&EPA
United States
Environmental Protection
Agency
Risk Reduction
Engineering Laboratory
Cincinnati, OH 45268
Research and Development
EPA/600/M-91/019 Jul. 1991
ENVIRONMENTAL
RESEARCH BRIEF
Waste Minimization Assessment for a
Manufacturer of Heating, Ventilating, and Air Conditioning Equipment
F. William Kirsch and Gwen P. Looby*
Abstract
The U.S. Environmental Protection Agency (EPA) has funded
a pilot project to assist small- and medium-size manufacturers
who want to minimize their generation of hazardous waste but
lack the expertise to do so. Waste Minimization Assessment
Centers (WMACs) were established at selected universities
and procedures were adapted from the EPA Waste Minimiza-
tion Opportunity Assessment Manual(EPA/625/7-88/003, July
1988). The WMAC team at the University of Tennessee in-
spected a plant manufacturing heating, ventilating, and air
conditioning equipment. Of the distinct process lines in the
plant, three generated hazardous waste: the manufacture of
fan coil units and air terminal units and the painting process.
The manufacture of fan coil units generated the most and the
greatest variety of these wastes. The team's report, detailing
findings and recommendations, suggested that to reduce ad-
hesive overspray, defectively glued insulation board, and adhe-
sive carrier vapor, the plant should consider using nonferric
screws instead of adhesives to attach insulation to sheet metal
parts, or replace solvent-based adhesives (wholly or in part)
with water-based adhesives. The amount of waste would be the
same, but it would be nonhazardous and could be disposed of
in municipal waste.
This Research Brief was developed by the principal investiga-
tors and EPA's Risk Reduction Engineering Laboratory, Cincin-
nati, OH, to announce key findings of an ongoing research
'University City Science Center, Philadelphia, PA 19104
project that is fully documented in a separate report of the same
title available from the authors.
Introduction
The amount of hazardous waste generated by industrial plants
has become an increasingly costly problem for manufacturers
and an additional stress on the environment. One solution to the
problem of hazardous waste is to reduce or eliminate the waste
at its source.
University City Science Center (Philadelphia, PA) has begun a
pilot project to assist small- and medium-size manufacturers
who want to minimize their formation of hazardous waste but
lack the inhouse expertise to do so. Under agreement with
EPA's Risk Reduction Engineering Laboratory, the Science
Center has established three WMACs. This assessment was
done by engineering faculty and students at the University of
Tennessee's (Knoxville) WMAC. The assessment teams have
considerable direct experience with process operations in
manufacturing plants and also have the knowledge and skills
needed to minimize hazardous waste generation.
The waste minimization assessments are done for small- and
medium-size manufacturers at no out-of-pocket cost to the
client. To qualify for the assessment, each client must fall within
Standard Industrial Classification Code 20-39, have gross
annual sales not exceeding $50 million, employ no more than
500 persons, and lack inhouse expertise in waste minimization.
The potential benefits of the pilot project include minimization
of the amount of waste generated by manufacturers, reduced
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waste treatment and disposal costs for participating plants,
valuable experience for graduate and undergraduate students
who participate in the program, and a cleaner environment
without more regulations and higher costs for manufacturers.
Methodology of Assessments
The waste minimization assessments require several site visits
to each client served. In general, the WMACs follow the proce-
dures outlined in the EPA Waste Minimization Opportunity
Assessment Manual(EPMG25S7- 88/003, July 1988). The WMAC
staff locates the sources of hazardous waste in the plant and
identifies the current disposal or treatment methods and their
associated costs. They then identify and analyze a variety of
ways to reduce or eliminate the waste. Specific measures to
achieve that goal are recommended and the essential support-
ing technological and economic information is developed. Fi-
nally, a confidential report that details the WMAC's findings and
recommendations (including cost savings, implementation costs,
and payback times) is prepared for each client.
Plant Background
The plant evaluated for this waste minimization assessment
manufactures various types of heating, ventilating, and air
conditioning equipment for both residential and commercial use.
