&EPA United States Environmental Protection Agency REPORT ON Destruction of Spores on Building Decontamination Residue in a Commercial Autoclave National Homeland Security Research Center Office of Research and Development ------- EPA/600/R-05/081 April 2005 Destruction of Spores on Building Decontamination Residue in a Commercial Autoclave by: Roy Sieber and Aaron Osborne Eastern Research Group, Inc. 14555 Avion Parkway, Suite 200 Chantilly, VA20151 Dr. Paul Lemieux U.S. Environmental Protection Agency Office of Research and Development National Homeland Security Research Center Research Triangle Park, NC 27711 EP-C-04-056 Project Officer Alice Gagnon U.S. Environmental Protection Agency Office of Research and Development National Risk Management Research Laboratory Research Triangle Park, NC 27711 U.S. Environmental Protection Agency Office of Research and Development National Homeland Security Research Center Decontamination and Consequence Management Division Research Triangle Park, NC 27711 ------- NOTICE The U.S. Environmental Protection Agency (EPA), through its Office of Research and Development, funded this study under Contract Number EP-C-04-056, Work Assignment 0- 7 to Eastern Research Group, Inc. (ERG). This report presents the methodology followed and the results of this study to evaluate the effectiveness of a commercial autoclave sterilizing simulated building decontamination residue. Simulated building decontamination residue consisting of wallboard, ceiling tiles, carpet, and upholstered furniture was prepared with 106 population biological indicator test strips of Geobacillus stearothermophilus. The residue was then autoclaved under different conditions to evaluate the influence of the following variables on sterilization: time, temperature, pressure, item type, moisture content, packing density, packing orientation, autoclave bag integrity, and autoclave process sequence. While the results of this study provide valuable data on autoclave performance, this report is not EPA guidance and should not be viewed as such. Mention of trade names, products, or services does not convey, and should not be interpreted as conveying, official EPA approval, endorsement, or recommendation. This report has been subjected to the Agency's peer and administrative review and has been approved for publication as an EPA document. ------- FOREWARD The U.S. EPA National Homeland Security Research Center (NHSRC), Decontamination and Consequence Management Division (DCMD), one of three divisions of NHSRC, is located in Research Triangle Park, North Carolina. The current focus of DCMD is on the decontamination of buildings that have been intentionally contaminated with biological or chemical agents. DCMD scientists study the biological or chemical contamination of air and indoor surfaces; provide methods for upgrading buildings in ways that increase occupant protection; supply information on decontamination methods, including safety, efficiency, cost; and analyze disposal options for decontamination wastes. This study was conducted as part of the DCMD research goal of evaluating commercial decontamination methods and systems. This report is being published to disseminate the findings of this study to the potential user community and other interested parties. 11 ------- ACKNOWLEDGMENTS This study was led by Dr. Paul Lemieux, U.S. EPA, Office of Research and Development, National Homeland Security Research Center, Decontamination and Consequence Management Division. ERG prepared simulated building decontamination residue and conducted the autoclave testing. The ERG test team included Roy Sieber, Aaron Osborne, Scott Sholar, and Steve Strackbein. Dave Dayton of ERG designed and built the temperature acquisition system described herein. Dr. Alan Woodard, New York State Department of Environmental Conservation, provided invaluable technical input during the planning and conduct of this study. The autoclave test would not have been possible without the facility access, cooperation, and technical expertise provided by Healthcare Environmental, Inc. Thank you to Richard Geisser, Vice President, Russ Hilton, Plant Manager, and all the dedicated members of the Healthcare Environmental team. in ------- ABSTRACT In the event of a terrorist attack on a building where biological weapons such as anthrax might be used, much of the porous material in the building will be shipped for disposal after decontamination activities. This material is collectively termed "building decontamination residue" (BDR). Although the BDR will have been disinfected or decontaminated, it is possible that residual biological agent will remain in the material. Autoclaves are commonly used to sterilize regulated medical waste by exposing the waste to elevated pressures and temperatures for extended periods of time (e.g., 31.5 psig, 275°F, and 40 minutes). However, some types of BDR may be densely packed or have low thermal conductivity and may require longer periods of time to reach the operating temperature of an autoclave. This report addresses whether the standard operating procedure in a commercial autoclave will provide sufficient time/temperature/pressure to adequately destroy bacteria spores bound on BDR. This study investigated the effect of several variables related to autoclaving BDR, including time, temperature, pressure, item type, moisture content, packing density, packing orientation, autoclave bag integrity, and autoclave process sequence. The test team created simulated BDR from wallboard, ceiling tiles, carpet, and upholstered furniture, embedded with 106 population Geobacillus stearothermophilus biological indicator (BI) strips and thermocouples to obtain time/temperature profile data associated with each BI strip. Study results indicate that bags of BDR should be placed in an autoclave so that all sides of individual bags are exposed to autoclave conditions, and not nested or stacked in a manner that precludes full exposure. All materials tested were effectively sterilized when dry. Increasing moisture content made autoclaving more difficult, but wet wallboard and ceiling tiles were also effectively sterilized. Autoclave cycles of 120 minutes at 31.5 psig/ 275°F and 75 minutes at 45 psig/ 292°F effectively sterilized the BDR material. Two standard autoclave cycles of 40 minutes and 31.5 psig/ 275°F run in sequence proved to be particularly effective, probably because the second cycle's evacuation step pulled the condensed water out of the pores of the materials, allowing effective steam penetration. iv ------- TABLE OF CONTENTS Page 1.0 INTRODUCTION 1-1 2.0 EXPERIMENTAL APPROACH 2-1 2.1 Autoclave Description 2-1 2.2 Testing Approach 2-1 2.3 Test Matrix and Conditions 2-2 2.3.1 Item Type 2-3 2.3.1.1 Wallboard 2-6 2.3.1.2 Ceiling Tiles 2-7 2.3.1.3 Carpet 2-8 2.3.1.4 Sofa 2-10 2.3.2 Autoclave Packing Density 2-10 2.3.3 Moisture Content 2-11 2.3.4 Temperature and Pressure 2-11 2.3.5 Time 2-12 2.3.6 Packing Orientation 2-12 2.3.7 Open Bags 2-13 2.3.8 Multiple Short Cycles 2-13 2.4 Test Schedule 2-13 3.0 RESULTS 3-1 3.1 Time/Temperature Data 3-1 3.2 Biological Indicator Data 3-1 3.3 Quality Assurance Data 3-2 3.3.1 Process Measurements 3-2 3.3.2 Experimental Measurements 3-2 3.3.2.1 RunTime 3-2 3.3.2.2 Temperature 3-10 3.3.2.3 Test Conditions 3-11 3.3.2.4 BI Test Strip Results 3-11 4.0 DISCUSSION 4-1 4.1 Time and Temperature Effect on Sterilization 4-1 4.2 Item Type and Moisture Content 4-2 4.3 Autoclave Packing Density and Location 4-3 4.4 Temperature and Pressure 4-5 4.5 Packing Orientation 4-5 4.6 Open Bags 4-6 4.7 Two Sequential Cycles 4-6 5.0 CONCLUSIONS 5-1 6.0 REFERENCES 6-1 Appendix A PHOTOGRAPHIC LOG ------- LIST OF TABLES Page Table 2-1. Originally Planned Healthcare Environmental Autoclave Test Matrix 2-4 Table 2-2. Healthcare Environmental Autoclave Test Matrix as Completed 2-5 Table 3-1. Biological Indicator Data 3-3 VI ------- LIST OF FIGURES Page Figure 2-1. Side View Sketch of Dense Packing Arrangement 2-7 Figure 2-2. Configuration of Sample Points in a Large Carpet Roll 2-10 Figure 3-1. Run 1 Time/Temperature Data 3-13 Figure 3-3. Run 4 Time/Temperature Data 3-15 Figure 3-4. Run 8 Time/Temperature Data 3-16 Figure 3-5. Run 5 Time/Temperature Data 3-17 Figure 3-6. Run 6 Time/Temperature Data 3-18 Figure 4-1. Run 2 Spore Viability 4-8 Figure 4-2. Run 4 Spore Viability 4-9 Figure 4-3. Run 5 Spore Viability 4-10 Figure 4-4. Run 1 Moisture Content and Item Type Comparison 4-11 Figure 4-5. Run 8 Moisture Content and Item Type Comparison 4-12 Figure 4-6. Run 5 Moisture Content and Item Type Comparison (Uncut Bags Only) 4-13 Figure 4-7. Run 6 Moisture Content and Item Type Comparison 4-14 Figure 4-8. Wallboard Packing Density Comparison 4-15 Figure 4-9. Carpet Packing Density Comparison 4-16 Figure 4-10. Run 2 Dense Packing Layer Comparison 4-17 Figure 4-11. Comparison of Sampling Points within Selected Wallboard Bags 4-18 Figure 4-12. Comparison of Sampling Points within Selected Ceiling Tile Bags 4-19 Figure 4-13. Autoclave Temperature Comparison for Wallboard 4-20 Figure 4-14. Autoclave Temperature Comparison for Ceiling Tiles 4-21 Figure 4-15. Horizontal Versus Vertical Packing Orientation for Wallboard 4-22 vii ------- Figure 4-16. Horizontal Versus Vertical Packing Orientation for Ceiling Tiles 4-23 Figure 4-17. Horizontal Versus Vertical Packing Orientation for Carpet 4-24 Figure 4-18. Cut Versus Uncut Wallboard Bags 4-25 Figure 4-19. Cut Versus Uncut Ceiling Tile Bags 4-26 Figure 4-20. Cut Versus Uncut Carpet Bags 4-27 Vlll ------- i.o INTRODUCTION In the event of a terrorist attack on a building where biological weapons (BW) such as anthrax might be used, much of the porous material in the building will be shipped for disposal after decontamination activities. These materials are collectively termed "building decontamination residue" (BDR). Although the BDR will have been disinfected or decontaminated, it is possible that residual BW agent will remain in the material. Many of these materials might be tightly packed and possibly wet. Autoclaves are commonly used to effectively treat regulated medical waste by exposing the waste to elevated pressures and temperatures for extended periods of time (e.g., 31.5 psig, 275°F, and 40 minutes at the test facility). However, BDR has low thermal conductivity and may require more time to reach the operating temperature of an autoclave. It is unknown whether the standard operating procedure in a commercial autoclave will provide sufficient time/temperature/pressure to adequately destroy bacteria spores bound on BDR. The primary objective of this study was to determine what recommended operating conditions at a commercial medical waste autoclave are sufficient to destroy bacteria spores found on BDR. The secondary objective of this study was to investigate the time/temperature dependence of Geobacillus stearothermophilus spore destruction as a function of autoclove operating conditions and BDR composition. The commercial autoclave tested is operated by Healthcare Environmental, Inc., in Oneonta, NY. Viability of bacteria spores was tested using 106 population biological indicator (BI) strips of viable spores of Geobacillus stearothermophilus, embedded in the materials processed by the autoclave. BDR materials tested included carpeting, wallboard, and ceiling tiles, both dry and wetted with water. Additionally, a sofa was processed to test the efficacy of autoclaving upholstered furniture. This study was performed according to an approved Quality Assurance Project Pla (QAPP), Destruction of Spores on Building Decontamination Residue in a Commercial Autoclave (1). 