Design and Scaling Methodology for Experimental Analysis of Wind Effects on Performance of Mechanical Ventilation System for Asbestos Abatement

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.