Tesis doctoral de María Isabel Montoya Rodríguez
During the last decades the number of accidents in chemical industries and during transportation of hazardous substances has significantly increased, with most of them occurring in highly populated areas. One of the possible accidents is a toxic gas cloud, which although less common than other major hazards could affect larger areas reaching populated zones and producing more severe consequences. This implies then, a great challenge to emergency managers who must plan and decide the areas where protection measures should be implemented: shelter in place and/or evacuation. The assessment of the effectiveness of shelter in place is subjected to three main stages: the calculation of the outdoor gas dispersion, the estimation of indoor concentration from outdoor concentration and the evaluation of human vulnerability. This thesis is mainly focused on the study of the second stage which is primarily a function of buildings leakage. initially we performed a bibliographic survey with special interest on the models to estimate indoor concentration from outdoor concentration, airtightness of dwellings and ventilation models. Then, through a sensitivity analysis, we found that the air exchange rate has a great influence on the effectiveness of shelter in place. Moreover, since this parameter is different for each building, the knowledge of the distribution of this variable in the affected population would lead to a more accurate assessment of the effectiveness of shelter in place, because if we assume it as a fix value, constant for all buildings, over or underestimations of the evacuation radius may occur. Therefore, with the aim of making an estimation of the airtightness distribution in catalunya, we applied the model developed by the lawrence berkeley national laboratory (lbnl), a model based on data from north american dwellings, to catalan dwellings. The results obtained were influenced by climate zones, due to the coefficients of the model, being more airtight the predictions for dwellings located in dry climates than for dwellings in humid zones. In the case of catalunya, where constructions techniques do not differ significantly from one zone to another and most of the dwellings consist of a heavy structure, a difference such as that predicted by the model of the lbnl is not expected. Consequently, we decided to develop a model for catalan dwellings using the air leakage database from the cete de lyon, since french dwellings are more likely to catalan dwellings than us dwellings. The model developed, named the upc-cete model, predicts the airtightness of single-family dwellings as a function of the floor area, the age, the number of stories and the structure type: light or heavy. The airtihgtness values predicted with this model were smaller than those predicted with the model of the lbnl, as was expected. finally, in order to validate and improve the model developed we carried out a series of trials to measure the air exchange rate in some catalan dwellings. Measurements in sealed rooms were also performed with the aim of assessing the reduction gained on the air exchange rate with regards to the air exchange rate of the whole dwelling. On average, we obtained reductions of 35% and found that larger reductions belonged to old dwellings with small floor areas and 1 or 2 stories. The improved model was incorporated on the methodology to assess shelter in place effectiveness on the stage concerning the estimation of the air exchange rate of the dwellings located on the affected zone; therefore, the assumption of a constant value is avoided. These measurements and the model constitute therefore the first proposal for estimating the airtightness distribution of single-family dwellings that could be used by catalan authorities for emergency response planning.
Datos académicos de la tesis doctoral «Contribution to the assessment of shelter-in-place effectiveness as a community protection measure in the event of a toxic gas release«
- Título de la tesis: Contribution to the assessment of shelter-in-place effectiveness as a community protection measure in the event of a toxic gas release
- Autor: María Isabel Montoya Rodríguez
- Universidad: Politécnica de catalunya
- Fecha de lectura de la tesis: 26/11/2010
Dirección y tribunal
- Director de la tesis
- EulÁ lia Planas Cuchi
- Tribunal
- Presidente del tribunal: josep Arnaldos viger
- jerí´me Tixier (vocal)
- joan josep Manyá cervelló (vocal)
- sylvain Brohez (vocal)