1-1 ------- 2.0 EXPERIMENTAL APPROACH 2.1 Autoclave Description This test was conducted at the Healthcare Environmental, Inc. facility located in Oneonta, Oswego County, approximately 90 miles from Albany, New York. The facility operates a permitted, regulated medical waste autoclave process with approximately 84 tons/day (TPD) capacity. The facility has two large autoclaves 8 feet in diameter and 32 feet long, which accept large bins (80 inches by 54 inches by 69 inches) on rollers. Each autoclave can process 6 bins, with a total mass of approximately 3,000-4,000 pounds per cycle. Photographs 17 through 20 show the autoclave configuration. All photographs of the test are provided in Appendix A to this report. The nominal autoclave operating cycle time is 40 minutes plus cool-down time to prepare for subsequent charges. At the start of each cycle, the autoclave is sealed and air is evacuated for 3 minutes using a vacuum pump to approximately -10 psig. Steam is then injected to reach and maintain the desired operating pressure and temperature, which are typically achieved in approximately 5 minutes. The nominal operating conditions during the cycles are 31.5 psig and 275°F. Steam is injected through three ports at the top of the autoclave, located at the front, center and rear. The steam is injected over distributor plates to cause turbulent, disbursed steam flow throughout the autoclave. At the end of each cycle, steam is evacuated by again pulling vacuum. Both autoclave units are identical. The facility continuously measures the operating temperature and pressure within each autoclave unit using a digital readout and paper chart recorder. 2.2 Testing Approach Autoclave performance was judged based on two parameters: real-time measurements from thermocouples embedded in each simulated load of BDR material tested and viability of 106 Geobacillus stearothermophilus BI test strips embedded within each load tested. The testing comprised a series of test runs at different conditions on one of the facility autoclaves (Unit Al). Section 2.3 discusses the conditions tested. 2-1 ------- For each test run, the BDR material processed was wired with 24 thermocouples to record the time/temperature profile at different locations embedded within the load. A BI pouch was paired with a thermocouple at each test location. Each BI pouch contained two Geobacillus stearothermophilus indicator strips, labeled 'A' and 'B'. After the test, the A strips were analyzed for a growth/no-growth indication, and a population assay was performed on the B strips if the A strips grew, as discussed in Section 3.2. Additionally, control thermocouples not embedded in BDR recorded the temperature inside and outside the autoclave. Three types of control BI test pouches, further explained in Section 3.3.2.4, were also collected: BI test pouches fully exposed to the autoclave conditions, BI test pouches packaged and handled similarly to other BDR but not autoclaved, and duplicate BI test pouches. 2.3 Test Matrix and Conditions As discussed in the QAPP, the following variables were identified as having a potential impact on sterilization capability: 1. Item type; 2. Autoclave packing density (i.e., loose packing versus dense packing); 3. Moisture content of autoclaved materials; 4. Autoclave temperature/pressure; and 5. Time in autoclave. The test matrix presented in Table 2-1 was designed to investigate the effects of each of these variables. Temperature data from initial test runs indicated that internal temperatures of densely packed material responded slowly to autoclave conditions, and therefore, this material was not likely being sterilized after 120 minutes, the maximum autoclave run time established for the test. After discussion among the EPA Work Assignment Manager (WAM), ERG WAM, New York State Department of Environmental Conservation (NYSDEC) representative, and the autoclave facility manager, originally planned Runs 2, 5, 6, and 7 were deleted and three 2-2 ------- additional factors were identified and tested to determine if they improved sterilization capability: 1. Positioning sample bags of BDR vertically instead of horizontally; 2. Cutting open the bags of BDR to facilitate steam penetration; and 3. Running two shorter process cycles in sequence instead of one long cycle. A revised test matrix was developed based on the temperature results of the initial runs and the objective of testing additional factors to improve sterilization. The changes to the test matrix were based partially on altering test conditions within easily adjusted facility operating constraints. Table 2-2 presents the revised test matrix. All run numbers discussed in this document are the revised test matrix run numbers. Run numbers were assigned based on the set of prenumbered thermocouples and corresponding BDR used in the run. Runs are typically discussed in the order in which they were conducted: 1, 2, 4, 8, 5, 6. Each variable tested is discussed in further detail below. 2.3.1 Item Type The BDR tested included %-inch thick, 4 feet by 8 feet sheets of LaFarge regular grade drywall (wallboard), %-inch thick, 2 feet by 4 feet Armstrong Contractor Series Ceiling Panels Model #942 (ceiling tiles), and Mannington Nepenthe II Blue commercial grade carpeting (Nylon 6,6 fibers). New, unused wallboard and ceiling tiles were purchased from a building material supplier. Used commercial carpeting, in rolls of varying sizes, was obtained from a carpet installation contractor. Additionally, a used queen-sized sleeper sofa was obtained from a thrift store. Test material was cut up and packaged to simulate likely BDR generated from a building decontamination scenario. Decontamination personnel are expected to size BDR to be easily handled and pack it for shipment using a double-bagging technique. The techniques used are similar to those from the State Department Sterling, Virginia mail facility anthrax cleanup (2). The steps used to reduce the size and package each of these items are discussed below. 2-3 ------- Table 2-1. Originally Planned Healthcare Environmental Autoclave Test Matrix Run 1 2 3 4 5 6 7 8 Item Type Mixed, loose pack Wallboard, dense pack Wallboard, dense pack Carpet Ceiling tiles, dense pack Ceiling tiles, dense pack Carpet Mixed, loose pack Temp/ pressure 275°F/ 31.5psig 275°F/ 31.5psig 292°F/ 45 psig Select based on runs 1, 2, 3 275°F/ 31. 5 psig 292°F/ 45 psig Select based on prior runs 292°F/ 45 psig Time Target time at 250°F(121°C)for all thermocouples is 15 minutes. Provide a minimum run time of 40 minutes. Extend run time as needed to achieve temperature targets. Position/Bin 1 Thermal Mass (~7001bs) Thermal Mass (~7001bs) Thermal Mass (~7001bs) Thermal Mass (~7001bs) Thermal Mass (~7001bs) Thermal Mass (~7001bs) Thermal Mass (~7001bs) Thermal Mass (~7001bs) Position/Bin 2 Loose Pack CT, Dry WB, Dry -250 Ibs (10 TC) Dense Pack WB, Dry -700 Ibs (12 TC) Dense Pack WB, Dry -700 Ibs (12 TC) Small rolls, loose pack, wet and dry -250 Ibs (8TC) Dense Pack CT, Dry -700 Ibs (12 TC) Dense Pack CT, Dry -700 Ibs (12 TC) Small rolls, loose pack, wet and dry -250 Ibs (8TC) Loose Pack CT, Dry WB, Dry -250 Ibs (10 TC) Position/Bin 3 Loose Pack CT, Wet WB, Wet -300 Ibs (10 TC) Dense Pack WB, Wet -850 Ibs (12 TC) Dense Pack WB, Wet -850 Ibs (12 TC) Small rolls, dense pack wet and dry -700 Ibs (8 TC) Dense Pack CT, Wet -850 Ibs (12 TC) Dense Pack CT, Wet -850 Ibs (12 TC) Small rolls, dense pack wet and dry -700 Ibs (8 TC) Loose Pack CT, Wet WB, Wet -300 Ibs (10TC) Position/Bin 4 Thermal Mass (-700 Ibs) Thermal Mass (-700 Ibs) Thermal Mass (-700 Ibs) Position/Bin 5 Carpet, small rolls, dry (4 TC) Open Open Large roll, wet (8 TC) Thermal Mass (-700 Ibs) Thermal Mass (-700 Ibs) Open Open Large roll, wet (8 TC) Sofa (4 TC) Comments Loose packing will provide one level of bagged BDR in each bin. (6 x 40 Ib. bags) Steam can easily penetrate to top and bottom of all bags. Similar to Run 1, but packing is denser, approximately 3 to 4 levels deep (25 x 40 Ib. bags per bin) Similar to Run 2, but temperature is increased to upper limit. Test packing style and temperature profile within carpet roll. Array thermocouples at varying depths within rolls. Similar to Run 2, ceiling tile instead of wallboard Similar to Run 5, temperature increased to upper limit. Test packing style and temperature profile within carpet roll. Array thermocouples at varying depths within rolls. Similar to run 1, temperature at upper limit. to (x TC) designates "x" thermocouples per bin. WB = Wallboard. CT = Ceiling Tile. CP = Carpet. ------- Table 2-2. Healthcare Environmental Autoclave Test Matrix as Completed Run 1 2 4 8 5 6 Original Matrix Run 1 3 4 8 Not Included Not Included Item Type Mixed, loose pack Wallboard, dense pack Carpet Mixed, loose pack Mixed, loose vertical pack Mixed, loose vertical pack Temp/ pressure 275°F/ 31.5psig 292°F / 45 psig 275°F/ 31.5 psig 292°F / 45 psig 275°F/ 31. 5 psig 275°F/ 31.5 psig Time 120 min 120 min 120 min 75 min 2 cycles each 40 min 2 cycles each 40 min Position/Bin 1 Thermal Mass (~8001bs) Thermal Mass (~8001bs) Thermal Mass (~8001bs) Thermal Mass (~8001bs) Thermal Mass (~8001bs) Thermal Mass (~8001bs) Position/Bin 2 Loose Pack WB, Wet and Dry -215 Ibs (10 TC) Dense Pack WB, Wet -850 Ibs (12 TC) Small rolls, dense pack, wet and dry -250 Ibs (8TC) Loose Pack WB, Wet and Dry -215 Ibs (10 TC) Vertical Pack CT, Wet and Dry CP, Wet and Dry -125 Ibs (12 TC) Vertical Pack CT, Wet and Dry CP, Wet and Dry -125 Ibs (12 TC) Position/Bin 3 Loose Pack CT, Wet and Dry -170 Ibs (10 TC) Dense Pack WB, Dry -750 Ibs (12 TC) Small rolls, loose pack wet and dry -850 Ibs (8TC) Loose Pack CT, Wet and Dry -170 Ibs (10 TC) Vertical Pack CT, Wet and Dry WB, Wet and Dry -125 Ibs (12 TC) Vertical Pack CT, Wet and Dry WB, Wet and Dry -125 Ibs (12 TC) Position/Bin 4 Carpet, small rolls, dry -150 Ibs (4 TC) Thermal Mass (-800 Ibs) Position/Bin 5 Thermal Mass (-800 Ibs) Open Large roll, wet (8 TC) Sofa (4 TC) Thermal Mass (-800 Ibs) Thermal Mass (-800 Ibs) Open Open Comments One level of bagged BDR in each bin. (6 bags) Steam could easily penetrate to top and bottom of all bags; however, still took a considerable amount of time. Went directly to higher temperature (skipped originally planned Run 2) because of the slow heating of Run 1 . Test packing style and temperature profile within carpet roll. Array thermocouples at varying depths within rolls. Similar to run 1, temperature at upper limit. Run time was terminated after 75 minutes due to concern of the sofa temperature rising significantly above the autoclave temperature, indicating the potential initiation of exothermic reaction. Test to determine if vertical packing and two sequential shorter cycles would be effective. Similar to Run 5, but