ENVIRONMENTAL PAINTS AND COATINGS
TRAINING PROGRAM
Contract No. 68-02-4465
Work Assignment Nos. 054 and 064
(Alliance 1-455-054 and 064)
Prepared for
U.S. Environmental Protection Agency
Stationary Source Compliance Division
Washington, D.C. 20460
November 1988
Prepared by
Ron Joseph
Ron Joseph & Associates, Inc.
and
Alliance Technologies Corporation
Alliance Technologies Corporation
213 Burlington Road
Bedford, Massachusetts 01730
(617) 275-9000
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Chapter
I
II
III
IV
EPA PAINTS AND COATINGS
TRAINING PROGRAM
CONTENTS
ENVIRONMENTAL TOPICS
Basic Understanding of Surface Coating Rules and Common
Terminology
What to Expect From a Paint Facility Air Quality Inspection
VOC Process Sampling
How to Set up a Compliance Plan and Schedule of Increments
of Progress
PAINTS AND COATINGS TOPICS
V What One Needs to Know About a Coating System
VI Why Paints and Coatings Cause Air Pollution
VII Brief Process Description of Selected VOC Surface Coating
Categories
VIII A Comprehensive Review of VOC-Compliant Liquid Coating
Technologies
IX A Review of Powder Coating Technologies and Application
Methods
X Selecting Spray Application Equipment
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CONTENTS
(Continued)
Chapter
CALCULATIONS
XI Equations for Calculating Weights and Volumes for Individual
Components From Material Safety Data Sheets
XII Calculations of VOCs From Product and Material Safety Data
Sheets
XIII Calculating Emissions of VOCs Expressed in Ibs/gal Solids,
as Applied.
XIV Calculating % Volume Solids for a Coating or Coating Mixture
XV Calculating Alternative Emission Control Plans ("Bubbles")
WORKSHOPS
XVI Introductory Workshop for Environmental Paints and Coatings
Program
XVII Selection of Coating Application Equipment (Several Scenarios)
XVIII Selection of Compliant Coating Systems (Several Scenarios)
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Chapter I
-------
CHAPTER I
BASIC UNDERSTANDING OF SURFACE COATING RULES
AND COMMON TERMINOLOGY
-------
BASIC UNDERSTANDING OF THE ENVIRONMENTAL SURFACE
COATING RULES AND THE COMMON TERMINOLOGY
Summary
This session briefly explains the relationship between the EPA, the
individual states, and local air pollution control districts. It explains
how the rules are written and describes their major elements. Enforce-
ment policies and future trends are discussed, as well as the options
available for companies that have difficulty getting into compliance. In
addition, common terminologies are defined.
The session is intended for non-environmentally trained people who
want a brief overview of the subject.
Chapter I
-------
CHAPTER I
BASIC UNDERSTANDING OF THE ENVIRONMENTAL SURFACE
COATING RULES AND THE COMMON TERMINOLOGY
Clean Air Act 1
Control Techinque Guidelines Written by EPA ~ 2
State Implementation Plans for Surface
Coating Operations 3
Enforcement 3
Fines 3
Basic Elements of SIP Rules for Surface Coating Operations 4
Specifics of Some Rules 7
Common Terminology Used in Rules 9
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CLEAN AIR ACT
Clean Air Act was written by Congress in 1970
Clean Air Act was amended in 1975 and again in 1977
Purpose of the Act is to protect health and welfare of the public
Clean Air Act set National Ambient Air Quality Standards (NAAQS) for:
• Sulphur Dioxide (S02)
• Particulates
• Carbon Monoxide (CO)
• Nitrogen Oxides (N02)
• Lead
• Hydrocarbons
• Ozone , / IPf*^-
Clean Air Act was to be enforced by the EPA.
EPA required the states to establish plans to achieve NAAQS.
These plans are known as State Implementation Plans (SIPs).
STATE IMPLEMENTATION PLANS (SIPs)
The SIPs for surface coating operations are strictly for stationary sources
Once written by the state, SIPs must be approved by the EPA
Once approved, the state SIP becomes a federal regulation
POLLUTANT
LEVEL
National Ambient
Air Quality
Standard
(NAA§S)
YEAR
CONCEPT OF STATE IMPLEMENTATION PLAN
Chapter 1
Pagel
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CONTROL TECHNIQUE
GUIDELINES WRITTEN BY EPA
Group I
• Automotive
• Metal Cans
• Metal Coil
• Metal Furniture
• Large Appliances
• Fabric, Paper, Vinyl
• Magnetic Wire
Group Group II
• Miscellaneous Metal Parts
• Graphic Arts, Photogravure
• Flatwood Paneling
Less Common Rules
(Primarily California)
• Aerospace
• Plastic Parts
• Architectural
Future Rules
(Primarily California)
• Marine
• Automotive Refinishing
• Solvent Usage (other than
degreasers
Chapter 1
Page 2
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STATE IMPLEMENTATION PLANS FOR SURFACE
COATING OPERATIONS
How Rules Are Written
Rules are proposed by State or District
One or more public workshops held to review draft Rule
Public hearing held to adopt Rule
After Rule is adopted, amendments can be made by using the above procedure
Industry can make major contributions to rule development
ENFORCEMENT
The local district or state has the primary responsibility for enforcing SIP rules for sur-
face coatings
retains oversight authority and can overrule decision by local districts or states.
FINES
Vary from state to state. Typical fines are $1,000 per day.
Maximum penalty is $25,000 per day
Ultimate penalty for totally disregarding rules:
Plant closure or Imprisonment of responsible personnel
Chapter 1 Page 3
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BASIC ELEMENTS OF SIP RULES FOR
SURFACE COATING OPERATIONS
(These Will Vary From State to State, Depending on the Rule).
Purpose of the Rule
Example:
Description: The purpose of this Rule is to limit the emission of volatile organic
compounds from the coating of miscellaneous metal parts and products as defined
in Section 8-19-204.
Applicability (facility exemption)
Example:
Exception, Low Usage Costings: The requirements of Sections 8-19-301 and 302
shall not apply to the use of any coating used in volumes less than 20 gal in any one
calendar year.
The provisions of subparagraphs (b)(1) and (b)(2) of this Rule, shall not apply to...
a facility which uses a total of less than one gallon of coating...in any one day.
Some rules exempt coating usages of any of the following:
Examples: > 100 tons/yr
> 25 tons/yr
> 20 gals/yr
> 1 gal/day
Chapter 1 Page 4
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BASIC ELEMENTS OF SIP RULES FOR SURFACE
COATING OPERATIONS (Continued)
Definition of Terms
Examples:
Air-dried Coatings: Any coating which is not heated above 90°C (194°) for the
purpose of curing or drying.
Baked Coatings: Any coating which is cured or dried in an oven where the oven
air temperature exceeds 90°C (194°F).
Coating Line: All operations involved in the application, drying and/or curing of
surface coatings.
Unconditional Exemptions (no petitions required)
Examples:
Exemption, Adheslves: The provisions of this Rule shall not apply to the application
of adhesives.
Exemption, Touch-ups: The provisions of this Rule shall not apply to touch-up
operations.
Conditional Exemptions (petitions required)
Example:
The provisions of subparagraph (b)(1) of this Rule shall not apply to any coating opera-
tion that...cannot meet a 65 percent transfer efficiency, provided that:
(A) A general coater submits a written petition to the Executive Officer... and approval
is granted by the Executive Officer.
Standards
Example:
After January 1,1986 except as otherwise provided by this Rule, a person shall not
apply to any miscellaneous metal part or product any coating with a VOC content in
excess of the following limits, expressed as grams of VOC per liter of coating applied,
excluding water,:
Baked Coatings 275 grams/liter
(2.3 pounds/gallon)
Air-Dried Coatings 340 grams/liter
(2.8 pounds/gallon)
Chapter 1
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BASIC ELEMENTS OF SIP RULES FOR SURFACE
COATING OPERATIONS
(Continued)
Record Keeping
Example:
• The user shall maintain a current list of coatings in use which provides all of the
coating data necessary to evaluate compliance.
• The user shall maintain records on a daily basis showing the type and amount
of each coating used, except that records for coatings which comply with 8-19-
302 may be maintained on a monthly basis.
• Such records shall be retained and available for inspection by the APCO for the
previous 12-month period.
Test Methods
Example:
Analysis of Samples: Samples of volatile organic compounds shall be analyzed as
prescribed in the Manual of Procedures, Volume III, Method 21 or 22.
Chapter 1 Page 6
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SPECIFICS OF SOME RULES
Transfer Efficiency
Some regulations require that a minimum transfer efficiency be achieved during the
coating application.
TRANSFER EFFICIENCY - M3SS "' VO'Ume * 8fl" ^^ ^P08"6"
Mass or Volume of Solid Coating Applied
Prohibition of Specifications
Regulations in California require that not only the coating applicator, but also the coat-
ing specifier must be in compliance with the regulation. The specifier may, but is not
required, to reside in California in order for this provision to apply.
Options Available for Companies that Cannot Comply Immediately
Do nothing and hope for the best (High Risk!)
Work toward compliance but do not identify company to regulators (High Risk!).
Consider alternate emission reduction plan (offsets, bubble, equivalency) (Note: Not
all rules allow for these options. EPA is disinclined to approve such plans.)
Petition for a variance (not all states have this provision).
Chapter 1 Page 7
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EMISSIONS OF VOC (LBS/KXX) FT* OF PAINTED SURFACE
Assumptions: VOC of Coating - 3.5 Ibs/gal; Density of VOC - 7.36 Ibs/gal; DFT - 1.0 mils
100
20
30 40 50 60
TRANSFER EFFICIENCY PERCENT ( *.)
70
80
90
100
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COMMON TERMINOLOGY USED IN RULES
(Abridged Definitions)
VOC = Volatile Organic Compounds
Any organic compound which participates in atmospheric photochemi-
cal reactions. Organic compounds with negligible photochemical reac-
tivity are excluded.
RACT = Reasonably Available Control Technology
Technologies that are technically available.
Require no major research.
Can be transferred from one industry to another.
No major economic impact.
BACT = Best Available Control Techniques
Maximum degree of emission reduction achievable through available
methods, processes, costs, environmental impacts and energy usually
taken into consideration.
Equivalency=
Averaging of high-VOC coatings against over-compliant, low-VOC
coatings.
Offsets =
Averaging of high-VOC coatings against more efficient process
controls.
Bubble =
Generally interpreted as a combination of offsets and equivalency.
Alternative Emission Control Plan =
Same as bubble
Precursor (Solvent) =
These react in sunlight to form photochemical smog.
Chapter 1 Page 9
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COMMON TERMINOLOGY USED IN RULES
(Abridged Definitions) • (Continued)
Non-Precursor (Solvent) =
These are considered to have negligible reactivity when exposed to
sunlight. Have a negligible effect on the formation of photochemical
smog.
Exempt Solvents=
Specified organic compounds that are not subject to the requirements
of a regulation. Such solvents include 1,1,1-trichloroethane and
methylene chloride.
Transfer Efficiency=
The ratio of the mass or volume of solid coating deposited on a part to
the mass or volume of solild coating applied.
Chapter 1 Page 10
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Chapter II
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CHAPTER II
WHAT TO EXPECT FROM A PAINT FACILITY
AIR QUALITY INSPECTION
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WHAT TO EXPECT FROM A PAINT FACILITY _
AIR QUALITY INSPECTION
Summary
This session describes all areas of a paint facility that are usually given attention during an
air quality inspection. These areas include:
• Appropriate record-keeping
• Use of compliant coatings and solvents
• Permits for spray booths
• Ovens and other equipment
• Meeting other regulatory requirements.
Chapter II
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CHAPTER II
WHAT TO EXPECT FROM A PAINT FACILITY
AIR QUALITY INSPECTION
What to Expect from a Paint Facility Inspection 1
South Coast Air Quality Management District 2
Mixing of Coatings 3
Sampling of Coatings 3
Spray Booths 4
Ovens 5
Solvent Recycling Machines 5
Mixing Room 5
Vapor Degreaser 5
Permits 6
Typical Statements Accompanying
Permits in the Bay Area 6
Transfer Efficiency 7
Hints for Improved Transfer Efficiency 7
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WHAT TO EXPECT FROM A PAINT FACILITY INSPECTION
• Appropriate coating usage logs must be maintained (see Table).
• Availability of Material Safety data sheets or Product Data Sheets.
• VOC Information on Data Sheets (grams of VOC, per liter of coating, less water and
less exempt solvent)
• VOC Information on can labels (South Coast AQMD Rule 443.1).
• Determine which rule(s) the coating facility is subject to. (Example: metal parts, plas-
tic, aerospace, general solvent.)
• If the facility is subject to exemptions, confirm that the exemptions have been ap-
proved. (If applicable, some local rules require formal petition.)
• If exemptions are granted on an annual basis, check that exemption is renewed
before the year expires.
• If the facility is operating under a variance, confirm that "order granting variance" is
available (This may only apply in some districts).
• If a non-complying coating has been specified by the customer, check whether
•prohibition of specification" applies (specific to some California rules).
• If the facility is operating under an alternate emission control plan (bubble), check
that the plan has been approved. Also confirm that the plan is still in effect and has
not expired.
Chapter II
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EXAMPLE
COATING USAGE LOGS
COMPANY NAME: Hazelwood Metal Fixtures, Inc. NAME OF OPERATOR:
DATE:
Manufacturer
Best Brands, Inc.
H
If
It
Rogers Inc.
n
Taylor Chemical Coatings
Htghcoaer Manufacturing Co.
Martex Paint & Filler
Hof Products/Techniques
Inc.
Product
Description
Mater -Reducible
Air-Dry Enamel
Pretreatment
Mash Primer
Urea - Molamlne
High-Sol Ids
Polyur ethane
Hater- Reducible
Epoxy
Aircraft Primer
Red. Water Redu-
cible Epoxy
Ordinance Primer
High-Solids
Agent Resistant
Polyurethane Ctg.
High Solid
Epoxy Coating
Acryl Ic Mater
Reducible
Bake Enamel
Epoxy Poiyttiide
Ctg. System (for
touchup & stenc 1 1
Color
only)
Product
Code
4000
Series
4860-50
5000
Series
6400
Series
44-GN-7
44-R-8A
921G002
921D001
921H010I
H.S,
611SG
24750
H-426
Mixing
Ratio
_
1:2
...
5:1:1
3:1:8
3!l;7
4.1:1}
2:1:0.3
—
1:1:1
VOC (Ibs/gal)
Actual
2.4
6.5
4.8
2.8
2.8
2.6
3.4
2.8
2.6
4.1
Per Rule
2.8
6.9
Exempt
Coating
2.8
2.8
2.8
3.5
2.8
2.8
Codes
1 & 2
Usage
(Gals)
Comments:
Type of Spray Equipment
(if applicable)
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SOUTH COAST AIR QUALITY MANAGEMENT DISTRICT
Rule 443.1. Labeling of Materials Containing Organic Solvents
•Applicable for containers larger than 1 quart.
• Not applicable to architectural coatings.
• Information must be provided either on data sheet shipped with container or on label
affixed to container.
• VOC information in grams of VOC per liter of coating, less water, less exempt sol-
vent.
• If material is to be thinned, thinning instructions must be provided, together with
resulting VOC content.
• For multi-component coatings (Example: polyurethanes, expoxies) mixing and thin-
ning instructions must be provided, together with resulting VOC content.
• For coatings with reactive diluents, the VOC content of portion that does not react
during curing process must be provided.
• For solvents greater than one gallon, a data sheet shipped with the container or a
label on the container must provide max. VOC content, as well as vapor pressure at
20°C.
Chapter II Page 2
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MIXING OF COATINGS
Does the painter have clear instructions about mixing coatings prior to application?
(a) Is he/she over-reducing?
(b) Is he/she following instructions for two-component coatings?
If mixing data is provided on the Coating Usage Log, is this consistent with what the painter
is doing?
SAMPLING OF COATINGS
• Only coatings that are currently being used by the painter may be sampled.
• Coatings in the storeroom may not be sampled unless those coatings are currently
being used.
• Sampling should take place at the source.
• Two-component coatings are often sampled individually and mixed only at the test-
Ing laboratory, using mixing instructions provided by the data sheet or the mixing in-
structions followed by the painter.
•Two-component coatings are sometimes sampled after mixing and are taken to the
laboratory for immediate analysis. The owner/operator of a facility is sjEfipgjy ad-
vised to take a sample alongside the inspector so a check can be carried out if neces-
sary.
• All coatings must be thoroughly shaken prior to sampling.
• Sampling containers must be clean.
• Containers must be properly labeled. Typical information should include:
_ What sample it is
- Date of sampling.
_ Batch number.
- Source from which sample was taken.
• Sample should be entered into a log.
• Sample container should be properly sealed, such as with tape.
• It may be necessary to store sample at a predetermined temperature (for example:
too high a temperature may cause gelling; too low a temperature may cause mois-
ture condensation, or freezing in sub-zero weather).
Chapter II Page 3
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SPRAY BOOTHS
•These are not control devices for VOCs.
•They capture particulates-not volatile organics.
•Two basic types:
- dry filter
- water wash
• Recommended pressure differential for dry filter booths: approximately 0.2 - 0.5 in-
ches on manometer (0.25 max. in South Coast).
• Must have permits, unless exempt.
• Filter booths should have no voids.
• Filter booths should not be overloaded with overspray.
• Water-wash booths should not have excessive foam and should not have excessive
overspray on water curtain.
• Paint usage should not exceed permit limits.
OVENS
• Must have permits unless exempt.
• Oven temperature gauge to be visible
• Some Rules state:
- Temperature less than 194°F - Coatings assumed to air dry
- Temperature greater than 194°F - Coatings assumed to bake
•Typical oven types:
- Convection
. Infrared
Chapter II
-------
SOLVENT RECYCUNG MACHINES
• May require a permit (depending on the Rule).
• Solvent reclamation should be into a closed drum.
MIXING ROOM
• May require a permit (depending on rule).
• Mixing and storage cans and drums should be closed (and grounded).
ABRASIVE BLASTING ROOMS
• May require a permit (depending on rule).
VAPOR DEGREASER
• May require a permit (depending on rule).
• Degreaser should be closed when not in use.
Chapter II Page 5
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PERMITS (GENERAL)
• Some permits state conditions for operation.
• Some permits limit maximum daily usage. Ensure that these maximums (which may
have been based on the original permit application) are not exceeded.
• Some permits provide no conditions.
• It is often assumed that even if there are no conditions on the permit, the equipment
is required to be operated according to:
(a) All parameters provided on permit application (including hourly usage, no. of
per day, and no. of days per year)
(b) Operating recommendations on equipment manufacturer's data sheets.
TYPICAL STATEMENT ACCOMPANYING SOME PERMITS:
In the absence of specific permit conditions to the contrary, the throughputs, fuel and
material consumptions, capacities, and hours of operation described in your permit ap-
plication will be considered maximum allowable limits. A new permit will be required before
any increase in these parameters, or any change in raw material handled may be made.
Chapter II Page 6
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TRANSFER EFFICIENCY
•What application equipment is being used?
• If the spray equipment is electrostatic, flow or dip, then one can assume compliance
with the Rule (other types of equipment such as turbine spray, may soon be included
in this list.)
• If application is by brush or roller, one can assume a transfer efficiency greater than
65%.
• If other methods of spray application are used, has a demonstration been conducted
to confirm that 65% transfer efficiency is being achieved?
HINTS FOR IMPROVED TRANSFER EFFICIENCY
• Small parts should be racked.
• Electrostatic spray equipment must have a good ground.
• All parts sprayed with electrostatic equipment should be well grounded.
• Conventional spray gun air pressures should be cut to approximately 40 psi.
• Fan pattern should be as narrow as practical.
Chapter II Page 7
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Chapter III
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CHAPTER III
VOC PROCESS SAMPLING
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Why is a Coating Sample Obtained During
an Inspection or Compliance Test?
1). To Determine the Compliance Status of the
Facility with NSPS, LAER, BACT or PSD
Permit
"Volume Weighted mass of VOC Per Unit
Volume of Coating Solids Applied."
2). To pbtain the Potential Mass of VOC
Emitted Per Unit Time.
-------
Processes to be Sampled
Subjected to NSPS/
SUBPART PROCESS
EE Metal Furniture Coating
MM Automobile and Light Duty Truck
QQ Publication RotoGravure
RR Pressure Sensitive Tape and Label
SS Large appliances
TT Metal Coil Coating
WW Beverage Can
BBB Rubber Tire
SSS Magnetic Tape
TTT Plastic Parts for Business Machines
VVV Polymeric Coating of Supporting
Substrates
-------
SIP
- Newspaper, Stamps, Money, Intaglio,
Offset, Flexographic Printing
- Floor Covering Coatings
- Steel Drums
- Pipe Tubing, Internal/External Coating
- NSPS Industries Installed Prior to
Applicability Date
-------
Coating/Ink Feed to Process
1). Batch- Manually Poured into Pans
Located Under Transfer
Rollers, Printing Cylinders.
Some Inks are Put in With
Spatulas.
2). Continuous - Pumped into Pans From
Barrels, Sumps Carboys.
-------
Types of Coating Ink
1). Solvent
- Multiple Solvents
Single Solvents
2). Water Reduced - Contains Water and
Solvent
"Latex Paint"
3). Low Viscosity
VOC > 60%
- High Solvent Low
Solid Content
- Rotogravure Inks
- Stains
- Magnetic Tape
4). Medium Viscosity
VOC 20 - 60%
- Automobile Paints
- House Paints
- Steel Coating
- Floor Covering
Coating
-------
5). High Viscosity - Intaglio, Offset Inks
VOC < 20%
6). Two Component Coatings - Epoxy
- Urethane
Requires Curing Agent to be Mixed with
Primary Coating Just Prior to Application
-------
Number of Samples
1). ONE Sample of Each Coating/Ink
Utilized In Process
- 6 Color Offset, 3 Color Intaglio
- Paints, Metallic, Solid Color
Clear Coat
- Different Colors May Have Different
VOC Contents
2). Two Components
- Separate Sample of Each Component
3). Duplicates
- Where Litigation is Possible, a Must
- Every 10th Sample
- Separate Sample
-------
Sample Containers
1). Tin Can -16 or 32 oz. Narrow Mouth,
Inner Seal Screw Cap BEST
2). Alternate - 16 oz./32 oz. Borosilicate
Glass, Narrow Mouth with
Teflon Inner Seal - Screw Cap
Tin Can Best - Meets DOT Shipping Require-
ments, No Leakage, Breakage, No Light
3). Plastic No Good - Volatiles Can Diffuse
Through Walls
8
-------
Where Are Samples Obtained?
1). 55 Gallon Drums-
2). Carboys -
3). Ink Fountains - Pumped to Pan Under
Pressure
4). Gallon - 5 Gallon Pails
5). Spigots Located In Sides of Storage Vessels
Caution - Do Not Sample from Spray Gun While
Spraying - Loss of VOC and Spattering
6). Obtain Sample From Container Holding
Coating ready for Application - After Final
Solvent/Water Reduction
7). Do Not Sample From Pans
- Dangerous, Hands Can be Caught in Rollers
- VOC Has Volatilized While in Application
Pan, Not Representative of Coating
-------
Sampling Equipment
- Sample Containers and Seals
- Tube if Sampling From Spigot
- Spatula
- Gloves
- Long Handle Tongs
- Wipes
- Labels
- Chain of Custody Seals
- Chain of Custody Sheets
- Record Book
- Mixing Paddles
- Grounding Clips
10
-------
Sampling Procedure
1). Identify All Coatings to be Sampled
2). Make Sure All Coatings Completely Mixed
- Mechanically Shaken
- Stirred Slowly
Water Thinned Coating Tend to
Incoporate Air Bubbles if Stirred too
Vigorously
3). Make Sure that Multiple Component
Coatings are Not Sampled Mixed, i.e.,
Separate Sample of Each Component
Obtained
-------
Closed Container with Spigot
J
To Ground
I
- Spigot
- Screw-on Extension
tube
- Ground the Can
1). Flush Spigot and Tube
into Waste Basket
2). Place Can Around
Tube, Tube Should be
Near Bottom of Can
Fill to Overflowing with
No Bubbles
3). Place Inner Seal in Can
and Screw on Cover
4). Wipe All Coating Off of
Can
12
-------
5). Label Can, Seal with Chain of Custody
Tape
6). Log Sample into Record Book and Chain
of Custody Sheet
Open Top Containers
- Barrels, Carboys, Pails, Sumps
- Low and Medium Viscosity Coatings
I. Ground Tin Can
II. Turn Upside Down and Place in Coating,
Approx. 1/2 Way Down.
