United States
Environmental Protection
Agency
Risk Reduction
Engineering Laboratory
Cincinnati, OH 45268
Research and Development
EPA/600/SR-94/114 September 1994
xx EPA Project Summary
Removal and Containment of
Lead-Based Paint Via Needle
Sealers
Paul B. Kranz, James E. Stadelmaier, and Paul M. Randall
This report describes a comparative
technical and economic evaluation of
using a dustless needlegun system ver-
sus a conventional abrasive grit blast-
ing system to remove lead-based paint
from steel structures. The study objec-
tives were to comparatively analyze the
operational and logistical aspects of
using dustless needleguns for lead-
based paint removal as they relate to
hazardous waste generation, worker
health and safety, and associated eco-
nomic factors.
The dustless needlegun system dem-
onstrated its ability to produce a sub-
stantial reduction (97.5%) in the
generation of hazardous waste when
compared with that of conventional
abrasive blasting. The needlegun also
substantially reduced (up to 99%) the
airborne concentrations of respirable
dusts and lead-containing particulates
generated during paint removal opera-
tions.
Labor costs were decidedly higher
(approximately 300%) for the dustless
needlegun system primarily because of
slower production rates that necessi-
tate more operating personnel. These
costs are substantially mitigated by re-
duction of costs associated with ex-
pendable abrasive blast material and
hazardous waste disposal.
Conventional abrasive blasting
proved decidedly superior in the qual-
ity of surface preparation based on pre-
scribed contract specifications.
The dustless needlegun system is
shown to be economically competitive
with conventional abrasive blasting
when considering the reduced require-
ments for containment, hazardous
waste disposal, and worker protection.
This Project Summary was developed
by EPA's Risk Reduction Engineering
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 use of abrasive blasting with ex-
pendable grit media for removing lead-
based paints from steel structures has
been the standard for many years, mainly
because of its efficiency both in removing
the lead-based paint and in achieving the
surface cleanliness and profiles required
for subsequent coating operations. In re-
cent years, however, the disadvantages
of using abrasive blasting have become
increasingly apparent. The process's gen-
eration of difficult-to-contain, airborne, lead-
contaminated particulates presents a high
potential of lead exposure to workers and
the local environment. Although sophisti-
cated systems to control or contain air-
borne particulates would minimize the
potential for environmental contamination,
they may result in more hazardous local-
ized environments for workers and result
in substantially higher overall costs for
lead-based paint removal operations. Ad-
Printed on Recycled Paper
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ditionally, using expendable abrasive grit
to remove lead paint generates excessive
amounts of waste material that requires
disposal as hazardous waste.
This is a study of the effectiveness and
applicability of using a dustless needlegun
system to remove lead-based paint from
steel bridges. The costs, generation of
hazardous waste, and environmental and
worker safety are compared with those
arising from conventional abrasive blast-
ing.
Procedure
The industrial participants for this pro-
gram were the New York State Thruway
Authority (NYSTA) and Pentek, Inc. The
NYSTA is responsible for the operation
and maintenance of the New York State
highway system. Pentek has been manu-
facturing dustless surface preparation
equipment for use by nuclear facilities and
hazardous waste remediation/cleanup con-
tractors since 1985.
The Pentek system is a form of power-
tool cleaning that combines material re-
moval and containment. The Pentek COR-
NER-CUTTER®* (Figure 1), a hand-held
needlegun for surface preparation in tight
spots and/or vertical and inverted horizon-
tal steel or concrete surfaces, is one of
three models of surface preparation tools
that Pentek manufactures.
Material is removed through the actions
of pneumatically operated reciprocating
cutting bits or steel needles that scarify
and pulverize the paint or coating. This
cutting action does not adversely affect
the structural integrity of steel substrates.
The surfaces of concrete substrates, on
the other hand, can be removed in con-
trolled layers of between 1/16- and 1/4-in.
thick. The removed material is contained
first by using an adjustable shroud lo-
cated at the tool's point of operation to
localize containment, and second, by trans-
Mention of trade names or commercial products does
not constitute endorsement or recommendation for
porting the contained materials via vacuum
to an attached VAC-PAC® containment
vessel (DOT 1.7-H drum). The vacuum
head of the containment drum (VAC-PAC®
system) is equipped with high-efficiency
particulate air (HEPA) filters that prevent
the escape of airborne dusts at the con-
tainment vessel. Based on field experi-
ences, Pentek claims to immediately
capture 100% of airborne dusts and 99.5%
of solid debris at the surface.