all bags were cut. to (x TC) designates "x" thermocouples per bin. WB = Wallboard. CT = Ceiling Tile. CP = Carpet. ------- 2.3.1.1 Wallboard The wallboard was cut into approximately 2 feet by 2 feet sections as described in the QAPP. Sample BDR bags were formed by placing five, 2 feet by 2 feet sections face to face in autoclave bags. Samples requiring wetting were submerged in tank of water for 30 seconds and placed on a drain rack for 5 minutes prior to being placed in the bag. Dry test bags weighed approximately 34 pounds, and wet bags weighed approximately 37 pounds. Samples were double bagged in 1.8 mil polypropylene autoclave bags, and the bags were individually goose- necked and taped shut using duct tape. A section of nylon rope was attached to the gooseneck to allow ERG personnel to easily and safely load and unload the bags from the autoclave bins. Three types of wallboard bags were created. Some test bags were assembled with one thermocouple and one test strip pouch placed together, between the second and third wallboard section. These are referred to as "1-sample" bags. Other test bags were assembled with three thermocouples paired with three test strip pouches placed between the first and second, second and third, and fourth and fifth wallboard sections. These are referred to as "3- sample" bags. Photographs 2 through 8 in Appendix A show how the bags were assembled. Additional bags were made without thermocouples and BI test pouches to be used as fillers when packing the autoclave bins. Bags were placed in the autoclave bins in either a loose packing or dense packing arrangement as indicated on the test matrix in Table 2.2. In the loose packing arrangement, six bags were placed per bin: two 3-sample bags and four 1-sample bags. Ten total samples were collected per bin in loose density packing. See Photograph 27 for the loose packing arrangement of wallboard bags. In the dense-packing arrangement, 23 bags were placed in each bin including three, 3-sample bags and three 1-sample bags. The remaining 17 bags were used to fill out the load. Bags were layered within the bin, in approximately three to four layers of four to six bags each. Bags were placed in the bin with one 3-sample and one 1-sample bag in each layer, so that sample bags were dispersed throughout the loaded bin. Twelve total samples were collected per 2-6 ------- bin in the dense packing arrangement. See the side view sketch in Figure 2-1 and Photograph 29 dense packing arrangement of bags. For the vertical packing arrangement, one dry 3-sample and one wet 3-sample bag were placed in a bin. Ropes tied to opposite edges of the autoclave bin wall were used to maintain the vertical alignment, as shown in Photograph 35. Figure 2-1. Side View Sketch of Dense Packing Arrangement 2.3.1.2 Ceiling Tiles Ceiling tiles were cut into approximately 2 feet by 2 feet sections as described in the QAPP. Samples were prepared similarly to wallboard; however, bags contained nine 2 feet by 2 feet sections placed face to face. Dry test bags weighed approximately 23 pounds, and wet bags weighed approximately 31 pounds. 2-7 ------- One-sample bags contained one thermocouple and one test strip pouch placed together, between the fourth and fifth ceiling tile section. Three-sample bags contained three thermocouples paired with three test strip pouches placed between the second and third, fourth and fifth, and seventh and eighth ceiling tile sections. Additional bags were made without thermocouples and BI test pouches to be used as fillers. As discussed previously, originally planned runs of densely packed ceiling tiles were deleted from the test matrix. In the loose packing arrangement, two 3-sample bags and four 1-sample bags were placed per bin. Ten total samples were collected per bin in loose density packing. See the Photograph 30 for the loose packing arrangement of bags. For the vertical packing arrangement, one dry 3-sample and one wet 3-sample bag were placed in a bin. Ropes tied to opposite edges of the autoclave bin wall were used to maintain the vertical alignment, as shown in Photograph 35. 2.3.1.3 Carpet Carpet was tested in two general configurations, small and large rolls. For small rolls, the contractor cut the carpet into strips 26 inches wide by 20 feet long, representing how carpet would most likely be removed from a building. Samples requiring wetting were soaked with a hose-end sprayer. After wetting, samples were rolled and placed on end to allow free- flowing water to drain. Small rolls were bagged in a similar manner to wallboard and ceiling tiles. Dry test bags weighed approximately 26 pounds, and wet bags weighed approximately 40 pounds. As a worst case, larger sections of carpet 6 feet wide and 24 feet long also were requested and obtained from the contractor. Large rolls were only prepared wet, and weighed approximately 200 pounds, which represented the maximum size that could be handled by two workers. Large rolls were wrapped in polypropylene and all seams sealed with duct tape. Photographs 10 through 15 in Appendix A show the assembly process for carpet bags. For the small carpet rolls, 1- and 3-sample bags were prepared. One-sample bags contained one thermocouple and one test strip pouch placed together, at the approximate mid- point of the radius of the carpet roll. Three-sample bags contained three thermocouples paired 2-8 ------- with three test strip pouches placed two laps in from the top, at the mid-point of the radius, and two laps from the center of the carpet roll. Additional bags were made without thermocouples and BI test pouches to be used as fillers. Bags with small rolls of carpet were placed in the autoclave bins in either a loose packing or dense packing arrangement. In the loose packing arrangement, two, 3-sample bags and two, 1-sample bags were placed in a bin. Bags that did not contain sample points were used to fill out the load. Eight total samples were collected per bin in the loose packing arrangement. In the dense packing arrangement, shown in Photograph 33, 25 bags were placed per bin including two 3-sample bags and two 1-sample bags. The remaining 21 bags were used to fill out the load. Bags were layered within the bin, in approximately three to four layers of six to eight bags each. Bags were placed in the bin so that two 3-sample bags were placed in the middle layer and two 1-sample bags were placed in the bottom layer. Eight total samples were collected per bin in the dense packing arrangement. For the vertical packing arrangement, one dry 3-sample and one wet 3-sample bag were placed in a bin. Ropes tied to opposite edges of the autoclave bin wall were used to maintain the vertical alignment, as shown in Photograph 35. The large roll of carpet was assembled with eight thermocouples paired with eight test strip pouches placed at eight locations throughout the roll. The locations were arrayed progressively deeper within the rolled carpet, as depicted in Figure 2-2. The large roll of carpet was placed in the autoclave on a wood pallet rather than in a bin, as shown in Photograph 34. 2-9 ------- Center of Carpet Roll Sample Point 2.3.1.4 Figure 2-2. Configuration of Sample Points in a Large Carpet Roll Sofa A used queen-sized sleeper sofa was obtained from a thrift store and autoclaved in Run 4. The sofa was not wetted prior to being autoclaved. Four thermocouple and test strip pouches were paired and embedded in different locations in the sofa. Samples were inserted in holes cut approximately 6 inches deep in a back cushion and a seat cushion. The holes were then covered with duct tape. One sample was also placed in between the folded sleeper mattress, and one in between the seat cushions. The sofa was wrapped in polypropylene and all seams sealed with duct tape, as shown in Photograph 16. The sofa was placed in the autoclave on a sheet of plywood. 2.3.2 Autoclave Packing Density The Healthcare Environmental autoclave is designed to operate with six loaded bins of material, loaded with approximately 700 pounds of material each. Wallboard was tested at two different bin packing densities. Low density packing involved placing six bags in a bin. In a low density arrangement, shown in Photograph 27, the 2-10 ------- bags formed a single layer at the base of the bin, and all bag surfaces were readily exposed to autoclave temperatures. High density packing, shown in Photograph 29, involved placing 23 bags in each bin. The bags were layered approximately three to four levels deep, exposing some bags directly to autoclave conditions while others were buried within the load in the bin. Ceiling tiles were only tested in a low density arrangement, as described above for wallboard. Runs of densely packed ceiling tiles were deleted from the test matrix because densely packed BDR material could not be brought up to autoclave temperatures within the 120-minute duration specified in the test plan. Carpet was tested in three configurations. Small rolls, approximately 1 foot in diameter and 26 inches long, were placed in bags. Six bags were placed in a bin for low density packing, as above (see Photograph 31). Twenty-five bags were placed in a bin for high density packing, as above (see Photograph 33). In addition, the effect of the autoclave on a large, intact roll of carpet 6 feet long and approximately 1.5 feet in diameter, shown in Photograph 34, was tested in Run 4. 2.3.3 Moisture Content Materials were tested both dry and wet. In this context, dry means in as-is condition at ambient humidity, with no additional moisture added. Wet conditions were created by briefly immersing wallboard and ceiling tile pieces in water and allowing them to drain. Immediately after draining, the wallboard and ceiling tiles were placed in sealed polyethylene bags. Carpet was soaked with a hose-end sprayer until saturated, and then allowed to drain. After draining, carpet pieces were rolled up and sealed in either polyethylene bags (small rolls) or wrapped in polyethylene sheeting (large rolls). Wet and dry bags of BDR were weighed to determine the additional water weight. On average, wetting increased the weight of wallboard bags by 9 percent, ceiling tile bags by 34 percent, and carpet bags by 53 percent. 2.3.4 Temperature and Pressure Temperature and pressure are related variables, as the autoclave is designed to operate at saturated steam conditions. The study investigated two conditions: 31.5 psig / 275°F, 2-11 ------- the typical operating pressure of the autoclave, and 45 psig / 292°F, the maximum operating pressure of the autoclave. Pressure is the parameter controlled by the autoclave controller. These temperatures and pressures are as measured in the interior space of the autoclave. Temperatures within the autoclaved items lagged behind these temperatures, as discussed in Section 2.3.5. 