Investigation of Infiltration Measurements Using Wind Induced Pressure Response on an Enclosure

Air infiltration into a building is unintentional air leakage, resulting in heat losses or gains and the consequent energy usage to recondition the building to comfortable levels. Methods of evaluating air infiltration provide accurate measures of air exchange rate but must be done per building and take significant experimentation and data collection. This warrants investigation into ways to decrease the time to evaluate building infiltration to decrease the associated costs. For this reason, interior pressure response is the subject of investigation in the present work. Interior pressure of a building responds to a pressure rise on the building face when an opening is present. There is a time delay for the interior pressure proportional to the opening area on the building face. This relationship is valid for larger openings and buildings, but no work has been done to validate the relationship for small openings and model structures. A model pressure box is designed and manufactured with pressure transducers to monitor face pressure and interior pressure when subjected to wind pressure. Wind pressure is induced by means of a wind tunnel equipped with a gust generator for rapid variation of pressure on the pressure box. Several opening areas are fabricated for the pressure box to test the relationship of pressure response time delay to opening area. Testing is done to characterize the flow field with the gust generator and validate the gust generator effectiveness. The gust generator is then used in pressure testing on the pressure box. Results of the pressure testing show there is a pressure response delay on the box interior; however, changing the opening area on the box face over the range of to of wall area does not affect the response delay time. Improvements to the wind tunnel are recommended to eliminate the significant high frequency turbulence present in the wind tunnel. A different material for the pressure box is also recommended due to difficulty in preparing the pressure box for testing