Conventional abrasive blasting (Figure
2) employs compressed air to propel ex-
pendable abrasive particles against the
surface to be cleaned, to produce a sur-
face profile required by Standards and
Specifications of the Steel Structures Paint-
ing Council No. 6 (SSPC-SP 6). The spent
abrasive and paint debris are manually
collected for disposal, usually as hazard-
ous waste.
Both paint removal technologies were
evaluated on NYSTA bridges located on
Interstate 90 in western New York. The
abrasive blasting evaluation was done on
NYSTA Bridge #10 on October 7 and 8,
Corner-Cutter®
pneumatic
operation housing
Removed paint
chips/dust/rust
2mm reciprocating
needles
Piston
Adjustable containment
shroud
Painted surface
Substrate
Figure 1. Pentek CORNER-CUTTER® schematic.
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Removed
paint and
spent
abrasive
grit
Abrasive
stream'
Compressed
air supply in
Removed
paint and
spent
abrasive
grit
Painted
surface
Blasting
grit and
compressed
air
Figure 2. Abrasive blasting process schematic.
1992, and the Pentek evaluation was done
at NYSTA Bridge #1 on October 13, 1992.
The evaluations consisted of observations
of work practices, equipment and labor re-
quirements, and time required to complete
various tasks as well as to physically mea-
sure background and work-in-progress air-
borne dust and lead concentrations during
the paint removal operations. Waste ma-
terials from both processes were collected
and analyzed for lead concentrations. In-
terviews were conducted with NYSTA,
Pentek, Inc., and paint removal contractor
personnel to obtain background informa-
tion and historical data relative to the evalu-
ations.
NYSTA Bridge #10 is of rolled beam
design and composed of approximately
151 tons of steel and 14,946 ft2 of surface
area, and the paint thicknesses ranged
from 10 mils (0.254 mm or 0.01 in.) to 13
mils (0.330 mm or 0.013 in.). Previous
testing by NYSTA had determined the
presence of lead-based paints as the
primer and finish coatings.
Historically, surface preparation of simi-
lar NYSTA bridges, using conventional
abrasive blasting methods to SSPC-SP 6
specifications, has generated an average
of 0.15 to 0.20 tons of waste (spent abra-
sive, paint and miscellaneous dirt, rust,
and mill scale) per ton of steel. Theoreti-
cally, this would equate to 22.7 to 30.2
tons of hazardous waste generated by
conventional abrasive blasting operations
at this structure. This waste has been
characteristically hazardous because of its
teachable lead content.
Bridge #1, also of rolled beam design,
is comprised of approximately 315 tons of
steel and approximately 25,000 ft2 of sur-
face area. The paint thickness on this
bridge was again estimated by the NYSTA
to range from 10 to 13 mils. As with Bridge
#10, previous testing by NYSTA had de-
termined the presence of lead-based
paints.
Historically, paint removal from similar
structures using the Pentek system would
generate hazardous paint waste at a rate
of 1 oz/ft2 of area cleaned because of its
leachable lead content.
The abrasive blast media consisted of
Ebony Grit 20, a nonsilica, lead-free abra-
sive.
Conventional Abrasive Blasting
To minimize the potential for cross-con-
tamination and to satisfy bridge painting
schedules and other logistical concerns,
these comparative evaluations were con-
ducted on two separate bridges. Because
of the similarity of structures and the paint
coatings used on each, we believed this
would not compromise the quality of the
data.
On Day 1 of the conventional abrasive
blasting evaluation on Bridge #10, back-
ground information regarding the process
was obtained and both cleanup activities
from the prior day's work and setup activi-
ties for work to be performed were ob-
served and recorded. Background
lead-in-air concentrations, used as a
baseline for both technology evaluations,
were also monitored. On Day 2, we ob-
served work procedures, conducted per-
sonal and area air monitoring, and
recorded appropriate measurements to as-
sess productivity and waste generation.
We interviewed employees and super-
visors to develop information relative to
time and labor requirements for daily
cleanup and job site mobilization and de-
mobilization activities. This information was
integrated with job site observations to
estimate the man hours required and their
associated costs.
