’ learning outcomes. The aim of the paper is to identify the factors that determine acceptable CO2 concentrations. Therefore, it studies air quality in free-running and naturally ventilated primary schools in Chile, aiming to identify the impact of contextual, occupant, and building design factors, using CO2 concentration as a proxy for IAQ. The monitoring of CO2, temperature, and humidity revealed that indoor air CO2 concentration is above 1400 ppm most of the time, with peaks of 5000 ppm during the day, especially in winter. The statistical analysis indicates that CO2 is dependent on climate, seasonality, and indoor temperature, while it is independent of outside temperature in heated classrooms. The odds of having acceptable concentrations of CO2 are bigger when indoor temperatures are high, and there is a need to ventilate for cooling.

scholarly journals Window operation behaviour and indoor air quality during lockdown: A monitoring-based simulation-assisted study in London

2021 ◽  
pp. 014362442110177
Author(s):  
Farhang Tahmasebi ◽  
Yan Wang ◽  
Elizabeth Cooper ◽  
Daniel Godoy Shimizu ◽  
Samuel Stamp ◽  
...  
Keyword(s):  
Air Quality ◽  
Indoor Air Quality ◽  
Indoor Air ◽  
Energy Demand ◽  
Natural Ventilation ◽  
Probabilistic Models ◽  
Performance Model ◽  
Outdoor Environment ◽  
Ventilation Strategies ◽  
The Impact

The Covid-19 outbreak has resulted in new patterns of home occupancy, the implications of which for indoor air quality (IAQ) and energy use are not well-known. In this context, the present study investigates 8 flats in London to uncover if during a lockdown, (a) IAQ in the monitored flats deteriorated, (b) the patterns of window operation by occupants changed, and (c) more effective ventilation patterns could enhance IAQ without significant increases in heating energy demand. To this end, one-year’s worth of monitored data on indoor and outdoor environment along with occupant use of windows has been used to analyse the impact of lockdown on IAQ and infer probabilistic models of window operation behaviour. Moreover, using on-site CO2 data, monitored occupancy and operation of windows, the team has calibrated a thermal performance model of one of the flats to investigate the implications of alternative ventilation strategies. The results suggest that despite the extended occupancy during lockdown, occupants relied less on natural ventilation, which led to an increase of median CO2 concentration by up to 300 ppm. However, simple natural ventilation patterns or use of mechanical ventilation with heat recovery proves to be very effective to maintain acceptable IAQ. Practical application: This study provides evidence on the deterioration of indoor air quality resulting from homeworking during imposed lockdowns. It also tests and recommends specific ventilation strategies to maintain acceptable indoor air quality at home despite the extended occupancy hours.

The impact of mechanical ventilation operation strategies on indoor CO2 concentration and air exchange rates in residential buildings

2020 ◽  
pp. 1420326X2096076
Author(s):  
Pedro F. Pereira ◽  
Nuno M. M. Ramos
Keyword(s):  
Mechanical Ventilation ◽  
Air Quality ◽  
Exchange Rates ◽  
Indoor Air Quality ◽  
Indoor Air ◽  
Residential Buildings ◽  
Ventilation Strategy ◽  
The Impact ◽  
Mechanical Extraction ◽  
Air Exchange

In Portugal, residential buildings commonly have their ventilation strategy changed after commissioning. This occurs due to the building managers' willingness to reduce shared costs with the electricity needed for fan operation. However, this option is not technically supported, and the effects of such a strategy on indoor air quality-related to human pollutants are yet to be quantified. CO2 was monitored in 15 bedrooms and air exchange rates were calculated for each room. The air exchange rate values ranged from 0.18 to 0.53 h−1 when mechanical extraction ventilation was off, and from 0.45 to 0.90 h−1 when mechanical extraction ventilation was on, which represents an average increase of 119%. With the current intermittent ventilation strategy, all rooms remain above 1500 ppm for a given percentage of time, and 12 rooms presenting CO2 concentrations above 2000 ppm. Simulations of theoretical CO2 concentrations, for a non-interrupted mechanical ventilation strategy show that no rooms would accumulate CO2 concentrations above 2000 ppm, and only 25% would present CO2 concentrations above 1500 ppm. Pearson correlations between the monitored CO2 and human and spatial factors identified two relevant parameters. Those parameters correspond to ratios between CO2 generation and floor area ([Formula: see text]), and airflow with CO2 generation ([Formula: see text]). The proposed ratios could be used as ways to optimise ventilation costs and indoor air quality.

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