United States
                 Environmental Protection
National Risk Management
Research Laboratory
Research Triangle Park, NC 27711
                 Research and Development
October 1996
4>EPA      Project Summary

                 Pollution  Prevention
                 Demonstration and  Evaluation  of
                 Paint Application Equipment  and
                 Alternatives to  Methylene
                 Chloride  and  Methyl  Ethyl Ketone
                 J.M. Elion, J.B. Flanagan, J.H. Turner, J.T. Hanley, and E.A. Hill
                  The report gives results of demon-
                 strations of technologies to prevent or
                 control emissions of hazardous air pol-
                 lutants (HAPs)  and  volatile  organic
                 compounds (VOCs) at the Marine Corps
                 Logistics Base in Albany, GA. The pro-
                 cesses with high solvent usage se-
                 lected for demonstration were: (1) paint
                 stripping using methylene chloride, (2)
                 cleaning paint equipment with methyl
                 ethyl ketone (MEK), and (3)  applying
                 paint by spraying solventborne  coat-
                 ings. For  Demonstration (1) N-methyl
                 pyrrolidone (NMP) was chosen to re-
                 place methylene chloride because it ef-
                 fectively removed Chemical Agent Re-
                 sistant Coatings (CARCs) in laboratory
                 tests, is nonflammable, and is not clas-
                 sified  as a HAP by EPA. The annual-
                 ized costs for NMP stripping are lower
                 than for methylene chloride stripping,
                 but implementation requires high capi-
                 tal  investment.  This  substitution will
                 lower HAPS 11% from 1992 levels. For
                 Demonstration (2), a blend of 40% pro-
                 pylene carbonate and 60% benzyl alco-
                 hol (PC/BA), by weight, was chosen to
                 replace MEK. This choice was based
                 on the results of laboratory screening,
                 materials  compatibility, and paint re-
                 moval efficiency tests.  No capital in-
                 vestment was required. Based on the
                 demonstration,  PC/BA cleans green
                 CARCs from the pumps as well as MEK,
                 and cleans epoxy primers better than
                 MEK. Advantages of  using PC/BA are
                 lower vapor pressure, reduced solvent
                 use and labor time for cleaning, and
                 classification of the hazardous waste
                 as non-regulated by the Resource Con-
servation Recovery Act. The disadvan-
tage is a higher cost for the PC/BA blend
than for MEK. This substitution will lower
emissions from HAPs 21% from 1992
levels. The objective of Demonstration
(3) was to determine if the amount of
paint applied to a vehicle could  be de-
creased by providing the painters with a
real-time readout of the amount of paint
they were using. A system was installed
that monitored paint use gravimetrically
by continuously measuring the weight
of the pot from which the  paint was
pumped to the spray guns. The system
worked reliably, and paint use measure-
ments were  obtained on 19 vehicles.
Results showed that,  for identical ve-
hicles, differences  up to 30%  in  the
amount of paint used occurred, indicat-
ing that potential exists for significant
reductions. No actual reductions were
shown during the demonstration.
  This Project Summary was developed
by EPA's National Risk Management
Research Laboratory's Air Pollution
Prevention and Control Division,  Re-
search Triangle Park, NC, 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).

  The Clean Air Act Amendments of 1990
(CAAA) and Executive Order 12856 man-
date that military depot activities  reduce
air emissions. Specifically, the CAAA re-
quires a reduction in hazardous air pollut-
ant (HAP)  emissions for "major" sources
and Executive Order 12856 requires that

military installations reduce HAP emissions
by 50% of their 1992 levels. Accordingly,
the U.S. EPA and the U.S. Marine Corps
Logistics Base (MCLB), Albany, GA, with
sponsorship from the Strategic Environ-
mental Research  and Development Pro-
gram (SERDP), conducted an initial evalu-
ation  and subsequent demonstration  of
pollution prevention (P2) technologies for
reduction of HAPs. Processes and related
high solvent usage sources were identi-
fied and P2 recommendations were made.
EPA and the host facility MCLB  performed
the research. Research Triangle Institute
personnel provided contractor support.
  MCLB carries  out  maintenance activi-
ties on a wide variety of equipment from
small  arms  to tanks, trucks,   and  other
vehicles. Much of the maintenance on the
vehicles requires removing existing paint
prior to repairing procedures and applying
new paint once the maintenance has been
performed.  The processes for paint strip-
ping,  repainting,  and cleaning of paint
equipment release significant amounts  of
  The  purpose of this research was  to
demonstrate viability  of P2 technologies
on a full production scale at the MCLB.
Three processes with  high solvent usage
were selected for demonstration:
  • stripping paint by immersion in meth-
    ylene chloride,
  • cleaning paint  equipment with  methyl
    ethyl ketone (MEK), and
  • applying    paint   by    spraying
    solventborne coatings.

