toxic gas

Incidents involving landfill gas in buildings have increased in recent years and these are of concern to developers and builders who are faced with the problem of developing sites where this gas is present. The principal components of landfill gas are methane (which is flammable) and carbon dioxide (which is toxic), but these two gases are also associated with coal strata, river silt, sewage and peat.

The entry of soil gas volatile organic compounds (VOCs) into houses has been recognized as a contributing factor in the degradation of indoor air quality. Typically, houses which are affected by soil gas VOCs are situated in close proximity to hazardous lands, i.e. landfill sites, lands affected by contaminated groundwater plumes, hydrocarbon spills, etc. Although there are hundreds of evaluations carried out yearly to assess the impact of soil-gas VOCs indoors, very few studies typically address the VOC concentration variability over time or the factors which influence this variability.

A sudden contamination of the outdoor air by some toxic gas can have several causes. The primary goal of the investigation was to determine the protection afforded by sheltering indoors. The object of a computational approach was a single family house with two floors. Three different models were utilized as computing tools: MOVECOMP to calculate the infiltration air flows, MULTIC to calculate the contaminant transport inside the building and TDYN to calculate the temperature decay of the building.

The study deals with the theoretical and experimental simulation of gas leaks in buildings. Such simulations may provide helpful information about the flow characteristics and dangerous concentrations as a function of the ventilation system (if any), the geometrical features and the thermal constraints on the room, and eventually about the positioning of gas monitoring devices.