Sixteen reference buildings have been defined by the U.S. Department of Energy, and created as EnergyPlus input files, for use in assessing new technologies and supporting the development of energy codes in pursuing building energy efficiency improvements. Infiltration rates in the EnergyPlus models of the reference buildings were input as constant airflow rates, and not calculated based on established building airflow theory. In order to support more physically-based airflow calculations, as well as indoor air quality analysis, models of the 16 reference buildings were created in the multizone airflow and contaminant transport program CONTAM. A number of additional inputs had to be defined for the CONTAM models, and changes in the interior zoning were required, to more realistically account for airflow. Annual airflow and contaminant simulations were performed in CONTAM for six of the buildings. While the assumed infiltration rates in EnergyPlus do not realistically reflect impacts of weather conditions, there are clear relationships between the outdoor air change rates calculated by CONTAM and weather. In addition, the envelope airtightness values assumed in either approach are seen to have a major impact on the air change rates. Contaminant analyses were performed for occupant-generated carbon dioxide, volatile organic compounds from indoor sources, outdoor particulate matter, and outdoor ozone. The airflow and contaminant calculation results provide a useful baseline for subsequent use of these models to investigate approaches to building ventilation and other technologies that are intended to simultaneously reduce building energy consumption while maintaining or improving indoor air quality.

Due to concerns about potential airborne chemical and biological releases in or near buildings, building owners and managers and other decision makers are faced with a number of options for increasing their building s level of protection against such events. Among the various technologies and approaches being proposed and implemented is shelter-in-place (SIP). SIP strategies involve having the building occupants stay in the building, generally in a space designated for such sheltering, until the event is over and the outdoor contaminant levels have decreased. While much guidance is available on the implementation of SIP in buildings, important technical issues remain about the degree of protection provided by a particular space and the factors in determining the level of protection. In particular, many recommendations suggest tightening the walls of SIP spaces, but there has been insufficient analysis of the relationship between shelter tightness and the protection provided by the SIP space. In order to address some of these questions, the National Institute of Standards and Technology (NIST) has undertaken a project to develop and demonstrate evaluation methods to relate shelter airtightness to the performance of shelter-in-place approaches for airborne chemical, biological and radiological (CBR) protection of building occupants. The focus of this effort is on short term sheltering, on the order of hours, rather than longer term sheltering which generally employ filtration and air cleaning equipment to supply clean air to the occupants of the space. This project has consisted of the following tasks: a literature review of SIP strategies and performance issues; development of a study plan for testing SIP airtightness evaluation methods; implementation of the study plan through a combination of experiments and simulations; and, finally, development of recommendations on SIP evaluation and possible performance criteria for candidate SIP spaces.

LoopDA 3.0 is an update to version 1.0 of the natural ventilation design tool developed by the National Institute of Standards and Technology. This software tool can be utilized to determine the size of natural ventilation openings necessary to provide a airflow rates that satisfy design requirements based on minimum ventilation and cooling load requirements.