First Demonstration
  For the  first demonstration,  n-methyl
pyrrolidone (NMP) was selected as the
alternative to methylene chloride for strip-
ping cured coatings from metal parts. NMP
was chosen during a scoping study for
the facility  demonstration because it ef-
fectively removed Chemical Agent Resis-
tant Coatings (CARC) in laboratory tests,
is  nonflammable,  and  is considered by
the EPA not to be a HAP. Two drawbacks
are that the NMP  must be heated  to be
effective, and NMP is subject to reporting
under the  Superfund Amendments and
Reauthorization Act (SARA).
  The first step in  preparing for the dem-
onstration was to  retrofit an existing tank
on the Base. The stripping tank required
plumbing to heat the bath with steam, and
a recirculating pump to provide enough
agitation  to  ensure uniform temperature
throughout  the bath.  An adjacent rinse
tank required  a  pump to draw recycled
NMP for rinsing stripped parts. Finally, a
vacuum distillation unit was installed  to
reclaim  used solvent  from the  stripping
bath and provide recycled NMP for rins-
ing. After the tank retrofit was completed,
the heating and recirculating systems were
tested using  water. The stripping tank was
then emptied  and  filled  with an  initial
charge  of 38 55-gal  (208 L) barrels  of
technical grade  NMP. An additional ten
barrels was  added  to the stripping tank
  The NMP, when  heated to 150 +10°F
(66 +6°C), was  able to  remove multiple
layers of CARC  and  strip parts  to the
base metal within 3-4  hours. The heated
NMP was able  to  successfully  remove
Plastisol®, a plastic coating,  from battery
tie-down brackets. These  parts were pre-
viously  stripped  in  a  hot alkaline bath,
followed by  scraping and  blasting to re-
move the coating. Also, NMP was able to
soften epoxy-based topcoats, but removal
usually required overnight soaking.

Second Demonstration
  For the second demonstration,  a blend
of propylene carbonate and  benzyl alco-
hol was chosen  to  replace methyl ethyl
ketone (MEK) for cleaning the paint appli-
cation  equipment (pumps,  hoses, and
guns). This demonstration consisted of a
preliminary  screening  to  identify several
possible solvent  alternatives, testing  to
select the most  effective  cleaners, and
full-scale demonstration at the MCLB.
  Sixty-five  alternative  cleaners  were
tested in preliminary  screening  for their
effect on fully cured  single-  and  plural-
component CARCs and an epoxy primer.
From these  65  alternatives,  5 were se-
lected for further testing. The cleaners were
tested for their compatibility with materials
that would   contact the paints  and the
cleaner. No  measurable  weight  gain  or
loss, pitting, or other  signs  of corrosion
were found among any of the five clean-
ers or MEK and the four metals tested:
aluminum,  stainless  steel,  nickel, and
brass.  Material  compatibility was  also
tested with four plastics (Teflon®,  acetal,
Nylon®, and Delrin®). Results showed
slight weight changes in all coupons tested
with the five cleaners  and with MEK.  Of
the five cleaners,  the two showing the
least overall weight gain  or  loss for the
four plastics were evaluated  for paint re-
moval efficiency  in  a  laboratory setting.
Overall,  both of the cleaners were compa-
rable to  MEK for  CARCs, and both clean-
ers were better  than  MEK  at removing
white primer.
  Based on  the  test results,  the blend  of
40% propylene carbonate  and 60% ben-
zyl  alcohol   (PC/BA) by  weight  was se-
lected by the research team  for  demon-
stration. Subsequently, four barrels of this
cleaner were shipped to the base, and the
cleaner was used as a direct replacement
for  MEK. No  capital  investment was re-
  Use of the PC/BA cleaner was  moni-
tored  by weighing the amount of cleaner
flushed through the system.  Amounts  of
cleaner used  for the initial prewash, the
final wash,  and the filter wash were re-
corded. Date  and time at start and finish
of each step were also recorded.
  Results  showed  that  PC/BA cleans
green CARC  from the pumps as well as
MEK,  and cleans epoxy primers from the
pumps better than MEK. Advantages  of
using  PC/BA  are lowered inhalation haz-
ard  to workers,  and reduced cleaner us-
age and labor  time  for cleaning.  Other
advantages are that  PC/BA is non-regu-
lated  by the source Conservation Recov-
ery  Act,  and  the use of  PC/BA  signifi-
cantly decreases downtime of the primer
pumps. The disadvantage is a higher cost
for  PC/BA than for MEK,  but the higher
cost may be  offset by cleaner  recovery
and reclamation, and  further waste reduc-