2.3.5 Time A minimum run time of 40 minutes at elevated temperature was established, according to standard operation of the Healthcare Environmental autoclave. Literature data indicate that 15 minutes at 250°F is required for assured moist heat sterilization (3,4). Therefore, the test plan called for extending the run time beyond 40 minutes to achieve a 250°F temperature target at all, or at least most embedded thermocouples. Even if the 250°F target had not been achieved, the test plan established a maximum run time of 120 minutes to enable the autoclave to process multiple test runs each day. Runs 1, 2, and 4 were terminated after 120 minutes, prior to all thermocouples reaching the target temperature. Run 8 was stopped after 75 minutes due to concerns that the sofa temperature was rising above the temperature of the autoclave, indicating a potential exothermic reaction in the sofa. Because such a reaction and possible associated hazards were not well understood, the run was terminated. Conducting two 40-minute runs in sequence was investigated in Runs 5 and 6. This variation is discussed further in Section 2.3.8. 2.3.6 Packing Orientation Material was tested both lying horizontally in the autoclave bins and positioned vertically, with all sides exposed. Material was positioned vertically by tying two ropes to the top of the bag and attaching the ends of the rope to opposite sides of the autoclave bin wall, as shown in Photograph 35. This packing orientation was introduced as a test variable to simulate using a rack system to position bags so that all sides are exposed to autoclave steam. We theorized that vertical orientation of the BDR would reduce compression from its own weight, and also would allow steam condensate to drain more easily as it formed. If these theories are correct, both would facilitate steam penetration and improve heating of the material in the autoclave. 2-12 ------- 2.3.7 Open Bags All BDR was double-bagged in 1.8 mil polypropylene bags. The bags were individually goose-necked and sealed with duct tape. This procedure was adopted based on packaging information from the State Department Sterling, Virginia mail facility anthrax cleanup (2). After autoclaving, some of the bags had clearly ruptured due to temperature and pressure changes. However, in many cases bag surfaces bubbled and became deformed in the autoclave, but it was not clear if they had fully opened. To test if the bags opening had an effect on sterilization, two bags in Run 5 and all of the bags in Run 6 were opened prior to autoclaving, by slicing two sides of each bag open with a utility knife across their entire length. 2.3.8 Multiple Short Cycles As steam in the autoclave was evacuated to end Runs 2, 4, and 8, the test team observed that, as the vacuum was drawn, most thermocouple readings converged toward a mid- point temperature. Not only were high readings falling, but most of the lower readings were rising and converged together. It is not known if this was a result of increased turbulence during the post-vacuum cycle, condensed water being drawn out of BDR under vacuum, or some combination of these and other factors. However, in consultation with EPA WAM, we decided that it would be worthwhile to further investigate this phenomenon. Therefore, in Runs 5 and 6, two complete normal autoclave operating cycles were run in succession. Each cycle consisted of a pre-vacuum, steam pressurization, and post-vacuum phase. The cycles were conducted in immediate succession and the autoclave remained sealed throughout both cycles. 2.4 Test Schedule ERG conducted BDR size reduction, wetting, sample placement, and packaging at its Chantilly, Virginia facility between February 15 and February 24, 2005. Materials were stored at room temperature until March 1, 2005. 2-13 ------- Materials were placed on truck trailers on March 1, 2005 and transported to Oneonta, New York by Roadway Express, Inc. Trailers were delivered in Oneonta on March 3, 2004. ERG sealed the trailers in Chantilly, and broke the seals in Oneonta. Test materials were unloaded and staged for processing on March 4, 2005, and autoclaved on March 5 and 6, 2005. 2-14 ------- s.o RESULTS This section presents the time/temperature, biological indicator, and quality assurance data collected during this test. Section 4 presents the analysis of the data. 3.1 Time/Temperature Data Real-time temperature measurements were monitored and recorded at each sampling point using a GEC Instruments Model S27TC temperature measurement system and Type "T" thermocouples. Figures 3-1 through 3-6 (located at the end of this section) present plots of the time/temperature data recorded during each of the six runs. Temperature data were recorded at each location approximately every 10 seconds. The figures also include readings from the control thermocouple inside the autoclave, the reference thermocouple outside the autoclave, and the autoclave set point pressure/temperature. Note that Figures 3-1 through 3-6 are designed to present an overview of all time/temperature data associated with each run. Section 4.0 provides further analysis of these data and distinction between the variables. The facility monitoring system collected additional process measurement data. Operating temperature and pressure within the autoclave were measured using the existing autoclave thermocouple and pressure gauge and synchronized against 24-hour clock time. The time, temperature, and pressure were recorded during the test on a 24-hour circular chart recorder. 3.2 Biological Indicator Data A BI test pouch, containing two BI test strips, was placed at each sampling point. Each BI strip contained a 106 population of Geobacillus stearothermophilus on Schleicher & Schuell filter paper (#470) encased in a glassine peel-open envelope. The test pouch consisted of medical grade paper with a plastic facing. Raven Biological Laboratories, Inc. (Raven) provided the BI pouches (American Type Culture Collection #7953, Lot #3167091, expiration January 2007). The strips within each pouch were designated 'A' strips and 'B' strips. Following the test, Raven cultured all A strips for an indication of growth or no-growth. For A strips indicating 3-1 ------- growth, Raven performed a population assay of the B strip to quantify the survivor population. Table 3-1 presents the results from these analyses. 3.3 Quality Assurance Data This section presents quality assurance data collected and compares all data collected with the acceptance criteria presented in Section 7.0 of the QAPP. 3.3.1 Process Measurements Autoclave temperature, autoclave pressure, and run time were recorded on a 24- hour circular chart recorder. Record data where accurate to the following levels, meeting the acceptance criteria: • Autoclave temperature: ± 5°F • Autoclave pressure: ±0.5psig • Run time: ± 1 minute 3.3.2 Experimental Measurements Quality data for each of the experimental measurements are presented in the following subsections. 3.3.2.1 Run Time The temperature logging system was synchronized to ± 1 minute with the autoclave data recorder clock at the beginning of each day. All time/temperature data was time stamped to ± 1 second. All data was time stamped and therefore is considered usable. 5-2 ------- Table 3-1. Biological Indicator Data Run Number 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 Thermocouple Number 101 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 115 116 117 118 119 120 121 122 123 124 125 Material Type (WB = Wallboard, CT = Ceiling Tiles, CP= Carpet) WB WB WB WB WB WB CT CT CT CT CT WB WB WB WB WB WB CT CT CT CT CT CP CP CP CP N/A Moisture Content (W = Wet, D = Drv) D D D D D D D D D D D W W W W W W W W W W W D D D D N/A Depth in Bin B B B B B B B B B B B B B B B B B B B B B B B B B B N/A Packing Density/ Additional Notes Loose Pack - Horizontal Loose Pack - Horizontal Loose Pack - Horizontal Loose Pack - Horizontal Loose Pack - Horizontal Loose Pack - Horizontal Loose Pack - Horizontal Loose Pack - Horizontal Loose Pack - Horizontal Loose Pack - Horizontal Loose Pack - Horizontal Loose Pack - Horizontal Loose Pack - Horizontal Loose Pack - Horizontal Loose Pack - Horizontal Loose Pack - Horizontal Loose Pack - Horizontal Loose Pack - Horizontal Loose Pack - Horizontal Loose Pack - Horizontal Loose Pack - Horizontal Loose Pack - Horizontal Loose Pack - Horizontal Loose Pack - Horizontal Loose Pack - Horizontal Loose Pack - Horizontal Control Inside Autoclave BI Test Pouch Number 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 165 166 167 168 217 Type of BI Control Sample Duplicate Duplicate Run 1 Full Exposure Control Growth/No Growth Result No Growth No Growth No Growth No Growth No Growth No Growth No Growth No Growth No Growth No Growth No Growth No Growth No Growth No Growth No Growth No Growth No Growth No Growth No Growth No Growth No Growth No Growth No Growth No Growth No Growth No Growth No Growth Population Assay Result (CFU) N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A ------- Table 3-1 (Continued) Run Number 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 2 Thermocouple Number 201 202 203 204 204 205 206 207 208 209 210 211 212 213 214 215 216 217 217 218 219 220 221 222 223 224 225 Material Type (WB = Wallboard, CT = Ceiling Tiles, CP= Carpet) WB WB WB WB WB WB WB WB WB WB WB WB WB WB WB WB WB WB WB WB WB WB WB WB WB WB N/A Moisture Content (W = Wet, D = Drv) D D D D D D D D D D D D D W W W W W W W W W W W W W N/A Depth in Bin B T M M M M M T T T B B B T M B B B B B T T T M M M N/A Packing Density/ Additional Notes Dense Pack Dense Pack Dense Pack Dense Pack Dense Pack Dense Pack Dense Pack Dense Pack Dense Pack Dense Pack Dense Pack Dense Pack Dense Pack Dense Pack Dense Pack Dense Pack Dense Pack Dense Pack Dense Pack Dense Pack Dense Pack Dense Pack Dense Pack Dense Pack Dense Pack Dense Pack Control Inside Autoclave BI Test Pouch Number 1 2 3 4 13 5 6 7 8 9 10 11 12 66 67 68 69 72 70 71 73 74 75 76 77 78 218 Type of BI Control Sample Duplicate Duplicate Run 2 Full Exposure Control Growth/No Growth Result No Growth No Growth No Growth No Growth No Growth Growth Growth Growth Growth No Growth No Growth No Growth No Growth No Growth No Growth No Growth No Growth Growth No Growth No Growth Growth Growth Growth Growth Growth Growth Growth Population Assay Result (CFU) N/A N/A N/A N/A N/A 183,000 220,000 150,000 61,000 N/A N/A N/A N/A N/A N/A N/A N/A <100 N/A N/A 283,000 9,330 13,000 47,300 13,000 39,700 330 ------- Table 3-1 (Continued) Run Number 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 4 Thermocouple Number 401 402 403 404 405 406 407 408 409 410 411 411 412 413 414 415 416 417 418 419 420 420 421 422 423 424 425 Material Type (WB = Wallboard, CT = Ceiling Tiles, CP= Carpet) CP CP CP CP CP CP CP CP CP CP CP CP CP CP CP CP CP CP CP CP CP CP CP CP CP CP N/A Moisture Content (W = Wet, D = Drv) W W W W W W W W D D D D D D D D D W W W W W W W W W N/A Depth in Bin N/A N/A N/A N/A N/A N/A N/A N/A B B B B B M B B B B B B B B M T T T N/A Packing Density/ Additional Notes N/A N/A N/A N/A N/A N/A N/A N/A Loose Pack - Horizontal Loose Pack - Horizontal Loose Pack - Horizontal Loose Pack - Horizontal Loose Pack - Horizontal Dense Pack Dense Pack Dense Pack Dense Pack Loose Pack - Horizontal Loose Pack - Horizontal Loose Pack - Horizontal Loose Pack - Horizontal Loose Pack - Horizontal Dense Pack Dense Pack Dense Pack Dense Pack Control Inside Autoclave BI Test Pouch Number 136 137 138 139 140 141 142 143 169 170 171 172 173 174 175 176 177 187 188 189 190 191 192 193 194 195 219 Type of BI