III. Turn Can Over and Slowly Bring to Top of
Container
IV. Fill to Overflowing
V. Place Inner Seal in Can
VI. Screw on Cover
VII. Wipe all Coating Off of Can
VIII. Label Can, Seal with Chain of Custody
Tape, Record in Record Book and
Chain of Custody Sheet 13
-------
GROUND
GROUND
GROUND
IV
V, VI
COVER
INNER SEAL
High Viscosity Inks
Offset and Intaglio Inks
Offset
1). Take Sample with Spatula and Fill Can to
Top
2). Inner Seal, Cover, Label and Chain of
Custody Tape
14
-------
Intaglio
1). Obtain Sample From Ink Fountain
- May Not be Able to Place Tube Within
Fountain Nozzle
2). Fill to Overflowing Inner Seal, Cover
Label and Chained Custody Tape.
Offset
15
-------
- Do Not Take From Top Surface
- Obtain Sample About 1/4-1/2 Way Down in
Pail
- Push Sample Off Spatula With Can Opening
Edge
- Work As Fast As Possible to Avoid Loss in VOC
Intaglio
\ ^ INK FOUNTAIN
,PRESSURE
COVER
INKING
ROLLER
BARREL
\
INK PAN
16
-------
Small Containers of Coating
1). Curing Agent
2). Anti - Oxidant
3). Coating
Obtain Closed Container as on Shelf
Do Not Open. Label and Seal
Dilutent Solvent
Obtain Sample as for Coating Following
Procedures for Specific Type of Storage
Vessel
Paper Work
1). Completely Fill Out Label
2). Obtain Manufacturers Formulation
17
-------
3). Obtain Blenders Worksheet
4). Obtain Permit VOC Requirements
5). Fill in C of C Seal, Place Over Top of Can
and Down Sides - Follow Can Contours
6). Record Book
- Plant
- Operation/Line
- Sample No.
- Type of Coating/Ink, Data off of Storage
Vessel Label
- How Sampled
- Who Witnessed Sampling
- Chain of Custody Sheet No.
- No. of Coatings/Ink Per Line
- Identify if Duplicate - In Book Only -
18
-------
SEALED
Initials
Date: . .—
SEALED
SURFACE COATINGS SAMPLE
DATE:
SOURCE:
TYPE OF COATING:
SAMPLED BY (Signature)
PLANT WITNESS (Signature):
SAMPLE ID NO.:
IS MANUFACTURER'S FORMULATION AVAILABLE:
IS AS APPLIED FORMULATION AVAILABLE: _
-------
CHAIN OF CUSTODY RECORD
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D«t.
Hvabci
!•«•• Iw Cki»|* •! Cuiicdr
-------
Chain of Custody
1). Very Important - Shows Who Had Control
or Handled Sample
2). Chain of Custody Sheet to Travel with
Samples - Inside of Shipping Box. Lab
Institutes Own Chain of Custody Following
it's own Procedures
3). Air Cargo Bill of Lading Becomes Part of
CofC
4). Make Sure All Areas on C of C Sheet Filled
Out Including type of Analysis to be per-
formed Before Enclosing in Box
5). Several Samples Can be Placed on One
Sheet
6). If Required by Litigation Use One C of C
Sheet Per Sample
7). Take Orange Copy for Your Records
21
-------
QA/QC
1). All Information Recorded in Record Book
2). Sample Can Full to Overflow Prior to Placing
Inner Seal in Can
3). Label Completly Filled Out and Placed on Can
4). C of C Tape Placed on Can Properly
5). Chain of Custody Sheet Completly Filled Out
6). Shipping Label Filled Out Correctly
7). Multicomponent Coatings -
Separate - Distinct Samples/Components
Handling
1). Clean Can Completly - No Coating Showing
at All
2). Place in Box with Packing Materials - Box
Should be Firm-DOT12-B
3). Seal Box with Strapping Tape
22
-------
4). Label Box with Sender/Receiver Person and
Addresses. Insert Completed Air Bill/Cargo
Bill in Proper Pocket and Seal.
5). Place Chain of Custody Tape On Edge of
Box. Seal with Clear Tape.
7
• / / / =
f
p
- STRAPPING TAPE
- CHAIN OF CUSTODY SEAL
6). Shippers
- Federal Express
-UPS
- Emery
- Purolator
-DHL
7). Box and Label Should Have the Following
DOT Designations:
23
-------
-Flammable Liquid UN NOS 1223
On Sides of Box Place
-Flammable Liquid Labels
-Orientation Arrows
-Danger Label
- Air Bill/Cargo Bill
-Request Restricted Articles Air Bill
- Quantity of Boxes
- Description - UN No. 1223
Total Volume of Liquid Shipped
8). Maintain Samples Between 40 and 100
Degrees F. Preferably at 70 Degrees F.
Keep Out of Sun and From Freezing.
9). SHIP ASAP DO NOT HOLD
Some Coatings Will Polymerize
Via Auto Catalysis. Becomes Solid
-If Laboratory Local Bring to Laboratory
the day after Sampling. DO NOT HOLD
IN OFFICE FOR LARGE BATCH.
24
-------
I DANGER-PELIGRO
FLAMMABIE LIQUID™N. O. S
m udi uani (tone ut in. * um^m u^m
FLAMMABLE LIQUID
MillUCIIIUH
n want
niUKBT
THIS END UP
-------
Problems
1). Partially Filled Can.
VOC Vapor in Head Space-LooseWhen
Can Opened and Vapor Escapes
2). Mulicomponant Coatings-if Obtained Mixed
Will Become Solid in Can, and Can not be
Analysed.
3). Holding Time
-14 Days Max. - Sampling to Analysis
- Autopolymerization
4). Temperature
- Too Hot - Can Explode, Polymerization
- Too Cold - Solidify
25
-------
VOC Analysis
Method 24: "Determination of Volatile Matter
Content, Water Content, Density, Volume
Solids and Weight Solids of Surface Coatings"
Applicability: To Determine Volatile Organic
Content of Paints Used in Auto, Appliance,
Metal Furniture and Metal Coil Coating. Used
for Both Water and Solvent Reducible Coat-
ings.
25
-------
Problems in Performing
Method 24 Analysis
Not Knowing What the Constituents
of the Coating Are.
Not Knowing When to use GC and
When to use Karl Fischer.
Inaccuracies in Karl Fischer Method
if Solvents are Azeotiropes
Inaccuracy in Final Calculation of
VOC, Less Water, When the Ration
of Water: VOC is Very High or Very
Low.
Inaccuracies if Competing Reactions
tale place During Test.
-------
Method 24 Should Not be Used for:
1). Printing Inks (Use Method 24A)
2). Glues and Adhesives (No Method
Recommended)
3). Two Package (Component)
Coatings - Particularly Coatings That
React During Curing to Form Volitile
Reaction Products
4). Coatings That Require Energy Other
Than Heat to Initiate Curing.
5). May Not Work on Coatings that Require
High Temperature Catalysis for Curing.
-------
Analytical Methods Utilized for Method 24:
1). Water Content
ASTM D3792 (GC Method)
or
ASTM D4017 (Karl Fischer Titration)
2). Volatile Matter
ASTM D2369
3). Density
ASTM D 1475
-------
Calculations
1). Volatiles Content
wgt. % Volatiles = 1- rrrrr; X100
a Solid wgt.
2). Density
Gross wgt. - Tare wgt. (g)
Calibrated Volume (ml)
= (g/ml)
(g/ml) (8.34) = Density as Ib/gallon
3. Water Content
, ,., (ml KFR) (liter KFR)
% Water wgt. = X100
Sample wgt. (g)
-------
4). VOC Content, Less Water
Ibs/gallon VOC Less Water=
(a - c) x (b)
100-(cxb)
8.34
Where: a = wgt. % Volatiles
b = Density (Ibs/gallon)
c = wgt. % Water
-------
Precision Requirements
Duplicate Measurements Required
Within Between
Lab Lab
Volatile Matter Content 1.5% W v 4.7%WV
Water Content 2.9% Ww 7.5%W w
Density 0.001 g/mL 0.002 g/mL
-------
Examples
Volatiles Content
a). 92.90%
b). 91.79%
Meets Precision Criteria of 1.5%
II. Density
a). 0.7839g/ml
b). 0.7839 g/ml
Zero Error Meets Precision Criteria
. Water Content
a). 95.64
b). 95.94
Meets Precision Criteria of 2.9%
Cannot Calculate VOC Less Water
-------
SLIDE 2^-1
METHOD 24
Determination of-Volatile Matter Content,
Water Content, Density, Volume Solids,
and Weight Solids of Surface Coatings
SLIDE 2^-
APPLICABILITY
For volatile organic content of pamts used in
auto, appliance, metal furniture and metal coil
coating. Can be usea for botn water reoucibte
ana solvent reducible coatinc
SLIDE 2-2
ADVANTAGES
• Less Costly
DISADVANTAGES
• Considerable error may be introduced in
measurement of organic content of water
reducible coatings since this is an indirect
measurement technique.
Note: Efor estimation procedures are required
by the method when testing water re-
ducible paints.
AA-1
-------
SLID: ZA-* NOTES
NOT APPLICABLE
1. 'For all kino's of coatings or pnntmg materials
Method 24A should be used for printing inks
No method has been specified for glues and
adhesives.
2. For two package (component) coatings, par-
ticularly H the coatings react dunng cunng and
form volatile reaction products.
3. For coatings that require energy other than heat
to initiate cunng May not work on coatings that
require hign temperature cataJysis for cunng
SLIDE Z--5
SUMMARY OF METHODS
WATER CONTENT
Standard Method of Test for Water in Water-
Reducible Paint by-Direct Injection Into a Gas
Chromatoaraph. ASTM D 37B2-79.
OR
ASTM Provisional Method of Test for Water in
Paint or Related Coatings by the Karl Fiscner
Titration Method.
:LID: 2^-5
SUMMARY OF METHODS (continued)
VOLATILE MATTER
Provisional Method of Test for Volatile
Content of Paints. ASTM D 2369-81.
DENSITY
Standard Method of Test for Density of
Paint. Lacquer, and Related Products.
ASTM D 1475-60.
AA-2
-------
SLIDE 24-7 KOT-S
DATA VALIDATION PROCEDURE
Run duplicate analyses on each sample
tested and compare results with the
within-laboratory precision statements
for each parameter.
SLIDE
ANALYTICAL PRECISION STATEMENTS
BETWEEN-
LABORATORY LABORATORY
Volatile Matter Content. VV. I.E'S.W. 47SW.
Water Content. W_ 2.9°., v7_ 7.5e.. W.
Density. D. a 001 kg/liter aOC2 kg'lnv
AA-2
-------
SLIDE 24- 9
CALCULATIONS
NONAQUEOUS VOLATILE MATTER
Solvent-borne Coatings
W0 = Wv
Waterbome Coatings
NOTES
w
W0 = Wu- W
WEIGHT FRACTION SOLIDS
w. = 1 - wv
Where:
W = weight fraction nonacueous volatile ir.stter, g/
V - volatile r.atter content.
v
W = water content.
w
W - weight solics, g/'g.
SLIDE: 24-:c
-------
SLIDE 24A-1 NOTES
METHOD 24A
Determination of Volatile Matte--
Content and Density of Pnnting Inks
and Related Coatings
SLIDE 24A-2
APPLICABILITY AND PRINCIPLE
Standard methods are used to determine
components of solvent-borne pnnunc i
or related coatings
The VOC weight fraction is
by measunng the weignt loss of a knovs-i
quantity which has been heated for a
specified length of time at a specifier
temperature
SLICE: 2i;-;
SAMPLING
Obtain a representative sample of
the ink or coating matenal.
SLIDE
ANALYSIS
1. Tare three aluminum foil dishes to the nearest
0.1 mg.
2 Using a 5 ml syringe without needle remove a
sample and weigh to the nearest 0.1 mg.
a Transfer Mo 3 g of sample to a tared weighing
dish
4. Reweigh the synnge to the nearest 01 mg
BE-:
-------
SLIDE 24A-5 NOTES
(cont)
ANALYSIS
5. Heat the weighing dish and sample in a
vacuum oven at an absolute pressure of
510 ± 51 mm Hg and a temperature of 120
±2°c.
-------
SLIDE 24A-7 NOTES
(cent)
ANALYSIS
9. Determine the density of the ink or coating
according to ASTM D 1475-60.
10. Determine the density of the solvent according
ASTM D 1475-60.
11. Calculate the weight fraction volatile organic
content (WJ.
SLIDE 24A-S
WEIGHT FRACTION
VOLATILE ORGANIC CONTENT
W = *1 cY1 ' McY2
0 ^~"~ ^~^~ ~~ "
McY1 * McY2
(For an explanation of this equation,
please refer to procedures for
this method in Volume I - VOC Reference
Methods.)
B5-2
-------
SLIDE «A-9 NOT£S
VOLUME FRACTION
VOLATILE ORGANIC CONTENT
(For an explanation of this equation,
please refer to procedures for
this method in Volume I - VOC Reference
Methods.)
BS-4
-------
Chapter IV
-------
CHAPTER IV
HOW TO SET UP A COMPLIANCE PLAN AND
SCHEDULE OF INCREMENTS OF PROGRESS
-------
SETTING UP A COMPLIANCE PLAN
AND SCHEDULE OF PROGRESS
Summary
In order to achieve compliance with a regulation, a facility needs to develop a plan that
consists of identifiable tasks. After the tasks have been identified, a timetable must be
established to ensure expeditious compliance.
This session describes the most common tasks that must be carried out and suggests
reasonable time frames to complete each one. Participants learn how to design a Gant
Chart (milestone chart) that will clearly show when compliance will finally be achieved.
Each company will have its specific requirements. Small companies can make
decisions rapidly. Larger companies need more time.
This chapter assumes a large, multi-division corporation. The time frames are given for
guidance only.
Chapter IV
-------
CHAPTER IV
SETTING UP A COMPLIANCE PLAN
AND SCHEDULE OF PROGRESS
Overview 1
Educate Management 2
Set up a Task Force 2
Identify Coating Needs 2
Establish a Preliminary Strategy 2
Prepare a Budget for the Compliance Project 2
Educate Personnel for Changes 3
Identify Specific Coating Needs 3
Identify Potential Coating 3
Conduct Laboratory Tests 3
Identify Your Equipment & Facility Needs 4
Educate Personnel 4
Conduct Field Trials 4
Customer Approval 4
Procurement of Coatings & Equipment 5
Environmental Actions 5
Installation & Start-up 5
Implement New Technology 5
Table of Increments of Progress
Hypothetical Example of Compliance Plan
-------
SETTING UP A COMPLIANCE PLAN
AND SCHEDULE OF PROGRESS
OVERVIEW
Identify all the tasks that will need to form part of your compliance plan. These will in-
clude the following tasks:
•Educate middle management
•Set up a task force
•Establish a budget
•Educate executive management
• Identify your coating requirements
•Identify potential coatings
•Conduct laboratory tests
•Identify equipment and facility needs
•Educate personnel
•Conduct field trials
•Obtain customer approval
•Procure coatings and equipment
•Obtain permits to construct and operate
•Installation
•Implementation
For each task, set a realistic time frame to complete the Action Item.
Compile a Gant Chart for the project.
Chapter IV Page 1
-------
SETTING UP A COMPLIANCE PLAN
AND SCHEDULE OF PROGRESS
Educate Middle Management About the Need to Comply
Get seed funding to initiate project
Hold a seminar to explain the problem
and the need to set up a task force
Set up a Task Force
•The Task Force should consist of:
*Chairperson (active or non-active)
* Materials and Processes
* Environmental
Purchasing
*Production
*Manufacturing Engineering
Program Management, Contracts or Marketing
QA and/or QC
Legal
(* = key persons on Task Force)
•Appoint a Project Coordinator
Identify all Non-Compliant Coatings and Solvents
That Need to be Substituted
• Compile a comprehensive list of all coatings
and solvents used.
• Establish VOC contents for each coating
•Compare VOC of each coating with regulated VOC
Establish a Preliminary Strategy to Bring Each Coating
or Solvent Into Compliance
Conduct a Preliminary Study to Determine Alternative
Methods of Compliance
Prepare a Budget for the Compliance Project
Example
of Time
2 weeks
3 weeks
4 weeks
3 weeks
4 weeks
3 weeks
Chapter IV
Page 2
-------
Example
of Time
Educate Executive Management About Need to Comply 3 weeks
•Explain problem
• Present budget
•Obtain authorization to communicate across corporate lines
Await Approval of Budget 3 weeks
Identify Specific Coating Needs
• Define your current performance requirements to
differentiate between "must haves" and "would-be'nice's"
• If necessary test your current coatings to determine
current performance requirements
Identify Potential Coating
• Make a list of potential vendors 3 days
• Prepare a letter outlining all of your important needs 2 days
• Meet with vendors to explain your needs 4 weeks
• Request commitment from vendors to work with you 3 weeks
Conduct Laboratory Tests
•Write test methods • 1 week
• Make arrangements with laboratory 3 days
• Request costs for testing 1 week
• Procure test panels (metals and/or plastic) 1 week
• Prepare samples 2 weeks
• Await test results 4 weeks
• Meet with laboratory to evaluate results 1 week
• Laboratory writes report 3 day
• Select most appropriate coating candidate(s) 3 days
Chapter IV
-------
Example
of Time
Identify Your Equipment and Facility Needs
• Make a list of all new equipment that may be required,
such as:
Spray booths, ovens, conveyors,
pretreatment equipment, .mixing
rooms, cranes, hoists, modification
of roof structure, etc.
Educate Personnel to Prepare for Changes
• Compile training program 2 weeks
• Arrange for one or more program sessions 2 days
• Conduct training programs 1 week
Conduct Field Trials
• Procure coating for production trial purposes 1 week
•Wait for coating to be delivered (allow time for
color matching, if necessary) 4 weeks
• Make arrangements with plant to run trials;
if necessary wait for plant to have a time slot
for running trials 3 weeks
• Conduct trials 3 days
• Evaluate results 3 days
• If necessary, ask coating vendor to reformulate
coating and go through the loop again ? weeks
Customer Approval
•Arrange to meet with customer to explain the
need for change (should be done early in the project) 2 weeks
• Provide customer with samples of the newly coated
product or the results of testing (to be done after
testing has been completed) 1 week
•Await customer approval (can be lengthy in the
case of military contracts) 6 weeks
• Negotiate contract changes 8 weeks
• If necessary, revise drawings 6 weeks
Chapter IV
Page 4
-------
Example
of Time
Procurement of Coatings and Equipment
• Deplete existing inventory of non-complying coatings 16 weeks
• Write specifications for new coatings and/or equipment 3 weeks
•Send RFQs to potential vendors (coatings, equipment,
building modifications) 2 weeks
• Await replies from vendors 3 weeks
•Place orders 2 weeks
• Await delivery 3-8 weeks
•Conduct incoming QC tests to confirm adequacy
of first batch of coating 1 week
• If necessary, allow time to have coating modified
until it meets requirements 3 weeks
Environmental Actions
•Compile record of all coating usage (this may
require obtaining MSDS sheets) 2 weeks
• If necessary, file for permits to construct
(spray booths, ovens, city permits, etc.) 3 weeks
•After installation, file for permits to operate 3 weeks
Installation and Start-Up:
• Install equipment 4 weeks
• Conduct start-up trials 2 weeks
•Train painters and maintenance staff 2 weeks
• Make necessary modifications 2 weeks
Implement New Technology
Chapter IV
PageS
-------
SCHEDULE OF INCREMENTS OF PROGRESS
TASKS
1234
MONTHS
567
89 10 11 12 13 14
2-170-1.900
-------
SCHEDULE OF INCREMENTS OF PROGRESS
TASKS
PREPARE PANELS
FOR LAB TESTING
SEND PANELS TO LAB
AND AWAIT RESULTS
MEET WITH LAB TO
EVALUATE RESULTS
WRITE REPORT FOR
TASK FORCE
PROCURE SMAPLES OF
COATINGS FOR
PRODUCTION TRIALS
ARRANGE FOR TRIALS
WITH FACTORY
AWAIT PAINT SAMPLES
RUN TRIALS
ESTABLISH EQUIPMENT
REQUIREMENTS
OBTAIN PERMITS TO
CONSTRUCT
PREPARE FOR PERSON-
NEL TRAINING
1
2
3
4
XX
X
1
5
• • • A
)
>
-IONTH!
6
<
X
XX
(. .X
A • •
C. . .X
3
7
• A
X
X.
8
X
x.x
9
10
11
,
12
13
14
2-170-2.900
-------
HYPOTHETICAL EXAMPLE OF A SCHEDULE OF INCREMENTS OF PROGRESS
TASKS
ARRANGE TO EDUCATE
MAMGEMENT
PREPARE PRESENTA-
TION
ARRANGE TO SET UP
TASK FORCE
DEFINE COATING
REQUIREMENTS
SEND LETTER TO
VENDORS INVITING
THEM TO MEET WITH
US.
MEETINGS WITH
VENDORS
AWAIT SMAPLES OF
TRIAL COATINGS
WRITE LABORATORY
TEST METHODS
DISCUSS TESTING
WITH OUTSIDE LAB
PURCHASE PANELS
2-170-1 .900
1
;.x
<.x
A • •
2
.X
w
V V
A A
X
x;
>
>
3
• • • A
x
X
cxx
4
x
1
5
-IONTHJ
6
3
7
8
9
10
1
11
12
13
14
-------
SCHEDULE OF INCREMENTS OF PROGRESS
TASKS
ADVISE CUSTOMER OF
NEED TO COMPLY
PROVIDE CUSTOMER
WITH SMAPLES OF NEW
COATINGS
NEGOTIATE CHANGE IN
CONTRACTS
PLACE ORDERS FOR
PRODUCTION QUANTITY
OF COMPLIANT COATIN
PLACE ORDERS FOR
EQUIPMENT
AWAIT DELIVERY OF
EQUIPMENT AND COATI
INSTALL EQUIPMENT
TRAIN PERSONNEL
START UP TRIALS
IMPLEMENTATION
MONTHS
1 2 3 4 5 6 7 8 9 10 11 12 13 14
G
X. .X
X.
X
X
)
<
XX
....
x
. . .X
XX
X
. . .X
X
-------
Chapter V
-------
CHAPTER V
WHAT ONE NEEDS TO KNOW ABOUT
A COATING SYSTEM
-------
WHAT ONE NEEDS TO KNOW ABOUT
A COATING SYSTEM
Summary
This chapter explains the functions of the various components of a coating system,
such as primers, primer surfacers, pretreatment "wash" primers, intermediate coats,
and topcoats. Guidelines are given regarding the specification of gloss levels. Dry film
thicknesses for each component of the coating system are recommended, and there
is an explanation of which coatings are likely to be compatible or incompatible with
other coatings.
CHAPTER V
-------
CHAPTER V
WHAT ONE NEEDS TO KNOW ABOUT
A COATING SYSTEM
Definitions of Paints and Organic Coatings 1
What are Paints and Organic Coatings? 2
What One Needs to Know About a Coating System 3
Color and Gloss 6
Typical Dry-Film Thicknesses for Components of a
Coating System 7
Intercoat Compatiblity 8
Quality of Coatings 9
What are the Most Common Tests That Will
Qualify a New Coating? 10
Solvent Base vs. Water-Borne 11
Air-Dry, Single-Component vs Baked Coatings 12
Single-Component vs. Two-Component Coatings 13
-------
WHAT ARE PAINTS AND ORGANIC COATINGS?
HOW ARE THEY MADE?
Summary
This chapter defines the terms "paints" and "organic coatings" and explains the pur-
poses of the most common ingredients, such as binders (resins), pigments, extenders,
additives, solvents, diluents, and thinners.
The chapter is intended for both technical and non-technical personnel and is accom-
panied by a short slide presentation about the paint-making process.
Chapter V
-------
DEFINITIONS OF PAINTS AND ORGANIC COATINGS
Organic Coating
(1) Generic term for paints, lacquers, enamels, printing inks, etc.
(2) Liquid, liquifiable, or mastic composition that is converted to a solid
portective, decorative, or functional adherent film after-application as a
thin layer (ASTM).
Paint
Any pigmented liquid, liquifiable, or mastic compostion designed for application to a
substrate in atfhjr^layer that is converted to an opaque solid film after application.
Used for protection, decoration or identification, or to serve some functional purpose,
such as filling or concealing surface irregularities, modifying light and heat radiation
characteristics, etc.
Chapter V • Page 1
-------
WHAT ARE PAINTS AND COATINGS?
Paints and organic coatings are thin films that are applied to surfaces such as metal,
wood and masonry for decoration and protection.
They are uniform mixtures made by blending together various liquid resins and pow-
ders.
•Paint" usually refers to domestic applications, such as house paint.