It operates 6000 hr/yr to produce approximately 700,000 units.
Manufacturing Process
The plant's five distinct process lines produce:
fan coil units by metal working, welding, cleaning,
rinsing, painting, brazing, Boehmiting, and
assembly;
electric heat component units by metal working,
coiling of wire, and assembly;
air treatment units such as air cleaners and
humidifiers by metal working, painting, and
assembly;
accessory components such as air volume control
units by metal working, cleaning, Boehmiting, and
assembly; and
• air terminal units such as air volume control units
by metal working, painting, and assembly.
Raw materials used in the production include sheet metal,
aluminum extrusions, copper tubing, purchased components,
formed plastics, and paint.
In this plant, the fan coil and air terminal production lines and the
painting process generate hazardous waste streams. Those
processes are described in more detail below.
The steps involved in manufacturing the fan coil units
include:
Metal working. Sheets of metal are punched,
formed, and sheared into desired shapes to form
fan coil housings. Spot welding is done as needed.
Painting. Approximately 30% of parts are painted
in the electrostatic paint line.
Producing the heat exchanger. Aluminum sheet is
drawn through a press to form fins for the heat
exchanger component of the fan coil units. Copper
tubing is bent to produce desired shapes. The fins
and coils are joined on an expanding machine.
Brazing. Coil and fin assemblies are brazed at
3000° Fto 4000° F in a natural gas- and gaseous-
brazing, flux-fired, spot brazing machine. Hand
brazing is performed as needed.
Washing. The coil and fin assemblies are dipped
in a 165° F phosphate wash tank and then rinsed.
• Boehmiting. Boehmiting is an etching process
that enhances the wettability of the aluminum
fin surface. The Boehmiting tank is heated to
200° F. Lime is added to it as needed. The
assemblies are rinsed with water on removal.
Assembling. The heat exchangers, metal housings,
insulation boards, and other components are
assembled into completed fan coil units.
The production of air terminal units requires:
Metal working. Sheets of metal are processed by
punching, shearing, and forming.
Painting. Approximately 10% of the parts are
transferred to the electrostatic paint line.
Assembling. The various components are
assembled into the air terminal units.
Painting parts from the production lines involves:
Washing. Parts are cleaned with a phosphate
wash and then rinsed with water.
Drying. Parts are conveyed through a natural gas-
fired 200°F dry-off oven.
Painting. Painting is done in two electrostatic paint
booths.
Existing Waste Management Practices
The plant is considering switching to water-based,
nonnazardous adhesives. The plant was dis-
satisfied with water-based adhesives in the past
because of the long drying time; however, the
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quantity of adhesive waste is large enough that
the plant may change back.
The paint line will be removed from the plant by
1991.
Waste Minimization Opportunities
The type of waste currently generated by the plant, the source
of the waste, the quantity of the waste, and the annual manage-
ment costs are given in Table 1.
Table 2 shows the opportunities for waste minimization that the
WMAC team recommended for the plant. The type of waste, the
minimization opportunity, the possible waste reduction and
associated savings, and the implementation cost along with the
payback time are given in the table. The quantities of hazardous
waste currently generated by the plant and possible waste
reduction depend on the production level of the plant. All values
should be considered in that context.
Table 1. Summary of Current Waste Generation
It should be noted that, in most cases, the economic savings of
the minimization opportunities result from the need for less raw
material and from reduced present and future costs associated
with hazardous waste treatment and disposal. Other savings not
quantifiable by this study include a wide variety of possible future
costs related to changing emissions standards, liability, and
employee health. It should also be noted that the savings given
for each opportunity reflect the savings achievable when imple-
menting each waste minimization opportunity independently
and do not reflect duplication of savings that would result when
the opportunities are implemented in a package.
ThisResearch Brief summarizes a part of the work done under
Cooperative Agreement No. CR-814903 by the University City
Science Center under the sponsorship of the U.S. Environmen-
tal Protection Agency. The EPA Project Officer was Brian A.
Westfall.
