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.
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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.
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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
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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.
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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.
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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.
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). 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
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