Document ID: EPA-HQ-OAR-2008-0053-0055
Agency: epa
Document Type: Supporting & Related Material
Title: 
Posted Date: 2009-06-01T04:00Z

SEQ CHAPTER \h \r 1 

MEMORANDUM

TO:		Jeff Telander, EPA/OAQPS/ESD/MICG

FROM:	David Hendricks, EC/R Incorporated

		Shannon Cox, EC/R Incorporated

DATE:		August 19, 2004

SUBJECT:	Trip Report for the Site Visit to W.C. Richards Company of
Carolina in Aberdeen, North Carolina on July 27, 2004.

I.	Purpose

	The purpose of this visit was to examine the paint manufacturing
processes and any emission control measures in place at W.C. Richards
Company of Carolina.  During the visit, our intent was to observe the
paint manufacturing operations firsthand and discuss: (1) the
facility’s air emissions associated with paint manufacturing; (2) the
measures employed to reduce emissions; (3) the costs incurred from the
control of emissions; and, (4) wastes generated as a result of emission
control measures.

II.	Place and Date

	W.C. Richards Company of Carolina

	101 East Maple Street

	Aberdeen, North Carolina 28315

	

	July 27, 2004

III. 	Attendees

	W.C. Richards Company of Carolina

	William F. Abel, Plant Manager

	U.S. Environmental Protection Agency, Research Triangle Park, NC

	Jeff Telander



	EC/R Incorporated

	David Hendricks

	Shannon Cox

	National Paint and Coatings Association

	David Darling, Director, Environmental Affairs

IV.	Discussion

A.	Overview of the Facility and Products

	W.C. Richards Company of Carolina (W.C. Richards) is a family-owned
business that was established in 1938.  The Aberdeen, North Carolina
facility has been in operation since about 1976.  Paint manufactured at
W.C. Richards is sold to the original equipment manufacturing sector
where it is typically applied to metal substrates.  The coatings are
also used on some fiberglass and plastic substrates.  Custom paint
blends are formulated to meet each customer’s performance
specifications.  Production is customer-driven so there is very little
product in stock at the facility.  Only formulations that are sold to
multiple customers are kept in stock.  Batch sizes range from 1 gallon
to 1,100 gallons, but the larger batch sizes are very rare.  The average
batch size is about 100 gallons.  Solvent-borne paints constitute about
50 to 60 percent of total production, high solids paints constitute
about 20 to 30 percent of overall production, and waterborne paints
account for about 30 percent of total production.  The facility operates
one shift per day and five days per week.  Twelve to fourteen people are
employed at the facility.  About 60,000 gallons of paint were produced
during the preceding year.  About 10 years ago, the plant was producing
400,000 to 500,000 gallons of paint per year.

B.	Emissions and Controls

	The amount of air emissions at the facility are dependent on the mix of
products, but the plant manager estimated that about 4,000 pounds of
volatile organic compounds (VOC) are emitted per year when the plant is
running at about 60 percent of capacity.  Emissions are estimated using
the AP-42 method, or by multiplying the estimated VOC content of the
product by the quantity in gallons and multiplying by a 2 percent loss
factor.  The calculation used for estimating emissions from waterborne
paints is presented as Calculation 1.  A similar calculation used for
estimating emissions from solvent-borne paints is presented as
Calculation 2.  

	Calculation 1.  VOC Emissions from Production of Waterborne Paints:

		3.4 * Quantity of Paint (gallons) * 2% = Emissions of VOC in pounds

	Calculation 2.  VOC Emissions from Production of Solvent-borne Paints:

		4.5 * Quantity of Paint (gallons) * 2% = Emissions of VOC in pounds

	The use of pigments and other solid raw materials contribute to
emissions of particulate matter (PM).  Emissions of PM are captured
through flexible vent hoses placed near process tanks as pigments and
other solids are added to a batch.  The PM is controlled through the use
of a baghouse.

	Pollution prevention measures are used to prevent VOC emissions and
include covers on tanks, scheduling of batches from production of light
colors to dark colors to reduce the frequency of cleaning, and reuse and
recycling of solvent used for cleaning.    

C.	Manufacturing Process

	Four main steps are used to manufacture paint at W.C. Richards: (1)
premix, (2) letdown, (3) quality control, and (4) filling.  Equipment
used for paint manufacturing includes bulk solvent storage tanks, bulk
resin storage tanks, small container raw material storage, portable
process tanks, stationary process tanks, high speed dispersers (HSDs),
vertical sand mills, pebble mills, and packages and containers for
product shipment.

	1.	Raw Material Storage and Assembly	

	Bulk raw materials are stored in 3,800 gallon tanks.  The facility has
four tanks for solvents and eight tanks for resin, but is currently
using only one of each type.  The tanks are filled from tanker trucks. 
Solvent tanks are located outside and resin tanks are located inside of
the facility.  A dyke surrounds each group of bulk storage tanks.  A
piping system ending in a manifold brings raw materials from the bulk
storage tanks to the manufacturing area.  During assembly of raw
solvents and resins, a portable process tank is rolled onto a scale
underneath the manifold.  Bulk raw materials are released from the
manifold into the process tank.  After filling, a small bucket is placed
under the manifold to catch any drips of material.  

