| The comfort and safety of building occupants is the main consideration of heating, ventilation, and air conditioning (HVAC) design. Infiltration, the unintentional transfer of air between the inside and outside environment, plays a large role in both the design of appropriate HVAC systems, and in the analysis of building safety during air contaminant events. Traditional single zone models can predict infiltration for small buildings, but require testing of the building to determine a leakage characteristic. The more advanced multi-zone models can predict infiltration and contaminant transport within buildings. Although multi-zone models can be built based on typical elements, they usually do not perform well until they have been calibrated through trial and error to match test data. The proposed resistance model builds from the multi-zone framework to develop a detailed model, suitable for buildings of all sizes, with the simplicity of a single zone model, for use as a design tool. This is achieved by first developing theoretical relationships between building fenestration and area weighted building airflow resistance. The area weighted building airflow resistance is then associated with the distribution of pressures on the building envelope to develop a single whole building resistance for the given boundary conditions. Correction factors for the internal partitions of the building, including both floors and walls, are presented. Additionally, an exploration of wind pressures specific for urban environments is explored. New shelter factors for reducing building pressures based on urban environments are developed and presented. In addition, recommendations for wind tunnel studies and numerical simulations to determine building wind pressures are given. Finally, verification of the model is demonstrated through both comparison to data in the literature as well as experimentation on a medium sized office and classroom building. Recommendations are also made for improving methods of measuring infiltration parameters and determining model inputs. |
