United States Environmental Protection Agency Risk Reduction Engineering Laboratory Cincinnati OH 45268 Research and Development EPA/600/S2-89/041 Feb. 1990 Project Summary Evaluation of Airborne Asbestos Concentrations Before and During an O&M Activity: A Case Study John Kominsky and Ronald Freyburg The current lack of information regarding the effect of Operation and Maintenance (O&M) activities on the potential for asbestos exposure to building staff and occupants prompt- ed this study. This report presents a statistical evaluation of airborne asbestos data collected before and during an O&M activity involving removal of thermal surface insulation from a feedwater preheated tank in a boiler room. Transmission electron microscopy (TEM) analysis on 0<4*ii-" pore-size polycarbonate (PC) is compared with TEM analysis on 0.8-p- pore-size mixed cellulose ester (MCE) membrane filters. This Project Summary was devel- oped by EPA's Risk Reduction Engi- neering Laboratory, Cincinnati, OH, to announce key findings of the research project that Is fully documented In a separate report of the same title (see Project Report ordering information at back). Introduction The U.S. Environmental Protection Agency (EPA) has issued guidance docu- ments to assist building owners in devel- oping an O&M program to control exposure to asbestos when asbestos- containing material (ACM) is present in the building. ACM includes surface mate- rial, thermal surface insulation, or other materials such as ceiling and floor tiles. In theory, an O&M program should be designed and implemented to protect building staff and occupants from the release of asbestos fibers and to warn them of potential hazards created by the disturbance of ACM under uncontrolled conditions. The O&M program should continue as long as the ACM remains in the building. The overall goal of an asbestos O&M program is to maintain the building environment free of asbestos contamina- tion. The specific program objectives are (1) to remove asbestos fibers that may have been released from the ACM, and (2) to minimize future release and distri- bution of fibers by controlling activities that might disturb the ACM. The O&M program focuses on the activities of custodial and maintenance workers and service contractors. Special procedures for routine cleaning by custo- dial workers are designed to achieve the first program objective, the collection of previously released asbestos fibers. Special work practices and procedures are designed for maintenance workers to achieve the second program objective, minimization of ACM disturbance. The work practices and procedures are tailor- ed to three types of projects: (1) those that are unlikely to involve any contact with ACM; (2) those that may cause accidental disturbance of ACM; and (3) those that involve small-scale manipu- lation or removal of ACM. The O&M program also specifies emergency re- sponse actions for asbestos-fiber-release episodes. ------- Objectives The following were the primary objec- tives of the study: • To document a one-site case study on the effectiveness of work practices and procedures in preventing the release of asbestos fibers outside the work area during an O&M activity involving removal of thermal ACM surface insulation. • To determine if 0.4-ii-pore-size poly- carbonate and 0.8-n-pore-size mixed cellulose ester membrane filters pro- duce equivalent estimates of airborne asbestos concentrations. Study and Design Methods Site Description The selected site, a boiler room of a commercial research laboratory, met the following criteria. 1, No abatement of ACM had occurred inside the building site within the preceding 6 months. 2. The asbestos was being abated as part of a scheduled maintenance operation. 3. The building owner agreed to co- operate with the EPA and to allow air to be monitored during the main- tenance activity. The O&M activity involved removing of approximately 57 ft2 of thermal surface insulation from a 6-ft-high feedwater preheated vessel with a 2.5 ft base. The feedwater vessel was to be replaced as part of scheduled maintenance of boiler room equipment. The vessel was located on the operating platform on the second deck of the boiler room, which measured 75 ft x 150 ft x 20 ft. An abatement contractor was removing the ACM removal. O&M Activity The glove-bag technique was used during removal of the thermal surface insulation. This containment method in- volved enclosing the vessel with one layer of 6-mil polyethylene plastic sheet- ing and splicing several sleeve and glove assemblies (standard glove bags) into the enclosure. The containment did not include a negative-pressure air filtration system. Two workers wearing full protective clothing and powered air-purifying respirators removed the surface insula- tion. All work was performed from outside the enclosure as the workers insert their hands