Job setup and mobilization required
seven workers for 1.5 hr each, mainly to
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establish traffic control, position equipment,
and install hanging enclosure tarps and
ground cover tarps. The work enclosures,
which are contractually required by the
NYSTA, consisted of canvas tarpaulins
suspended from cables attached to the
bridge structure so as to form a three-
sided enclosure: the closed sides face
traffic during abrasive blasting operations.
The tarpaulins extended from the under-
side of the bridge structure to the ground
cover tarps placed below. The suspended
tarps were fastened at the grommeted
edges with clips to minimize sailing due to
winds or passing traffic.
Abrasive blasting operations on Day 2
were done simultaneously on the interior
eastbound and westbound lanes. Two op-
erators with abrasive blasting nozzles
were used per section, which consisted of
six 32-in. x 12-in. flange I-beams placed
20 ft on center with connecting 13-in. steel
channel bracing mechanically fastened
with nuts and bolts. Approximately 1180
ft2 of surface was completed during the 4-
hr evaluation. Grit use, based on past
experiences, was estimated to be 4 to 7
tons/day of average production per ves-
sel, based upon 1/2 ton/hr of grit use per
nozzle operator. This use was expected
to produce specification surface prepara-
tion at a rate of 120 ft2/hr per operator.
Before beginning the evaluation phase,
the two nozzle operators working on the
westbound section were each fitted with
two air sampling pumps (low volume) cali-
brated to provide a flow rate of 1.5 to 1.7 L
of air/min using a digital calibrator. Total
and respirable dusts emitted during the
blasting process were collected with the
use of Millipore 37mm, 0.8^. mixed cellu-
lose ester filter (MCEF) matched-weight
cassettes, with cyclone separators for re-
spirable dust collection.
During the abrasive blasting operation,
it was very apparent that the tarpaulins
installed to enclose the operation were
less than 100% efficient in containing the
abrasive blast grit and paint removal resi-
dues. Visible plumes of dust were noted
escaping from the enclosure.
Before the abrasive blasting operation
evaluation, cleanup activities from previ-
ous blasting were observed. The cleanup
activities, described by NYSTA and the
contractors as typical, consisted of manu-
ally dry sweeping spent abrasive and paint
residues, progressively elevating ground
tarps to consolidate wastes, and then
manually shoveling the collected materi-
als into openhead 55-gal steel drums. Six
laborers cleaned this section in 1.5 hr.
The cleanup operation was noted to be
very dusty. The roadway above required
additional cleanup; the overspray or de-
posits of fugitive dusts were dry swept
and shoveled to drums.
Pentek Dustless Needlegun
System
The Pentek system was evaluated on
October 13, 1992, at NYSTA Bridge #1.
Evaluation consisted of observing and
documenting mobilization, paint removal,
and cleanup and demobilization activities,
as well as performing personal and area
air monitoring and making necessary mea-
surements to assess productivity and
waste generation.
Job setup and mobilization, requiring
four workers for 0.5 hr each, consisted
primarily of positioning equipment. No con-
tainment enclosures or ground cover tar-
paulins were used.
Three operators, each with a CORNER-
CUTTER® unit, removed paint at the evalu-
ation area, which consisted of four 34-in.
x 12-in. flange I-beams with connecting
13-in. steel channel bracing and connect-
ing hardware. Paint from approximately
119 ft2 of surface was removed during the
3.25-hr evaluation period.
Before the evaluation began, two of the
three CORNER-CUTTER® operators were
each fitted with two air sampling pumps
having appropriate media for collecting to-
tal and respirable dusts emitted during the
paint removal operations.
During the Pentek system paint removal
operations, there were no visible emis-
sions of dust or paint residues. The COR-
NER-CUTTER® units removed the finish
paint coat layers with little difficulty; how-
ever, the orange primer required consid-
erably more effort and time.
When this paint removal operation
ended, it was apparent that nearly all paint
residues had been effectively contained
and collected by the Pentek system. Some
minor residues (large paint chips and rust)
were easily collected using the vacuum
hose attached to the CORNER-CUTTER®.
Cleanup operations, i.e., wiping down, dis-
assembling, and storing of equipment, re-
quired four workers for 0.5 hr. This
operation would normally only be done
after job completion, not on a daily or
shift-by-shift basis.