•Coating" is usually referred to when used for industrial purposes. Examples are:
epoxies, polyurethanes, baking enamels, chlorinated rubbers, etc.
All paints are coatings.
Paints and Coatings Consist of:
• Binders (or resins)
• Pigments
• Extender Pigments
• Additives
• Solvents
• Diluents
• Thinners
Chapter V Page 2
-------
WHAT ONE NEEDS TO KNOW ABOUT
A COATING SYSTEM
Primers
• Primers are Paints and/or Coatings
• Promote adhesion between substrate and overcoatings.
• Provide corrosion resistance to metal substrates.
• Prevent bleeding of chemicals from masonry or wood surfaces.
• Contribute to film thickness of the coating system.
Typical Corrosion-Resistant Primers
• Passivating inhibitive pigments.
(Example: zinc chromate, barium chromate, strontium chromate, zinc
phosphate)
• Cathodic protection pigments (Example: metallic zinc powder)
Primer Surfacer
• Primarily to fill minor imperfections (small porosities or scratches) on surface.
• Must be capable of being applied to 2 - 3 mils dry film thickness.
• Must dry quickly to a hard film.
• Must sand easily without balling.
• Must be compatible with primer and overcoatings.
Chapter V Page 3
-------
WHAT ONE NEEDS TO KNOW
ABOUT A COATING SYSTEM
(Continued)
Pretreatment Primers
• Generally 2-component (resin + acid)
• Acid provides etching action on steel, aluminum, zinc, cadmium, and to a lesser
extent, on stainless steel, copper, brass, and titanium.
• Used as an alternative to chemical pretreatments such as phosphating of steel
or conversion coating of aluminum.
• Provides adhesion base between metal and overcoatings.
• Provides limited corrosion resistance. Should be overcoated soon after applica-
tion (within one day).
• Must be applied to a dry-film thickness of 0.3 - 0.5 mills Greater film thickness
can lead to delamination.
• Mixed coating must be discarded after approximately 8 hours.
• When coating very stable metals such as aluminum, stainless steel, brass, cop-
per, etc., it may be necessary to dilute the acid content, or rinse the excess, un-
reacted acid from the dried film before applying next overcoat.
• Pretreatment coatings should not be applied over chemically pretreated metals
(zinc or iron phosphates or conversion coated aluminum).
Intermediate Coat
• Provides a "tie" between primer and topcoat.
• Provides compatibility between primer and topcoat.
• Contributes to film thickness of coating system.
• Frequently used in industrial maintenance coating systems.
Chapter V Page 4
-------
WHAT ONE NEEDS TO KNOW
ABOUT A COATING SYSTEM
(Continued)
Topcoats
• They are paints and/or coatings.
• Sometimes applied directly over bare, clean substrate.
• Usually applied over primer, primer surfacer or intermediate coat.
• Provide barrier between substrate and environment.
• Glossy, decorative topcoats are often loosely referred to as "enamels"
• Sometimes, painters in industry use the word "paints" when they really mean
"topcoats."
Typical properties of topcoats:
• Decorative
• High, medium or low gloss
• Color
• Sunlight-resistant
• Abrasion-resistant
• Hard
• Smooth (or slick)
• Non-slip
• Chemical-resistant
• Solvent-resistant
• Fungus-resistant (mildew)
• Resistant to destructive organisms (Example: barnacles)
• Camouflage properties
Chapter V Page 5
-------
COLOR AND GLOSS
Typical Gloss Levels
% Reflectance
Very high-gloss
High-gloss
Medium-gloss
Semi-gloss
Low-gloss
Lusterless
Federal Standard 595 Colors
• Five-digit description (Example: 24533 Green).
• Prefix indicates gloss level: Example:
14533
24533
34533
Instruments for Measuring Gloss
60% Specular Gloss
> 95
> 75
> 50-75
> 30-50
> 10-30
< 10
Gloss Green
Semi-Gloss Green
Lusterless Green
es°
85° Gloss
For Low-Gloss
Coatings
80°
60° Gloss
General-
Purpose
\ I / 20°
20° Gloss
For Extreme High-
Gloss Coatings
Degree Specular
Renectance
Extreme High Gloss 20
Low to High Gloss 60C
Very Low Gloss (Lusterless) 85C
Chapter V
Page6
-------
TYPICAL DRY-FILM THICKNESSES
FOR COMPONENTS OF A COATING SYSTEM
General Metal
Finishing
Primer
Primer Surfacer
(Prior to sanding)
Intermediate Coat
Topcoat (per application)
High-Build Topcoats
(per application)
0.8 - 1 .2 mils
2 - 3 mils
N/A
1 .0 - 1 .5 mils
N/A
Industrial
Maintenance
Finishing
0.8 - 1 .2 mils
N/A
3-5 mils
1 .0 - 1 .5 mils
3 - 5 mils
Typical Dry-Film Thickness for Coating System:
General metal finishing = 3-4 mils
Industrial maintenance = 8-12 mils
Chapter V
-Page?
-------
INTERCOAT COMPATIBILITY
Not all coatings are compatible with each other (Example: lacquer over alkyd enamel)
Generally Compatible Systems For Topcoats Applied Over Primers
Topcoat I Weak solvent I Weak solvent I Strong solvent
Primer Weak solvent Strong solvent ' Strong solvent
Generally Incompatible Systems For Topcoats Applied Over Primers
Topcoat I Strong solvent I Tough coating
Primer • Weak Solvent • Soft coating
Generally, coatings of the same resin system are compatible.
Polyurethane topcoats are compatible with epoxy primers!
Some resin systems are temporarily incompatible when recoated with the same coat-
ing. Example: Some acrylic-modified coatings have a "critical" recoating period. Lift-
ing (wrinkling) occurs during the "critical" recoating period.
How can one check for compatibility?
• Apply the first coat of paint. Let it dry for the required amount of time. Then apply
the next coat of paint. If the second coat wrinkles or lifts within 10-15 minutes,
the two coats are not compatible under those conditions.
• Allow a longer recoating time, and try the test again. If lifting continues to occur,
then the coatings are not compatible.
• If the recoating time is long enough, and lifting does not occur, then the coatings
are compatible under those conditions.
Chapter V Page 8
-------
QUALITY OF COATINGS
Can one assume that the quality of paints of the same type are equal?
• NO!! Especially with the development of the new technology coatings, one
cannot assume that the quality is always acceptable.
• It is necessary to test all new technology coatings be before selecting the
best one.
• Coatings from large companies are sometimes acceptable, sometimes poor.
• Coatings from small companies are sometimes acceptable, sometimes poor.
If a paint has passed all laboratory tests, does this mean that the qualilty is
acceptable?
• NO!! Laboratory tests only address the properties of the paint under
laboratory conditions.
• It is necessary to test all new paints under production conditions before select-
ing the paint.
Chapter V Page 9
-------
WHAT ARE THE MOST COMMON TESTS THAT
WILL QUALIFY A NEW COATING?
• Drying time
• Color and gloss
• Viscosity and viscosity stability
• Pot life (for two-component paints)
• Application properties
• Adhesion to the substrate
• Salt spray resistance for primers
• Exterior durability for primers and topcoats
• Chemical Resistance (if applicable)
• Recoatability
• Physical tests, such as flexibility, impact resistance, hardness
abrasion resistance
• Water resistance, humidity resistance, hydrocarbon resistance
• Compatibility with various types of paint application equipment
• Other tests specific to the end-use requirements
Chapter V Page 10
-------
SOLVENT BASE VS. WATER-BORNE
Solvent Base
Painters more familiar with solvent-
based coatings
Easier to adjust viscosity
Flash-dry more rapidly
Some high-solids formulations
to to have high viscosities; therefore,
it:
• is difficult to control film
thickness
• is difficult to avoid orange peel
• can lead to gloss differences
Water-Bornes
Generally, but not always, have lower
VOCs
More difficult to consistently adjust
viscosities
Some are slower drying
Latexes dry extremely quickly
Often have softer and less abrasion-
resistant films
More sensitive to surface preparation
Generally provide numerous possible
film defects.such as craters, edge pull,
texture variations
Chapter V
Page 11
-------
AIR-DRY, SINGLE-COMPONENT VS. BAKED COATINGS
Air-Dry, Single-
Component Coatings
Can be applied to all substrates
(metals, plastics, etc.).
Some regulations have higher VOC
standards for air-dry than for bake
coatings.
* Can dry at temperatures from
ambient up to 194°F.
Do not require oven.
Lower energy usage.
Take longer to achieve through hard-
ness.
Baked Coatings
Some regulations require lower VOC
limits than for air-dry coatings.
* Generally must cure above 250°F.
Require high-temperature oven.
High-energy usage.
Produce hard films.
Often have excellent physical proper-
ties.
Films tend to flow out better to provide
smooth finishes.
Often have better chemical resistance.
Cannot be applied to plastics.
Cannot be applied over machined or
other surfaces that are sensitive to
warpage.
Can cause outgassing on sand cast-
ings.
* By EPA definition, coatings which cure below 194°F are considered to air- or force-
dry, whereas coatings that cure above 194°F are considered to be bakina formula-
tions. In fact, most true baking coatings must be heated to at least 250°F so they
will undergo a chemical reaction that allows the coating to cure.
Chapter V
Page 12
-------
SINGLE-COMPONENT VS. TWO-COMPONENT COATINGS
Single-Component Coatings
(Such as alkyds)
Easy to use
Can keep unused coatings
Require no special mixing
No pot life
Constant viscosities throughout the
day
Spray lines do not have to be flushed
out as frequently as with two-
component coatings.
Generally softer films.
Generally less abrasion-resistant
films.
Generally less
properties.
chemical-resistant
Two-Component Coatings
(Such as polyurethanes)
Require accurate special mixing.
May require induction time of up to
30 minutes (primarily for epoxies).
Must be used within pot life.
Viscosities increase throughout the
day.
Spray lines may not be left without
flushing with solvents.
Generally higher wasteage of spray
lines.
Higher wastage of unused coatings.
More hazardous waste.
Generally have superior physical
properties.
Generally have superior chemical-
resistant properties.
Usually considerably more
expensive.
Chapter V
Page 13
-------
Chapter VI
-------
V
CHAPTER V\
WHY PAINTS AND COATINGS CAUSE AIR POLLUTION
-------
WHY PAINTS AND ORGANIC COATINGS
CAUSE AIR POLLUTION
SUMMARY
This session explains why the solvent (evaporative) portion of paints and organic
coatings cause air pollution. There is an explanation of why some solvents are more
acceptable than others and how to understand the methods by which the regula-
tions measure the amount of solvents in coatings. In addition, the session discusses
how to consider water-based coatings and clears up many misconceptions
prevalent in the industry.
CHAPTER VI
-------
CHAPTER VI
WHY PAINTS AND ORGANIC COATINGS
CAUSE AIR POLLUTION
Why Paints and Organic Coatings Cause Air Pollution 1
EPA Definition, Volatile Organic Compound (VOC) 3
How Environmental Regulations Regulation Reactive
Volatile Organic Compounds 4
Comparison of 'Old" and "New" Coatings 6
High-Solids Coatings 7
Water-Reducibles 8
Exempt Solvents 9
How Environmental Regulations Regulate Reactive
Volative Organic Compounds 11
Rule 66-Type Regulations 12
-------
WHY PAINTS AND ORGANIC COATINGS
CAUSE AIR POLLUTION
Paints and organic coatings consist of:
• Binders (Resins)
• Pigments
• Extender Pigments
• Additives
• Solvents
• Diluents
• Thinners
In general, binders, pigments, extender pigments and additives are the solid (non-
evaporative or non-volatile) portion of the coating.
Some of the non-volatile ingredients may evaporate into the air during the curing
cycle.
COMPOSITION OF COATING
Solvents, Diluents
and Thinners
Binder (Resins)
tenderPJgmerrt
Additives
Volatiies
Non-Volatiles (Solids)
Solvents, diluents and thinners evaporate during:
• Mixing
•Application
• Curing
Solvents, diluents and thinners are known as the "Volatiies."
With the exception of water, the solvents, diluents and thinners are volatile organic
compounds (VOCs).
Volatile organic compounds (VOCs) react with nitrogen oxides in the air and in the
presence of sunlight to form oxidants. These reactions are photochemical in nature.
Chapter VI
Page 1
-------
WHY PAINTS AND ORGANIC COATINGS CAUSE
AIR POLLUTION (Continued)
These oxidants, of which ozone (Oa) is the major portion, are more commonly
known as "photochemical smog."
Various factors affect formation of smog. Ideal conditions occur on warm, windless,
sunny days.
Volatile organic compounds do not form oxidants (smog) at the same rate. Some
are highly reactive and form oxidants within hours.
Less reactive compounds require longer periods of exposure to sunlight for reaction.
Given a sufficient exposure period to sunlight and sufficient quantities of nitrogen
oxides, almost all volatile organic compounds will form oxidants (smog).
Those VOCs that react with nitrogen oxides and sunlight are known as precursors
to the formation of oxidants (smog).
Those VOCS that demonstrate negligible reactivity are non-precursors and are often.
referred to in VOC coatings rules as "exempt solvents" (VOCs).
Many coating regulations allow exempt solvents (VOCs) to be exempt from the
regulations.
Precursor VOCs Include:
• Xylene (Xylol)
• Toluene (Toluol)
• VM & P Naphtha
• Mineral Spirits
• Isopropyl Alcohol (I PA)
• MEK
• MIBK
• Trichlorethylene
• Most others
Exempt solvents Include:
•Water (not a VOC)
• 1,1,1 -Trichloroethane *
• Methylene Chloride
• Most Freons
* Commercial 1,1,1-Trichloroethane does contain some VOCs. These
act as inhibitors against corrosion.
Chapter VI Page 2
-------
EPA DEFINITION
VOLATILE ORGANIC COMPOUND (VOC)
Any organic compound which participates in atmospheric photochemical reactions;
that is, any organic compound other than those which the Administrator designates
as having negligible photochemical reactivity. VOC may be measured by a
reference method, an equivalent method, or by procedures specified under any
regulation.
Negligible Photochemically Reactive Materials:
• Methane
• Ethane
• 1,1,1 -TCA (methyl chloroform)
• Methylene Chloride
•Trichlorofluoromethane (CFC-11)
• Dichlrodifluormethane (CFC-23)
• Chlorodifluoromethane (CFC-22)
•Trlfluoroethane (CFC-23)
•Trichlorotrifluorethane (CFC-113)
• Dichlorotetrafluoroethane (CFC-114)
• Chloropentafluoroethane (CFC-115)
Chapter VI Page 3
-------
HOW ENVIRONMENTAL REGULATIONS REGULATE REACTIVE
VOLATILE ORGANIC COMPOUNDS
Regulations refer to any of these terms:
•Volatile organic compounds (VOC's)
• Reactive organic compounds (ROC's)
• Photochemically reactive organic compounds (PROC's)
Regulations set standards on the basis of pounds of VOC's (ROC's or PROC's)
emitted per gallon of liquid coating.
COATING
VOC'S
LBS/GAL
SOLIDS
1 Gallon
Some regulations set standards in terms of pounds of VOC emitted per gallon of
solids applied.
Some regulations differentiate between coatings that air or force dry below 194°F.
and coatings that cure above 194°F (Bake Coatings).
If a standard surface area is to be coated, then a coating with a high VOC content
will emit significantly more VOC's into the air than a low VOC content coating.
ft is generally assumed that all of the VOC's in the coating evaporate at some time.
What about coatings that contain water or exempt solvents?
All regulations subtract water and exempt solvents from the standard limits. There-
fore, regulations set limits in terms of:
• VOC, as applied, less water (Ibs/gal)
• VOC, as applied, less water (Ibs/gal solids)
Chapter VI
-------
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PAGES
-------
COMPARISON OF "OLD" AND "NEW" COATINGS
Conventional Solids
High-Solids
VOC=4.4Ibs/gal
VOLUME = 60%
VOLSOUDS-40%
- ' " ' ''
VOC=2.8lbs/gal
VOLUME = 38%
VOL. SOLIDS = $2%
Note:
- Percent volume are only approximate
- Regulations set standards of VOC in Ibs/gal
or grams/liter
Chapter VI
Page 6
-------
HIGH-SOLIDS COATINGS
Air-Dry
(Force Dry)
Baking
VOC=2.8lbs/gal
VOLUME = 38%
VOC=2.3 Ibs/gal
VOLUME a 32%
Note:
• Percent volume are only approximate
- Regulations set standards of VOC in Ibs/gal
or grams/liter
Chapter VI
Page?
-------
WATER-REDUCIBLES
VOL WATER = 50%
VOLVOC
VOC « 24 IbS/gal
VOLUME m 38%
Note:
- Percent volume are only approximate
- Regulations set standards of VOC in Ibs/gal
or grams/liter
Chapter VI
Pages
-------
EXEMPT SOLVENTS
EXEMPT SOLVENT
= 50%
VOL. VOC = 19%
VOC = 2.8 ibs/gal
VOLUME = 38%
Note:
- Percent volume are only approximate
- Regulations set standards of VOC in Ibs/gal
or grams/liter
Chapter VI
Page9
-------
CONVERSIONS
Lbs/Gal (#/gal)
Grams/Liter (g/L)
3.5
3.0
2.8
2.3
420
360
340
275
1lb/gal = 119.8 g/L
Chapter VI
Page 10
-------
HOW ENVIRONMENTAL REGULATIONS REGULATE REACTIVE
VOLATILE ORGANIC COMPOUNDS
General Comments
Solvents (or thinners) may be added to coatings to adjust viscosity, provided that
the resulting VOC does not exceed the limits of the rule.
If water is added to a coating to adjust its viscosity, the VOC content (Ibs/gal less
water) is unaffected.
Example:
A water-based coating has a VOC, less water, of 2.8 Ibs/gal. The coating is reduced
with water in the ratio 1 part coating to 1 part water. What is the VOC content, less
water, of the mixed coating?
Answer:
It remains 2.8 Ibs/gal because the water content is not included in the calculation.
Chapter VI Page 11
-------
RULE 66-TYPE REGULATIONS
Rule 66 (or state equivalent) placed composition restrictions on the use of "good"
solvents (low photochemical reactivity) and "bad" solvents (high photochemical reac-
tivity).
Some states place no restrictions on the use of solvents in coatings.
Some states require all coatings and solvents to meet Rule 66 (or state equivalent)
Most states provide that either the new prohibitive VOC regulations or Rule 66 (or
state equivalent) shall apply. Both rules do not have to apply simultaneously.
Chapter VI Page 12
-------
Chapter VII
-------
CHAPTER VII
A BRIEF DESCRIPTION OF SURFACE COATING SOURCES
-------
CHAPTER VII
A BRIEF DESCRIPTION OF SURFACE COATING SOURCES
Can Coating 1
Paper Coating 3
Fabric Coating 5
Metal Coil Coating 6
Flat Wood Paneling Coating 8
Automobile & Light-Duty Truck Coating 10
Metal Furniture Coating 11
Magnetic Wire Coating 13
Miscellaneous Metal Parts Coating 14
Architectural Surface Coating 16
Aerospace Coating 18
Wood Furniture Surface Coating 20
Graphic Arts 21
Marine Coating 23
Plastic Parts for Business Machines 24
Flexible & Rigid Disc Coating 26
-------
The information in this chapter has been excerpted from various
readily available documents published by EPA. A list of the references
used is provided as a bibliography at the end of the chapter.
-------
CAN COATING
There are two types of cans: 3-piece cans and 2-piece cans. Three-piece cans are made
from a rectangular sheet (body blank) and two circular ends. The sheet is rolled into a
cylinder and solderd shut. One end is attached in manufacturing and the other is at-
tached during packaging of the product. Two-piece cans are drawn and wall-ironed
from a shallow cup. The end (or cover) is attached during packaging.
Cans are used as containers for items such as drinks, meats, fruits, vegetables, oil, and
paints. There are independent and captive can manufacturers. The independents are
a service industry which coats and fabricates cans for customers' needs and specifica-
tions. Captive can manufacturers coat and fabricate containers for only their own
company's use.
Common materials used in can manufacturing include tin plate, tin-free steel, black
plates, and aluminum. Gauges from 0.006 to 0.015 inches are used, with sheets of sizes
30" x 32" to 37" x 42". Aluminum is the most common material used in 2-piece can
manufacturing.
The interior base coat of 3-piece cans is roll coated onto the sheets of metal as a protec-
tive lining between the metal and the product. This coating must not react with the
metal and alter tastes, odors, or appearance of the contents. With respect to containers
for foods, any coatings must be approved by Federal Drug Administration regulations.
Common resins for the interior base coats include: butadienes, rosin esters, phenolics,
epoxies, and vinyls. Exterior base coats are usually white for both 2- and 3-piece cans,
and provides a protective coating to the metal and to serve as a background for the
lithograph or printing operations. Some resins used include: polyesters, alkyds, and
acrylics. Conventional inks are used for printing. An overvarnish is usually applied
directly over the inks to add a glossy quality, to protect against abrasion and corrosion,
and to reduce the coefficient of kinetic friction, allowing mobility on conveyor tracks.
Some common solvent-thinned coating resins include: acrylics, epoxies, alkyds, and
polyesters.
The primer coat (or size coat) is roll coated before the application of exterior base or
ink to give adhesion to the coating. This coat also strengthens the metal to withstand
deformation or tooling. This coat is usually done with epoxy, epoxy esters, acrylics,
vinyls, or polyester resins.
More than 30 different solvents are used in interior/exterior base coats, overvarnish
and size coats. These include: mineral spirits,xylene, toluene, diacetone alcohol, methyl
isobutyl ketone, methyl ethyl ketone, and isophorone.
Coatings used for sideseams and sometimes as the exterior of 3-piece cans usually con-
tain vinyl and epoxy-phenolic resins. Solvents used in side-seam coatings are xylene,
butyl acetate, paraffins, nitropropane, cellosolve acetate (TM), and toluene. The end
Chapter VII Page
-------
sealing compound is usually a dispersion of a synthetic rubber in heptane or hexane,
and lines the edge of the can ends to form a gasket.
Two-piece can manufacturing (shown in Figure 1) is a continuous, high-speed process
that includes both fabrication and coating operations. Beverages are the most common
example of 2-piece cans. The metal for 2-piece cans is received in coil form and is con-
tinuously fed through an extrusion process that draws and wall-irons the cups into cans
in a lubricating solution and trims the uneven edge of the cans. The cans are then
cleansed to remove the lubricating solution, rinsed with hot water, and dried. A white
base coat may then be applied using a reverse-roller method. The coating is cured at
350 to 400 F.
Inks are applied to printing blankets on a rotary printer and transferred to the cans as
they rotate on a mandrel. Varnish (protective coating) may then be roll coated direct-
ly over the inks and then cured. After printing, the cans are necked, flanged and tested.
Flanging assists in p end assembly once the can is filled. Necking allows use of an ap-
proximately 12 psig of air pressure.
Three-piece can manufacturing consists of two parts: sheet coating and can fabricating.
Sheet coating may be divided into base coating of one or both sides and the printing or
lithographing. Base coat operations (shown in Figure 2) consist of applying an interior
coating for 3-piece cans and can ends, an exterior background coating, or a size coat if
the customer desired. Sheets are roll coated on one side only. Sheets are then picked
up by wickets and transported through a curing oven.
Sheet printing or lithograph operations (shown in Figure 3) usually consists of apply-
ing one or two colors of ink either on the exterior base coat, the size coat, or directly
on the metal. A varnish is applied directly over the wet inks by a direct roll coater. If
more than two colors are needed, another set of inks is then applied, followed by an
overvarnish. Some inks now may be applied more than two colors at a time (ultraviolet
light curable inks), and some inks do not require an overvarnish.
Can fabrication consists of forming cans from the coated sheets. Some cans have fiat
surfaces, and some are beaded for extra strength. Beverage 3-piece can fabricating
(shown in Figure 4) consists of cutting the sheets into can body size blanks and feeding
them into a "body maker" in which they body blank is formed into a cylinder. The seam
is welded, cemented, or soldered, and is then coated (sprayed) on the exterior and in-
terior of the seam with an air-dry lacquer to protect the exposed metal. On some cans
other than beverage containers, the coating is usually sprayed only on the interior. The
cylinders are flanged to provide proper can end assembly and may be necked-in,
depending on the customers' specifications. The interiors of beverage cans are sprayed
to provide a protective lining between the can and the beverage. Non-beverage cans
are not usually spray coated.
Open cylinders move through an "end double seamer" which attaches one end onto the
cylinder. The cans are leak-tested and prepared for shipment. Can ends are stamped
from coated sheets of metal in a reciprocating press and their perimeter is coated with
a synthetic rubber compound that functions as a gasket when the end is assembled on
the can.