Third Demonstration
  For the third demonstration, the objec-
tive was to determine  if the  amount  of
paint  required to coat a vehicle could be
reduced by providing the painters with a
real-time readout of how much paint they
were  using. The study  began  with the
design,  specification, purchase,  and in-
stallation of a  paint monitoring system in a
paint  booth. The system monitored paint
use gravimetrically by continuously mea-
suring the weight of the 5-gal (18.9  L) pot
that held the  paint to be pumped to the
spray  guns. The system included program-
mable digital  scales,  a small printer, and
large  remote  displays visible from  within
the  paint booth.  Displays continuously
showed the cumulative amount of paint
  The initial portion of the test period was
devoted to  baseline or control measure-
ments taken  "without feedback" of paint
consumption.  During  this  period, the dis-
plays  were  not visible to the painters. Af-
ter sufficient baseline information had been
gathered, the displays  were installed  in
the  paint booth and the  painters were
instructed  in  how the displays could be
used  to control  their usage rate. "Target"
levels for  High Mobility Multipurpose
Wheeled Vehicles (HMMWVs) and 5-ton
(4.5-tonne)  trucks were set based on the
lowest usage  during the baseline period.
  The system proved to work reliably, and
paint usage measurements were obtained

on nineteen vehicles:  10 HMMWVs, five
5-ton cargo trucks, and four other vehicles.
Measurements show that,  for one set  of
identical vehicles (the 10  HMMWVs), paint
consumption differed by up  to 30% be-
tween the  highest and  lowest vehicles.
This  indicates that a potential for signifi-
cant  reductions  may exist.  However, dur-
ing the brief study period,  no statistically
significant decrease in paint usage was
seen between the baseline (without feed-
back) and  the  experimental (with  feed-
back) portions of the demonstration. This
may  be  due to the brevity  of the  demon-
stration and to the presence of monitoring
personnel at the  paint booth during the
baseline period.  However,  the  system
could still provide reductions in paint us-
age and other benefits when used in com-
bination with other strategies such as mix-
ing only the amount needed for each ve-
hicle rather than the current  practice  of
mixing  paint in multiples of 5 gal. The
system could also be used in training new
employees,  and in assessing  the impact
of equipment inspection and maintenance
practices on paint consumption.
  It is recommended that MCLB continue
to collect paint usage  data for  several
months to determine if measurable reduc-
tions in  paint usage are realized after the
staff becomes  accustomed to the equip-
  The MCLB has  already replaced 1,1,1-
trichloroethane vapor  degreasers with
aqueous parts washers. This change alone
will reduce emissions from HAPs by 16%.
By eliminating the methylene chloride for
immersion stripping,  the  MCLB can  re-
duce emissions another  11%. By replac-
ing MEK with a  PC/BA blend for cleaning
paint application equipment, the MCLB can
reduce emissions from HAPs an additional
21%. These three changes combined re-
sult in  a reduction  of emissions of 48%.
The MCLB  plans to replace solventborne
CARCs with waterborne  CARCs in 1996
to achieve  over 50% reduction in emis-
sions from HAPs.

   J.M. Elion, J.B. Flanagan, J.H. Turner, J.T. Hartley, and E.A. Hill are with Research
     Triangle Institute, Research Triangle Park, NC 27709.
   J.K. Whitfield is the EPA Project Officer (see below).
   The complete report, entitled "Pollution Prevention Demonstration and Evaluation
     of Paint Application Equipment and Alternatives to Methylene Chloride and
     Methyl Ethyl Ketone, "(Order No. PB97-104632; Cost: $49.00, subjectto 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:
           Air Pollution Prevention and Control Division
           National Risk Management Research Laboratory
           U. S. Environmental Protection Agency
           Cincinnati, OH 45268
United States
Environmental Protection Agency
Center for Environmental Research Information (G-72)
Cincinnati, OH 45268

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