Air sampling consisted of pre-work
samples, done to establish a baseline of
background airborne dust and lead in air,
and work-in progress samples of operator
breathing zones and work areas for both
the abrasive blasting and Pentek system
operations. All air sampling was conducted
over the 4-hr period coinciding with the
technology evaluations. Work area
samples for the abrasive blasting opera-
tions were taken within the tarpaulin work
enclosure approximately 25 ft from the
points of operations. For the Pentek op-
erations, work area samples, taken ap-
proximately 25 ft from the point of
operations, were more vulnerable to
changing air currents from the thruway
traffic. Quantities of waste generated by
the abrasive blasting operations were de-
termined by examining New York State
Hazardous Waste Manifests and extrapo-
lating these data based on total surface
areas of the bridge versus total surface
area of paint removed.
Waste quantity generated by the Pentek
operations was determined by performing
net and tare drum weights of the VAC-
PAC® system collection drum. This figure
could then be extrapolated to total amount
for an entire structure based on surface
area of paint removal during the evalua-
tion.
Results and Discussion
The economic evaluations depicted here
are not intended to be all-inclusive or rep-
resentative of all relative project costs.
Specifically excluded are costs related to
capital equipment, equipment mainte-
nance, vehicles, utilities and fuel, contain-
ment structures, and personal protective
equipment. For simplicity and uniformity,
a standard labor rate of $15/hr was as-
sumed for all labor classifications. Labor
activities were divided into five categories:
paint removal operations, support labor,
mobilization, demobilization, and cleanup.
Production rates in square foot per hour
per operator were used to calculate a
total labor cost assuming work on identi-
cal 15,000-ft2 bridges. Based on demon-
strated production rates, approximately
eight Pentek systems, each using three
CORNER-CUTTERS®, would be needed
to equal the production rate of the two-
operator abrasive blasting process. This
translates into approximately an eightfold
increase in production labor requirements
and a greater-than-tenfold increase in as-
sociated production costs for the Pentek
system.
Labor requirements for support, mobili-
zation, and demobilization were also higher
for the Pentek system, primarily because
of the number of workers required.
Cleanup labor costs were substantially
higher for the abrasive blasting process.
These comparative labor costs are shown
in Table 1.
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Table 1. Total Estimated Labor Costs
Abrasive Blasting Pentek
Labor Category ($) ($)
Paint removal
Support
Mobilization
Demobilization
Cleanup
Labor Totals
1,500
1,125
945
210
5.460
9,240
18,450
6,090
1,440
720
240
26,940
Table 2 shows the amount of waste
generated during the evaluation periods
and extrapolates these numbers to a com-
plete bridge. As can be seen, abrasive
blasting generates approximately 40 times
more waste than the Pentek system be-
cause abrasive blasting uses expendable
blasting media. Note that only 31 tons of
waste were disposed from this job, and
that, based upon use estimates, approxi-
mately 50.8 tons of abrasive grit would be
used.
Table 3 summarizes total costs for la-
bor, materials, and hazardous waste dis-
posal. Material costs were based on the
assumption that the abrasive blast media
was the only expendable material used.
This cost was based on each operator
using 0.5 ton of grit/hr.
The results of the air sampling done
before and during the evaluations are pre-
sented in Table 4. Air sampling was done
for 4-hr periods on two abrasive blast op-
erators and two Pentek CORNER-CUT-
TER® operators in addition to sampling
work areas proximate to the paint removal
activities.
For the 8-hr time-weighted averages
(TWA), the abrasive blasting sampling data
indicate OSHA Permissible Exposure Lim-
its (PELs) were exceeded for total dust,
respirable dust, and total airborne lead on
three samples and for respirable lead on
two of four samples.
The Pentek air sampling results exhib-
ited no detectable airborne lead or respi-
rable dust, and only negligible amounts of
total dust.
The contract specifications for the
bridges evaluated called for SSPC-SP 6
(commercial blast) to remove all visible
paint and residues from two-thirds of the
bridge surface area before repainting. The
abrasive blasting operation was able to
surpass this level of surface preparation
for all areas of the structure.
The Pentek system demonstrated a less
efficient removal of paint, especially the
orange primer coat; it also was less effec-
tive while performing around irregular sur-
faces such as nuts and bolt heads and in
inaccessible corners. The NYSTA bridge
inspectors indicated that a post-blast would
be needed for the Pentek-cleaned sec-
tions to meet SSPC-SP 6 specifications.