and arms through the built-in sleeves of the glove bags. A nozzle to wet the insulation with an amended water solution was introduced through an auxiliary sleeve. During removal, asbes- tos-containing debris fell to the bottom of the bag. Some debris escaped through seams in the bag and fell approximately 7 ft to the uncovered floor of the boiler room. Analysis of this material showed that it contained approximately 42 per- cent chrysotile, 33 percent amosite, and 10 percent crocidolite. Subsequent to the removal of the insulation, all substrate surfaces were repeatedly wire-brushed and wet-wiped to removal all residual material. The asbestos-containing debris and the plastic glove bags were then placed in double 6-mil polyethylene bags and dis- posed of at an approved sanitary landfill. Sampling Strategy Table 1 presents an air-sampling ma- trix. Area air samples were collected before and during removal of the thermal surface insulation from the feedwater vessel. Both the before- and during- removal samples were collected in the perimeter area of the feedwater vessel. Outdoor area air samples were also collected before removal. Two side-by-side air samples were lected at each sampling location, or a 25-mm, 0.4-n-pore'size PC filter the other one a 25-mm, 0.8-ii-por< MCE filter. When this study was de ed and implemented, EPA recomme using either of these membrane filt< collect airborne asbestos fibers. Ci Asbestos Hazardous Emergency sponse Act (AHERA) guidance spe the same filter types but a different size (0.45-n) for the MCE filter. Sampling Methods Two side-by-side area air sar were collected at each sampling loc Each pair of samples consisted of mm, 0.4-n-pore-size PC filter and mm, 0.8-n-pore-size MCE filter. Eac mm filter was mounted on a 5-ji size, MCE backup diffusing filte cellulose support pad and was con in a three-piece cassette with a 5 conductive cowl and face cap. The and cowl sections of the cassettes sealed with vinyl adhesive tai prevent air filtration through the sej the cassettes during sampling. Thi cassettes were 4 to 5 ft above th< and arranged in a horizontal lii clipping them to a sturdy stand. Th cassettes were approximately 5 err and oriented in the same direction filter face, angled slightly dowr During sampling, the face caf removed to expose the full face filter to the air stream. The filter assembly was attachec electric-powered vacuum pump. Ai calibrated precision rotameter was to regulate the airflow through th assembly at 9.3 to 11.3 L/min. The air samples were generall lected for 6 to 7 hr to achieve a mi Table 1. Air Sampling Matrix Location and Number of Samples Perimeter Outdoors Samples Collected PC' MCE" PC MCE Total samples 19 Field Blank PC MCE Before asbestos removal During asbestos removal 10 9 10 flc 5 0 5 0 1 1 1 1 "Polycarbonate filter. bMixed cellulose ester filter. CA ninth sample could not be analyzed. ------- ir volume of 3200 L for each sample. At le end of the sampling period, filters «re turned upright before being disconn- ected from the vacuum pump and were ored in this position. nalytical Methods The MCE membrane filters and the PC lembrane filters were analyzed by TEM. 'he TEM analytical protocols used for le PC membrane filters are those found i WERL SOP 87-1, Revision. MCE lembrane filters were prepared accord- ig to protocols found in the Asbestos azard Emergency Response Act in inal Rule; counting rules and other nalytical protocols were consistent with lose used for the PC membrane filters. ITT Research Institute performed the EM Level II analyses on the field •amples under separate contract with PA's Risk Reduction Engineering Labo- tory (RREL) in Cincinnati, Ohio. duality Assurance The Quality Assurance Project Plan 1APP) contains the complete details of e quality assurance procedures follow- 1 during this research project. These rocedures are summarized in the (lowing subsections. ample Chain-of-Custody Sample chain-of-custody procedures, n integral part of both sampling and nalytical activities, and were imple- ented for all air and bulk samples ollected. The applied field custody pro- edures documented each sample from e time of its collection until its receipt y the analytical laboratory. Internal labo- atory records then documented the custody of the sample through its final disposition. Standard sample custody (traceability) procedures were used during this project. Each sample was labeled with a unique sroject identification number, which was •ecorded in the field log book along with jther information specified by the QAPP. Quality Assurance Sample Analyses Specific quality assurance procedures for ensuring the accuracy and precision of the TEM analyses of air samples included the use of lot and field blanks and replicate and duplicate analyses. Lot Blanks — Lot blanks are filters chosen before the start of field work. These blanks are