Chapter VII Page 2
-------
CANS
COIL
EXTERIOR BASE COATER
PRINTER AND OVER-VARNISH
COATER
I
u
V
OVEN
INTERIOR BODY SPRAY
AND EXTERIOR END SPRAY
AND/OR ROLL COATER
LEAK
TESTER
NECKER AND
FLANGER
OVEN
MS2/7/A
Figure 1. Diagram of two-piece aluminum can fabricating and coating operation.
-------
COATING
TRAY
APPLICATION
ROLLER
SHEET(PLATE)
FEEDER
BASE COATER
WICKET OVEN
SHEET (PLATE)
FEEDER
Figure 2. Sheet base coating operation.
MS2/7/B
-------
BLANKET
CYLINDER
INK
' APPLICATORS
VARNISH
TRAY
APPLICATION
ROLLER
SHEET (PLATE)
FEEDER
LITHOGRAPH
COATER
OVER-VARNISHED
COATER
WICKET
OVEN
SHEET
(PLATE)
FEEDER
Figure 3. Sheet printing operation.
MS2/7/C
-------
CAN END, AND THREE-PIECE BEER AND BEVERAGE CAN FABRICATING OPERATION
r
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-
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0
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SCROLL
STRIP SHEARER
COMPOUND LINER
END FORMER
TAB FORMER
0
0
ENDSEAMER
OVEN
BODY
BLANKS'
o
FORMED
SOLDERED
OR CEMENTED
0
BODY HARM
SIDE It AM.
SPRAY
PALLETIZED LOAD
LEAK TESTER
INSIDE NECKERANOFLANGER
BODY
SPRAY
Figure A. Can end. and three piece beer and beverage can fabricating operation.
-------
PAPER COATING
In organic solvent paper coating (a typical coating line is shown in Figure 5) the paper
may be given several desirable properties. These include: water resistance, surface ap-
pearance/texture (i.e., glazed paper), and coating (i.e., carbon paper). Resins are dis-
solved in an organic solvent or solvent mixture to form the coating. This mixture is
applied to a web (continuous roll) of paper by knife, reverse roller, or rotogravure tech-
niques. Several classes of coatings can be used, including: film-forming materials, pas-
ticizers, pigments, and solvents. Many organic solvents are used. The most common
solvent are toluene, xylene, methyl ethyl ketone, isopropyl alcohol, acetone, and
ethanol.
In knife coating (shown in Figure 6) the web is held flat by a roller and moved beneath
a knife, which spreads the coating across the entire width of the paper in a uniform
thickness. The thickness of the coating can be set by adjusting the position of the knife
relative to the paper surface. Knife coalers function best when applying higher viscosity
coatings (up to 10,000 centipose [cp]).
Reverse Roller Coating (shown in Figure 7) applies a constant thickness of coating to
the paper web, usually by using three rolls, each rotating in the same direction. A trans-
fer roll picks up the coating solution from a trough and transfers it to a coating roll. A
"doctor roll" removes excess material from the coating roll. The gap between the doc-
tor roll and the coating roll can be adjusted to determine the thickness of the coating.
The coating roll turns in a direction opposite to that of the paper. This reverse direc-
tion of the coating roll reduces striations in the coating. Reverse roller coaters operate
best with low viscosity coatings (300 to 500 cp).
Rotogravure printing uses a roll coating technique where an image consists of minute
cells or indentations specifically engraved or etched into the coating roll's (also known
as the rotogravure cylinder) surface. This roll is continuously revolved through an ink
source and the ink is held in these indentations and transferred to the paper. The
gravure printer can print patterns or a solid sheet of color on a paper web.
Most solvent emissions from coating paper come from the drying and curing process.
Ovens can range from 20 to 200 feet in length and can be divided into five temperature
zones. The first zone is where the paper enters the oven. This zone is usually at the
lowest temperature (approximately 110° F), and the emissions are the highest here. The
next four zones continuously increase the temperature and cure the coating after most
of the solvent has evaporated. A typical curing temperature is 250° F, although tempera-
tures of 400° F are possible. Exhausts can be discharged independently into the atmos-
phere or they may be collected and their combined exhaust may be sent to a common
air pollution control device.
Paper coater ovens have a constant flow of air over the paper web to heat it uniformly
and to facilitate the solvent's evaporation. This constant flow of air also serves to keep
solvent concentration low.
Chapter VII Page 3
-------
The coating line is the largest source of solvent emissions. Solvents may also be lost in
the form of fugitive emissions from other stages of processing and cleaning. Some sour-
ces of these fugitive emissions include: solvent storage and transfer, solvent evapora-
tion during cleaning operations, and storage and disposal of solvent soaked cleaning
rags.
Chapter VII Page
-------
HEATED AIR
FROM BURNER'
REVERSE ROLL
COATER
UNWIND
ZONE1
EXHAUST
t
n
/
OVEN
ZONE 2
EXHAUST
t
HOT AIR NOZZLES
, —
>1
^^^ o
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o o ^^
TENSION ROLLS
MS2/7/D
Figure 5. Typical paper coating line.
-------
ROLL
PAPER WEB
Figure 6. Knife coating of paper.
MS2/7/E
-------
DOCTOR ROLL
COATING ROLL
METERING GAP
TRANSFER ROLL
COATED PAPER WEB
BACKING ROLL
COATING RESERVOIR
Figure 7. Four-roll reverse roll coater for paper.
MS2/7/F
-------
FABRIC COATING
Fabric coating is used to impart properties to fabrics such as strength, water repellan-
cy or appearance. The coating is spread onto the fabric by means of a knife or a roller
spreader. Common coatings include latexes, acrylics, polyvinyl chlorides,
polyurethanes, and rubber.
The process of fabric coating (illustrated in Figure 8) begins with milling. In general,
milling is only needed for coatings which contain rubber. Here the pigments, curing
agents, and fillers are added to yield a homogeneous mass that can later be dissolved
in a solvent. This step does not produce many organic emissions as few organic solvents
are used.
The milling step is followed by mixing, which is the dissolution of solids from the mill-
ing process in a solvent. Mixing is usually performed at ambient temperatures. Vinyl
coaters lose significant amounts of solvents in this step, although otherwise, only minor
amounts of fugitive emissions are released.
Coating application, the next step in fabric coating, accounts for 25 to 35 percent of all
solvent emissions from a coating line. Coating is usually done by a knife coaler (Figure
9) or by a roller coater (Figure 10). These are both high-speed coating techniques. In
knife coating, the substrate is held flat by a roller and moved beneath a knife, which
spreads the coating across the entire width of the substrate in a uniform thickness.
Roller coating is a more accurate technique in terms of coating thickness. Here the
coating is applied to the fabric by hard rubber or steel rolls. The gap between the rollers
determines the thickness of the coating.
Rotogravure printing is widely used in vinyl coatings of fabrics and produces significant
amounts of solvent emissions. This method uses a roll coating technique where an
image consisting of minute cells or indentations specially engraved or etched into the
surface of the coating roll. The roll is continuously revolved through an ink source and
the ink is held in these indentations and transferred to the fabric. A protective coating
is also applied by rotogravure techniques.
The final step in fabric coating is the drying and curing of the fabric. This step accounts
for 65 to 75 percent of the emissions from the coating line. Typical drying ovens process
fabric on a continuous basis using a web or conveyor feed system. The heat of the oven
speeds the evaporation of the solvents and may be used to produce chemical changes
in the fabric itself to impart desired properties to the fabric.
The coating line is the largest source of solvent emissions. Solvents may also be lost in
the form of fugitive emissions from other stages of processing and cleaning. Some sour-
ces of these fugitive emissions include: solvent storage and transfer, solvent evapora-
tion during cleaning operations, and storage and disposal of solvent-soaked cleaning
rags.
Chapter VII Page 5
-------
PIGMENTS
RUBBER
CURING
AGENTS
1
SOLVENT
MILLING
MIXING
DRYING AND
CURING
COATING
APPLICATION
•FABRIC
-COATED PRODUCT
Figure 8. Typical fabric coating operation.
MS2/7/H
-------
COATING
KNIFE
COATED FABRIC TO DRYER
EXPANDED COATED FABRIC
COATING
SUBSTRATE
SUBSTRATE
HARD RUBBER OR STEEL ROLLER
Figure 9. Knife coating of fabric.
MS2/7/G
-------
COATED FABRIC
SUBSTRATE
Figure 10. Roller coating of fabric.
MS2/7/J
-------
METAL COIL COATING
The metal coil coating industry typically coats metal sheets or strips (which can be of
aluminum alloys, steel, plated steel, steel alloys, zinc, brass, or copper) using roll coat-
ing techniques on one or both sides on a continuous line basis with the possible addi-
tions of printing or embossing. The coated metal is cut and fabricated by drawing,
stamping, roll-forming, or other shaping methods, into finished products which may be
used for many things such as cans, cars, appliances, and aluminum siding.
There are two branches of coil coating: toll coaters and captive coaters. Toll coaters
are service coaters who produce products for customers. Captive coaters are part of a
greater plant that coats the metal and fabricates the product from the coated metal.
Coil coating is done on a coating line, which consists of the coater(s), the oven(s), and
the quench area(s). Emissions from a coil coating line are mainly volatile organics and
other compounds (e.g., aldehydes) which result from curing. The major emissions from
a typical coating operation include: hydrocarbons, carbon monoxide, nitrogen oxides,
and aldehydes.
Typical coatings include acrylics, adhesives, organosols, plastisols, vinyls, and silicones,
among others. The most common solvents include xylene, toluene, methyl ethyl ketone,
butanol, and diacetone alcohol.
A coil coating line (shown in Figure 11) begins by power feeding the metal sheet
through a splicer, which joins one coil of metal to another coil for continuous, nonstop
operation. The metal is then accumulated so that during a splicing operation, the ac-
cumulator rollers can descend to provide a continuous flow of metal throughout the
line. The metal is then cleaned (120°F to 160°F), brushed and rinsed. The metal is then
treated for corrosion protection and for proper coating adhesion with various pretreat-
ments (which depend on the type of metal being coated and types of coatings used).
The prime coat is applied on one or both sides of the metal by roller methods (shown
in Figure 12). The pick-up roll takes the coating and transfers it to the applicator roll.
The metal is coated as it passes between the applicator roll and a large back-up roll.
The coated metal then enters a large, multi-temperature zone oven for curing, which
may be done at 100°F to 1000°F. As the metal exits the oven, it is cooled in a quench
chamber by spraying water, or by a blast of air, followed by water cooling. A topcoat
may be applied and cured in a manner similar to the prime coat. After cooling, the
coated metal passes through another accumulator, is sheared at the spliced section,
most often waxed, and finally recoiled.
Another method of applying a prime coat on aluminum coils or a single coat on steel
coils is to electrodeposit a water-borne coating to one or both sides of the coil. Here
the coil enters a V-shaped electroplating bath that has a roll on the bottom. As the
metal goes around the roll, electrodes are activated to permit the coagulation of paint
particles on either one or both sides of the coil. The coated coil is then rinsed and wiped
Chapter VII -Page 6
-------
to remove the water and excess paint particles. For steel coils, the electrodeposited
coating must be baked in an oven. Aluminum coils prime coated in this way are stable
enough to be topcoated without curing and baked later as a two-coat system.
Organic vapors are emitted in all three areas of the coating line. The oven emits ap-
proximately 90 percent of the organic vapors and most of the other pollutants. Of the
remaining 10 percent of organic vapor emission, approximately 8 percent are emitted
from the coater, and the remaining 2 percent are emitted from the quench area.
Chapter VII Page 7
-------
PRIME
COATER
ACCUMULATOR
SPLICER
METAL CLEANING PRETREATMENT
P
\
UNCOILED
METAL
TOPCOAT
COATER
PRIME PRIME
OVEN QUENCH
ACCUMULATOR
TOPCOAT
OVEN
TOPCOAT
QUENCH
RECOILING
METAL
US2T7K
Figure 11. Diagram of coil coating line.
-------
APPLICATOR
ROLL
PICKUP
ROLL
INTO OVEN
PICKUP ROLL
FLOW OF METAL INTO COATER
Figure 12. Typical reverse roll coater.
MS2/7/L
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FLAT WOOD PANELING COATING
Printed interior paneling products are made by applying a decorative finish to the sur-
face of lauan (a hardwood), hardboard, or particle board. The basic steps of paneling
coating (shown in Figure 13) begin with sanding or brush dusting the board to provide
a smooth, dust-free surface. The next step is the application of filler. Filler is normally
applied by reverse-roll coating (shown in Figure 14A). The reverse-roll coater consists
of a coating applicator roll that rotates in the direction of panel movement, followed
by a wiper roll that rotates opposite to the direction of the panel. Coating is forced into
the depressions in the wood and excess coating is removed. Filler provides a smooth,
even base for the rest of the coating operation.
Fillers must be chosen to dry quickly, sand easily, seal, and not shrink with age. Com-
mon fillers include: polyester filler, which is ultraviolet cured; water-based filler, which
is very common; lacquer-based filler; polyurethane filler; and alkyd-urea-based filler.
Filler is sometimes applied twice to guarantee complete coverage of porous paneling,
followed by the application of a separate sealer. The sealer may be water- or solvent-
based. Both filling and sealing operations are followed by oven curing and sanding.
Groove cutting is often the next step, followed by groove coating. Groove cutting can
be performed at other points in the coating process (for example, before filling).
Groove color may be applied in several ways, although air sprays are the most com-
mon. Groove coats are usually pigmented, low-resin solids that are reduced with water
before use.
The next step for printed paneling is the application of a base coat upon which the wood
grain or other pattern will be printed later. Base coats must dry quickly and provide
good coverage. In printed paneling, the following coatings are used: lacquer, synthetic,
vinyl, modified alkyd urea, catalyzed vinyl, and water-based (used primarily for lauan-
based paneling). Base coats are usually applied by direct-roll coalers (shown in Figure
14B).
After passing through an oven, the panel is printed. Inks are applied by an offset gravure
printing operation. Several colors may be used to reproduce the appearance of wood,
marble, leather, or whatever pattern is desired. Most lauan printing inks are pigments
dispersed in alkyd resin, with some nitrocellulose added for better wipe and printability.
Water-based inks are not used in large amounts.
After printing (or after base coat application if no printing is done), a clear protective
topcoat is applied by one or two direct-roll coalers or curtain coalers. Pressure-head
curtain coating (shown in Figure IS) meters coating into a pressure head, then forces
it through a calibrated slit between two knives, onto the paneling. These are wet-on-
wet applications. Most topcoats are organic-solvent-based coatings, some are synthetic,
formed from solvent-soluble alkyd or polyester resins, urea formaldehyde cross-Unk-
ings, or other resins. Some water-based topcoats are used (often containing alkyd-urea
Chapter VII Page 8
-------
catalysts). The synthetic topcoats are catalyzed and cured by a hot-air oven; other top-
coats are cured in infrared or ultraviolet ovens.
Natural-finish hardwood paneling coating is a much more involved process, done in
few plants. In this process, knots in the wood are filled with a putty material. A groove
is then cut into the wood, and it is painted with an opaque finish. After this, the board
is sanded and then stained by a direct-roll coater. The panel is then dried in a high-
velocity or infrared oven.
A thin wash coat (known as a toner if it is colored with dyes or transparent pigments)
may be directly rolled on to seal the stain and to improve the clarity and lightness of
the finish. The plywood is then filled by a reverse-roll coater, then dried and polished
in a brush unit.
A primer sealer is then applied by direct-roll coating. This coating protects the wood
from moisture, provides a smooth base for the topcoat, and adds luster to the grooves.
The sealed board is then dried, sanded and buffed. The surface of the panel is then em-
bossed and valley printed to give a distressed or antique appearance. Print steps may
now be added. The panel is dried and then sealed with a direct-roll coater. One or more
topcoats may then be added to give strength, protection, and gloss to the panel. Direct-
roll coating is generally used for this, although curtain coating is a viable option. This
final coating is cured and the panel is done.
The VOC emission sources in a coating line are shown in Figure 16. Most emissions of
VOCs occur at the coating lines. Fugitive emissions also occur at paint mixing and
storage sites. The solvents in organic-based coatings are usually mixtures including
methyl ethyl ketone, methyl isobutyl ketone, toluene, xylene, butyl acetates, propanol,
and ethanol, among others. Organic solvents most often used in water-based coatings
are glycol, glycol ethers, propanol, and butanol.
Chapter VII Page 9
-------
FEEDER
BRUSHER
SANDER
RLLER
(RRC)
OVEN
SANDER
CUT
GROOVE
GROOVE
COAT
(SPRAY)
COOLING
OVEN
TOPCOAT
IDRC
ORCC)
INKS
(OFFSET
GRAVURE)
OVEN
RRSTOR
SECOND
BASECOAT
(DRC)
OVEN
SEi
OR
BAS
(DF
SP
ftLER
RRST
ECOAT
1C OR
RAY)
INSPECTION
PACKAGING
SHIPMENT
RRC = REVERSE ROLL COATING
DRC = DIRECT ROLL COATING
CC = CURTAIN COATING
Figure 13. Printed Interior paneling line (lauan, hardboard, and particle board).
MS2/7/M
-------
•PUCATOR _, I 00ef
—i I r~
APPLICATOR
COATING
DOCTOR BLADE
REVERSE ROLLER
PANEL
A. REVERSE ROLL COATER
COATING
APPLICATION
PANEL
B. DIRECT ROLL COATER
Figure 14. Simplified schematic of roll coalers.
MS2/7/0
-------
COATER HEAD
PRODUCT
COATING
TROUGH
COATING
RESERVOIR
t
Figure 15. Pressure-head curtain eoater.
MS2/7/0
-------
FEEDER
C
GAMDFR
l>
C
BRUSHER
j>
\
FILLER
(RRC)
A <
OVEN
SANDER
1
C
CUT
GROOVE
5
^
GROOVE
COAT
COOLING
OVEN
TOPCOAT
(DRC
ORCC)
INKS
(OFFSET
GRAVURE)
SEALER
OF FIRST
BASECOAT
(DRC OR
SPRAY)
INSPECTION
DAf*lf AfSIMfS
SHIPMENT
RRC = REVERSE • ROLL COATING
DRC r DIRECT - ROLL COATING
CC = CURTAIN COATING
4 = FUGITIVE VOC
/ = VENTED VOC
I = PARTICULATE
Figure 16. Emission source in the coating line.
MS2/7/R
-------
AUTOMOBILE AND LIGHT-DUTY TRUCK COATING
The automobile and light-duty truck (less than 8,500 pounds gross vehicle weight) as-
sembly industry receives parts from a variety of sources and produces finished vehicles
prepared for sale. The coating process is a multiple-step operation performed on an
assembly line. An example of a "typical" assembly line is shown in Figure 17. Coating
consists of coating the vehicle body as well as the separate components of the
automobile (e.g., chassis, hoods, doors, fenders, etc.)
The first step is to clean the various body surfaces to remove oil and grease. The cleaners
are often solvents. A phosphating process follows and prepares the surface for the
prime coat. The primer is applied to protect metal surfaces from corrosion and to en-
sure good bonding of the topcoat. The primer may be solvent-based or waterborne.
Solvent-based primer is applied by a combination of manual and automatic spraying,
flow coat or dip processes. Waterborne primer is most common now and is usually ap-
plied in an electrodeposition (EDP) bath. The coated part is passed through a solvent
flashoff area (evaporation area) and is then oven-cured. If EDP is used to apply the
primer coat, the resulting coat may be too thin and rough to smooth over (eliminate)
all surface defects. If this is the case, a guide coat (primer-surfacer) is applied and oven-
cured before the topcoat is applied. Recent developments have produced an EDP
method which yields a thicker coating that reduces the necessity to use a guide coat.
Note that each coat is usually followed by a flashoff and bake cycle.
Some vehicles are coated with an extra coating called a chip guard or antichip primer.
This coat is applied along the bottom of the doors and fenders to protect against damage
by stones and gravel. These coatings are of flexible urethane or plastisols.
The next coating applied is the topcoat (color). This is applied by a combination of
manual and automatic spraying. Multiple applications are required to produce an ade-
quate appearance and provide durability. The piece may be oven-baked after each top-
coat application, or only after the final application.
After the topcoat has been applied and cured, the painted body piece is taken to a trim
operation area where the vehicle is assembled. Additional coating will be performed
if needed to correct paint defects or damage.
In the past, single coating (not clearcoated) lacquer and enamel topcoats have been
used. Since 1980, the entire domestic auto industry has been converting to a composite,
two-coating topcoat system which consists of a thin layer of a highly pigmented basecoat
followed by a thick layer of clearcoat, referred to as basecoat/clearcoat.
Solvent emissions occur in the application and curing stages of the surface coating
operations. Approximately 70 to 90 percent of the VOC emitted during the application
and curing process is emitted from the spray booth and flashoff areas, and 10 to 30 per-
cent from the bake oven.
Chapter VII Page 10
-------
FROM BODY SHOP
METAL
PRETREATMENT
DRY-OFF OVEN
PRIME
APPLICATION
AREA
PRIME CURE OVEN
FIRST
TOPCOAT
APPLICATION ARE/I
I
RRST TOPCOAT
CURE OVEN
SECOND TOPCOAT
APPLICATION AREA
(IF ANY)
SECOND TOPCOAT
CURE OVEN
(IF ANY)
THIRD TOPCOAT
APPLICATION
AREA
(IF ANY)
COATED PARTS FROM
OTHER LINES
THIRD TOPCOAT
CURE OVEN
(IF ANY)
I
TRIM APPLIED
(SEATS, RUGS,
DASH. TIRES, ETC.)
REPAIR
TOPCOAT
APPLICATION
AREA
REPAIR TOPCOAT
OVEN
(LOW
TEMPERATURE)
FINISHED
PRODUCTS
Figure 17. General flow diagram for automotive and light truck assembly plants. Main bodies
may be on separate lines from hoods and fenders.
MS2/7/S
-------
METAL FURNITURE COATING
Metal furniture coating primarily utilizes solvent-borne coatings applied by spray, dip
and flow coating processes. Coatings are generally about 1 mil thick. These coatings
must be resistant to abrasion, able to withstand regular cleaning with harsh detergents,
and able to maintain a good appearance. The coatings that are used consist primarily
of solvent-borne resins. Acrylics, amine, vinyls, and cellulosics are also used. Office fur-
niture sometimes employs metallic coatings. The solvents used are mixtures of
aliphatics, xylene, toluene, and other aromatics.
Sprav coating is the most common application technique (outlined in Figure 18). Fur-
niture pieces are loaded onto an overhead conveyor and moved to a 3- or 5-state washer.
For example, a 3-state washer contains the following steps: (i) alkaline cleaners to
remove the oil and grease from the metal; (ii) iron phosphate treatment improves the
adhesion characteristics of the metal's surface; (iii) the metal is rinsed in hot water.
After washing the parts, pass through a dry-off oven and then go into a touchup booth.
Here a reinforcement coating may be applied manually by spray guns.
The topcoat operation applies paint by manual or automatic electrostatic spraying.
Color can be changed easily. In manual operations, the operator will purge the line with
solvent, wipe the gun, and connect the line to a new color coating supply. In some larger
operations, different spray guns may be used, each attached to a different feed line.
Dip Coating (shown in Figure 19) is the second most common method of paint applica-
tion. Dip coating may be done manually or automatically. The metal will first pass
through a wash stage (as in spray coating). In dip coating, the furniture pieces are
lowered into a paint tank. They are then raised from the tank and suspend in a flashoff
area over a drainboard. The items are then moved into an oven and cured. The paint
for dip coating is usually a solvent-based alkyd. Color changes are not easy with dip
coating because separate tanks would be needed, each containing separate colors.
Flow Coating (shown in Figure 20), although not very common in coating metal furni-
ture, may also be used. This process has a wash stage similar to both dip and spray coat-
ing. Furniture items are moved into a flow coating chamber where paint is directed at
the object from many angles through as many as 100 nozzles. These nozzles form a cur-
tain of paint through which the item must pass. After application, the coated objects
are held over a drain board in a flashoff area and are then oven cured. Color changes
are not easily accomplished with flow coating, as several chambers would be needed.
One factor that affects the emissions from the coating application step is the transfer
efficiency. This is the portion of applied paint that actually coats the metal. For example,
in electrostatic spray coating, the application efficiency can range from 60 percent for
complex-shaped objects, to 90 percent for simple shapes. Application efficiency is ap-
proximately 90 percent for both dip and flow coating, regardless of the shape.
Chapter VII Page 11
-------
In electrostatic spray coating, approximately 70 percent of the solvent evaporates prior
to the curing step. In flow coating, approximately 80 percent of all solvent emissions
are released in the application and flashoff areas. The remainder come from the curing
ovens. For dip coating, approximately 40 percent of the solvent emissions are released
during application and flashoff.