Conclusions
The economic and product quality as-
pects tend to favor conventional abrasive
blasting over the Pentek system for re-
moving lead paint; however, the decision
to specify a lead paint removal system
should be strongly influenced by the in-
creased volumes of hazardous waste gen-
erated and the potential for negative effects
to worker health and safety and to the
environment.
The Pentek dustless needlegun system
labor costs were approximately 300%
higher than those of the conventional abra-
sive blasting process; however, the over-
all costs were mitigated by the 97.5%
reduction in generation of hazardous
waste. Additionally, fugitive emissions of
airborne dusts were reduced up to 99%,
which serves to enhance the level of envi-
ronmental protection and worker health
and safety.
The dustless needlegun system is eco-
nomically competitive when factoring in
costs of sophisticated containment struc-
tures and engineered systems necessary
to ensure worker health and safety and
protection of the environment.
The full report was submitted in fulfill-
ment of CR-816762 by Erie County De-
partment of Environment and Planning
under the sponsorship of the U.S. Envi-
ronmental Protection Agency.
Table 2. Hazardous Waste Generation and Disposal Costs
Removal
System
Abrasive
blasting
Pentek
Removal
Area
(ft2)
1,180
119
Waste Generated (Ib)
Theoretical
4,170*
7.4*
Actual
4,807
11.5
Lb Waste
(ft2)
4.1
0.1
Est. Total
Waste (Ib)
61,500
1,500
Total Waste
(tons)
30.8
.75
Disposal
Costs
($/ton)'
300
300
Total
Disposal
Costs ($)
9,240
225
* Industry average for bulk waste including transportation.
f Theoretical waste generated based upon . 175 ton waste/ton of steel cleaned.
t Theoretical waste generated based upon 11.5-mil. paint thickness and paint solids density of 66.3 Ib/ft.3
Table 3. Total Costs
Abrasive Blasting Pentek
Category ($) ($)
Labor
Materials
Hazardous waste
disposal
Total
9,240
1,957
9,240
20,437
26,940
0
225
27,165
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Table 4. Air Sampling Analytical Results
Sampling Period
8-hr TWA'
Sampling
Point
Background
Background(D)n
Abrasive blast
area
Abrasive blast
area (D)
Abrasive blast
operator #1
Abrasive blast
operator #2
Pentek area
Pentek area (D)
Pentek
operator #7
Pentek
operator #2
Total
Dust
(mg/m3)
0.6
ND
41.2
34.1
8.0
89.2
0.2
ND
2.9
2.7
Respirable
Dust
(mg/m3)
0.2
ND
12.5
11.9
0.7
12.3
ND
ND
ND
ND
Total Pb
(mg/m3)
0.01
ND
0.32
1.4
0.1
0.89
ND
ND
ND
ND
Respirable
Pb
(mg/m3)
ND"
ND
0.26
0.1
ND
0.24
ND
ND
ND
ND
Total
Dust*
(mg/m3)
0.3
ND
20.6"
17.1*"
4.0
44.6***
0.1
ND
1.5
1.4
Respirable
Dust*
mg/m3
0.1
ND
6.3**
5.9***
0.4
6.2***
ND
ND
ND
ND
Total
Pb§
mg/m3
.005
ND
0.2**
0.7***
0.05
0.45***
ND
ND
ND
ND
Respirable
Pb§
mg/m3
ND
ND
0.1**
0.05
ND
0.12***
ND
ND
ND
ND
ft
Assuming no exposures during remainder of 8-hr work day.
OSHA PEL = 15 mg/m3.
OSHA PEL = 5 mg/m3.
OSHA PEL = .05 mg/m3.
Not detectable.
Duplicate sample.
Exceeds OSHA PEL.
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Paul B. Kranz is with Erie County Department of Environment and Planning,
Buffalo, NY 14202; James E. Stadelmaier is with Recra Environmental, Inc.,
Amherst, NY 14228; and the EPA author Paul M. Randall (also the EPA
Project Officer), is with the Risk Reduction Engineering Laboratory,
Cincinnati, OH 45268 (see below).
The complete report, entitled "Removal and Containment of Lead-Based Paint
Via Needle Sealers," (Order No. PB94-193216; Cost: $19.50, 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
Official Business
Penalty for Private Use
$300
BULK RATE
POSTAGE & FEES PAID
EPA
PERMIT No. G-35
EPA/600/SR-94/114
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