Valutazione sperimentale dei ricambi d'aria naturali propriamente detti in differenti ambienti confinati

A planning that follows the rules of the energetic thrift and of the rational use of energy, as actually happens, has imposed the adoption of air less permeable buildings and with short natural ventilation (infiltrations), so causing an increase of concentrations of substances which make pollution, produced inside the rooms. Besides the problems born in the last half century referred to the indoor pollution, caused by a too short natural ventilation uncontrolled by definite rules, in this work we wanted to develop a practical investigation about the real air changing inside some building tipologies taken as example, using a method based on forced immission of carbon dioxide in the selected rooms. The obtained results show an insufficient level of natural air changing for almost all rooms studied and emphasize the actual tendency of architectural projects to a total building isolation. In fact the results, obtained in the more recent buildings, are shorter than the others (’90 age building: 0.026 air change/hour; pre-fabbricated building of 1995: 0.13 a.c./hour). Another alarm comes from the obtained air change rates of the bathrooms; these values, that change from 0.42 a.c./h for the ‘500 building to 0.1 a.c./h for the ’800 a.c./h, are very insufficient for a good quality of indoor air. All these results have been later compared with quality standards and minimum ventilation shares contained in the present Italian legislation, UNI rules and ASHRAE indications, to show as the present dispositions aren’t conformed at all to guarantee a good quality of the internal air. By this analysis we reached, in a second time, some proposals for the future.