Control Sample Duplicate Duplicate Run 4 Full Exposure Control Growth/No Growth Result Growth Growth Growth Growth Growth Growth Growth Growth No Growth Growth Growth Growth Growth Growth Growth Growth Growth Growth No Growth No Growth No Growth No Growth Growth Growth Growth No Growth No Growth Population Assay Result (CFU) 63,700 370,000 473,000 131,000 140,000 277,000 280,000 113,000 N/A 72,000 54,300 13,700 100 117,000 537,000 197,000 347,000 <100 N/A N/A N/A N/A 100,000 18,300 80,000 N/A N/A ------- Table 3-1 (Continued) Run Number 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 8 Thermocouple Number 801 802 803 804 805 806 807 808 809 810 810 811 812 812 813 814 815 816 817 818 819 820 821 822 823 824 825 Material Type (WB = Wallboard, CT = Ceiling Tiles, CP= Carpet) WB WB WB WB WB CT CT CT CT CT CT WB WB WB WB WB WB CT CT CT CT CT Couch Couch Couch Couch N/A Moisture Content (W = Wet, D = Drv) D D D D D D D D D D D W W W W W W W W W W W D D D D N/A Depth in Bin B B B B B B B B B B B B B B B B B B B B B B N/A N/A N/A N/A N/A Packing Density/ Additional Notes Loose Pack - Horizontal Loose Pack - Horizontal Loose Pack - Horizontal Loose Pack - Horizontal Loose Pack - Horizontal Loose Pack - Horizontal Loose Pack - Horizontal Loose Pack - Horizontal Loose Pack - Horizontal Loose Pack - Horizontal Loose Pack - Horizontal Loose Pack - Horizontal Loose Pack - Horizontal Loose Pack - Horizontal Loose Pack - Horizontal Loose Pack - Horizontal Loose Pack - Horizontal Loose Pack - Horizontal Loose Pack - Horizontal Loose Pack - Horizontal Loose Pack - Horizontal Loose Pack - Horizontal N/A N/A N/A N/A Control Inside Autoclave BI Test Pouch Number 101 102 103 104 105 106 107 108 109 110 111 112 114 113 115 116 117 118 119 120 121 122 213 214 215 216 220 Type of BI Control Sample Duplicate Duplicate Run 8 Full Exposure Control Growth/No Growth Result No Growth No Growth No Growth No Growth No Growth No Growth No Growth No Growth No Growth No Growth No Growth No Growth No Growth Growth No Growth No Growth No Growth No Growth No Growth No Growth No Growth No Growth No Growth No Growth No Growth No Growth No Growth Population Assay Result (CFU) N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A <100 N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A ------- Table 3-1 (Continued) Run Number 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 5 Thermocouple Number 501 502 503 504 505 505 506 507 508 509 510 511 512 513 514 515 516 517 518 518 519 520 521 522 523 524 525 Material Type (WB = Wallboard, CT = Ceiling Tiles, CP= Carpet) WB WB WB CT CT CT CT WB WB WB CT CT CT CP CP CP CP CP CP CP CT CT CT CT CT CT N/A Moisture Content (W = Wet, D = Drv) W W W W W W W D D D W W W W W W D D D D D D D D D D N/A Depth in Bin N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A Packing Density/ Additional Notes Vertical - Uncut Vertical - Uncut Vertical - Uncut Vertical - Cut Vertical - Cut Vertical - Cut Vertical - Cut Vertical - Uncut Vertical - Uncut Vertical - Uncut Vertical - Uncut Vertical - Uncut Vertical - Uncut Vertical - Uncut Vertical - Uncut Vertical - Uncut Vertical - Uncut Vertical - Uncut Vertical - Uncut Vertical - Uncut Vertical - Cut Vertical - Cut Vertical - Cut Vertical - Uncut Vertical - Uncut Vertical - Uncut Control Inside Autoclave BI Test Pouch Number 159 160 161 43 44 45 46 130 131 132 50 51 52 202 203 204 179 180 181 182 60 61 62 63 64 65 221 Type of BI Control Sample Duplicate Duplicate Run 5 Full Exposure Control Growth/No Growth Result No Growth No Growth No Growth No Growth No Growth No Growth No Growth No Growth No Growth No Growth No Growth No Growth No Growth No Growth Growth Growth No Growth No Growth No Growth No Growth No Growth No Growth No Growth No Growth No Growth No Growth No Growth Population Assay Result (CFU) N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A 500 470 N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A ------- Table 3-1 (Continued) Run Number 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 6 Thermocouple Number 601 602 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 616 617 618 619 620 621 623 624 625 626 Material Type (WB = Wallboard, CT = Ceiling Tiles, CP= Carpet) WB WB WB WB CT CT CT WB WB WB CT CT CT CP CP CP CT CT CT CT CP CP CP N/A CT CT CT Moisture Content (W = Wet, D = Drv) W W W W D D D D D D D D D W W W W W W W D D D N/A W W W Depth in Bin N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A Packing Density/ Additional Notes Vertical - Cut Vertical - Cut Vertical - Cut Vertical - Cut Vertical - Cut Vertical - Cut Vertical - Cut Vertical - Cut Vertical - Cut Vertical - Cut Vertical - Cut Vertical - Cut Vertical - Cut Vertical - Cut Vertical - Cut Vertical - Cut Vertical - Cut Vertical - Cut Vertical - Cut Vertical - Cut Vertical - Cut Vertical - Cut Vertical - Cut Control Inside Autoclave Vertical - Cut Vertical - Cut Vertical - Cut BI Test Pouch Number 147 148 149 150 17 18 19 133 134 135 24 25 26 198 199 200 30 31 32 33 184 185 186 222 37 38 39 Type of BI Control Sample Duplicate Duplicate Run 6 Full Exposure Control Growth/No Growth Result Growth No Growth No Growth No Growth No Growth No Growth No Growth No Growth No Growth No Growth No Growth No Growth No Growth No Growth No Growth Growth No Growth No Growth No Growth No Growth No Growth No Growth No Growth No Growth No Growth No Growth No Growth Population Assay Result (CFU) <100 N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A <100 N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A N/A ------- Table 3-1 (Continued) Run Number Control Control Control Control Control Control Control Control Control Thermocouple Number N/A N/A N/A N/A N/A N/A N/A N/A N/A Material Type (WB = Wallboard, CT = Ceiling Tiles, CP= Carpet) N/A N/A N/A N/A N/A N/A N/A N/A N/A Moisture Content (W = Wet, D = Drv) N/A N/A N/A N/A N/A N/A N/A N/A N/A Depth in Bin N/A N/A N/A N/A N/A N/A N/A N/A N/A Packing Density/ Additional Notes N/A N/A N/A N/A N/A N/A N/A N/A N/A BI Test Pouch Number 205 206 207 208 209 210 211 212 223 Type of BI Control Sample Negative Control - Dry Wallboard Negative Control - Wet Wallboard Negative Control - Dry Ceiling Tiles Negative Control - Wet Ceiling Tiles Negative Control - Dry Carpet Negative Control - Wet Carpet Negative Control - Dry Empty Bag Negative Control - Wet Empty Bag Negative Control - Dry Empty Bag Growth/No Growth Result Growth Growth Growth Growth Growth Growth Growth Growth Growth Population Assay Result (CFU) 1,200,000 1,670,000 1,270,000 1,800,000 1,300,000 703,000 990,000 1,430,000 843,000 N/A - Not applicable. ------- 3.3.2.2 Temperature All thermocouples were checked for quality using the procedure outlined in Section 6.3 of the QAPP prior to the test. All thermocouples met the acceptance criteria and were accurate to within ± 0.7°F compared to a known reference thermometer. Reference testing was conducted at 275°F. Thermocouples placed into each load were connected to a data logger through a 27-channel interface device. The thermocouple at each sample location was uniquely numbered using a system where the last two digits ran in a sequence from 01 to 24. Channels 25, 26, and 27 were used as spares or controls. Numbered thermocouples were connected in the same sequence to corresponding data logging channels. For example, thermocouple 101 was connected to channel 01, 102 to 02, and so forth. The instrumentation technician made the connections, which were verified by the ERG test director. One thermocouple channel was used to monitor ambient conditions outside the autoclave to verify the data acquisition system was functioning properly. This temperature stayed relatively constant throughout each run, varying between 60 and 75°F. A thermocouple also was mounted near the top of one of the autoclave bins in each run, fully exposed to autoclave conditions. These data tracked closely with the process temperature measurements for all runs except Run 2. The thermocouple reading for the fully exposed autoclave temperature in Run 2 (thermocouple 225) suddenly dropped approximately 20°F, 18 minutes into cycle. After the autoclave cycle was complete, the thermocouple and corresponding BI test pouch were found to have fallen from their mount on the autoclave bin wall into the bulk of BDR mass being tested. For all subsequent runs, the thermocouple was mounted using a c-clamp rather than duct tape, and a second control thermocouple was placed near the bottom of the bin so that fully exposed thermocouples were placed near the top and toward the bottom of an autoclave bin. Note that a fully exposed control BI test pouch was only placed next to the top control thermocouple. Fully exposed control thermocouple readings were consistent with process temperature readings on all subsequent runs. 3-10 ------- During the runs, thermocouples 102, 401, and 423 failed and either stopped providing a signal or sent negative temperature readings. Significant signal noise was also observed in thermocouples 108, 117, 118, 121, and 814. During Run 1, condensate from steam that traveled inside the sheathed thermocouple wire collected on the thermocouple connectors outside the autoclave. The condensate collecting within the connectors likely caused the signal noise and in some cases failure of the thermocouples in Run 1. After Run 1, the connectors were inverted to force the condensate to drip off the wires instead of collecting in the connectors, which eliminated most of the signal noise and failure problems. Of the 162 time/temperature data series, 156 were collected satisfactorily, resulting in 96 percent complete data. Therefore, the acceptance criteria of at least 80 percent of the data being collected satisfactorily was met. No data from the three thermocouples that failed were used for the analyses in this report. Data from the five thermocouples with significant noise were used. Most of the noise resulted in abrupt temperature spikes or dips of less than 50°F. However, there were two data spikes for thermocouple 118 where the temperature reading more than doubled for approximately 20 seconds. This is characteristic of no signal being received by the data logger for a short period. Data from the data point immediately preceding the spikes were extrapolated and used for data analyses instead of the temperature spike data for these two instances for thermocouple 118. All other temperature data were used as recorded. 