Further physical modeling efforts allowed for the development and validation of an infiltration model by researchers at Lawrence Berkeley National Laboratory (LBNL). This model combined data derived from blower door tests with annual weather data to generate time-resolved ventilation rates for a given home in a specific location. This model has been incorporated into the ASHRAE Handbook of Fundamentals (1989), and it has been used in the development of ASHRAE Standards 119 and 136. Other infiltration models have been developed elsewhere, including one by Deru and Burns at the National Renewable Energy Laboratory (NREL), for use in whole-building performance simulation.