	Packages of pigments and empty containers are stored in a building
apart from the main building.  Any flammable materials are brought into
the main building because it is equipped with a sprinkler system. 
Purchase orders and batch tickets list a coded set of ingredients.  All
packages of pigments are labeled with the same codes used on the batch
tickets.  During assembly of pigments, the worker uses an electric scale
to weigh out the amount of pigment specified on the coded batch ticket
into a paper grocery bag.  The assembled raw materials are set on a
pallet and brought into the production area.  Most of the pigments used
at W.C. Richards do not contain hazardous metals.  However, to meet the
requirements of certain end-users, some pigments containing hazardous
metals are used at the facility.  The plant manager estimated that less
than 1,000 pounds of pigments containing hazardous metals are used per
year.  At one point, a surcharge was levied on products that contained
heavy metals to offset the waste disposal costs incurred by the facility
for disposal of hazardous wastes and to encourage customers to allow
W.C. Richards to substitute alternative materials for the hazardous
pigments.  Due to increased competition from other manufacturers, W.C.
Richards is no longer able to levy the surcharge.  

	2.	Premix

	W.C. Richards has both portable and stationary process tanks.  Due to
the generally small batch sizes, the large stationary process tanks have
not been used for several years.  During premix, resins, wetting agents,
and pigments are loaded into the portable process tank.  A flexible vent
hose is placed near the opening of the tank as pigments are loaded to
capture and vent dust into a baghouse.  The portable process tank is
placed under a stationary HSD.  The agitator shaft of the HSD is lowered
into the process tank and mixes the raw materials.  All process tanks
are covered during mixing.  Some products require a milling stage
following mixing with the HSD to further disperse the pigments. While
the milling stage is generally conducted after the HSD process,
sometimes raw materials are blended in a mill as a first stage.  

	Both vertical sand mills and pebble mills are used at the facility for
grinding.  If a vertical sand mill is used, the portable process tank
containing the intermediate product is rolled near the mill.  A flexible
hose is used to transfer the intermediate product from the portable
process tank and into the bottom of the mill.  The intermediate product
is pumped up through a cylinder filled with media and a series of discs
connected by a shaft.  A screen surrounds the cylinder to hold in the
media.  The discs are rotated to act similarly to the agitator shaft of
an HSD.  Pigments are dispersed as the intermediate product flows
through the media-filled cylinder.  The product is then pumped from the
top of the mill through a flexible hose and into a second portable
process tank.  Using the vertical sand mill, the grinding process
requires only the time necessary for the intermediate product to flow
through the mill.  If the pebble mill is used for grinding, the
intermediate product is loaded into the mill and is dispersed at one
time.  As the mill circulates, the media disperses the pigment.  The
grinding process requires one or two days using the pebble mill.  While
heat-up from the grinding process itself is sufficient for grinding
using the vertical sand mill, if the pebble mill is used for grinding
the HSD must be used as a first stage to ensure that the temperature of
the intermediate product is at least 120 degrees when it is loaded into
the pebble mill.  Water jackets are used to prevent excessive heat-up
during use of the vertical sand mill.

	Portable process tanks and mills are cleaned to avoid contamination
from batch changes.  Recycled solvent is typically used for this
cleaning operation.  Once the recycled solvent is spent it is stored for
incineration.  Mills are cleaned using batch solvent.  The batch solvent
is used to flush the mill and is then added to the letdown tank or used
in another batch.  If water is used instead of solvent to clean the
tanks and mills after production of waterborne paint, the wastewater can
be combined with solvent stored for incineration.  To clean the agitator
shaft on the HSD, a drum with solvent is placed under the shaft.  A
brush is dipped into the solvent and brushed along the agitator shaft to
remove residual materials.  The plant manager attempts to schedule paint
production from batches of light colors to dark colors to reduce the
frequency of cleaning.

	3.	Letdown

	After premix, the next step of the process is called letdown.  During
this stage, remaining ingredients are added to the intermediate product
to bring the batch to its final volume.  The materials are added into
the same portable process tank that was used for premix.  

	4.	Quality Control

	Following letdown, a sample of the product is tested in the quality
control (QC) lab.  Each formulation is quality tested for a series of
parameters including color, sag, viscosity, and grind.  Small ovens are
used to force samples to dry and for testing baking enamels.  After a
batch passes QC, a sample of the final product is kept for one year. 
The first time a new formulation is created, the paint manufacturing
process is carried out in a small scale in the QC lab prior to
production of the full batch size.   

	5.	Filling

	After a batch passes QC, it is filled into containers of various size. 
All filling is conducted by hand as the facility does not have
sufficient production volume to warrant the use of automated equipment. 
The final product is filled into one gallon containers, five gallon
containers, or drums.          	

V.	Summary and Conclusion

	Waterborne, solvent-borne, and high solids paints for the original
equipment manufacturing sector are produced at the W.C. Richards Company
of Carolina facility in Aberdeen, North Carolina.  Paint is produced
using four main steps: premix, letdown, quality control, and filling. 
Emission controls consist of the use of vents and baghouses for capture
and control of particulate matter and the use of pollution prevention
practices including covered process tanks, reuse and recycling of
solvent for equipment cleaning, and batch scheduling to reduce the need
for equipment cleaning for prevention of VOC emissions.  The plant
manager stressed that W.C. Richards faces tough competition from larger
companies.  He also stated that the cost of complying with an emission
standard would present an economic challenge to the facility and could
force the 潣灭湡⁹畯⁴景戠獵湩獥⹳̍഍ഄ̍഍ഄ഍഍

഍

഍഍