3.3.2.3 Test Conditions The ERG test engineer recorded the test conditions on log sheets as identified in the QAPP. The ERG test engineer and ERG test director verified and signed all log sheets for each run. 3.3.2.4 BI Test Strip Results Raven Biological Laboratories, Inc. analyzed the BI test strips. All samples were successfully analyzed, providing alOO percent complete data set. 3-11 ------- Three sets of control BI pouches were analyzed. First, two duplicate sample pouches were placed within each test run, adjacent to the sample pouch it was duplicating. Of the 12 duplicate pouches, 10 yielded the same results as the corresponding sample pouches (i.e., growth was found in both in one case and no growth was found in both in nine cases). However, at two of the sample points (thermocouples 217 and 812) the growth/no-growth results for the duplicates did not match (i.e., the 'A' strip for the duplicate indicated growth and the 'A' strip for the sample did not). The 'B' strips for the duplicates were assayed and no viable survivor population was found (<100 CPU), consistent with the A strip of the original sample. These data suggest that, in some cases, a growth indication alone may be a false positive result (2 of the 12 cases measured). However, the growth/no-growth indication coupled with the BI assay data is a reliable measure of sterilization and spore viability. Additionally, nine blind control samples were analyzed that were not exposed to autoclave conditions, but in all other respects handled the same as other BI test pouches. These nine controls all yielded positive results for growth, and the assay data confirm that no significant reduction in viable spores was caused by the handling, packaging, and shipping of the BI pouches. Finally, one blind control test pouch was autoclaved in each run, not embedded in any building material and exposed fully to autoclave conditions. These controls for all runs except Run 2 yielded negative results for growth. Upon analyzing the assay data for the Run 2 control, only a 104 reduction in viable spores was achieved. As mentioned previously, the thermocouple and corresponding BI test pouch for Run 2 fell from their mount on the autoclave bin wall and became embedded in the BDR mass in Run 2. This caused the BI test pouch not to be fully exposed to the autoclave conditions and is likely the cause of the remaining spore viability. No growth was observed in every other quality assurance sample fully exposed throughout the test. 3-12 ------- Run1 -31.5psig/275°F Multiple BDR Types Loose Pack LL 230 - 1 £ 190 20 40 80 100 60 Time (min) Figure 3-1. Run 1 Time/Temperature Data DWB - Dry Wallboard; WWB - Wet Wallboard; DCT - Dry Ceiling Tiles; WCT - Wet Ceiling Tiles; DCP - Dry Carpet; CON - Fully Exposed Control; REF - Exterior Reference Temperature 120 •101 DWB •103 DWB •104 DWB 105 DWB •106 DCT •107 DCT •108 DCT 109 DCT 110 DCT 111 WWB 112WWB 113WWB 114 WWB 115 WWB •116 WCT •117 WCT 118 WCT 119 WCT 120 WCT •121 DCP •122 DCP 123 DCP 124 DCP •125 CON •126 REF ------- 310 290 270 Run 2 - 45psig/292°F Wallboard - Dense Pack 70 50 20 40 100 120 140 60 80 Time (min) Figure 3-2. Run 2 Time/Temperature Data DWB - Dry Wallboard; WWB - Wet Wallboard; T - Top of Dense Pack Bin; M - Middle of Dense Pack Bin; B - Bottom of Dense Pack Bin CON - Fully Exposed Control; REF - Exterior Reference Temperature •201 DWB-B •202 DWB-T 203 DWB-M 204 DWB-M 205 DWB-M 206 DWB-M 207 DWB-T 208 DWB-T 209 DWB-T •210 DWB-B •211 DWB-B •212 DWB-B •213WWB-T •214 WWB-M •215 WWB-B •216WWB-B •217 WWB-B •218 WWB-B •219WWB-T •220 WWB-T •221 WWB-T 222 WWB-M •223 WWB-M 224 WWB-M •225 CON •226 REF ------- Run4-31.5psig/275°F Carpet - Loose, Dense, and Large Roll 20 40 60 80 100 Time (min) Figure 3-3. Run 4 Time/Temperature Data 120 140 •402 WCP Roll •403 WCP Roll •404 WCP Roll •405 WCP Roll 406 WCP Roll 407 WCP Roll 408 WCP Roll •409 DCP Loose •410 DCP Loose 411 DCP Loose 412 DCP Loose 413DCPDense-M 414 DCP Dense-B 415 DCP Dense-B 416 DCP Dense-B •417 WCP Loose •418 WCP Loose •419 WCP Loose 420 WCP Loose •421 WCP Dense-M 422 WCP Dense-T 424 WCP Dense-T •425 CON •426 REF DCP - Dry Carpet; WCP - Wet Carpet; Roll - Large Carpet Roll; T - Top of Dense Pack Bin; M - Middle of Dense Pack Bin; B - Bottom of Dense Pack Bin CON - Fully Exposed Control; REF - Exterior Reference Temperature ------- Run 8 - 45psig/292°F Multiple BDR Types Loose Pack 50 20 40 60 80 Time (min) Figure 3-4. Run 8 Time/Temperature Data DWB - Dry Wallboard; WWB - Wet Wallboard; DCT - Dry Ceiling Tiles; WCT - Wet Ceiling Tiles; CON - Fully Exposed Control; REF • Exterior Reference Temperature •801 DWB •802 DWB •803 DWB 804 DWB 805 DWB •806 DCT •807 DCT •808 DCT 809 DCT 810 DCT 811 WWB 812 WWB 813 WWB 814 WWB 815 WWB •816 WCT •817 WCT 818 WCT 819 WCT 820 WCT •821 SOFA •822 SOFA 823 SOFA 824 SOFA •825 CON •827 REF ------- Run5-31.5psig/275°F Multiple BDR Types Vertical - Two Cycles 50 10 20 30 70 80 90 40 50 60 Time (min) Figure 3-5. Run 5 Time/Temperature Data DWB - Dry Wallboard; WWB - Wet Wallboard; DCT - Dry Ceiling Tiles; WCT - Wet Ceiling Tiles; DCP - Dry Carpet; WCP - Wet Carpet; CON - Fully Exposed Control; REF - Exterior Reference Temperature 100 •501 WWB •502 WWB 503 WWB •504 WCT •505 WCT •506 WCT •507 WWB •508 WWB 509 WWB •510 WCT •511 WCT 512 WCT 513 WCP 514 WCP 515 WCP 516 DCP 517 DCP 518 DCP •519 DCT •520 DCT •521 DCT •522 DCT 523 DCT 524 DCT •526 CON •527 REF ------- oo 50 Run6-31.5psig/275°F Multiple BDR Types - Vertical Two Cycles - All Bags Cut 10 20 30 50 60 70 40 Time (min) Figure 3-6. Run 6 Time/Temperature Data DWB - Dry Wallboard; WWB - Wet Wallboard; DCT - Dry Ceiling Tiles; WCT - Wet Ceiling Tiles; DCP - Dry Carpet; WCP -Wet Carpet; CON - Fully Exposed Control; REF - Exterior Reference Temperature 80 •601 WWB •602 WWB 603 WWB •604 DCT •605 DCT •606 DCT •607 DWB •608 DWB 609 DWB •610 DCT 611 DCT 612 DCT 613 WCP 614 WCP 615 WCP •616 WCT •617 WCT •618 WCT 619 DCP 620 DCP 621 DCP •623 CON •624 WCT •625 WCT 626 WCT •627 REF ------- 4.0 DISCUSSION As discussed previously, the following variables were identified as having a potential impact on sterilization capability: 1. Item type; 2. Autoclave packing density (i.e., loose packing versus dense packing); 3. Moisture content of autoclaved materials; 4. Autoclave temperature/pressure; and 5. Time in autoclave. During the test, three additional factors were identified as potentially influencing sterilization capability: 1. Positioning sample bags of BDR vertically instead of horizontally; 2. Cutting open the bags of BDR to facilitate steam penetration; and 3. Running two shorter process cycles in sequence instead of one long cycle. One additional factor that may affect sterilization not investigated in this study was the packaging technique. BDR was cut up, double bagged in 1.8 mil autoclave bags, and goose-necked closed with duct tape, to mimic BDR generated from a likely disposal incident. Other packaging techniques (e.g., bag/container type, bag thickness, quantity of BDR per bag, and sealing method) that may also influence sterilization ability were not evaluated. This section first discusses the impact of the observed time/temperature profiles on BDR sterilization, measured using the BI growth/no-growth and assay results. The section then presents how each of the variables above affected the temperature profile and associated sterilization results. 4.1 Time and Temperature Effect on Sterilization Figures 4-1 through 4-3 present the time and temperature affect on sterilization for Runs 2, 4, and 5. All figures are located at the end of this section. On each figure, the time/temperature profile is plotted, and the lines are color coded to indicate whether the 4-1 ------- associated BI data indicated viable spores or no viable spores. A viable spore designation is used if growth was found in both the growth/no-growth test and the assay analysis. Sterilization or a no viable spore designation is used if no growth was found in the growth/no-growth test with an 106 initial BI population. In a limited number of cases, the growth/no-growth test indicated a positive result; however, no quantifiable population was measured by the subsequent assay analysis (reported result of <100 CPU). These data series are labeled as indeterminate. No figures are provided for Runs 1, 8, and 6 because no viable spores were found in these runs. The temperature profiles for these runs can be viewed on Figures 3-1,3-4, and 3-6, respectively. Each of these runs contained loose pack BDR materials, processed at different conditions. The spores were sterilized in all cases where the target of 15 minutes at 250°F was achieved. While spores were also sterilized in several instances below this target, 15 minutes at 250°F was required to ensure sterilization. The effect of each variable on sterilization is discussed in the following subsections. 4.2 Item Type and Moisture Content The temperature profiles for Runs 1, 8, 5, and 6, presented in Figures 4-4 through 4-7, respectively, show the influence of item type on temperature profile. Within each of these runs, different item types were autoclaved under the same conditions. An average data series is provided for each item type on each figure. The average data series were calculated as the arithmetic average of the temperature at each time T, at every sampling location of that type. For example, in Run 1, there were five wet ceiling tile sampling locations. The temperature plotted for the wet ceiling tile series at T = 20 minutes is the average of the temperatures at each of the five wet ceiling tile locations at T = 20 minutes. Where averages were calculated, the number of sample points averaged is presented next to each series. As shown on the figures, dry carpet and dry ceiling tiles heated more rapidly than wet carpet and wet ceiling tiles, respectively. Dry wallboard and wet wallboard heated at approximately the same rate in three of the four runs where comparison can be made (Figures 4- 4-2 ------- 4, 4-5, 4-7). In Run 5 (Figure 4-6), the wet wallboard heated significantly faster. These differences are believed to be functions of the moisture content of each material. The difference between dry and wet carpet and ceiling tile results are likely due to the significant water absorbing-capacity of carpet (53 percent increase in weight when wet) and ceiling tiles (34 percent increase in weight when wet). The significant water content of the wet carpet and ceiling tiles increases the thermal load needed to boil the water and heat the material in the autoclave and may also decrease steam penetration. Wallboard does not absorb as much water when wet (9 percent increase in weight when wet). This would explain the relatively similar results for wet and dry wallboard observed on Figures 4-4, 4-5, and 4-7. With respect to differing item types, wet wallboard heated faster than wet ceiling tiles, which heated faster than wet carpet. This relationship was observed in all runs and is consistent with the relative water-absorbing capacity of each material, as discussed above. When moisture content is eliminated as a variable and dry BDR items are compared to each other, there is no apparent trend. For example, dry carpet heated fastest in Run 1, but slower than dry ceiling tiles and dry wallboard in Run 6. Similarly, dry ceiling tiles heated fastest in Run 6, but slower than dry wallboard and dry carpet in Run 5. These observations suggest that trends and differences in heating rates between BDR item types depends primarily on the moisture content of wet items, and not on the BDR material itself. The sofa, tested dry, heated more rapidly than wallboard and ceiling tiles in the one run where it was tested (Figure 4-5). If it had been saturated with water, the results may have been significantly different, based on the findings for ceiling tiles and carpet. 