analyzed by the analytical laboratory to check for filter contamination. Two laboratories analyzed 5 percent of the total number of PC filters and 5 percent of the total number of MCE filters used in the 1987 field studies by TEM Level II in accordance with the Yamate procedure. The PC filters were all from the same lot. The filters were considered "acceptable" for use if the average asbestos structure count per 10 grid openings was less than 3. If the average asbestos structure count for the group exceeded 3 asbestos struc- tures per 10 grid openings, the entire lot of filters was considered contaminated. The TEM analysis of the PC filter lot blanks showed background filter contam- ination of 1.8 asbestos structures per 10 grid openings (or 180 asbestos structures in 1000 grid squares examined). The TEM analysis of the MCE filter lot blanks showed background filter contamination of 0.12 asbestos structures per 10 grid squares (or 12 asbestos structures in 1000 grid openings examined). There- fore, the analysis of the lot blanks showed that the background asbestos filter contamination was within specific limits. Field Blanks — Field blanks are filters taken into the field and handled in the same manner as exposed air sample filters to check for contamination that might not be a result of air sampling. During setup of the air sampling pump, preloaded filter cas- settes were selected as field blanks. These filters were labeled and handled in a manner similar to that used for the sample filters, but they were not attached to the sampling pump. Field blanks were collected and TEM-analyzed for both PC and MCE filters (Table 2). The analysis of the field blanks showed that asbestos filter contamination was within the guide- line of an average of 3 asbestos structures per 10 grid openings. Replicate and Duplicate Analysis — Replicate sample analysis provides a means of assessing analyst precision and refers to a second analysis of the same grid preparation by the same analyst. Three samples collected on PC and three samples collected on MCE membrane filters were randomly selected for repli- cate analysis. Duplicate sample analysis provides a means of assessing analytical variability introduced by the filter preparation pro- cedure and refers to the analysis of a second grid preparation from the original filter. Three samples collected on PC filters and three samples on MCE mem- brane filters were randomly selected for duplicate analysis. Statistical Analyses Methods The data were grouped according to time of sampling (before and during removal activities), location of sample (outside the work area and outdoors), and filter type (MCE and PC). The data were then log-transferred (base e) and tested for normality by use of the Shapiro-Wilk procedure to determine an appropriate statistical analytic approach for the com- parisons. The transformed data sug- gested reasonable normality; hence, parametric statistical procedures were chosen for further analysis of the data. Samples with a structure count of zero were assigned an estimated airborne asbestos concentration of zero structures per cubic centimeter (s/cm3). A concen- tration of zero s/cm3 was used in all summary statistic calculations and plots. Table 2. TEM Level II Analyses of Field Blanks Asbestos Structures Type of Filter Polycarbonate Cellulose ester Number of Field Blanks 2 2 Total Number 4 1 Average Number per 10 Grid Openings 2 0.5 Range per 10 Grid Openings 0-4 0-1 Blank Guideline 3.0 ------- Because the data were log-transformed for comparisons, zero s/cm3 concen- trations were replaced by the sample's analytical sensitivity before the data transformation. (The analytical sensitivity for TEM, also referred to as the detection limit, is the estimated airborne asbestos structure concentration calculated when a single structure is counted in a sample). This approach is recommended by the AHERA Final Rule for the clearance z- test. Results and Discussion Airborne Asbestos Concentration Data Both 0.8-ii MCE and 0.4-p PC membrane filters were used to measure the airborne asbestos concentrations before and during removal of the thermal surface insulation. Summary statistics (arithmetic mean, standard deviation, and coefficient of variation) for the asbestos concentrations determined by TEM analysis of the cellulose ester and PC filters are presented in Tables 3 and 4, respectively. The results are presented by sampling phase (before and during removal) and sampling location (per- imeter area and outdoors). Figures 1, 2, and 3 present the mean asbestos con- centrations for MCE and PC filter types jointly. Comparison of Airborne Asbestos Concentrations on the Two Filter Types The paired sample t-test revealed no statistically significant difference in mean airborne asbestos concentrations be- tween the two filter types (t = 1.10, p = 0.2842). The asbestos concentrations