Chapter VII Page 12
-------
LOAD
3-STAGE
WASHER
DRY OFF
OVEN
UNLOAD
CURING
OVEN
FLASH-OFF
AREA
ELECTROSTATIC
SPRAY BOOTH
Figure 18. Flow diagram - electrostatic spray coating operation.
MS2/7/T
-------
LOAD
3-STAGE
WASHER
DRY OFF
OVEN
UNLOAD
CURING
OVEN
FLASH-OFF
AREA
DIP
TANK
Figure 19. Flow diagram - dip coating operations.
MS2/7/U
-------
LOAD
3-STAGE
WASHER
DRY OFF
OVEN
UNLOAD
CURING
OVEN
FLASH-OFF
AREA
FLOW
CHAMBER
Figure 20. Flow diagram - flow coaling operations.
MS2/7/V
-------
MAGNETIC WIRE COATING
Magnetic wire coating is the process of electrically insulating wire by applying a var-
nish or enamel. A typical wire coating line is shown in Figure 21. The wire is unwound
from a spool and fed into an annealing furnace. The annealing furnace serves two func-
tions. The first is to soften the wire, making it more pliable, which lets it travel through
the pulley network easily. The annealing also acts to burn off any oil or dirt on the wire.
The wire then proceeds into the coating applicator. Here the wire is typically passed
through a bath of coating where it picks up a thick layer of coating. The coated wire
then travels through an orifice or coating die (shown in Figure 22) which removes ex-
cess coating, leaving a uniform coating on the wire. The wire is then dried and cured in
an oven. The wire is then passed through the coating applicator to receive another coat.
This may be repeated four to 12 times.
Coating resins used in magnetic wire coating include: polyester amide imide, polyester,
polyurethane, epoxy, polyvinyl formal, and polyimide. These coating resins maybe dis-
solved in any of several solvents. The most commonly used solvents are cresUic acid,
cresols, xylene, and mixtures of Cs - Ci2 aromatics.
The most important source of solvent emissions is the curing oven. Since magnetic wire
uses a dip coating technique, emissions from the coating applicator are low.
Chapter VII Page 13
-------
DRYING
AND
CURING
OVEN
COATING
DIE
COATING
BATH
Figure 21. Typical wire coating line.
MS2/7/W
-------
TO DRYING OVEN
COATED WIRE
COATED DIE
EXCESS COATING
X
FROM COATING BATH
Figure 22. Wire coating die.
MS2/7/X
-------
MISCELLANEOUS METAL PARTS COATING
A wide a assortment of metal parts and products are coated for decorative or protec-
tive purposes. General categories of products that fall into this discussion include: farm
machinery (i.e., tractors, lawn mowers), small appliances (i.e., fans, mixers), commer-
cial machinery (i.e., computers, typewriters), industrial machinery (i.e., pumps, com-
pressors), and fabricated metal products (i.e., metal-covered doors, frames). The
coatings used in these industries vary, depending on the product. Both enamels and lac-
quers are used, although enamels are the most common. Typical coatings include:
alkyds, acrylics, epoxies, polyesters, vinyls, silicones, plastisols, and phenols. These coat-
ings usually contain several different solvents, although the most commonly used sol-
vents include: esters, alcohols, ethers, ketones, aliphatics, aromatics, and terpenes.
Coating lines in this broad category of coating are unique, depending upon age, product,
design, and application technique. There are several common methods of application
techniques (shown in Figure 23) that may be used. These methods usually include
spray, dip, or flow coating for both single coats and primers. Spray coating is usually
used for the topcoat. The first step for all coating is the cleaning of the metal to remove
grease, dust, and any corrosion. Pretreatment may also be done to improve adhesion.
A 5-stage cleansing process is most common. In this process, the metal is cleaned with
an aqueous caustic solution, rinsed with water, cleaned with a non-caustic solution,
treated with phosphate, and then rinsed again with water. An oven is often used to
remove water after cleaning.
For single-coat operations, spray coating is the most common method, although flow
coating and dip coating are done. Two-coat operations usually use dip or flow coating
for the primer and spray coating is almost always used for the topcoat. In flow coating,
the metal parts are moved by conveyor into a booth where a series of nozzles (station-
ary of oscillating) shoot out streams of coating from multiple locations. The coatings
are said to "flow" over the metal pa rt. The excess coating drains into a sink and is reused.
The transfer efficiency (the portion of coating which is not lost or wasted during the
application process, expressed as a percent) of this technique is approximately 90 per-
cent.
Spray coating provides a 40 to 70 percent transfer efficiency. This technique is per-
formed in a booth to contain overspray, to minimize contamination, and sometimes to
control the atmosphere in which the coating is applied. Spray booths must be main-
tained at a slight negative pressure to capture overspray. Electrostatic spraying with
disc, bell and other types of spray equipment are commonly used to increase transfer
efficiency to 70 to 90 percent. Transfer efficiency also depends on the part being coated,
and if done manually, the expertise of the operator. After coating and flashoff (evapora-
tion area), the parts are baked in single or multi-pass baking ovens.
Chapter VII Page 14
-------
Organic emissions from the coating of miscellaneous metal parts and products are
emitted from the application and flashoff area and the ovens (if used). For spray and
flow coating, the bulk of the VOCs are evaporated in the application and flashoff areas.
For dip coating operations most of the VOC emissions come from the flashoff area and
the oven. VOCs may also be emitted during mixing and transfer of coatings.
Chapter VII Page 15
-------
CLEANSING AND
PRETREATMENT
FLOWCOAT
DIP
SPRAY
a) Conveyorlzed or batch single coat operation.
CLEANSING AND
PRETREATMENT
b) Conveyorlzed two coat operation.
c) Manual two-coat operation air dried.
FLOWCOAT
DIP
SPRAY
PRIMER
OVEN
OVEN
SPRAY
FLASHOFF
OVEN
TOPCOAT
CLEANSING AND
PRETREATMENT
SPRAY
PRIMER
AIR DRIED
SPRAY
TOPCOAT
AIR DRIED _
MS2/7/Y
Figure 23. Techniques commonly used in coating miscellaneous metal parts and products.
-------
ARCHITECTURAL SURFACE COATING
Architectural surface coatings (ASCs) include a wide variety of coatings applied in situ
to stationary structures and their appurtenances, mobile homes, pavements, or curbs.
Traffic coating refers to the painting of the lines and markings on streets, parking lots,
and curbs.
Waterborne coatings are essentially waterborne latex (or emulsion) types and contain
lower amounts of solvents. Solvents used in waterborne ASCs include ketones, esters,
alcohols, and glycols. Solvents used in solvent-borne ASCs include aliphatic hydrocar-
bons, aromatics, and alcohols. Surface air drying is the main source of VOC emissions
from ASCs. Solvents used for thinning solvent-borne ASCs and for cleanup following
application of solvent-borne ASCs also contribute to VOC emissions.
There are many categories of architectural coatings, the main categories of which are
presented below:
Exterior wall paints consist of flat or low-gloss coatings for the protection and decora-
tion of exterior surfaces. Exterior coatings may be applied by brush, spray, or roller.
Solvent-borne coatings and latex coatings are comparable in performance.
Sash, trim and trellis coatings are semigloss and gloss exterior coatings commonly
known as enamels. Solvent-type coatings are alkyd resin-based, while waterborne coat-
ings are acrylic or polyvinyl acetate latexes. Solvent-borne coatings have several ad-
vantages over waterborne coatings, including better adhesion and longer working time.
Interior wall paints consist of both flats and enamels. To provide extra scrubability and
print resistance, interior latex enamels are made with harder polymers. Gloss, scrub
and levening of the latexes are nearly as good as their solvent-borne counterparts.
Latexes are more susceptible to waterborne stains, such as ink.
Stains are intended to coat wood surfaces and reveal some property of the substrate,
color or texture, or both, as well as provide a protective coating. There are interior, ex-
terior, semitransparent, and opaque stains. All types of stains are available as latexes
and solvent-borne types. Solvent-borne stains adhere better to wood than waterborne
latexes. Semitransparent stains have shorter lifespans than opaque stains. This is due
to the fact that semitransparent stains do not shield the wood surface from destructive
ultraviolet radiation, as opaque stains do.
Clear finishes include varnishes, lacquers and shellacs. Varnishes consist mainly of a
binder. The sole purpose of a varnish is to protect surfaces without hiding their natural
beauty. The binding ingredients of interior varnishes may be alkyd, epoxy, or urethane
resins. Exterior varnishes usually consist of oil-phenolic resins. Solvent-borne var-
nishes are generally superior to waterborne varnishes in terms of adhesion, coverage,
gloss, weathering, and stain resistance.
Chapter VII Page 16
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Porch, deck and floor coatings are designed for interior and exterior use on horizon-
tal wood and concrete surfaces. Abrasion resistance is the key to the durability of these
coatings. Solvent-borne coatings are somewhat superior in abrasion resistance, but
latex coatings also have acceptable performances. Solvent-borne coatings have supe-
rior adhesion to both wood and concrete. Latexes are not suitable for use in garages
where oil and gasoline are present, which decreases adhesion.
Traffic paints are used to mark roads, highways and parking lots. Unlike most other
coatings, traffic paints do not protect or enhance the surfaces upon which they are ap-
plied. Their sole purpose is the delineation of traffic lines and parking spaces. A criti-
cal property of traffic paints used on roads and streets is drying time. Until the paint
has dried, traffic cannot pass over it. The paint must not be smeared. Applying traffic
paints constitutes a disruption of traffic. If a traffic paint has a long drying time (greater
than 90 seconds), the crew applying the paint must set out (and remove) traffic cones
to keep traffic off the fresh paint. A slow-moving truck sprays the markings on the road-
way; a second vehicle, equipped with flashing light, follows behind to warn traffic.
The most common type of traffic paint is a chlorinated rubber paint that contains a
volatile organic solvent. This paint has excellent adhesion on both new and old asphalt
surfaces and concrete pavement. This paint has a short drying time (30 to 90 seconds).
Waterborne traffic paints are available and appropriate for some applications. They
have drying times of 60 to 90 minutes. Thermoplastic coating is available as a 100-per-
cent-solids material that is heated to 350-400°F and extruded as thick (30 mil) films on
the roadway surface. It is not suitable for extremely hot or cold climates. Two-com-
ponent, 100-percent solids, epoxy coatings are another option and are more durable
than the more common coatings such as chlorinated rubber paints. They are especial-
ly well suited to areas where sand and salt are used to keep roads open in winter.
Barn and fence coatings are low-cost house paints designed to chalk in order to main-
tain a clean appearance. The chalk and any dirt on the coating are washed off by rain.
They are generally only available in two colors: white and red. Solvent-borne coatings
have superior surface penetration and adhesion.
Roof coatings are bituminous waterproofing materials. These are used where a good
waterproof seal is required and where cost is more important than appearance. There
are two major sources of bitumen: petroleum, which yields asphalt, and coal tar. These
coatings are classified into four groups: primers, asphaltic roof coatings and adhesives,
plastic cement, and miscellaneous waterproofing coatings.
Chapter VII Page 17
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AEROSPACE COATING
Surface coating of aerospace crafts can be a fairly involved process, especially when the
coating of non-commercial planes, such as spacecrafts is concerned. Solvents used in-
clude acetone and methyl ethyl ketone. If the craft is a non-military/space vehicle, the
first step is to prepare the skin of the aircraft to receive the coating. This could require
sandblasting or blasting with plastic beads, followed by a solvent wipe.
There are several possible coatings that may be placed on an aerospace vehicle. The
first possible coating that may be applied to a space-bound craft is a temporary protec-
tive coating which is applied to aerospace components to protect them from any
mechanical environmental damage during manufacturing. This coating would be
removed by a stripper before final coatings are applied. A pretreatment coating which
contains a small quantity of acid is applied for surface etching and is applied directly to
metal surfaces to provide corrosion resistance and ease of stripping. A maskant for
chemical processing may be applied directly to an aerospace component to protect the
surface areas when chemical milling, anodizing, aging, bonding, plating, or etching on
the surface. An adhesive bonding primer may be applied to aerospace metal adhesive
bond detail components for corrosion inhibition and adhesion. A flight test coating
may also be applied to protect the test aircraft from corrosion and provide required
marking during flight test evaluation.
A primer coat may be applied to all types of crafts. This serves two functions. First, it
provides an intermediate surface to maximize the bonding between the topcoat and the
substrate. Second, this coating provides important resistance to corrosion and the en-
vironment. The topcoat is the final coating or series of coatings applied over a primer
or directly to the aerospace component for purposes such as appearance, identifica-
tion, protection, and minimization of aerodynamic drag. With regard to military/space
vehicles, electric or radiation effect coatings may also be applied, which include the
prevention of radar detection.
The aforementioned coatings are applied manually with spray techniques. The use of
mobile hydraulic scaffolding is common and permits the operator to move about and
over the entire aircraft The spray applications methods used include air spray, airless
spray, air-assisted airless spray, and electrostatic spray.
Transfer efficiency (the portion of applied coating that actually coats the plane, ex-
pressed as a percent) is an important factor when discussing aerospace coating. An air
spray produces a fine spray, but the air that aspirates the coating through the nozzle
also introduces turbulence. This air turbulence interferes with the movement of the
paint to the substrate and causes excessive "overspray," or waste (low transfer efficien-
cy). Airless spraying only uses air to pressurize the tank that delivers paint to the spray
gun and minimizes overspray, although the particle size is larger and heavier, and paint
may be wasted when these heavier particles drip to the floor before bitting the sub-
Chapter VII Page 18
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strate. Air-assisted airless spray has better transfer efficiency than either air spray and
airless spray.
In electrostatic spraying, the paint droplets are electrically charged at the gun, and
electrical potential is applied to the substrate, resulting in a very high transfer efficien-
cy. A new type of improved transfer efficiency technique is the use of lamimar airflow
over the surface of the craft during coating operations. For this system, the coating is
sprayed into the air stream where a larger portion of it is impacted onto the surface of
the plane. This results in both a higher transfer efficiency and a thinner coat, both of
which are desirable.
VOC emissions come from low transfer efficiencies and also from solvent emissions
during flashoff and curing processes, as in most coating operations. The most promis-
ing coating technology for topcoats for aerospace vehicles in the future (for reducing
VOC emissions) seems to be two-component, reaction-type chemistries, such as
polyurethanes.
Chapter VII Page 19
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WOOD FURNITURE SURFACE COATING
The wood furniture industry is a very large source of VOC emissions. The traditional
coatings contain very little solids material because approximately 90 percent of the
coating is solvent. Also, because the coatings have such a low solids content, many ap-
plications of coating are needed to build the coating film. Most wood products are
coated in a similar fashion, although furniture will receive a much more elaborate series
and greater number of finishes than kitchen cabinets.
The standard sequence of coating steps is as follows: body stain, wash coat, filler, sealer,
glaze and shading, and the final topcoat. In large furniture factories, pieces of furniture
are loaded onto a conveyor line. Workers stationed along the line perform specific
finishing operations as the furniture piece passes to them. Coatings are usually applied
by air spray, although dip coating may be used occasionally. Each coating operation
usually has a separate spray booth, and typically, one to three spray gun operators. After
the coating has been applied, the furniture goes either to another spray booth or to a
drying area.
Wood furniture coatings generally do not need to be oven cured, although if they are,
only low temperatures may be used. Ovens are mainly used to flashoff and dry solvent
because the oven temperatures are not hot enough to really bake or cure the coating.
The wood cannot be heated above 130°F. At higher temperatures, the natural moisture
in the wood may be driven out and damage the coating. Coating lines without ovens
rely on air drying.
The coating operation may include various glazes, shading stains, wiping stains, and
padding stains that are usually added between the sealer and topcoat. These stains are
usually sprayed on and wiped by hand. The more expensive the piece of furniture, the
more hand-rubbing work is done.
VOC emissions from a wood furniture coating line come almost entirely from the coat-
ings. Conventional coatings usually consist of nitrocellulose resins and organic solvents.
Common solvents used include: acetone, acetates, alcohols, aromatic hydrocarbons,
esthers, glycol ethers, ketones, and mineral spirits.
The coating step that has the highest emissions is the application of the topcoat. Ap-
plying the topcoat usually requires two to three coats. More than 85 percent of topcoats
are nitrocellulose lacquers, which have many desirable properties, the most important
of which is the excellent appearance of the finish. About IS percent of topcoat materials
are other synthetic organic resins such as urea formaldehyde and catalyzed urethane
finishes. These are very durable and are used on cheaper furniture and institutional
furniture.
Chapter VII Page 20
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GRAPHIC ARTS
The graphic arts industry includes printing operations which fall into four principal
categories: rotogravure, flexography, lithography, and letterpress. Printing operations
of any sizeable volume use presses where the image carrier is curved and mounted on
a cylinder that rotates, or the image is engraved or etched directly on the cylinder. This
setup is referred to as a rotary press. In direct printing, the image is transferred direct-
ly from the image carrier to the substrate. In offset printing, the image is first trans-
ferred to an intermediate roll (blanket roll) and then to the substrate. When the
substrate is fed to the press from a continuous roll, it is referred to as a "web."
In rotogravure printing, the image areas are recessed relative to nonimage areas. The
rotating cylinder picks up ink from an ink tray (see Figure 24). Excess ink is scraped
from the blank area by a steel doctor blade, and the ink is then transferred directly from
the roll to the web. The web is then cured at low temperatures in an oven. Typical ink
solvents include alcohols, aliphatic napthas, aromatic hydrocarbons, esters, glycol
ethers, ketones, and nitroparaffins. Major emission points in rotogravure printing in-
clude the ink trays, wet printing cylinders, wet printed web, drier exhaust, and general
solvent cleanup.
Flexography is based on the fact that the image areas on the image cylinder are raised
above the non-image areas. The image carrier is made of rubber and attached to the
cylinder. A feed cylinder rotates in an ink fountain and delivers ink to a distribution
roll which in turn transfers ink to the image cylinder (see Figure 25). After the ink is
transferred from the image cylinder to the substrate, the ink dries by evaporation in a
high-velocity, low-temperature (less than 120°F) air dryer. Typical ink solvents are al-
cohols, glycols, esters, hydrocarbons, and ethers. VOCs are emitted from the ink foun-
tains, feed cylinder, distribution roll, image cylinder, printed web, dryer exhaust, and
general solvent cleanup.
Lithography employs a planographic image carrier (the image and on-image areas are
on the same plane) that is mounted on a plate cylinder. The image area is made water-
repellent, while the non-image area is made water-receptive. The plate cylinder rotates
and first encounters an aqueous fountain solution that typically contains up to 25 weight
percent isopropyl alcohol which wets the non-image areas of the plate. The image plate
then contacts only the ink that adheres to the image area. In offset lithographic print-
ing, the ink is transferred from the image plate to a rubber-covered blanket cylinder.
The blanket cylinder than transfers the image to the web. If lithographic heat-set inks
(which contain approximately 40 percent solvent) are used, a heated dryer is required
to solidify the printed ink. Other inks containing 5 percent solvent dry by absorption
into the substrate (i.e., paper) or by oxidation. VOC emission come from the ink foun-
tains and inking rollers, the water fountains and associated dampening rollers, the final
evaporation of the applied ink, and general solvent cleanup. When heat-set inks are
used, the drying oven is the major source of VOC emissions.
Chapter VII Page 21
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The final form of the printing operations is letterpress. Here the image areas are raised
relative to the blank, or non-image, areas. The image carrier may be made of plastic or
metal. Viscous ink is applied to the image carrier and transferred directly to the sub-
strate. Letterpress dominates periodical and newspaper publishing. Newspaper ink is
composed of petroleum oils and carbon black, containing no organic solvents. Web
presses printing on nonporous substrates employ solvent-borne inks that dry by
evaporation. Sheet-fed presses employ solventless inks that dry by oxidation. VOCs are
emitted from web letterpress printing lines from the image carrier and inking
mechanism of the press, the dryer, the chill rolls, the printed product, and general sol-
vent cleanup. Approximately 60 percent of the solvent is evaporated in the drying
process.
Chapter VII Page 22
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PLATE
CYUNDER
DISTRIBUTION
ROLLERS
INK FOUNTAIN
Figure 24. Rotogravure Ink System
(A) Etched Cylinder
(B) Impression Cylinder
Figure 25. Ink Distribution system for flexography.
MS3/1/A
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MARINE COATING
The construction of a new ship requires the following coating procedures: steel plates
are coated with 0.5 mil weldable preconstruction primer coating; plates are cut and
fabricated into panels that are then assembled into ship sections in shops; preconstruc-
tion primer may then be removed by blasting, after which welding areas are marked off
and the remaining areas painted (interior and exterior) with primer and/or first coat;
units are assembled, welded, and tested for strength before the final finish coating, in-
cluding topcoat and any antifouling coat, is applied. All coating (except at the plate
stage) is usually carried out in the open, usually because of the size of the substrate. A
ship coating system consists of several layers of primer, intermediate coat, topcoat (or
finish coat) and antifoulant coat (exterior, below the water line).
Recreational boats are generally built from fiberglass reinforced polyester, aluminum,
or occasionally, wood. Fiberglass-polyester boats are the most common. Glass-rein-
forced polyester (GRP) boats are constructed by applying glass cloth to preformed
molds, saturating the glass with a catalyzed polyester resin, and allowing the composite
GRP to harden. GRP boasts receive a 15 mil polyester gel coat curing the mold-
ing/fabrication process. The gel consists of about 60 percent (volume) polyester resin
and 40 percent stryrene monomer. Approximately half of the styrene is retained; the
other half evaporates.
Of the aluminum boats that are constructed, only a small portion are coated. The
aluminum boats that are coated undergo three basic steps. First, the surface is prepared
for coating, which may include cleaning and roughening. The prepared surface is usual-
ly sprayed with a thin layer of wash primer containing zinc chromate, phosphoric acid
and polyvinyl butryl (VOC content is approximately 63 percent). The primer coat is fol-
lowed by an alkyd finish coat, applied by standard air-spray or airless spray equipment.
Coatings are usually heat cured.
Sources of VOC emissions include low-transfer efficiencies for air-spray equipment
and evaporation during drying and curing of coatings. General coatings used in the in-
dustry include: epoxy amine, epoxy polyamine, polyurethane, vinyl, chlorinated rubber,
alkyds, inorganic zinc, and acrylics.
Chapter VII Page 23
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PLASTIC PARTS FOR BUSINESS MACHINES
Plastic parts for business machines and computers may be coated in two ways. Metal-
filled coatings may be applied to interior surfaces to provide electromagnetic inter-
face/radio frequency interference (EMI/RFI) shielding from signals that would
otherwise pass through plastic housings. Coatings may also be applied as decorative
and protective finishes. These coatings are used to match colors or to protect the piece
from environmental stresses (such as abrasion, salt, and solvent). Figure 26 shows the
steps involved in each type of coating procedure. Not all plastic parts must undergo
coasting processes. However, if both are planned, EMI/RFI shielding is performed
first.
To understand why decorative coatings are used, the methods of molding the plastic
parts should be mentioned. There are two standard forms of molding: structural foam
injection molding (SFIM) and straight injection molding (SIM). SFIM creates plastic
parts that have flows on their surface and usually need significant surface coating. SIM,
on the other hand, has the ability to create molded-in color and texture, requiring lit-
tle or no decorative coating. While SFIM does not produce perfect pieces, it is one-
third to two-thirds less expensive than SIM.
Coatings used as EMI/RFI shielding must meet standards regarding conductivity and
adhesion. Conductivity is required for both EMI/RFI shielding and electrostatic dis-
charge (ESD) protection. EMI/RFI shielding is best achieved with coatings with
grounded, high-conductivity coatings. However, ESD protection is best achieved with
grounded, low-conductivity coatings. EMI/RFI coatings must also pass tests, such as
exposure to high temperature, humidity, and thermal cycling. Only coatings that pass
these tests are considered to be safe from the risk of electrical shock, fire, or personal
injury.
Coatings for plastic parts are spray-applied. There are three basic spraying techniques:
air-atomized spray, air-assisted airless spray, and electrostatic air spray. Air-atomized
spray is the most common method. This technique used compressed air to atomize the
coating and to direct the spray. Transfer efficiencies (the portion of the applied coat-
ing that actually coats the part) tend to be low for this method (giving rise to higher
emissions for this process). EMI/RFI coating done in this manner has fewer emissions
than decorative coatings, because of the lower pressures used. EMI/RFI coating is
usually done on the inside of the parts where coating that bounces off the coating sur-
face is more likely to hit another surface of the same piece.