The EPA contact, Emma L George, can be reached
at:
Pollution Prevention Research Branch
Risk Reduction Engineering Laboratory
U.S. Environmental Protection Agency
Cincinnati, OH 45268
Waste Generated
Lubricating oil vapor
Boron-based brazing gas
Source of Waste
Evaporation of lubricating oil from the fin press
in the fan coil unit production line.
Exhaust containing brazing flux fumes from the
Annual Quantity
Generated
37,500 gal
440 gal
Annual Waste
Management Cost
$01
O1
Phosphate wash sludge
Lime sludge
Solvent-based (thermoplastic)
pverspray on paper and defec-
tively glued insulation board
Adhesive carrier vapor
natural gas-fired, spot brazing machine and the
hand-braizing process.
Sediment from the heated phosphate wash tank
in the fart coil production line.
Sediment from the gas-fired Boehmite etch tank in
the fan coil production line.
Assembly of components into fan coil units.
Assembly of components into fan coil units.
Water-based adhesive overspray Assembly of components into fan coil units
on paper and defectively glued
insulation board. (The water-based
adhesive waste is considered non-
hazardous and is disposed of in
municipal waste.)
660 gal
1,980 gal
107bbl
345 gal
43bbl
Hydraulic motor oil
Ethylene-vinyl acetate adhesive
overspray on paper and defec-
tively glued insulation board
Waste from the expander in the fan coil prod-
uction line.
Assembly of components into air terminal units.
1,320 gal
64bbl
3,900
13,200
23,250
O1
2,365
7,245
13,905
Phosphate wash sludge
Paint sludge
Sediment from the heated phosphate wash
tank in the paint line.
Overspray collected in water in the paint booths.
The paint sludge and water are separated, and
the water is then recycled
1 ,980 gal
6,875 gal
11.700
72,375
1 Plant reports no waste management costs associated with the evaporation.
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Table 2. Summary of Recommended Waste Minimization Opportunities
Waste Generated
Minimization Opportunity
Annual Waste Reduction
Quantity Percent
Net Annual Implementation Payback
Savings Cost Years
Adhesive overspray,
defectively glued in-
sulation board, and
adhesive carrier vapor
Paint sludge
Lubricating oil vapor
Discontinue use of all 214 bbl
adhesives. Use nonferric 345 gal (vapor)
screws to attach insulation
to sheet metal parts. Imple
mentation will require the
selection of an acceptable
fastening method and the
purchase of appropriate tools
Replace all solvent-based 345 gal (vapor)
adhesives with water-based
(nonhazardous) adhesives
To eliminate production de
lays resulting from the long
drying time required by water
based glues, install an over
head conveyour system so
that freshly glued parts will
travel on the conveyor and
will be delivered to the oper-
ator dry. The same quantity
of solid waste will be generated,
but all waste will be nonhazardous
Dispose of water-based adhesive
waste in municipal waste
Modify the use of adhe- 311 gal (vapor)
sives to maximize the use
of water-based (nonhazar-
dous) glue. Spot glue 10%
of the surface area with the
quick-drying solvent based
adhesive and cover the rem-
aining 90% with the slow-
drying water-based adhesive
The same quantity of solid
waste will be generated, but
all waste will be nonhazardous.
Dispose of water-based adhesive
waste in municipal waste.
Reduce exhaust-air flow rate 1,719 gal
to minimize paint mist loss
in the paint booth.
Retrain paint personnel to 330 gal
improve spray technique
and thus reduce overspray
loss.
Install a recirculating air- 18,750 gal
oil condensing system
adjacent to the fin press
to reclaim evaporating oil.
100
100
$58,350 '2
$6,400
0 1
100
25.6903
31,740
90
23.1203
5,100
0.2
25
50
44,910'
8,810'
56,250'
2,100
3,500
7,400
0.1
1 Includes savings on raw materials cost.
2 Savings are reduced by a yearly materials cost.
3 Savings are reduced by a net increase in the cost of adhesives
.S. GOVERNMENT PRINTING OFFICE: 1991 - S4H-028/40035
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