Protecting Building Occupants from Exposure to Biological Threats

NIST Case Study

Building Retrofits for Increased Protection against Airborne Chemical and Biological Releases

In March 2007, the National Institute of Standards and Technology (NIST) released improved guidance on retrofitting buildings to increase protection against chemical and biological attacks.[15] Intended for building owners, managers, engineers, and other decision makers, the report includes:

• a technical evaluation of the protective effects of 14 retrofit options using building airflow and contaminant transport modeling in 3 buildings. Each was subjected to computer-simulated generic particle and gaseous releases to determine the reduction in occupant exposure following the various retrofits;
• case studies in which specific retrofit options were investigated for 2 buildings: a high-rise office building with central air-handling systems and a one-story office building with multiple rooftop air handling units. These included development of pre-installation designs and cost estimates; and
• guidance on the application and effectiveness of the retrofits studied.

The authors note that the information presented “must be considered in the context of a specific building’s characteristics, including layout, system type and design, and occupancy [and that the] level of protection in a given situation is highly dependent on these characteristics and the nature of the contaminant release.”[15] The authors also stress that while “it is extremely difficult to make general statements about what [retrofit] strategies will be effective in a given situation and to what degree . . . .better protection is a worthy goal, even if the degree of protection cannot be characterized in general terms.”[15]

In conjunction with the report, NIST also developed an economic analysis tool for use in selecting cost-effective approaches to mitigating chemical and biological attacks. The Life-Cycle Cost Analysis Tool for Chem/Bio Protection of Buildings can help building owners and managers make consistent comparisons of chemical and biological protection strategies based on established economic evaluation practices.