Air-assisted airless spray is not very common, although it is growing in popularity. The
coating is atomized without air by forcing the liquid coating through specially designed
nozzles. Transfer efficiencies for air-assisted airless spraying are better than for air-
atomized spraying. Electrostatic air spray is only rarely used because plastic parts are
not conductive. When this type of coating is done, the coating is usually charged, and
Chapter VII Page 24
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the parts being coated are grounded. This creates -an electric potential between the
coating and the plastic. The atomized coating is attracted to the plastic by electrostatic
force. Electrostatic air spraying has a high transfer efficiency.
EMI/RFI shielding is usually done by either zinc-arc spraying (a process that emits no
VOC) or by using organic solvent-based waterborne, metal-filled coatings. Electrotess
plating, conductive plastics, metal inserts, vacuum metallizing, and spattering are also
possible methods, although none are very common.
Zinc-arc spraying is a two-step process in which the surface to be coated (usually the
interior of a housing) is first roughened by sanding or grit-blasting and then spray-
coated with molten yin<* .Zinc-arc spraying is usually done manually, although some
robots are available for this process.
Organic solvent-based conductive coatings contain particles of nickel, silver, copper,
or graphite in either acrylic or urethane resin. Nickel-EDed acrylic coatings are most
commonly used because of their shielding ability and cost. Conductive coatings can be
applied with most conventional spray equipment. They are usually applied manually
with air spray guns, although air-assisted airless spray guns are sometimes used. Coat-
ing involves three steps: surface preparation (cleaning and surface roughening by light
sanding), coating application, and curing (usually at room temperature, although some
must be cured in an oven).
The most common exterior coatings for plastic pans are organic, solvent-based two-
component catalyzed urethanes. The isocyanate catalysts in these coatings allow low-
temperature curing. The most commonly used waterborne paints are waterbome
acrylics.
There are several problems with coating plasticparts. Somephistics are easny damaged
by organic solvents that are present in organic, solvent-based and waterborne coatings.
Plastics also have a tendency to deform at temperatures that are commonly used to cure
coatings on metal parts.
Chapter VII Page 25
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EMI/RFI
SHIELDING
PROCESS
SURFACE
PREPARATION
/METAL-
f FILLED
VCOATING
DECORATIVE/
PROTECTIVE
EXTERIOR
COATING PROCESS
SURFACE
PREPARATION
( SPRAY A
I COATING J
f CURE J
Figure 26. Coating processes for plastic parts used i n business machines.
MS3/1/B
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FLEXIBLE AND RIGID DISC COATING
A magnetic data storage disc consists of a flat, circular substrate material that is coated
with a thin magnetic film. A disc is categorized as being "flexible" or "rigid" on the basis
of the substrate material used. Data is stored on a disc by selective magnetization of
portions of the coated disc surface. Flexible discs (also known as "floppy disks" or "dis-
kettes") have a thin, durable plastic film substrate. Flexible discs are enclosed in a plas-
tic envelope and are coated with a lubricating material to facilitate rotation of the disc
in the envelope. Rigid discs (also known as "hard discs") have a circular, non-flexible
substrate typically made of aluminum alloy.
Disc manufacturing has five steps that involve coating: coating preparation, substrate
cleaning, substrate coating, disc polishing, and disc overcoating. Coating preparation
consists of milling and mixing a magnetic surface coating in liquid form. Organic sol-
vents are used and are typically thinned to about 75 percent VOC by volume.
The next step is substrate cleaning. Disc substrates are cleaned before coating to
remove surface contaminants and oxidation. This is often done with a detergent solu-
tion that emits no VOCs. Sometimes, however, organic solvents may be used for clean-
ing. Conventional degreasing units may be used, or special devices that use a
solvent-soaked cleaning head (typically isopropyl alcohol).
Substrate coating is done by applying a liquid magnetic coating to the flexible disc sub-
strate material in a web coating process in large rolls. The coated substrate subsequently
cut into individual flexible disks. Rigid disks (and some flexible discs) are coated in-
dividually in spin coating units.
After the magnetic coating has cured, disc polishing is performed to increase surface
smoothness, resolution, and gloss. The discs are rotated and polished with special
devices. The polishing heads are typically soaked with an organic solvent (isopropyl al-
cohol).
The final stage of disc preparation is disc overcoating. The polished discs are coated
with a lubricating material. These coatings generally use organic solvents which are
usually fully halogenated organic compounds (such as trichlorotrifluoroethane).
Emissions from coating preparation arise as fugitive emissions from mixing operations.
Evaporative VOC emissions also occur form large solvent sinks used to clean coating
vats and mixing equipment (methyl ethyl ketone is the most common cleanup solvent).
Both of these sources are considered minor emission sources. VOC emissions also
originate from evaporation from substrate cleaning, coating application and disc polish-
ing while the solvent evaporates and the disc dries.
Chapter VII Page 26
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BIBLIOGRAPHY
Can Coating
U.S. EPA, Office of Air Quality Planning and Standards. "Beverage Can Surface
Coating Industry-Background Information for Proposed Standards" EPA-
450/3-80-036a, September 1980.
U.S. EPA, Office of Air and Waste Management, Office of Air Quality Planning and
Standards. "Control of Volatile Organic Emissions from Existing Stationary
Sources. Volume II: Surface Coating of Cans, Coils, Paper, Fabrics,
Automobiles, and Light-Duty Trucks." Chapter 2, EPA-450/2-77-008, May 1977.
Paper Coating
U.S. EPA, Office of Air and Waste Management, Office of Air Quality Planning and
Standards. "Control of Volatile Organic Emissions from Existing Stationary Sour-
ces. Volume II: Surface Coating of Cans, Coils, Paper, Fabrics, Automobiles,
and Light-Duty Trucks." Chapter 5, EPA-450/2-77-008, May 1977.
Fabric Coating
U.S. EPA, Office of Air and Waste Management, Office of Air Quality Planning and
Standards. "Control of Volatile Organic Emissions from Existing Stationary
Sources. Volume II: Surface Coating of Cans, Coils, Paper, Fabrics,
Automobiules, and Light-Duty Trucks." Chapter 4, EPA-450/2-77-008, May
1977.
Metal Coil Coating
U.S. EPA, Office of Air and Waste Management, Office of Air Quality Planning and
Standards. "Control of Volatile Organic Emissions from Existing Stationary
Sources. Volume II: Surface Coating of Cans, Coils, Paper, Fabrics,
Automobiles, and Light-Duty Trucks." Chapters, EPA-450/2-77-008, May 1977.
U.S. EPA, Office of Air Quality Planning and Standards. "Metal Coil Surface Coat-
ing Industry-Background Information for Proposed Standards." EPA-450/3-
80-036a, October 1980.
Flat Wood Paneling
U.S. EPA, Office of Air Quality Planning and Standards. "Control of Volatile Organic
Emissions from Existing Stationary Sources. Volume VII: Factory Surface Coat-
ing of Flat Wood Paneling." EPA-450/2-78-032, June 1978.
U.S. EPA, Office of Enforcement, Office of General Enforcement. "Enforceability
Aspects of RACT for Factory Surface Coating of Flat Wood Paneling." EPA-
340/1-80/005, April 1980.
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BIBLIOGRAPHY
(Continued)
Automobile & Light-Duty Truck Coating
U.S. EPA, Office of Air Quality Planning and Standards. "Automobile and Light-Duty
Truck Surface Coating Operation-Background Information for Proposed Stan-
dards." EPA-450/3-79-030, September 1979.
U.S. EPA, Office of Air and Waste Management, Office of Air Quality Planning and
Standards. "Control of Volatile Organic Emissions from Existing Stationary Sour-
ces. Volume II: Surface Coating of Cans, Coils, Paper, Fabrics, Automobiles,
and Light-Duty Trucks." Chapter 6, EPA-450/2-77-008, May 1977.
Metal Furniture Coating
U.S. EPA, Office of Air Quality Planning and Standards. "Control of Volatile Organic
Emissions from Existing Stationary Sources. Volume III: Surface Coating of
Metal Furniture." EPA-450/2-77-032, December 1977.
U.S. EPA, Office of Air Quality Planning and Standards. "Surface Coating of Metal
Furniture—Background Information for Proposed Standards." EPA-450/3-80-
007a, September 1980.
Magnetic Wire Coating
U.S. EPA, Office of Air and Waste Management, Office of Air Quality Planning and
Standards. "Control of Volatile Organic Emissions from Existing Stationary Sour-
ces. Volume IV: Surface Coating for Insulation of Magnet Wire." EPA-450/2-
77-033, December 1977.
Miscellaneous Metal Parts Coating
U.S. EPA, Office of Air Quality Planning and Standards. "Control of Volatile Organic
Emissions from Existing Stationary Sources. Volume VI: Surface Coating of Mis-
cellaneous Metal Parts and Products." EPA-450/2-78-015, June 1978.
Architectural Surface Coating
State of California Air Resources Board. "Consideration of Model Organic Solvent
Rule Applicable to Architectural Coatings." Internal Report, June 1977.
State of California Air Resources Board. "Results of 1984 Architectural Coating
Sales Survey." ARB/SS-846-03, July 1986.
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BIBLIOGRAPHY
(Continued)
Aerospace Coating
South Coast Air Quality Management District, 9150 Flair Drive, El Monte, CA 91731.
"Aerospace Assembly and Component Coating Operations." Rule 1124.
U.S. EPA, Office of Air Quality Planning and Standards. "Summary of Technical In-
formation for Selected Volatile Organic Compound Source Categories." Chap-
ter 14, EPA-400/3-81-007, May 1981.
Wood Furniture Surface Coating
U.S. EPA, Office of Office of Air Quality Planning and Standards. "Summary of Tech-
nical Information for Selected Volatile Organic Compound Source Categories."
Chapter 16, EPA-400/3-81-007, May 1981.
Graphic Arts
U.S. EPA, Office of Air Quality Planning and Standards. "Control of Volatile Organic
Emissions from Existing Stationary Source. Volume VIII: Graphic Arts-
Rotogravure and Flexography." EPA-450/2-78-033, December 1978.
Marine Coationg
State of California Air Resources Board. "Consideration of a Proposed Model Rule
for the Control of Volatile Organic Compounds from Marine Coating Opera-
tions." Internal Report, June 1978.
U.S. EPA, Office of Office of Air Quality Planning and Standards. "Summary of Tech-
nical Information for Selected Volatile Organic Compound Source Categories."
Chapter 15, EPA-400/3-81-007, May 1981.
Plastic Parts for Business Machines
U.S. EPA, Office of Office of Air Quality Planning and Standards. "Surface Coating
of Plastic Parts for Business Machines-Background Information for Proposed
Standards." EPA-450/3-85-019a, December 1985.
Rexible & Rigid Disc Coating
Bay Area Quality Management District Staff, 939 Ellis Street, San Francisco, CA
94109. "Technical Report and Suggested Control Measures: Flexible and Rigid
Disc Manufacturing." August 1986.
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Chapter VIII
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CHAPTER VIII
A COMPREHENSIVE REVIEW OF VOC-COMPLIANT
LIQUID COATING TECHNOLOGIES
-------
A COMPREHENSIVE REVIEW OF
VOC-COMPUANT UQUID COATING TECHNOLOGIES
Summary
This chapter reviews the advantages and disadvantages of 10 of the
most commonly used VOC-compliant liquid coating technologies, in-
cluding water-based air and baked coatings, single- and plural-com-
ponent solvent-based coatings, autodeposited and electrodeposited
coatings.
The data presented is intended to serve as an invaluable guide to per-
sons who need to make decisions on a compliant liquid coating system.
Chapter VIII
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CHAPTER VIII
A COMPREHENSIVE REVIEW OF VOC-COMPUANT
LIQUID COATING TECHNOLOGIES
Low-Cure Water-Reducibles, Alkyds & Acrylis
VOCs Less Than 2.8 Ibs/gal (340 g/L) 1
High-Bake Water-Reducibles, Alkyds, Acrylics Polyesters
VOCs Less than 2.3 Ibs/gal (275 g/L) 2
Water-Reducible Epoxy Coatings
VOC less than 2.8 Ibs/gal (340 g/L) 3
High-Solid Alkyds and "Acrylics" Air- or Force-Dry
VOCs Less Than 3.5 Ibs/gal (420 g/L) 4
High-Solid Alkyds, Acrylics and Polyesters, Solvent-
Based, Baking Coatings
VOCs Less Than 2.3 Ibs/gal (275 g/L) 5
High-Solid Epoxy Primers and Top Coats, Solvent-Based
VOCs Less Than 2.8 Ibs/gal (340 g/L) 6
High-Solid Polyurethanes (Two-Component)
VOCs Less Than 2.8 Ibs/gal (340 g/L) 7
High-Solid Polyrethanes, Moisture-Curing Industrial Coatings
VOCs Less Than 3.5 Ibs/gal (420 g/L) 8
Polyurethane End Uses 9
Autophoretic Coatings Amchem (Sole Source) 10
Autophoretic Coatings, Typical Line Comprises 11
The Principle of Electrodeposition 12
Typical Electrocoating Line 13
Electrocoatings (Anodic and Cathodic)
VOC Less Than 2.3 Ibs/gal (275 g/L) 14
Electrodeposition (Anodic versus Cathodic) 15
Electrodeposited Coatings, Typical End Uses 16
-------
LOW-CURE WATER-REDUCIBLES, ALKYDS & ACRYUCS
VOCs Less Than 2.8 Ibs/gal (340 g/L)
ADVANTAGES
Some emulsion systems available at
very low VOCs
For use on steel, aluminum and plastics
One-component material
No pot life limitations
Relatively easy cleanup when
prescribed
procedures are followed
Low-cure temperatures (ambient
air-dry 10-30 mins. or force-dry at
150°F for 10-20 mins.)
Can be spray-applied with standard
equipment
Touch-up with itself
Water is primary solvent
Available in low-gloss and semi-gloss
and up to approximately 85-90% on
GO gloss
Can be used for textured finishes
Available in wide range of colors
Lower fire hazard
Lower toxitity
Lower costs for reducing solvents and
cleanup
Exterior durability better than
conventional solvent-based
counterparts
Appearance reasonably good (not as
high in gloss as conventional
solvent-based counterparts, but
technology is improving)
Chemical resistance better than
conventional solvent-based
counterparts
Solvent resistance better than con-
ventional solvent-based counterparts
DISADVANTAGES
Generally, poorer chemical resistance,
compared with 2-part polyurethanes or
high-bake water-reducibles.
3-step equipment cleanup: water,
solvent, water.
Does not meet standards for "high"
performance in industry, such as
heavy-duty maintenance, aerospace,
appliance, automotive.
More sensitive to substrate cleanliness
than most solvent systems.
Requires greater learning curve with
regard to viscosity management than
other compliant coatings.
Currently not available in high-gloss
levels greater than 90 units @ 60°
Generally, primers do not have as good
a salt-spray resistance as conventional
solvent-based counterparts.
Chapter VIII
-------
HIGH-BAKE WATER-REDUCIBLES, ALKYDS, ACRYUCS & POLYESTERS
VOCs Less Than 2.3 Ibs/gal (275 g/L)
ADVANTAGES
DISADVANTAGES
High-bake emulsions available at very
tow VOCs.
Excellent film performance, often
equivalent to polyurethanes
For metal substrates only, due to high
temperature of bake, except for
high-temperature plastics
No pot life limitations
One-component material
Water is primary solvent
Can be spray-applied with standard
equipment
Touch-up with itself
Available in all gloss levels
Can be used for texture finishes
Meet industry standards for many
top-of-the-line applications, such as
computers, business machines, lighting
fixtures, appliances, automotive, coil, etc.
Available as primers and topcoats
In many cases, can be applied directly
to metal without need for primer
Lower fire hazard
Lower toxicrty than solvent-based
system
Lower costs for reducing solvents and
cleanup
Requires high-temperature oven (about
350DF) for 15-25 minutes
High-energy usage
Not for use on plastics, except
high-temperature plastics
Unreliable performance on porous
castings due to outgassing
Touch-up may require second bake or
use of another air-dry coating
Not applicable where parts such as
machined surfaces high tight
dimensional tolerances and cannot
tolerate warpage
Surface cleanliness is more critical than
for solvent systems
Chapter VIII
Page 2
-------
WATER-REDUCIBLE EPOXY COATINGS
VOC Less Than 2.8 Ibs/gal (340 g/L)
ADVANTAGES
DISADVANTAGES
Primers available in chromate and
non-chromate formulations
Primers meet military specifications
MIL-P-85582 and MIL-P-53030
Can dry quickly, even in highly humid
enviomments if there is good ventilation
With good ventilation, can often be
recoated within 30 minutes.
Compatible with many types of
top-coats.
Can be applied with conventional spray
equipment
Primer available in small range of colors
Topcoats can be made in wide range of
colors (but not in small quantities)
3-Component material; base, curing
agent, water
Must be mixed using prescribed
procedures
Relatively expensive as packaged, but
competitive with solvent-based epoxies
Pot life can vary from about 6 hours to
more than 8 hours, depending on air
temperature and humidity
Sometimes difficult to dean equipment
and skin
Chapter VIII
Pages
-------
HIGH-SOLID ALKYDS AND "ACRYUCS" *
AIR-OR FORCE-DRY
VOCs Less Than 3.5 Ibs/gal (420 g/L)
ADVANTAGES
Single-component coatings
Properties similar to those of lower solids
alkyds
Available at VOC levels of 3.5 Ibs/gal, with a
few at 2.8 Ibs/gal VOC
Formulated as primers & topcoats
Some can be reduced with 1,1,1, -
Trichloroethane to speed drying & reduce
coating viscosity
Those that are formulated with
1,1,1 ,-Trichloroethane solvent are easy to
apply
Ambient (room) temperature air-drying
Can be force-dried below 194°F
Can be spray-applied with conventiona air
spray, airless, air-assisted airless &
electrostatic
Available in a wide range of colors and all
gloss levels
Touch-up with itself
Can be applied to most substrates
Less sensitive to surface cleanliness of
substrate than most other coatings
Preferred choice of coating for many
low-to-medium cost items or large
machinery that cannot be subjected to
high-temperature ovens
Average cost: $10-20 per gallon
•Note: So-called "acrylic air-drying" coatings are usually not based on pure acrylic resins. In-
stead, they are alkyd coatings that have been modified with acrylic resins to Improve
the chemical and physical properties. Baked coatings are primarfly based on straight
and modified acrylic systems.
"Note: These comments apply generally to the high-solids formulations. Compliant alkyds
which are formulated with 111. Trichloroethane perform very much like conventional
solids alkyds and do not exhibit the same disadvantages as high-solids coatings.
DISADVANTAGES
High solids formulations generally
have long ambient air-drying times
(approx. 6-8 hours) **
Often difficult to maintain film
thickness lean than 1.5 mils **
Generally, higher viscosities than
comparable poryurethanes. Some
formulations require coating to be
heated during spray application **
Gloss variations from one surface to
the next **
Long recoating times-sometimes
several hours or overnight **
Often have a "critical" recoating
period
Not generally used for texture
finishing
Not readily available in quantity
custom colors **
Generally soft coatings with a pencil
hardness of HB
Tend to have limited resistance to
UV radiation
Chalking and color fading are
prevalent; when exposed to sunlight
Chapter VIII
-------
HIGH-SOUDS ALKYDS, ACRYUCS AND POLYESTERS,
SOLVENT-BASED, BAKING COATINGS
VOCs Less Than 2.3 Ibs/gal (275 g/L)
ADVANTAGES
DISADVANTAGES
Excellent high performance properties
Single Component
Available at VOC levels of 2.3 Ibs/gal (275
9/L)
Available in wide range of colors and gloss
levels
Can be applied directly to metal substrates
Excellent for appliances such as washers,
driers, dish washers, refrigerators
With proper controls, can achieve uniform
thin-film thickness (approx. 1 mil)
Excellent hardness, 2H available
In most cases, does not need special
applicaiton equipment
Good adaptability to high-speed lines
Rim properties better than alkyds
Some energy savings because of lower
solvent concentrations.
Must be baked at elevated
temperatures (300°F) for curing
High-energy usage
Remains tacky at ambient
temperature and leaves walls, floors
of spray booths tacky
High viscosities of compliant coatings
require special application equipment
Not for plastic substrates
Stains caused by the spray washer
cleaning process often
•photographed" through the coating
finish
Slight changes in application
temperature can greatly affect
viscosity
Some coatings must be
spray-applied at temperatures of
100-110dF
Difficult to achieve smooth finishes
Requires dose application controls
Operators require a learning curve
Applied costs are greater than for
-conventional solids baking enamels
Chapter VIII
Pages
-------
HIGH-SOUDS EPOXY PRIMERS AND TOP COATS,
SOLVENT-BASED
VOCs Less Than 2.8 Ibs/gal (340 g/L)
ADVANTAGES
DISADVANTAGES
Available to meet some military primer and
topcoat specifications (MIL-P- 53022,
MIL-C-22750)
Possible to formulate in wide range of colors
and gloss levels
Achieves excellent hardness and chemical
resistant properties
Can air-dry at ambient temperature within 3-5
hours and force-dry at 150 F within 30
minutes
Primarily used in military, marine and
chemical plant applications.
For application to steel, aluminum or plastic
2-Component systems
Poor resistance to UV exposure
(sunlight)
Difficult to apply thin films less than 1.5
mils, particularly when painting
complex shapes
Very few sources of supply
Generally not available in small
quantities of custom colors
Generally require a short induction
period of 20-30 mins. before coating
can be applied
Pot life limitations of 4 to 6 hrs. at
ambient temperature
Average cost $15-25/gallon
Application equipment must be
cleaned before coating starts to set
Sensitive to cleanliness of substrate
Chapter VIII
Page6
-------
HIGH-SOLIDS POLYURETHANES (TWO-COMPONENT)
VOCs Less Than 2.8 Ibs/gal (340 g/L)
ADVANTAGES
Excellent physical film performance
Excellent resistance to most solvents
Excellent chemical reisitance
Excellent outdoor durability (primarily
aliphatic potyurethanes)
Cure at ambient (room) temperatures or
at elevated temperatures
For application to steel, aluminum and
plastics
Can be spray-applied with standard
equipment
Available in large and small quantities,
wide range of colors, quick turnaround
Good range of gloss and texture levels
Can touch-up with itself
Meets performance standards for
top-of-the-line products such as
computers, business machines, aircraft,
truck cabs, etc.
Can often be applied directly to dean
plastic surfaces
Hard, mar-resistant coatings with pencil
hardness up to 6H
Available as "polyester" or "acrylic"
potyurethanes
•Polyester" coatings have better
chemical resistance
•Acrylic1 coatings have better exterior
UV (sunlight) resistance
DISADVANTAGES
Two-component system
Limited pot We-sometimes less than 6
hours
With high-solids formulations,
reasonably difficult to obtain Class "A"
smooth finish
High-solids formulations (VOC less than
2.8 Ibs/gal) may require proportioning
spray equipment
Can be difficult to achieve uniform film
thicknesses on complex shaped parts
Equipment must be cleaned before
coating begins to set up
Relatively expensive (usually more than
$30/gallon). Aliphatic potyurethanes for
exterior exposure are more expensive
than aeromatic poJyurethanes for interior
exposure
Must be handled with care, and painters
must use special respirators
Potyurethanes can have harmful effects
on some people, particularity if they do
not wear appropriate respirators
May need to be applied over epoxy
primer
Must be applied over dean, pretreated
or primed surfaces
High gloss, high-solids acrylic
potyurethanes are generally not available
at 2.8 Ibs/gal (340g/l), but are available at
3.5 Ibs/gal
At the present time, high gloss, acrylic
potyurethanes are not readily available in
small quantities of "automotive" colors,
but are available in fleet" colors
Chapter VIII
Page?
-------
HIGH-SOLIDS POLYURETHANES,
MOISTURE-CURE INDUSTRIAL COATINGS
VOCs Less than 3.5 lbs\gal (420 g/L)
ADVANTAGES
DISADVANTAGES
Single-component system
No pot life limitations
Has all of the advantages of two-
component polyurethane coatings
Achieves chemical-resistant
properties more quickly
than some two-component
polyurethane
A technology with less field history
than 2-oomponent polyurethanes
Currently, only two or three
companies supply in range of colors
and gloss levels
Not yet available in wide range of
colors or in small quantities
May have limited shelf life (less than
6 months)
Very sensitive to moisture
contamination; therefore, requires
special effort to keep moist air from
the packaged or stored coating
Drying time is affected by moisture
in air. In very dry climates, the drying
time may be longer than usual.