4.3 Autoclave Packing Density and Location The effect of autoclave packing density is best isolated from other variables by examining the data for Runs 2, 4, and 8. Wet and dry wallboard were tested in both loose pack (one layer of bags) and dense pack arrangement (approximately four layers of bags) in Runs 2 and 8, respectively. Both runs were conducted at 45 psig (292°F). Figure 4-8 presents average 4-3 ------- time/temperature profile data for each set of conditions. Carpet was tested in both a loose pack and dense pack arrangement in Run 4 at 31.5 psig (275°F); Figure 4-9 presents average time/temperature profile data. As shown by these figures, loose pack items heat significantly faster than dense pack. Most of the dense pack sample points never achieved the target temperature of 250°F for 15 minutes, and resulted in significant remaining spore viability (see Figures 4-1 and 4-2). The majority of the positive growth results found during the test were in the dense packing configuration. The temperature profile within the thermal mass was investigated using data from Run 2. Figure 4-10 presents average data from dense pack wallboard in Run 2 at varying levels within the mass. Top layer data points are from thermocouples in bags at the top of the mass, exposed to the autoclave conditions; middle layer data points are from bags in between other bags; and bottom layer data point are from bags touching the bottom of the bin. As shown by these data, the bags at the bottom of the bin heated fastest, indicating conduction through the metal bin may be a factor in heating the BDR. However, remaining viable spores were found in all three layers of densely packed material. Selected wallboard bags were examined to investigate the temperature profile within the 3-sample bags. Figure 4-11 presents two examples, comparing the temperature profile within a dry loose pack wallboard bag and a dry dense pack, middle layer wallboard bag. As shown in the loose pack bag, while the center of the bag generally heated more slowly, all three temperature readings gradually converge, and the spores were all sterilized at all three locations. However, there was not enough time for the bag in the dense pack configuration to reach a sterilization temperature. Sterilization was only achieved between the first and second sheet. Figure 4-12 presents the temperature profile within selected loose pack ceiling tile bags. Similarly, the center of the bags heated slowest. However, all sample points came up to temperature and all spores were sterilized in the loose pack arrangement. 4-4 ------- 4.4 Temperature and Pressure As mentioned previously, autoclave temperature and pressure are related variables, as the autoclave is designed to operate at saturated steam conditions. Two conditions were investigated: 31.5 psig/275°F, the typical operating pressure of the autoclave, and 45 psig/292°F, the maximum operating pressure of the autoclave. The effect of autoclave temperature and pressure is best isolated from other variables by examining the data from Runs 1 and 8. Loose pack, wet and dry wallboard and ceiling tiles were processed in Run 1 at 31.5 psig/275°F and in Run 8 at 45 psig/292°F. Figure 4-13 compares the wallboard data collected for Run 1 versus Run 8, and Figure 4-14 compares the ceiling tile data for both runs. For both materials, the higher temperature and pressure accelerated the BDR heating process significantly. However, all Bis from both runs exhibited no growth. Run 1 at the lower temperature was conducted for 120 minutes while Run 8 at the higher temperature was terminated after 75 minutes. 4.5 Packing Orientation Materials were tested both lying horizontally and positioned vertically. The vertical packing arrangement was only tested in loose packing configuration using two 40- minute autoclave cycles in sequence. The packing orientation variable is best isolated by comparing wallboard and ceiling tile data between Runs 1 and 5 and carpet data between Runs 4 and 5. Figures 4-15 through 4-17, respectively, present the average data for these runs for each item type. In reviewing these figures, only data for the first 40 minutes should be considered for comparison purposes, as that is when the postvacuum cycle began during Run 5, which is different from Runs 1 and 4. Accounting for the different starting temperatures between the runs, the data appear variable and no firm conclusions can be drawn about the influence of packing orientation on autoclave performance. 4-5 ------- 4.6 Open Bags Runs 5 and 6 were performed under the same conditions, except that two of the eight bags tested were sliced open prior to autoclaving in Run 5 and all of the bags were sliced open prior to autoclaving in Run 6. Figures 4-18, 4-19, and 4-20 present the average data from these runs, comparing results for cut and uncut bags for wallboard, ceiling tiles, and carpet, respectively. The data available to make this comparison are limited and somewhat variable. In most cases, the data presented are for three sample locations within one bag of BDR. As seen on Figure 4-18, wet wallboard in an uncut bag heated most rapidly. On Figure 4-19, ceiling tiles in cut bags heated most rapidly. On Figure 4-20, dry carpet in an uncut bag heated most rapidly, but wet carpet in an uncut bag heated most slowly. This uncut bag of wet carpet was the only bag in Runs 5 or 6 to contain biological indicators with surviving spores. All other biological indicators from these runs exhibited no surviving spores. It is worth noting that even bags that were not cut open prior to autoclaving had a tendency to rupture in the autoclave when subjected to the pressure differentials and heat of the autoclave cycle. Based on these data, we cannot draw any firm conclusions regarding the impact of cutting bags open prior to autoclaving. 4.7 Two Sequential Cycles As illustrated in Figures 3-5 and 3-6, conducting two standard autoclave cycles in sequence proved to be quite effective in bringing BDR items up to the full autoclave temperature rapidly after steam is applied during the second cycle. We believe that applying a vacuum between the first and second cycles is what is particularly effective about this approach. The first cycle acts to preheat the material, although it is likely that the initial contact between the steam and the BDR material results in immediate condensation, filling pore spaces within the material. Consequently, steam supplied later in the cycle does not penetrate well into the material, and the material only slowly heats due to free convection and conduction from the bin walls. Applying a vacuum prior to the second cycle likely pulls the condensate away from the 4-6 ------- material, and when steam is subsequently applied, it penetrates well into the material, which quickly rises to the full autoclave temperature. In fact, Run 6 was terminated early because all BDR materials had been over 270°F for 15 minutes well before the second cycle was scheduled to be completed. When subjected to two autoclave cycles in sequence, all biological indicators except for those in the one bag of wet carpet in Run 5 exhibited no surviving spores. Two autoclave cycles did not consistently result in no-growth for BI test strips placed in wet carpet. It may be necessary to further process wet carpet beyond two cycles to effectively sterilize it. 4-7 ------- 310 oo Run 2 Wallboard Dense Pack 45psig/292°F 20 40 60 80 100 120 140 Time (min) •No Viable Spores Viable Spores Spore Viability Indeterminate Figure 4-1. Run 2 Spore Viability ------- 310 Run 4 Carpet - Loose, Dense, and Large Roll 31.5psig/275°F 20 40 100 60 80 Time (min) •No Viable Spores Viable Spores Spore Viability Indeterminate Figure 4-2. Run 4 Spore Viability 120 140 ------- Run 5 Multiple BDR Types Vertical - Two Cycles 31.5psig/275°F 10 20 30 40 60 50 Time (min) •No Viable Spores Viable Spores 70 80 90 100 Figure 4-3. Run 5 Spore Viability ------- 310 Dry Carpet (4 points) Wet Wallboard (5 points) Dry Wallboard (4 points) Wet Ceiling Tiles (5 points) Run 1 Multiple BDR Types Loose Pack 31.5psig/275°F Dry Ceiling Tiles (5 points) 50 20 40 60 Time (min) 80 100 120 Figure 4-4. Run 1 Moisture Content and Item Type Comparison Each line on this graph is an average of multiple sample points. The number of sample points averaged is presented next to each series. ------- Sofa (4 points) Wet Wallboard (5 points) Dry Wallboard (5 points) Dry Ceiling Tiles (5 points) Wet Ceiling Tiles (5 points) Run 8 Multiple BDR Types Loose Pack 45psig/292°F 50 10 20 30 40 50 Time (min) 60 70 80 Figure 4-5. Run 8 Moisture Content and Item Type Comparison Each line on this graph is an average of multiple sample points. The number of sample points averaged is presented next to each series. 90 ------- Dry Carpet (3 points) Wet Wallboard (3 points) —| Dry Wallboard (3 points) Wet Carpet (3 points) RunS Multiple BDR Types Vertical - Two Cycles 31.5psig/275°F Wet Ceiling Tiles (3 points) Dry Ceiling Tiles (3 points) 10 20 30 40 50 Time (min) 60 70 80 90 100 Figure 4-6. Run 5 Moisture Content and Item Type Comparison (Uncut Bags Only) Each line on this graph is an average of multiple sample points. The number of sample points averaged is presented next to each series. ------- 310 Wet Wallboard (3 points) Dry Ceiling Tiles (6 points) |Dry Wallboard (3 points) Wet Ceiling Tiles (6 points) Dry Carpet (3 points) Run 6 Multiple BDR Types Vertical - Two Cycles All Bags Cut 31.5psig/275°F Wet Carpet (3 points) 10 20 30 40 Time (min) 50 60 70 80 Figure 4-7. Run 6 Moisture Content and Item Type Comparison Each line on this graph is an average of multiple sample points. The number of sample points averaged is presented next to each series. ------- 310 290 270 250 230 Run 8 Dry Wallboard Loose Pack (5 points) jRun 8 Wet Wallboard Loose Pack (5 points) Run 2 Wallboard Dense Pack 45psig/292°F Run 2 Wet Wallboard Dense Pack (12 points) Run 2 Dry Wallboard Dense Pack (12 points) Run 8 Multiple BDR Types Loose Pack 45psig/292°F 50 20 40 60 80 Time (min) 100 120 140 Figure 4-8. Wallboard Packing Density Comparison Each line on this graph is an average of multiple sample points. The number of sample points averaged is presented next to each series. ------- 310 Wet Carpet Loose Pack (4 points) | Dry Carpet Loose Pack (4 points) Wet Carpet Dense Pack (3 points) Run 4 Carpet - Loose, Dense and Large Roll 31.5psig/275°F [LargeWet Carpet Roll (7 points) Dry Carpet Dense Pack (4 points) 50 20 40 60 80 Time (min) 100 120 140 Figure 4-9. Carpet Packing Density Comparison Each line on this graph is an average of multiple sample points. The number of sample points averaged is presented next to each series. ------- 270 250 230 210 IWet Wallboard Bottom Layer (4 points) | Dry Wallboard Bottom Layer (4 points) j^ Wet Wallboard Top Layer (4 points) Wet Wallboard Middle Layer (4 points) Dry Wallboard Top Layer (4 points) Run 2 Wallboard Dense Pack 45psig/292°F Dry Wallboard Middle Layer (4 points) 20 40 60 80 Time (min) 100 120 140 Figure 4-10. Run 2 Dense Packing Layer Comparison Each line on this graph is an average of multiple sample points. The number of sample points averaged is presented next to each series. ------- oo 270 250 230 210 190 g> 170 +- re 0) Q. Run 1 Dry Wallboard Loose Pack Between 4th and 5th sheet Between 2nd and 3rd sheet Between 1st and 2nd sheet Between 4th and 5th sheet Run 1 Multiple BDR Types Loose Pack 31.5psig/275°F Between 2nd and 3rd sheet Between 1st and 2nd sheet Run 2 Dry Wallboard Dense Pack - Middle Layer Run 2 Wallboard Dense Pack 45psig/292°F 70 50 20 40 60 80 100 120 140 Time (min) Figure 4-11. Comparison of Sample Points Within Selected Wallboard Bags Note: 1st sheet was always on top in the bins. ------- Run 5 Dry Vertical Ceiling Tiles Between 7th and 8th sheet Between 4th and 5th sheet Between 2nd and 3rd sheet Run 1 Multiple BDR Types Loose Pack 31.5psig/275°F Between 7th and 8th sheet Between 4th and 5th sheet Run 5 Multiple BDR Types Vertical - Two Cycles 31.5psig/275°F Between 2nd and 3rd sheet Run 1 Dry Horizontal Ceiling Tiles 50 20 40 60 Time (min) 80 100 120 Figure 4-12. Comparison of Sample Points within Selected Ceiling Tile Bags Note: 1st sheet was always on top in the bins. ------- to o 290 270 250 230 210 190 0) Q. Run 8 - 292°F Wet Wallboard (5 points) Run 8 - 292°F Dry Wallboard (5 points) Run 1 - 275°F Wet Wallboard (5 points) 1 - 275°F Dry Wallboard (4 points) Run 1 Multiple BDR Types Loose Pack 31.5psig/275°F Run 8 Multiple BDR Types Loose Pack 45psig/292°F 0 20 40 80 100 60 Time (min) Figure 4-13. Autoclave Temperature Comparison for Wallboard Each line on this graph is an average of multiple sample points. The number of sample points averaged is presented next to each series. 