Design and Scaling Methodology for Experimental Analysis of Wind Effects on Performance of Mechanical Ventilation System for Asbestos Abatement
1Eindhoven University of Technology, Eindhoven, The Netherlands; 2Institut National de Recherche et de Sécurité, Nancy, France; 3KU Leuven, Leuven, Belgium
Asbestos abatement processes involve the risk of suspended asbestos fibers, with potentially fatal health hazards, escaping into the outdoor environment. This has led authorities to impose guidelines towards asbestos abatement procedures. The abatement process involves sealing the asbestos containment zone and maintaining a negative pressure within by means of mechanical ventilation system. Governments have ascertained regulatory margins for this depressurization; however, a possible breach during which asbestos fibers can escape into the environment due to the influence of meteorological (wind) conditions are not yet addressed. Experiments will be conducted in an atmospheric boundary layer wind-tunnel (ABLWT) in order to assess the effects of wind conditions on the mechanically induced negative pressure in asbestos containment zones.
This paper discusses the preparatory stages of the ABLWT test which includes the design and the methodology to scale down the ventilation system and the calibration of the individual ventilation components. For this, an idealized building (dimensions 18 x 18 x 18 m3) with asbestos containment zone at the upper half is considered. The ventilation system for this zone is designed in accordance with the French national safety guidelines and comprises thirty-four air inlets with check valves, four negative pressure units, one air inlet for tuning, airlock for materials and airlock for people. The geometrical scale for the building and the scaling factors for the characteristic parameters of the ventilation components are determined following a well-established methodology that will be discussed in the full paper. Based on this, a geometrical scale of 1:40 is determined for the ABLWT test.
Modeling and Experimental Validation of the Dynamics of VOC Emitted from Particleboard into a Ventilated Chamber
1INRS, France; 2IMT Nord-Europe
Stores and storage areas are workplaces where the quantity of new products is high, leading to potentially significant sources of pollutants like volatile organic compounds (VOC). Moreover, storage areas are generally poorly ventilated compared to sales areas. In order to prevent long-term exposure of workers to VOC in such environments, it is required to elaborate the best ventilation strategy given that their volumes are very high, with high ceiling. Hence, the ventilation by pollutant dilution that is often deployed may not be the best way in terms of indoor air quality, thermal comfort and energy consumption. In order to design the appropriate ventilation system, the dynamics of VOC emissions from products is first investigated to provide a better understanding of their interactions with ventilation. A 3D CFD simulation, including an emission model, was carried out and validated against experiments. A particleboard into a ventilated chamber with controlled airflow rates was used, where the concentrations of eight VOCs were monitored as functions of time. The air change rates, turbulence data, air velocities and VOC concentrations were all in agreement with those encountered in real environments. Results highlight that the model is able to reproduce the overall behavior of each VOC, and several examples of the use of such tool for improving the design of ventilation systems are presented.
VentMapping™: Using Computational Fluid Dynamics for Air Filtration System Design
Controlling contaminants in an indoor environment can be highly complex. The best air filtration solution looks at locations and volumes for point sources of contaminants, natural airflow and currents within the space, existing barriers and enclosures, and other factors that influence how air and contaminants move throughout the space. Using Computational Fluid Dynamics (CFD), we can model current airflow patterns and contaminant movement and simulate the impact of different solution options to select the optimal system design. In this session, we’ll show you how CFD and computer modeling can be used for air filtration system design. Includes real-world examples and Q&A. We'll cover:
- Basics of industrial ventilation and ambient air filtration design
- Factors that influence airflow within a facility
- What is computational fluid dynamics?
- Uses of computer modeling for ambient dust collection system design and optimization