Currently may be more expensive
than 2-component polyurethanes
Has other disadvantages of
2-component polyurethanes
Average cost greater than $35/gallon
Chapter VIII
-------
POLYURETHANE END USES *
Transportation
Aircraft skins
Missiles and other aerospace products
Over-the-road trucks
Buses
Railcars
Automotive refinishing
Automotive OEM (newty introduced high-gloss dear coat over metallic base coat)
Chip-resistant primer surfacers (baked)
Flexible coatings for plastic facias, bumpers
Military
Aircraft
Ground support equipment such as tanks, personnel earners, vehicles, etc. with
resistance to live chemical agents (CARC)
Architectural & Maintenance
Structures and vessles in chemical plants
Offshore drilling rigs
Bridge maintenance
Topcoats for urethane roofs
Anti-grafitti coatings in many metropolitan cities
Pipelines
Product Finishing
Machine tools
Garden lawnmowers, snowblowers, tractors
Plastic housings, keyboards, etc. in computer & business machines markets
Computer & business machines, medical & laboratory equipment
Wood coatings for furniture
Coil coated stock for under-the-hood components
Reference: T. A. Potter and J. L Williams, M of Coating Technology,"
59, No. 749, June 1987, 69-70.
Chapter VIII Page 9
-------
AUTOPHORETIC COATINGS
AMCHEM (SOLE SOURCE)
ADVANTAGES
Very low VOC contents:
Product 701 -1.6 Ibs/gal, less water
Product 861 - 0 Ibs/gal
Excellent corrosion resistance
Requires thorough degreasing of steel, but
does not require phosphatizing
Excellent flexibility and impact resistance
(Product 861)
Uniform coating film thickness (0.6 -1.0 mils)
No external electric current required to
deposit coating
All cut edges and high-energy areas are well
coated; therefore, ideal for fasteners
Hardness 2H - 5H pencil
Can achieve uniform appearance
No runs, sags, or similar defects as with
other organic liquid coatings
Performance comparable to powder
coatings electrodeposited coatings and
poryurethanes
Can coat assemblies comprised of steel,
affecting the plastics and rubber components
Excellent for applying uniform coating inside
tubular steel ana otherwise inaccessible
areas
Low-temperature cures (20p-250°F)
achieves fully cured properties immediately.
Can be topcoated with most organic liquid
coating systems
Drying oven can be infrared. Convection
oven is not required.
Low hazardous waste.
Very high transfer efficiencies, greater than
Little or no fire hazard
Excellent for parts such as leaf springs, helix
springs, fasteners, brake housings, clutch
housings, etc.
DISADVANTAGES
On
(cold or hot rolled). Not intended for
aluminum, zinc or plastics.
Surface cleanliness is critical
Currently black (low-and I
is only color being marketed,
i soon.
Intended for I
with high steel throughput. Not
intended for small shops or a
multitude of component
configurations.
System is comprised of at least 7
separate stages, most of which are
by immersion
Requires significant space allocation
when compared with
unsophisticated liquid spray coating
lines.
Parts hanging is important in order to
achieve reliably uniform appearance
on all parts
Requires frequent bath monitoring
Currently sole-souroed by Amchem
Products, Ambler, PA.
Chapter VIII
Page 10
-------
AUTOPHORETIC COATINGS
TYPICAL COATING LINE COMPRISES
1
2
&
Alkaline Alkaline
Spray Clean Immersion
3
Plant Water
Rinse
6
Autophoretic
Coating Immersion
Dl
Mist
4
Dl Water
Rinse
7
9
Plant Water Dl Final Hot Water Rinse
Rinse Rinse For Curing or
n*t*Sn«« ««««*»•% /OAfv^ oc
TYPICAL APPLICATIONS
AUTOMOTIVE
• Leaf springs
• Coil springs
• Chassis parts
• Engine mounts
• Axle supports
• Brake housings
• Automotive frames
• Other
NON-AUTOMOTIVE
• Appliances such as: structural
components for ranges and
cavities for microwave ovens
• Plating racks
• Lamp housings
Chapter VIII
Page 11
-------
THE PRINCIPLE OF ELECTRODEPOSITION
• Metal parts pass through a multi-stage cleaning and treating
process (Six stage zinc or iron phosphate, chrome or chromic acid
seal rinse, Dl rinse)
• Metal parts are immersed in tank containing the coating (5-20%
solids dispersed in water).
• Parts are connected to a DC power supply
• Parts are charged either positive (anode) or negative (cathode).
• Coating, with an opposite electrical charge is deposited on the
parts.
• As coating deposits uniformly, it isolates the parts from the electric
field and the coating process slows down!
Coated parts go through oven at 275-375°F for 15-30 minutes.
Chapter VIII Page 12
-------
TYPICAL ELECTROCOATING UNE
METAL PRETREATMENT
Six-seven stage iron or zinc phosphating
including seal rinse and Dl rinse
BAKING OVEN
275-375°F
10-20 min
POST
RINSE
DRY OFF
OVEN
(Optional)
ANODIC OR CATHODIC
ELECTROCOATING
ULTRA FILTRATION
UNIT
Chapter VIII
Page 13
-------
ELECTROCOATINGS (Anodic and Cathodic)
VOC Less Than 2.3 Ibs/gal (275 g/L)
ADVANTAGES
For application to steel, galvanized steel and
aluminum.
Very high transfer efficiencies, greater than
98% achievable
Excellent uniform finishes with no runs, sags,
etc.
Low concentration of coating dissolved in
water (5-20% solid dispersions in water)
Little or no risk of fire
Excellent uniform film thickness; (approx. 1.0
mils)
Can coat most inaccessible areas, crevices,
threads, etc.
Coats all sharp edges
Low reject rate
Automated process
Primers applied by electrocoating can be
top-coated without sanding
Excellent corrosion and chemical reisitance
Low labor requirement
Low fire hazard
Low hazardous waste
Low water pollution
Typical applications include automobile
bodies, dish washers, dryers, shelving,
refrigerators, lighting fixtures, automotive
wheels, office furniture, etc.
Available in wide range of colors
Can produce extremely high gloss finishes
Electrocoatings are available in
epoxy/urethane hybrids and other hybrids.
Some coatings combine properties of
corrosion-resistant primers and one-coat
enamels
Excellent hardness (F-2H) and good flexibility
DISADVANTAGES
A very sophisticated coating process
Generally Intended mainly for very
high-volume throughput of metal
(greater than 10 million fr/year '
Not for plastics or other electrically
non-conductive substrates
Very high capital expenditure for
cleaning and pretreatment system,
coating tanks, oven, etc.
Must be baked for 15-30 mins @
275-375°F
Requires proper system design to
ensure that all hidden areas are
coated
Coating process is very sensitive to
cleanliness of substrate
Not intended for multicolor finishing
requirements; generally only one or
two colors are used
Not intended for small finishing
operations using low volume of
coatings
Requires large floor space
1 Ray Praenti, et al. Industrial
Finishing 9/87, p.54
Chapter VIII
Page 14
-------
ELECTRODEPOSITION
Anodic
Cathodic
Historically the first type of E.D. used
primarily for primers
Primarily used as primers
Coating incorporates some dissolved
metal ions, this has the following effect:
- Poorer chemical resistance
- Poorer corrosion resistance
- Color variation
Baking schedules are approximately
200-375°F for 10-20 mins.
Some coatings can be used as primers
and/or topcoats in one application
- Excellent chemical resistance
- Excellent corrosion resistance
- Excellent color consistency
Baking schedules are approximately
275-400°F for 10-20 mins.
Chapter VIII
Page 15
-------
ELECTRODEPOSITED COATINGS
TYPICAL END USES
• Truck beds
• Engine blocks
• Water coolers
• Microwave ovens
• Dryer drums
• Compressors
• Furnace parts
• Housings for the automotive industry
• Shelving
• Washers
• Air conditioners
• File cabinets
• Switch boxes
• Refrigerators
• Transmission housings
• Lighting fixtures
• Farm machinery
• Fasteners
Chapter VIII Page 16
-------
Chapter IX
-------
CHAPTER IX
A REVIEW OF POWDER COATING TECHNOLOGIES
AND APPLICATION METHODS
-------
A REVIEW OF POWDER COATING TECHNOLOGIES
AND APPLICATION METHODS
Summary
The general advantages and disadvantages of powder coatings are compared and specific
information is presented on several common and less common resin systems, including
polyesters, epoxies, hybrids, polyurethanes, TGIC, nylon, polypropylene, polyethylene,
polyvinyl chloride, and acrylics.
The two most common methods for applying powders, electrostatic spray and fluidized
bed are compared.
Chapter IX
-------
CHAPTER DC
A REVIEW OF POWDER COATING TECHNOLOGIES
AND APPLICATION METHODS
Powder Coatings (Electrostatic and
Ruidized Bed) VOCs Essentially Zero 1
Electrostic Application 2
Ruidized Bed Application 2
Properties of Specific Resin Powder Coatings 3
Polyethylene Powders 3
Polypropylene Powders 3
Nylon Powders 3
Polyvinyl Chloride Powders 3
Thermoplastic Polyester Powders 4
Epoxy Powders, Decorative (Thin-Rim) 4
Functional, Corrosion-Resistant,
Epoxy Powders (Thick-Film)
Epoxy Polyester Hybrids 4
Polyester Powders (Thermoset)
(a) Urethane Polyesters 5
(b) Polyester TGIC Powders 5
Powder Coating End Uses 6
Powder Coatings Applied by Turboelectric Charging 7
Manufacturers of Electrostatic Spray Equipment 7
Powder Coating Vendors 7
-------
POWDER COATINGS
(Electrostatic and Fluldized Bed) VOCs Essentially Zero
ADVANTAGES
Excellent physical performance
properties
Excellent salt spray resistance
Almost zero VOCs
Considerably less generation of
hazardous waste (if any)
Excellent for special end uses, such as
metal furniture, appliances, wheels, bicycle
frames, etc.
Usually does not require a primer
Available in several resin formulations:
acrylics, polyurethane, epoxy, polyester,
nylon, epoxy/polyester hybrids, etc.
Very high transfer efficiencies 90% achiev-
able
Reasonable range of colors and textures
Equipment available to reclaim and reuse
most of powder "overspray"
Available in various gloss levels,
depending on resin system
Can be applied electrostatically or
in fluidized bed
Economical for long runs of one or
two colors
Relatively clean process
DISADVANTAGES
Capital equipment outlay greater than for
conventional coatings
Cannot be used in all applications
Not for use on plastics
Requires high-temperature oven
(350°-450^)
High-energy usage
Not for parts that cannot tolerate
warpage
Not recommended where thin films
(less than 2 mils) are required
Custom colors not available in quantities
of less than 50 Ibs
Unique application techniques
Must be applied to well-cleaned and
treated metal surfaces
Not recommended for short runs of multi-
ple colors
Chapter IX
-------
POWDER COATINGS
(Continued)
ELECTROSTATIC APPLICATION
ADVANTAGES
Powder can be applied to hot or cold parts
Adaptable to robotic or reciprocating
application
High percentage recovery of unused pow-
der (up to 95% possible)
Requires less skill than application of
liquid coatings
DISADVANTAGES
Difficult to adequately coat "Faraday
Cages." These are areas such as
comers, cages, holes, etc. in which there
is a reduced electric field to attract the
coating.
Not easy to achieve high film thicknesses
(greater than 5 mils), unless part is
preheated
FLUIDEED BED APPLICATION
Applies excellent film to otherwise inac-
cessible areas
Coats all sharp edges
Can provide heavy film build in one
application
Relatively inexpensive equipment
Cannot easily control film thicknesses due
to differing heat contents of metal assemb-
ly (i-e., light gauge metal next to casting)
Must preheat metal part sometimes to
greater than 400°F before applying pow-
der
May require special fixturing to ensure total
coverage
Chapter IX
Page 2
-------
.0)
PROPERTIES OF SPECIFIC RESIN POWDER COATINGS
POLYETHYLENE POWDERS
• Thermoplastic properties
• Excellent chemical resistance and toughness
• Excellent electrical insulating properties
• Cured films have good release properties, allowing for easy cleaning
• Used for coating laboratory instruments and equipment
POLYPROPYLENE POWDERS
• Thermoplastic properties
• Excellent chemical-resistant properties
NYLON POWDERS
• Thermoplastic properties
• Tough finishes, abrasion, wear, and impact-resistant
• Low coefficient of friction and good lubricity
• Used on mechanical components of machinery where sliding, rotation, etc. takes
place, e.g., spline shafts, shift forks, etc.
POLYVINYL CHLORIDE POWDERS
• Thermoplastic properties
• Good chemical resistance
• Good exterior durability
(1) Source: "User's Guide to Powder Coating,1 AFP/SME Powder Coating Div. E. Miller,
Editor, Published AFP/SME, Michigan 1985.
Chapter IX Page 3
-------
PROPERTIES OF SPECIFIC RESIN POWDER COATINGS(1)
(Continued)
THERMOPLASTIC POLYESTER POWDERS
• Thermoplastic properties
• Excellent decorative coatings for exterior exposure, e.g., patio metal furniture
EPOXY POWDERS, DECORATIVE (Thin-Film)
• Thermosetting properties
• Very popular decorative thin-film coating for indoor applications such as toys,
shelving, power tools, kitchen furniture, etc.
• Should not be used for outdoor applications because of its poor resistance to
sunlight
FUNCTIONAL, CORROSION-RESISTANT, EPOXY POWDERS (Thick-Film)
• Excellent for internal and external surfaces of pipes and pipelines, rebars, valves,
fittings, joints
• Some coatings can tolerate elevated temperatures up to 250°F
• Some coatings can be used in aggressive chemical gaseous environments such as
hydrogen sulphide, carbon dioxide, methane
• Application by several technologies, including blow coating, powder lance, electros-
tatic, fluidized bed, hot spray
• Some coatings can cure in very short times, such as 10 seconds at 450°F
• Excellent electrical insulation properties, and can be used on automotive alternators,
electric motors, switch gear, etc.
EPOXY POLYESTER HYBRIDS
• Thermosetting properties
• Properties similar to epoxy coatings, but generally have poorer chemical resistance
and better weatherability. Also better resistance to overbake yellowing.
• Excellent electrostatic spray properties, with improved penetration into comers and
recesses
• Used for a wide variety of indoor applications, such as: transformer covers, oil
filters, air conditioning housings, and power tools.
(1) Source: "User's Guide to Powder Coating,1 AFP/SME Powder Coating Div. E. Miller,
Editor, Published AFP/SME, Michigan 1985.
Chapter IX Page
-------
PROPERTIES OF SPECIFIC RESIN POWDER COAT1NGS(1)
(Continued)
POLYESTER POWDERS (Thermoset)
(a) Urethane Polyesters
• Outstanding thin-film appearance and toughness
• Excellent exterior durability of thin-film
• Similar properties to liquid polyurethanes
• Applications include: lighting fixtures, steel and aluminum automotive wheels,
garden tractors, playground equipment
(b) Polyester TGIC powders
• Excellent mechanical properties at high film thickness
• Good edge coverage
• Applications include: outdoor furniture, air conditioning units, steel and aluminum
automotive wheels, and aluminum extrusions
ACRYLIC POWDERS
• Excellent exterior durability
• Excellent resistance to alkalis
• Thin-film coating
• Typical applications include: refrigerator cabinets and doors, washing machine
parts, range side panels, and garden tractors
(1) Source: 'User's Guide to Powder Coating," AFP/SME Powder Coating Div. E. Miller,
Editor, Published AFP/SME, Michigan 1985.
Chapter IX Page 5
-------
POWDER COATING END USES
Automobile parts.
Appliances (dishwashers, washing machines, refrigerators, etc.)
Metal office furniture
Lawn mowers and snowblowers
Metal patio furniture
Tools
Bicycles
Fire extinguishers
Metal shelving
Bathroom faucets
Microwave ovens
Coil springs
Motor mounts
Shock absorbers
Oil filters
Disk drive housings
Automobile wheel rims
Tubular exercise equipment
Chapter IX Pa9e 6
-------
POWDER COATINGS APPUED BY
TURBOELECTRIC CHARGING
The electrostatic charge is generated by using compressed air to force the powder against
the inside of the gun barrel.
Friction charges the power before it leaves the gun.
Apparently, the external electrostatic field is eliminated. This reduces or eliminates the
Faraday Cage effect.
MANUFACTURERS OF ELECTROSTATIC SPRAY EQUIPMENT
Ransberg-Gema, Indianapolis, Indiana
Volstatic, Inc., Florence, Kentucky
Nordson Corporation, North American Division, Amherst, Ohio
DeVilbiss Company, Toledo, Ohio
POWDER COATING VENDORS
Glidden Industrial Coatings, Cleveland, Ohio
Ferro Corporation, Coatings Division, Cleveland, Ohio
Morton Chemical Division, Morton Thiokol, Inc. Reading, PA.
H. B. Fuller Company, Vadnais Heights, Minnesota
Thermoclad Company, Erie, PA
O'Brien Corporation. Fuller O'Brien Powder, Coatings Division, Houston, Texas
Pratt & Lambert, Inc. Cheektowaga, New York
Atochem, Glen Rock, New Jersey
Parboil, Baltimore, Md.
Chapter IX Page
-------
Chapter X
-------
CHAPTER X
SELECTING SPRAY APPLICATION EQUIPMENT
-------
SPRAY APPLICATION
EQUIPMENT
Summary
This session discusses the advantages and disadvantages of the most com-
mon spray application methods for organic coatings. These include:
• Conventional air atomizing spray
• Air-assisted airless
• Airless
• High-volume, low-pressure turbine
• Electrostatic (various)
• Dip
• Heated
• Plural Component
• Robots and Reciprocals
Chapter X
-------
CHAPTER X
SPRAY APPLICATION EQUIPMENT
Conventional Air Atomized Spray 1
Air-Assisted Airless Spray 3
Airless Spray 5
High-Volume, Low-Pressure Spray (Turbine) 7
Electrostatic Applications 11
Electrostatic Turbobells & Disks 12
Flow Coating 13
Dip Coating Applications 14
Paint Robots 16
Hot Spray 18
-------
CONVENTIONAL AIR ATOMIZED SPRAY
The conventional air atomizing spray gun was the first method ever used to
spray-apply paint and coating materials, and it is still the most widly used
spray gun in use today. It has a great deal of appeal for spray painters be-
cause of operator control. Basically, the function of the air atomizing spray
gun is to use compressed air to disperse coating material into small droplets
and to propel the droplets toward a target.
Where Used
• Fabricators and repair shops
• Quality furniture and cabinet manufacturers and refinishers
• Contract and custom coaters
• Do-it-yourself handyman
Typical Application Pressure:
-Typical air-spray pressure
for siphon and pressure spray 40 to 60 psi
-Typical fluid pressure
for pressure spray 5 to 15 psi
Equipment Manufacturers
Blnk Mfg. Co.
9201W. Belmont Avenue, Franklin Park, IL 60131
DeVilbiss Co.
300 Phillips Ave., Toledo, Ohio 43692
Graco Inc.
P.O. Box 1441, Minneapolis, MN 55440
SpeeFlo Mfg. Co.
4631 Winfield Road, Houston, Texas 77039
Kremlin, Inc.
211 South Lombard Road, Addison, IL 60101
Chapter X Pagel
-------
CONVENTIONAL AIR-ATOMIZED SPRAY
(Continued)
Advantages Disadvantages
• Low equipment cost • Uses high volume of air
• Low maintenance • Develops excessive spray
._ „ _ _, . ,_, ... dust and overspray fog
• Excellent material atomization
_ „ _,_ . • Does not adapt to high-volume
• Excellent operator control matter® output
• Quick color change capabilities . ^ ^^ efficiencies
• Coating can be applied by syphon
or under pressure
Chapter X Page 2
-------
AIR-ASSISTED AIRLESS SPRAY
Air-assisted airless spray combines compressed air with hydraulic pressure to atomize
the coating material into finer droplets than is achieved with pure airless spray. With
the compressed air-assist, the normal airless hydraulic pressure can be reduced by
50% or more, which allows the operator to have more control with improved applica-
tion results.
Where Used
• High-volume furniture production and cabinet manufacturers
• Maintenance coatings
• Military contractors
• Where improved transfer efficiency is required
Typical Application Pressure:
-Fluid 800-1500 psi
-Air 10 psi
Equipment Manufacturers:
Blnks Manufacturing Company
9201W. Belmont Ave., Franklin Park, IL 60131
Graco, Incorporated
P.O. Box 1441, Minneapolis, MN 55440
Chapter X Page 3
-------
AIR-ASSISTED AIRLESS SPRAY
(Continued)
Advantages
• Low coating usage
• Fair-good operator control
on air pressure
• Few runs and sags
• Good atomization
Disadvantages
• High maintenance
• Expensive fluid tips
• Poor operator control
on fluid pressure
• Not appropriate for fine
finishing.
Chapter X
-------
AIRLESS SPRAY
Airless atomization of paint and coating materials is accomplished by hydraulic pres-
sures. It does not directly use compressed air to atomize the fluid. Pressure is applied
to the fluid with hydraulic pumps. Depending on the solids and viscosity of the fluid,
pressure will range between 500 and 4,000 psi.
As the paint or coating material is forced through a small diameter orifice in the spray
gun tip, it is atomized into small particles coupled with high-velocity, and the particles
are carried to the target.
Where used
• Commercial and maintenance painters
• Rail and marine, structural steel fabricators
• High-volume production lines
• Application of viscous undercoatings and elastomers
• For large, relatively uncomplicated surfaces (buildings, steel structures, ships,
roof coatings, and insulations.
Typical application pressure:
• Medium viscosity metal primer requires 1,600 to 3,000 psi.
Equipment manufacturers:
Blnks Mfg. Co.
9201W. Belmont Ave., Franklin Park, IL 90131
Devilbiss Co.
300 Phillips Ave., Toledo, OH 43692
Graco Inc.
P. O. Box 1441, Minneapolis, MN 55440
Nordson Corp.
555 Jackson St., Amherst, OH 44692
Chapter X Page 5
-------
AIRLESS SPRAY
Advantages
• Low air usage
• High-volume material output
• Limited overspray fog
• Large spray patterns
• Application of heavy viscous
coatings
• Excellent for large surfaces
• Good transfer efficiency
on large surfaces
• Fast application speeds
Disadvantages
• Expensive fluid tips
• High Maintenance
• Difficult to blend sprayed
coating material
• Minimum operator control
during application
• Not for intricate finishing
• Not for high-quality appearance
items
• Can cause injuries to operator
if not used with adequate caution
Chapter X
Page 6
-------
HIGH-VOLUME, LOW-PRESSURE SPRAY (TURBINE)
The turbine low-pressure spray equipment is a totally self-contained unit. It does not
require compressed air for operation. A high-speed turbine generates the high volume
of air used during spray operation. The air is heated by the turbine to approximately
110°F, and this temperature is consistent, regardless of the termperature of the sur-
rounding air.
The principle is to atomize the coating material at low air pressure and propel the
atomized droplets to the object at low velocity, utilizing the high-volume air supply.
Where used:
• High-solids coating applications
• Small parts production line operations
• Will meet EPA transfer efficiency requirements
(pending approval)
Equipment manufacturers:
Can Am Products, Inc.
30850 Industrial Road, Livonia, MI 48150
Bessam Air
P. O. Box 46478,26881 Cannon Road, Cleveland, OH 44146
Chapter X Page 7
-------
HIGH-VOLUME, LOW-PRESSURE SPRAY
(TURBINE)
Advantages
• Low blowback and
spray fog
• Good transfer efficiency
• Will apply high-viscosity,
high-solids coatings
• Portable
• Easy to clean
• Can use up to 4 guns
per turbine
• Can be used for intricate
parts
• Good operator controls
on the gun
Disadvantages
• High initial cost
• Slower application speed
(controversial)
• Does not finely atomize
some high-solids
coating materials
(controversial)
• High cost for turbine
maintenance
• Requires operator training
• Still relatively new on the
market
Chapter X
-------
ELECTROSTATIC APPLICATIONS
Electrostatic application of paint and coating materials is based on the simple law of
physics that dissimilar electrical charges attract. An electrical circuit is formed by con-
verting 110 volts alternating current through a high-voltage power supply of negative
60,000 to 80,000 volt, producing low ampage direct current.
The electrostatic principle can be applied to all methods of spray application:
• Air atomizing
• Airless
• Air-assisted airless
The negative potential (voltage) is transmitted through an electrical cable to the spray
gun equipped with an electrode that charges the atomized paint.
Providing the object to be coated is properly grounded, the atomized paint that would
normally bypass the object is now attracted to the object and contributes to the final
overall coating application.
All paints and coating materials have potential for electrostatic application. However,
conventional coating formulations may require some modification to improve on the
electrical properties.