120 ------- 2QO 270 Run 8 - 292°F Dry Ceiling Tiles (5 points) Run 1 - 275°F Dry Ceiling Tiles (5 points) Run 8 - 292°F Wet Ceiling Tiles (5 points) Run 1 Multiple BDR Types Loose Pack 31.5psig/275°F Run 1 - 275°F Wet Ceiling Tiles (5 points) Run 8 Multiple BDR Types Loose Pack 45psig/292°F 50 0 20 40 80 100 60 Time (min) Figure 4-14. Autoclave Temperature Comparison for Ceiling Tiles Each line on this graph is an average of multiple sample points. The number of sample points averaged is presented next to each series. 120 ------- to to Run 5 Wet Vertical Wallboard (3 points) Run 1 Wet Horizontal Wallboard (5 points) Run 1 Dry Horizontal Wallboard (4 points) Run 1 Multiple BDR Types Loose Pack 31.5psig/275°F Run 5 Dry Vertical Wallboard (3 points) RunS Multiple BDR Types Vertical - Two Cycles 31.5psig/275°F 0 20 40 80 100 60 Time (min) Figure 4-15. Horizontal Versus Vertical Packing Orientation for Wallboard Each line on this graph is an average of multiple sample points. The number of sample points averaged is presented next to each series. 120 ------- 310 -^ to 2 0) Run 5 Dry Vertical Ceiling Tiles Uncut Bags Only (3 points) Run 5 Wet Vertical Ceiling Tiles - Uncut Bags Only (3 points) Run 1 Dry Horizontal Ceiling Tiles (5 points) Run 1 Multiple BDR Types Loose Pack 31.5psig/275°F Run 1 Wet Horizontal Ceiling Tiles (5 points) RunS Multiple BDR Types Vertical - Two Cycles 31.5psig/275°F 20 40 80 100 60 Time (min) Figure 4-16. Horizontal Versus Vertical Packing Orientation for Ceiling Tiles 120 Each line on this graph is an average of multiple sample points. The number of sample points averaged is presented next to each series. ------- -^ to Run 5 Dry Vertical Carpet (3 points) Run 4 Wet Horizontal Carpet (4 points) Run 4 Carpet - Loose, Dense and Large Roll 31.5psig/275°F Run 4 Dry Horizontal Carpet (4 points) Run 5 Multiple BDR Types Vertical - Two Cycles 31.5psig/275°F Run 5 Wet Vertical Carpet (3 points) 50 20 40 100 60 80 Time (min) Figure 4-17. Horizontal Versus Vertical Packing Orientation for Carpet 120 140 Each line on this graph is an average of multiple sample points. The number of sample points averaged is presented next to each series. ------- to 310 290 Run 5 Wet Wallboard Uncut (3 points) Run 6 Dry Wallboard Cut (3 points) RunS Multiple BDR Types Vertical - Two Cycles Wallboard Bags Uncut 31.5psig/275°F Run 6 Wet Wallboard Cut (3 points) Run 5 Dry Wallboard Uncut (3 points) Run 6 Multiple BDR Types Vertical - Two Cycles All Bags Cut 31.5psig/275°F 50 10 20 30 40 60 70 50 Time (min) Figure 4-18. Cut Versus Uncut Wallboard Bags 80 90 100 Each line on this graph is an average of multiple sample points. The number of sample points averaged is presented next to each series. ------- J^. K> 310 290 270 250 130 110 50 Run 5 Wet Ceiling Tiles Cut (3 points) Run 5 Dry Ceiling Tiles Cut (3 points) Run 5 Dry Ceiling Tiles Uncut (3 points) 10 Run 5 Wet Ceiling Tiles Uncut (3 points) RunS Multiple BDR Types Vertical - Two Cycles Cut and Uncut Bags 31.5psig/275°F 20 30 40 60 70 50 Time (min) Figure 4-19. Cut Versus Uncut Ceiling Tile Bags 80 90 100 Each line on this graph is an average of multiple sample points. The number of sample points averaged is presented next to each series. ------- Run 5 Dry Carpet Uncut (3 points) Run 6 Dry Carpet Cut (3 points) RunS Multiple BDR Types Vertical - Two Cycles Carpet Bags Uncut 31.5psig/275°F Run 5 Wet Carpet Uncut (3 points) Run 6 Multiple BDR Types Vertical - Two Cycles All Bags Cut 31.5psig/275°F Run 6 Wet Carpet Cut (3 points) 50 10 20 30 40 60 50 Time (min) Figure 4-20. Cut Versus Uncut Carpet Bags 70 80 90 100 Each line on this graph is an average of multiple sample points. The number of sample points averaged is presented next to each series. ------- s.o CONCLUSIONS Based on variables evaluated in this study, the following conclusions can be drawn regarding processing of BDR material in a commercial-scale autoclave. Conclusions regarding sterilization are based on a finding of no growth, using 106 population BI test strips. General Conclusions • Achieving an internal BDR material temperature of 250°F or higher for 15 minutes or longer destroyed all biological indicators. The following approaches were most effective in achieving this: using a loose packing configuration, processing dry BDR material, establishing higher autoclave operating temperature and pressure, and running multiple autoclave cycles in sequence. • Bagged wallboard (wet or dry), ceiling tiles (wet or dry), and dry carpet can be effectively sterilized under appropriate time, temperature, and packing conditions. Time, temperature, and packing requirements are provided below. • Dry upholstered furniture can be effectively sterilized. No conclusions are drawn regarding wet upholstered furniture. Time, Temperature, and Pressure Effects • An autoclave cycle of 120 minutes at 31.5 psig/ 275°F effectively sterilized wallboard, ceiling tiles, and dry carpet, when loaded in the autoclave as described below. • An autoclave cycle of 75 minutes at 45 psig/ 292°F effectively sterilized wallboard and ceiling tiles, when loaded in the autoclave as described below. • Two standard autoclave cycles of 40 minutes and 31.5 psig/ 275°F run in sequence effectively sterilized wallboard, ceiling tiles, and dry carpet, when loaded as described below. Available data suggest the second cycle can be shortened to 20 minutes. Two autoclave cycles did not consistently result in no growth for BI test strips placed in wet carpet. It may be necessary to further process wet carpet beyond two cycles for effective sterilization. It appears that evacuating the autoclave between the first the second cycle is critical, allowing the second cycle to successfully sterilize the BDR. Autoclave Loading • Bags of BDR material should be placed in the autoclave so that all surfaces are exposed to autoclave conditions. Bags lying flat against a metal surface, such as the base of an autoclave bin, are considered to be fully exposed to autoclave conditions. 5-1 ------- Bags of BDR material stacked or nested such that they are not fully exposed to autoclave conditions may not be reliably sterilized under the conditions tested. Bags of !/2 inch wallboard slabs up to 5 layers thick and 5/8 inch ceiling tiles up to 9 layers thick can be effectively sterilized under the time, temperature, and packing density conditions described above. Dry commercial grade carpet rolls formed from pieces 26 inches wide and 20 feet long can effectively sterilized under the time, temperature, and packing density conditions described above. 5-2 ------- 6.0 REFERENCES 1. Quality Assurance Project Plan, Destruction of Spores on Building Decontamination Residue in a Commercial Autoclave, prepared by Eastern Research Group, Inc., Chantilly, VA, February 21, 2005. 2. "Work Plan, Waste Removal and Facility Cleaning, Department of State SA-32 Diplomatic Pouch and Mail Facility Sterling, VA." Submitted by U.S. Army Corps of Engineers, Rapid Response Program and SE&I, Rev 3, November 12, 2002. 3. Boca, Pretorius, Gochin, Chapoullie, and Apostolides, 2002. "An Overview of the Validation Approach for Moist Heat Sterilization, Part I." Pharmaceutical Technology. September, 2002, pg. 62-70. 4. Barkley, W. and Richardson, 1, 1994. Laboratory Safety, pg. 715-734, in Gerhardt, P., Murray, R., Wood, W., and Krieg, N. Methods for General and Molecular Bacteriology, ASM. Washington, DC. 6-1 ------- Appendix A PHOTOGRAPHIC LOG ------- Photo 1. Healthcare Environmental's Oneonta, New York Facility Photo 3. Stacks of Size Reduced Wallboard and Ceiling Tiles Photo 2. Wallboard Size Reduction Photo 4. Submersing Wallboard Sheets Photo 5. Wallboard on Dry Rack Photo 6. Assembled Sample Point A-l ------- Photo 7. Sample Point (Thermocouple Paired with a BI Test Pouch) Photo 9. Palletized Bags of Ceiling Tiles Photo 8. Sample Point Between Sheets of Drywall Photo 10. Bulk Quantity of Used Commercial Carpet Photo 11. Carpet Wetting Photo 12. Sample Point within Carpet A-2 ------- Photo 13. Water Draining out of Assembled Carpet Roll Photo 14. Assembled Bags of Small Carpet Rolls Photo 15. Assembled Large Carpet Rolls Photo 16. Sofa Wrapping Photo 17. Empty Autoclave Photo 18. Empty Autoclave Bin A-3 ------- . Photo 19. Autoclave Bins on Transfer Cart Photo 20. Bins Loaded into Autoclave Photo 21. Flange Port Photo 22. Fabricated Flange Port to Allow Thermocouple Wires to Pass Through Photo 23. Connectors Not Inverted Allowing Condensate to Collect in the Connectors Photo 24. Connectors Inverted to Allow Condensate to Drip Off the Wires A-4 ------- 1 Photo 25. Data Acquisition System Photo 26. Pallets of BDR Material Photo 27. Loose Pack Wallboard Bin Photo 28. Wallboard Bags After Autoclaving Photo 29. Dense Pack Wallboard Bin Photo 30. Loose Pack Ceiling Tile Bin A-5 ------- Photo 31. Loose Pack Carpet Bin Photo 33. Dense Pack Carpet Bin Photo 32. Loose Pack Carpet Bin After Autoclaving Photo 34. Large Carpet Roll on Pallet for Autoclaving Photo 35. Vertical Orientation Photo 36. Vertical Packaging Orientation After Autoclaving A-6 ------- Photo 37. Full Exposure Control Sample Photo 38. Stringing Thermocouple Wires Along the Top of the Bins Photo 39. Connecting Thermocouple Wires Photo 40. Removing BI Test Pouches From Sofa Photo 41. Removing BI Test Pouches from BDR Photo 42. BI Test Pouches Packed for Shipment to Laboratory A-7 ------- &EPA United States Environmental Protection Agency Office of Research and Development National Homeland Security Research Center Cincinnati. OH 45268 Official Business Penalty for Private Use $300 EPA/600/R-05/081 April 2005 PRESORTED STANDARD POSTAGE & FEES PAID EPA PERMIT NO. G-35 Recycled/Recyclable Printed with vegetable-based ink on paper lhat contains a minimum of 50% post-consumer fiber content processed chlorine free ------- |