measured on 0.8-ii-pore-sized MCE filters are plotted against the corresponding measurements made on 4-ii-pore-size PC filters (Figure 4). Neither filter typ< sistently demonstrated a tenden show higher or lower airborne ast concentrations. Because of this lack of statis significant different asbestos co trations between the two filter type because PC filter blanks indica marginal (but not significant) co (nation problem, data from the membrane filters were used fc remaining comparison. Comparison of Airborne Asbestos Concentrations in Perimeter Area Before and During O&M Activity The mean airborne asbestos o tration (0.0600 s/cm3) in the per area during ACM removal was c than the mean concentration (( s/cm3) before the O&M activity samples collected on MCE filters Table 3. Summary Statistics of TEM Analyses on Mixed Cellulose Ester Filters Airborne Asbestos Concentration, s/cm3 Location Sample Size Mean Standard Deviation Coefficient of Variation Before Removal Outdoors Perimeter 5 10 0.0004 0.0246 0.0004 0.0194 0.9170 0.7868 During Removal Outdoors Perimeter 0" 8 0.0600 0.0295 0.4919 "No samples were collected. Table 4. Summary Statistics of TEM Analyses on Polycarbonate Filters Airborne Asbestos Concentration, s/cm3 Location Sample Size Mean Standard Deviation Coefficient of Variation Before Removal Outdoors Perimeter 5 0.0009 10 0.0329 0.0008 0.0237 0.8810 0.7226 During Removal Outdoors Perimeter Qa 9 0.0606 0.0467 0.7710 *No samples were collected. ------- Mean Asbestos Concentration (•/cm*) Perimeter Outdoors Figure 1. Mean airborne asbestos concentrations on cellulose ester filters before and during removal of thermal surface insulation. Mean Asbestos Concentration (s/cm») During Perimeter Outdoors Figure 2. Mean airborne asbestos concentrations on polycarbonate filters before and during removal of thermal surface insulation. ------- Mean Asbestos Concentration (a/cm*) ilycarbonato Before During Outdoors Figure 3. Mean airborne asbestos concentrations on two filter types before and during removal of thermal surface insulation. 0.16 Polycarbonate Concentration. s/c« (Thl« HIM r«pra*«nt« • 1:1 corr»«pond«fte* b*t«««n I liter*) 0.02 0.04 0.06 0.08 Caltaloa* Ecltr Concentration. a/CM9 0.12 Figure 4. Relationship between airborne asbestos concentrations measured on 0.8-n-pore-size mixed cellulose ester and 0.4-ii-pore-sizo polycarbonate membrane filters. ------- ). Student's t-test showed this increase o be statistically significant (t = 2.54, p = 0.0216). The increase in airborne isbestos concentration was most likely tttributable to the asbestos-containing jebris that escaped the plastic enclosure md fell to the boiler room floor. Conclusions The principal conclusions reached dur- ng this study of O&M procedures are: . Inadequate sealing of a glove-bag type enclosure resulted in a statis- tically significant increase in airborne asbestos concentrations in the perim- eter area during removal of the ther- mal surface insulation. I. The TEM analysis of paired O.S-ii- pore-size MCE and 0.4-ii-pore-size PC filters produced statistically equiv- alent estimates of airborne asbestos concentrations. (At the time of this study, EPA sampling guidance recommended the use of 0.8-ii-pore- size cellulose ester or 0.4-p-pore-size PC filters to collect airborne asbestos fibers, whereas AHERA specifies the same filter type but a pore size of 0.45-n for cellulose ester filters.) Recommendations This research study illustrates that O&M activities involving the removal of thermal system ACM may result in elevated asbestos fiber concentrations in adjacent areas of the building. Research is needed to develop or identify effective minicontainment systems for controlling the release of asbestos fibers into adja- cent building areas. The full report was submitted in ful- fillment of Contract Number 68-03-4006 by PEI Associates, Inc., under the spon- sorship of the U.S. Environmental Protec- tion Agency. ------- John Kominsky and Ronald Freyburg are with PEI Associates, Inc., Cincinnati, OH 45246. Thomas J. Powers is the EPA Project Officer (see below). The complete report, entitled "Evaluation of Airbornen Asbestos Concentrations Before and During an O&M Activity: A Case Study"," (Order No. PB 89-224 463/AS; Cost: $13.95, subject to change) will be available only from: National Technical Information Service 5285 Port Royal Road Springfield, VA 22161 Telephone: 703-487-4650 The EPA Project Officer can be contacted at: Risk Reduction Engineering Laboratory U.S. Environmental Protection Agency Cincinnati, OH 45268 United States Environmental Protection Agency Center for Environmental Research Information Cincinnati OH 45268 BULK RATE POSTAGE & FEES F EPA PERMIT No. G-3! Official Business Penalty for Private Use $300 EPA/600/S2-89/041 000085836 TOXICSPEST*" " USEPft REGION V LIBRARY 2JO 3 DSAR8QHS ST Rn 1670 CHICAGO IL 60604 ------- |