Building Retrofits Reduce Chem/Bio Hazards Risks

A new report from the National Institute of Standards and Technology (NIST) and the U.S. Environmental Protection Agency (EPA) offers building owners and managers information on retrofit options to improve the safety of buildings against airborne chemical and biological hazards. The new guide can be used to determine whether or not—and how—to harden existing buildings against accidental chemical releases or possible terrorist threats.

NIST researchers evaluated 14 alternative retrofit techniques based on data from simulated airflow and contaminant transport computer modeling as well as a case study in which retrofits were designed for a high-rise and single story building. In conjunction with the report, NIST also developed a life-cycle cost analysis tool for chemical and biological protection of buildings that helps building owners and managers to compare life-cycle costs of installation, operation and maintenance to determine the most cost-effective combination of retrofit options for their structure.

Retrofit options considered include enhanced particle filtration, sorbent-based gaseous air cleaning, ultraviolet germicidal irradiation, photocatalytic oxidative air cleaning, work area air capture and filtration equipment such as mail handling tables, ventilation system recommissioning, building envelope air-tightening, building pressurization, relocation of outdoor air intakes, shelter-in-place, isolation of vulnerable spaces such as lobbies, system shutdown and purge cycles, and automated heating, ventilating and air-conditioning (HVAC) operational changes in response to contaminant sensing.

Potential advantages, disadvantages and knowledge gaps are discussed for each technology. For example, the researchers note that filtration and air cleaning options have the advantage of being always in operation. But, as the report notes, their disadvantage is a current lack of standards for testing and rating gaseous air cleaning systems and other air cleaning approaches. The study also notes the potential for increased energy efficiency and improved indoor air quality results from various retrofit options, which could play a role in life-cycle cost comparisons of different strategies.

The analysis of retrofit strategies useful against chemical and biological building contamination and the development of software tools to select cost-effective ways to mitigate the hazards was performed under an Inter-Agency Agreement (IAG) with the EPA's National Homeland Security Research Center, Decontamination and Consequence Management Division.

The new NIST/ EPA report, Building Retrofits for Increased Protection Against Airborne Chemical and Biological Releases (NISTIR 7379/EPA/600/R-06/157), is available at http://fire.nist.gov/bfrlpubs/build07/PDF/b07006.pdf and www.epa.gov/nhsrc. The Life-Cycle Cost Analysis Tool (EPA/600/C-06/016) is available at http://www2.bfrl.nist.gov/software/LCCchembio/index.htm and www.epa.gov/nhsrc. A primer on the software is included in an appendix to NISTIR 7379/EPA/600/R-06/157.