Guidance for Filtration and Air-Cleaning Systems to ...

[Pages:78]Guidance for

Filtration and Air-Cleaning Systems to Protect Building Environments

from Airborne Chemical, Biological, or Radiological Attacks

Department of Health and Human Services

Centers for Disease Control and Prevention National Institute for Occupational Safety and Health April 2003

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Ordering Information

To receive documents or other information about occupational safety and health topics, contact the National Institute for Occupational Safety and Health (NIOSH) at

NIOSH Publications Dissemination 4676 Columbia Parkway

Cincinnati, OH 45226-1998 Telephone: 1-800-35-NIOSH (1-800-356-4674)

Fax: 1-513-533-8573 E-mail: pubstaft@ or visit the NIOSH Web site at niosh

This document is in the public domain and may be freely copied or reprinted. Disclaimer: Mention of any company, product, policy, or the inclusion of any reference does not constitute endorsement by NIOSH.

DHHS (NIOSH) Publication No. 2003-136

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Foreword

The Occupational Safety and Health Act of 1970 [Public Law 91-596] assures so far as possible every working man and woman in the Nation safe and healthful working conditions. The Act charges the National Institute for Occupational Safety and Health (NIOSH) with conducting research and making science-based recommendations to prevent work-related illness, injury, disability, and death.

On October 8, 2001, the President of the United States established by executive order the Office of Homeland Security (OHS), which is mandated "to develop and coordinate the implementation of a comprehensive national strategy to secure the United States from terrorist threats or attacks." In January 2002, the OHS formed the Interagency Workgroup on Building Air Protection under the Medical and Public Health Preparedness Policy Coordinating Committee of the OHS. The workgroup included representatives from agencies throughout the Federal Government, including NIOSH, which is part of the Department of Health and Human Services, Centers for Disease Control and Prevention. In May 2002, NIOSH, in cooperation with this workgroup, published Guidance for Protecting Building Environments from Airborne Chemical, Biological, and Radiological Attacks. This document provided building owners, managers, and maintenance personnel with recommendations to protect public, private, and government buildings from chemical, biological, or radiological attacks.

With U.S. workers and workplaces facing potential hazards associated with chemical, biological, or radiological terrorism, the occupational health and safety dimension of homeland security is

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increasingly evident. As with most workplace hazards, preventive steps can reduce the likelihood and mitigate the impact of terrorist threats. This publication is the second NIOSH Guidance document aimed at protecting workplaces from these new threats. It provides detailed, comprehensive information on selecting and using filtration and air-cleaning systems in an efficient and cost-effective manner. Filtration systems can play a major role in protecting both buildings and their occupants.

Prevention is the cornerstone of public and occupational health. This document provides preventive measures that building owners and managers can implement to protect building air environments from a terrorist release of chemical, biological, or radiological contaminants. These recommendations, focusing on filtration and air cleaning, are part of the process to develop more comprehensive guidance. Working with partners in the public and private sectors, NIOSH will continue to build on this effort.

John Howard, M.D. Director National Institute for Occupational

Safety and Health

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Contents

Foreword . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . iii Acknowledgments. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . viii Abbreviations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . x Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xii 1. Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 2. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 3. Filtration and Air-Cleaning Principles . . . . . . . . . . . . . . 8

3.1 Particulate Air Filtration . . . . . . . . . . . . . . . . . . . . . . 8 3.2 Gas-Phase Air Cleaning . . . . . . . . . . . . . . . . . . . . . . . 15 4. Recommendations Regarding Filter and Sorbent Selection, Operations, Upgrade, and Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 4.1 Particulate Filter Selection, Installation,

Use, and Upgrade . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 4.2 Sorbent Selection, Installation, and Use. . . . . . . . . . 26 4.3 Bypass and Infiltration . . . . . . . . . . . . . . . . . . . . . . . 30 4.4 Operations and Maintenance . . . . . . . . . . . . . . . . . . 32 4.5 Note on Emerging Technologies . . . . . . . . . . . . . . . . 35 5. Economic Considerations. . . . . . . . . . . . . . . . . . . . . . . . . 37 5.1 Initial Costs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37 5.2 Operating Costs . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38 5.3 Replacement Costs . . . . . . . . . . . . . . . . . . . . . . . . . . 38 5.4 Cost Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

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Contents (continued)

6. Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

7. Key References and Bibliography . . . . . . . . . . . . . . . . . . 43 7.1 Key References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43 7.2 Bibliography . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46

Appendix A: OHS Building Air Protection Workgroup Members . . . . . . . . . . . . . . . . . . . . 49

Appendix B: CBR Threats . . . . . . . . . . . . . . . . . . . . . . . . . . 51 Chemical Warfare Agents . . . . . . . . . . . . . . . . 51 Toxic Industrial Chemicals and Materials. . . . 52 Biological Agents . . . . . . . . . . . . . . . . . . . . . . . 54 Toxins. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54 Radiological Hazards . . . . . . . . . . . . . . . . . . . . 55

Appendix C: Gas-Phase Air-Cleaning Principles . . . . . . . . . 56

Contents (continued)

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Tables

Table 1. Comparison of ASHRAE Standards 52.1 and 52.2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

Table 2. Mechanisms of agent vapor filtration by ASZM-TEDA carbon. . . . . . . . . . . . . . . . . . . . . . . . 53

Table 3. Application of activated carbon impregnates. . . . . 58

Figures

Figure 1. Common air contaminants and their relative sizes . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

Figure 2. Scanning electron microscope image of a polyester-glass fiber filter . . . . . . . . . . . . . . . 9

Figure 3. Four primary filter collection mechanisms . . . 10 Figure 4. Fractional collection efficiency versus particle

diameter for a mechanical filter . . . . . . . . . . . . 11 Figure 5. ASHRAE Standard 52.2 test data for

a MERV 9 filter showing how collection efficiency increases as the filter loads . . . . . . . 15 Figure 6. Scanning electron microscope image of activated carbon pores . . . . . . . . . . . . . . . . . . . 16 Figure 7. Comparison of collection efficiency and particle size for different filters . . . . . . . . . . . . . . . . . . . 21 Figure 8. Relationship among total cost, filter life, and power requirements . . . . . . . . . . . . . . . . . 24 Figure 9. Effect of face velocity on the collection efficiency and the most penetrating particle size . . . . . . . 26 Figure 10. Breakthrough curves for cyanogen chloride at various filter bed depths . . . . . . . . . . . . . . . 59

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Acknowledgments

This document was produced by the National Institute for Occupational Safety and Health (NIOSH) in cooperation with the White House Office of Homeland Security (OHS), Interagency Workgroup on Building Air Protection. The Interagency Workgroup on Building Air Protection was formed under the Medical and Public Health Preparedness Policy Coordinating Committee (PCC) of the OHS to focus on building air protection issues associated with an airborne chemical, biological, or radiological (CBR) attack. Workgroup participants provided guidance and direction at various times during this document's development. A list of the workgroup members is given in Appendix A. This document was written by a group of Federal Government employees under the direction of CDR G. Scott Earnest, Ph.D., P.E., C.S.P. and CDR Michael G. Gressel, Ph.D., C.S.P. Contributing authors to the document and their agency affiliations are listed below.

National Institute for Occupational Safety and Health CDR G. Scott Earnest, Ph.D., P.E., C.S.P. CDR Michael G. Gressel, Ph.D., C.S.P. CAPT R. Leroy Mickelsen, M.S., P.E. Ernest S. Moyer, Ph.D. CAPT Laurence D. Reed, M.S.

Department of the Army Chris J. Karwacki Robert W. Morrison David E. Tevault, Ph.D.

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