The electrostatic method of applying paint and coating materials lends itself to other
types of equipment:
• Reciprocating rotating disk
• High-speed turbo bells
Electrostatic disk and bell applications are proven methods for high output production
conveyor lines where several hundred parts of similar geometry are to be painted. The
coating material is fed to the Disk or Bell where it is negatively charged and centrifugal-
ly spun out by high-speed rotation into a predetermined field where a conveyorized
line carries the objects through the field. A properly engineered system could process
several thousand square feet of finished surface area per hour.
The majority of electrostatic spray installations are used to coat metallic surfaces that
are conductive. There are, however, systems used to coat non-conductive surfaces:
• wood,
• plastic,
• and composites.
Prior to painting, non-conductive surfaces must be pretreated with either a chemical
salt or a coating that will create the necessary electrical attraction; then it can be
processed in the same way as conventional conductive objects.
Chapter X Page 9
-------
ELECTROSTATIC APPLICATIONS
(Continued)
Where Used
• Outdoor patio furniture, metal office furniture
• Tubular and wire products
• Contract custom coalers
• Miscellaneous metal parts for all industries
• Military contractors
• Wood gun stock and miscellaneous wood furniture
(after special conductive treatments have been applied)
Equipment Manufacturers:
Blnks Mfg. Co.
9201W. Belmont Ave., Franklin Park, IL 60131
DeVllblss Co.
300 Phillips Ave., Toledo, OH 43692
Nordson Corp.
555 Jackson St., Amherst, OH 44001
Ransberg-Gema, Inc.
3939 W. 56th St., Box 88220, Indianapolis, IN 46208
Chapter X Page 10
-------
ELECTROSTATIC APPLICATIONS
(Continued)
Advantages
• Coating wrap on edge of parts
• Material savings through improved
transfer efficiency
• High production output ideally
adapts to
automation
• Close pack of parts on conveyor
line desirable
• Reduced manpower requirement
• Lower spray booth air velocity
(60ft/min)
• Can be used with solvent-based and
water-based coatings
• Recognized by EPA for its improved
transfer efficiency
• Can be used with wide range of application
processes: air-atomized spray, airless,
air-assisted airless, disks and bells
• Disks and bells can achieve transfer
efficiencies greater than 90%.
Disadvantages
• High equipment and maintenance
cost
• Parts hangers and hooks must be
conductive, requiring frequent
cleaning
• Automated lines must be adapted
to long runs of similarly shaped
parts.
• Will not properly coat recessed
areas
• Wrap is not always as good as
expected
• Faraday Cage affects coating of
comers, cavities, etc.
• Very difficult to ensure a good
ground on small parts
• Beware of arcs in the presence of
solvent fumes
• Painters are wary of electrostatic
shocks
• Painters must be properly trained
• Isolation stand required when
applying water-based coatings
• Transfer efficiency does not
always meet expectations
• Special precautions required
to prevent electrostatic discharges
< Does not always yield sufficiently
atomized droplets of high solids
coatings
Chapter X
Page 11
-------
ELECTROSTATIC TURBOBELLS & DISKS
ADVANTAGES DISADVANTAGES
Atomizes water-borne and high Not for manual applications
solids coatings into micro-fine particles Not fOr snort ^^ gf muft^je geometries
Very high transfer efficiencies >90%
Turbine rotational speed 10,000-
50,000 rpm
Choice of cup or disc spray head
Quick color changing capabilities
Electrostatic charge up to 100KV
Excellent film thickness control
Excellent for large, automated
production lines
Programmable operations can
independently control rotational
speed, fluid flow, shaping air, and
voltage
Chapter X Page 12
-------
FLOW COATING
Row coating is a process in which the paint or coating material is flowed over an ob-
ject, completely covering the surface.
Commercially designed flow coating equipment has a liquid reservoir and recirculating
pumping system. The coating material is pumped from the reservoir through the flow
coating nozzle or outlets, where the parts are conveyorized through the coating
material. After being coated, the parts proceed into a solvent vapor-laden chamber
where the coating material is collected and returned to the reservoir. It is in the solvent-
laden chamber that the coating material levels itself on the surface of the part.
Because flow coating is so dependent on solvent vapor, this process has given way
to other more efficient coating processes.
Where used:
• Autmotive and appliance industries
• Heavy industry with high production output
Equipment Suppliers:
Geo Koch & Sons
P. O. Box 358, Evansville, IN
Cincinnati Industrial Machinery Co.
3280Hageman Street, Cincinnati, OH 45241
Chapter X Page 13
-------
FLOW COATINGS
(Continued)
ADVANTAGES
• High-transfer efficiency greater
than 90%
• High-volume production output
• Used on many parts and sub-
assemblies
• Coating gets into recesses and other
inaccessible areas
DISADVANTAGES
• High solvent demand
• Primer or shop coat only
• Sensitive to coating formulation
• Not for decorative finish
• Can produce runs and sags
Chapter X
Page 14
-------
DIP COATING APPLICATIONS
Dip applications of coating materials are utilized throughout the finishing community.
The applications range from simple basket dipping of large numbers of small parts into
a tank of coating material, to highly sophisticated conveyorized production lines where
immersion and withdrawal speeds are controlled as the parts enter and exit a well-
monitored tank of coating material. Such a process will coat parts with identical coat-
ing thicknesses and provide an identical appearance.
Where used:
• Paint brush handles
• Toilet seats
• Wood and metal furniture
• Miscellaneous wood and metal parts
• Large metal castings
Equipment suppliers:
Geo Koch Sons,
P. O. Box 358, Evansville, IN 47744
Innocoat Div. DPP
37 North Ave., Norwalk, CT 06851
Rapid Engineering,
P. O. Box 700, Seven Mile Road, Comstock Park, MI 49321
Chapter X Page 15
-------
DIP COATINGS (Continued)
Advantages
• Uniform coating
• Maximum transfer
efficiency >90%
• Cost effective
• Can coat recesses and
inaccessible areas
• Can use solvent-borne or
water-based coatings
Disadvantages
• Coating material must be
closely monitored
• Adapt to unique part
configuration
• Parts hanging is critical
• Withdrawal rate is critical
• Drag-out can be high if not
controlled
• Not intended for decorative
finishing
• Not recommended for
short production runs
• Not for multiple colors
• Not for high-solids
coatings
• Not for two-component
coatings
Chapter X
Page 16
-------
PAINT ROBOTS
The programmable robot is the latest addition to automating the application of paint
and coating materials.
Ultimately, the robot will replace the hand-spray operator; however, it is the skill of the
hand-spray operator that is used to program the robot.
A hand-held manipulator is moved through the application sequence by the spray
operator simulating the actual motion required to spray paint an object. The initial
recorded program may be refined to achieve maximum efficiency prior to implementa-
tion.
It is important to recognize the limitations of the program and allow for hand-spray
touchup or supplement to completely spray a difficult geometry.
Where used
• Automotive and aircraft parts
• Farm machinery and equipment
• Wood products
• Miscellaneous metal parts and subassemblies
• Camouflage pattern painting
Equipment manufacturers
DeVllblss Co.
300 Phillips Ave., Toledo, OH 43692
Graco Inc.
P.O. Box 1441, Minneapolis, MN 55440
Kremlin Inc.
211 South Lombard Road, Addison, IL 60101
Chapter X Page 17
-------
PAINT ROBOTS
(Continued)
Advantages
• Consistent, uniform coatings
from one part to the next
• Coating application conserves
manpower
• Adaptable to all methods of
spray
equipment
• Predictable results regardless
of the season
• Less solvent required to
reduce coating viscosity
• Can be used in combination
with all types of spray equipment
• Excellent for coating the same
configuration thousands of times
Disadvantages
• High initial cost
• Not recommended for short
runs of dissimilar parts
• Some limitation on quality
of applied coating
• Requires skilled personnel
to program
• High maintenance costs
• Must control coating viscosity
and temperature of application
• Not recommended for premixed,
two-component coatings
Chapter X
Page 18
-------
HOT SPRAY
The hot spray paint method has been used for many years, and is adaptable to any
spray system. Now more than ever, higher solids VOC-compliant coatings will perform
more satisfactorily when heat is used to reduce application viscosity.
Coating manufacturers usually standardize viscosity measurements at 77°, which is
considered to be ambient room temperature. When heated to between 110° and 120°F,
the viscosity of an average pigmented alkyd enamel will decrease by 25% to 30% below
the established standard.
Hot spray paint heaters are usually located between the source of the paint supply and
the spray gun. The heaters are thermostatically controlled to maintain constant paint
temperatures. Hot spray systems can be designed to either recirculate the coating
material from the heater to the spray gun and return to the heater, or to go through the
heater and dead-end at the spray gun.
Where used:
• Wood furniture and cabinet manufacturers
• Machine tool manufacturers
• Implement and farm machinery
• Over the road semitrucks and trailers
Equipment Manufactured by:
Binks Mfg. Co.
9201W. Belmont Ave., Franklin Park, EL 60131
DeVlIbiss Co.
300 Phillips Ave., Toledo, OH 43692
Nordson Corp.
555 Jackson St., Amherst, OH 44692
Speeflo Mfg. Co.
4631 Winfield Road, Houston, TX 77039
Kremlin Inc.
211 South Lombard Road, Addison, IL 60101
Chapter X Page 19
-------
HOT SPRAY (Continued)
Advantages
• Omit solvent additions for viscosity
reduction
• Constant application viscosity
regardless of ambient temperature
and weather conditions
• High film build with fewer coats
• Improved leveling, smoother surfaces
• Potential for improved transfer
efficiency
• Several designs available
• Can be used in conjunction with
most types of spray equipment
• Different designs available
Disadvantages
• Additional maintenance and
equipment costs
• Fast solvent flash-off can develop
pinhole and solvent entrapment if
coating is applied too heavily
• Additional fluid hose to spray gun
for recirculating
• Will use more paint
• Not recommended fprpremixed
two-component coatings
• Not intended for water-based
coatings
Chapter X
Page 20
-------
Chapter XI
-------
CHAPTER XI
EQUATIONS FOR CALCULATING WEIGHTS
AND VOLUMES FOR INDIVIDUAL COMPONENTS
FROM MATERIAL SAFETY DATA SHEETS
.
-------
\
EQUATIONS TO CALCULATE WEIGHT AND VOLUME
FOR INDIVIDUAL COMPONENTS FROM
MATERIAL SAFETY DATA SHEETS
Summary
This short session provides the equations for determining the weight
and volume of individual components as they appear on Material Safety
Data Sheets.
Chapter XI
-------
CHAPTER XI
EQUATIONS TO CALCULATE WEIGHT AND VOLUME FOR INDIVIDUAL
COMPONENTS FROM MATERIAL SAFETY DATA SHEETS
Equation for Calculating Weight of a Volatile Component
From a Material Safety Data Sheet 1
Equation for Calculating Volume of a Volatile Component
from a Material Safety Data Sheet 2
Equation for Calculating Volume, Given the Percent (%)
Weight of a Component 2
Example for Calculating Volume 3
Table of Solvent Densities 4
Conversion Factors 5
-------
IMPORTANT CONCEPTS IN CALCULATING WEIGHT AND VOLUME
OF VOC. WATER AND EXEMPT SOLVENT.
*WEIGHT WATER
% WEIGHT EXEMPT
SOLVENT
* WEIGHT VOC
% WEIGHT SOLIDS
•7
\
r~
1 GALLON
L-.
MATERIAL SAFETY DATA SHEETS (MSDS) USUALLY PROVIDE INFORMATION IN PERCENTAGES <%), SUCH
AS %WT OF VOC, OR % VOLUME OF VOLATILES.
IN THIS SECTION WE WILL DERIVE EQUATIONS WHICH WILL ENABLE US TO CALCULATE
THE WEIGHT OF A COMPONENT (SUCH AS VOC, WATER, ETC)
VOLUME OF A COMPONENT, (SUCH AS VOC, WATER, ETC.)
1. TO CALCULATE WEIGHT OF A COMPONENT, SUCH AS VOC. WATER. EXEMPT SOLVENT, ETC:
WEIGHT OF COMPT. (LBS) =• % WEIGHT OF COMPONENT X DENSITY OF COATING (LBS/CAL)
ISO
-------
2. TO CALCULATE VOLUME OF COMPONENT, SUCH AS VOC, WATER, EXEMPT SOLVENT. ETC.;
VOLUME OF COMPT. (GALS) - % VOLUME OF COMPONENT X VOLUME OF COATING (GALS)
100
FOR PURPOSES OF THE CALCULATIONS, WE CAN ASSUME THE VOLUME OF THE COATING TO BE 1 GALLON,
THEREFORE:
VOLUME OF COMPONENT (GALS) - % VOLUME OF COMPONENT
100
3. TO CALCULATE VOLUME OF A COMPONENT FROM % WEIGHT OF THAT COMPONENT.
UNFORTUNATELY, THE MSDS DOES NOT PROVIDE US WITH THE % VOLUME OF INDIVIDUAL COMPONENTS,
SUCH AS VOC, WATER, EXEMPT SOLVENTS, ETC.
TO WORK WITH THE AVAILABLE DATA WE MUST FOLLOW THE BASIC EQUATION FOR THE DENSITY OF
ANY SUBSTANCE:
DENSITY OF COMPONENT (LBS/GAL) - WEIGHT OF COMPONENT (LBS)
VOLUME OF COMPT (GALS)
ALTERNATIVELY:
VOLUME OF COMPONENT (GALS) - WEIGHT OF COMPONENT (LBS)
DENSITY OF COMPONENT (LBS/GAL)
-------
BUT THE MSDS USUALLY ONLY PROVIDES US WITH THE * WEIGHT OF THAT COMPONENT,
THEREFORE, USING THE RELATIONSHIP:
WEIGHT OF COMPONENT (LBS) = % WT OF COMPT. X DENSITY OF COATING (LBS/CAL)
WE CAN NOW COMPUTE THE VOLUME AS FOLLOWS:
VOLUME OF COMP. (GALS) = %_
EXAMPLE;
CALCULATE THE VOLUME OF A VOC IN A COATING, GIVEN THE FOLLOWING INFORMATION PROVIDED
BY THE MSDS:
% WEIGHT OF VOC = 15.3 „„,„*„-*•
DENSITY OF COATING (LBS/GAL) - 8.91 LBS/GAL
DENSITY OF VOC = 7.04 (LBS/GAL)
SOLUTION;
THE VOLUME OF VOC (GALS) «= 15.3 x 8.91
100 X 7.04
= 0.19 GALS
-------
BASIC CALCULATIONS OF VOCs
SOLVENT DENSITIES
Acetate
Amyl
Butyl
Cellosolve
Acetone
Alcohols
Butyl
Ethyl
Isopropyl (IPA)
Cellosolve
Butyl
Ketones
Methylisoamyl
MEK
MIBK
VM & P Naphtha
Mineral Spirits
Toluene
Trichloroethane (1,1,1)*
Trichloroethylene
Xylene
Water
Density
9/L
879
882
975
792
810
789
789
931
903
813
805
800
750
785
866
1466
881
1000
Density
Ibs/gal
-7.33
7.36
8.14
6.61
6.76
6.58
6.58
7.77
7.52
6.76
6.72
6.67
6.28
6.55
7.23
12.23
7.35
8.34
* 1,1.1 Trichloreothane is an exempt solvent
Chapter XI
•Page 4
-------
CONVERSION FACTORS
1 liter = 0.2642 U.S. gallons
1 pound = 453.6 grams
1 U.S. gal = 3785 cc. (milliliters)
grams/litre = 1 x 3.7B5
453.6 1
gms/lrtre = 0.008344 Ibs/gal
Ibs/gal = 119.84 gms/liter
-------
Chapter XII
-------
CHAPTER XII
CALCULATIONS OF VOCS FROM PRODUCT
AND MATERIAL SAFETY DATA SHEETS
-------
CHAPTER XII
CALCULATIONS OF VOLATILE ORGANIC COMPOUNDS (VOCs)
FROM PRODUCT AND MATERIAL SAFETY DATA SHEETS
(Basis of Calculation: Percent of Weight of Solvent)
Calculate the VOC of a Single-Component
Coating Reduced Prior to Application 1
Calculate the VOC of a Two-Component Coating 3
Calculate the VOC, less Water, of a Two-Component
Coating Reduced With Water 5
Calculate the Actual VOC of a Two-Component
Coating Reduced With Water 7
Equation for Calculating the VOC of a Water-Base
Coating, as Applied, Less Water 9
Calculate the VOC, as Applied, Less Water,
for a Water-Bome Coating 11
Equation for Calculating the VOC of a Water-Borne
Coating, as Applied, Less Water and Exempt Solvent 13
Calculate the VOC of a Water-Borne Coating,
as Applied, Less Water and Exempt Solvent 15
Equation to Calculate the VOC, as Applied,
Less Water, of a Water-Borne Coating to Which
a Solvent is Added Prior to Coating Application 19
Calculate the VOC of a Water-Borne Coating, as
Applied, Less Water, to Which Solvent is Added
Prior to Coating Application 21
Equation for Calculating the VOC From a Materia
Safety Data Sheet (% Weight Basis) 23
Calculate the VOC for One Solvent From a
Material Safety Data Sheet (% Weight Basis) 24
Calculate the VOC of Several Solvents From a
Material Safety Data Sheet (% Weight Basis) 26
-------
CALCULATIONS OF VOLATILE ORGANIC COMPOUNDS (VOCs)
FROM PRODUCT AND MATERIAL SAFETY DATA SHEETS
(Calculations based on percent weight of solvent)
Summary
VOC calculations are provided for:
• Single-component coatings as packaged
• Single-component coatings reduced for spray application
• Two-component coatings as packaged
• Two-component coatings reduced for spray application
• Water-based coatings
• Solvent-based coatings reduced with exempt solvents
The calculations are fairly basic and do not require sophisticated mathematics. They
are intended for environmental engineers, production personnel, and paint and coat-
ings chemists. Chapter XI should precede this chapter.
Chapter XII
-------
TO CALCULATE THE VOC OF A SINGLE PACKAGE COATING
THAT IS REDUCED PRIOR TO APPLICATION
PROBLEM:
CALCULATE THE VOC CONTENT OF AN ALKYD ENAMEL WHICH IS REDUCED
PRIOR TO APPLICATION, GIVEN THE FOLLOWING INFORMATION:
COATING HAS VOC = 3.8 #/GAL
REDUCER HAS VOC = 6.8 ///GAL
COATING IS REDUCED 257. WITH REDUCER.
-------
SOLUTION TO PROBLEM:
NO. OF PARTS fGALS) X VOC (t/GAL) = VOC («)
COATING 1 X 3.8
REDUCER 0.25 X 6.8
1.25 (GALS)
3.8
1.7
5.5 («)
THEREFORE VOC =
VOC («/)
NO. OF GALS
= 5.5
1 .25
VOC = A.4 ft/GAL)
-------
TO CALCULATE THE VOC CONTENT
OF A TWO COMPONENT COATING
PROBLEM:
CALCULATE THE VOC CONTENT OF A TWO-COMPONENT COATING, SUCH AS
A POLYURETHANE, BASED ON THE FOLLOWING INFORMATION:
VOC OF COMPONENT A = 3.0 0/GAL
VOC OF COMPONENT B = 2.0 ///GAL
VOC OF REDUCER = 7.0 #/GAL
MIXING RATIO = 4 PARTS A; 1 PART B; 1 PART REDUCER
-------
Solution to Problem:
VOC Is calculated by averaging as follows:
No of Parts (gals) x VOC(#/gal) = VOC(#)
ComptA 4
ComptB 1
Reducer 1
6 (gals)
x 3.0
x 2.0
x 7.0
12.0
2.0
7.0
21.0(#)
VOC(#/gal) = VOC(#)
No. of gallons
21.0
"iio"
3.5 #/gal.
-------
TO CALCULATE THE VOC CONTENT
OF A TWO-COMPONENT COATING
WITH WATER
PROBLEM:
CALCULATE THE VOC CONTENT, AS APPIED, LESS WATER, FOR AN EPOXY
WATER-REDUCIBLE PRIMER, GIVEN THE FOLLOWING INFORMATION:
VOC OF COMPONENT A
VOC OF COMPONENT B
WATER
3.0 ///GAL
' 2.0 0/GAL
- 0 0/GAL
MIXING RATIO = 4PARTS A; 1 PART B; 7 PARTS WATER
-------
Solution to Problem:
Since we are Interested In the VOC, as applied, less water,
we can Ignore the water used for reduction.
No. of parts (gals) x VOC(#/gal) = VOC(#)
ComptA 4
ComptB 1
5 (gals)
x
X
3.0
2.0
12.0
2.0
14.0 (#)
VOC(#/gal) = VOC
No. of gals.
14.0
2.8 (#/gal)
-------
PROBLEM:
CALCULATE THE 'ACTUAL1 VOC CONTENT OF A TWO-COMPONENT
WATER-REDUCIBLE EPOXY PRIMER, WHICH IS REDUCED WITH WATER, GIVEN
THE FOLLOWING INFORMATION:
VOC OF COMPONENT A •= 3.0 ///GAL
VOC OF COMPONENT B = 2.0 0/GAL
MIXING RATIO = 4 PARTS A; 1 PART B; 7 PARTS WATER
-------
Solution to Problem:
In this problem, we must consider the water as the problem
requests the actual VOC.
No. of Parts (gals) x VOC(#/gal) = VOC(#)
ComptA 4
ComptB 1
Water 7
x
x
x
3.0
2.0
0.0
12 (gals)
12.0
2.0
0.0
14.0
Actual VOC (#/gal)
VOC
No. of Gallons
14.0
12
1.17(#/gal)
8
-------
TO CALCULATE VOC OF A WATER BASE COATING
\o
AS APPLIED
Given:
Water
VOC
Solkte
Density of coating Obs/gal) or WPG
% Weight Solids
% Weight Water
Density of Water
Wt. of VOC
VOC. less water =
VOC, less water =
Vol. of VOC (gals) -I- Vol. of Solids (gals)
(Wt. of all volatiles Qbs) - Wt. of Water (Ibs))
Volume of Coating (gals) - Volume of Water (gals)
% Wt. volatiles
Wt. of all volatiles = x Density of Coating
= (1-
100
% Wt. SoHda
100
Weight of Water - % Wt. Water
100
Volume of Coating = 1 Gallon
% Wt. Water
Volume of Water =
100
) x Density of Coating
x Density of Coating
Density of Coating
Density of Water
-------
Combining these into one equation:
* Q _ ( x Den9lty of Coating
VOC, less water = L" 10° ' * 10° _ _ -
IB_ ( % Wt. Water x Density of Coating }
100 Density of Water
Simplifying:
(100 - % Wt. Solids - % Wt. Water) x Density of Coating
VOC, less water = % Wt. Water x Density of Coating .
" Density of Water
-------
CALCULATION OF VOC, AS APPLIED. LESS WATER
FOR A WATER-BORNE COATING
PROBLEM:
CALCULATE THE VOC, AS APPLIED, LESS WATER, FOR A WATER-BORNE
COATING, GIVEN THE FOLLOWING:
DENSITY OF COATING
% WEIGHT SOLIDS
% WEIGHT WATER
DENSITY OF WATER
= 11.3 Ibs/gal
= 35.0
= 50.0
= 8.33 Ibs/gal
-------
Solution to Problem:
[100-35-50] x 11.3
VOC, as applied, less water =
100-(50x11.3)
8.33
170
32"
VOC, as applied, less water = 5.31 ibs/aal
To convert to G/L = 5.31 x 119.8
= 636.1 G/L
12
-------
TO CALCULATE VOC OF A WATER-BORNE COATING, AS
APPLIED, LESS WATER AND EXEMPT SOLVENT
Ul
Water
Exempt
VOC
Solids
Given: Density of Coating Oba/gal) or W.P.Q.
% Weight Solids
* Weight Water
% Weight Exempt Solvent
Denelty of Wster « 8.33 Ibe/gal.
VOC. less water and
exempt solvent, ae applied
^m
wi.
100
100
WtOf
aaai
WL
% Wt of
(WL of all vetattto* lb») - WL of Hhtor |b«) - Wt of Emmpt SoTvwit Ibo)
Vol. of Costing testa) - (Vol. of VMor -f Vol. Emmvt 8olvmSlo«to)
of Cotflno
x Domlty of
aoHrsnt
100
-------
% Wt. Water Density of Coating
Volume of Water « 10Q x Density of Water
, ^ . m % Wt. Exemp Solvent Penalty of Coating
Volume of Exempt Solvent - ^ x Dens|ty of Exempt So|vent
Combining these Into one equation:
DtnMy
w«^, . , Ki-%w^*"d') -i**^) -(%WLB;;;pt8olvtH *
VOC, leaa water, leee m u' 100 ™
exempt aolvent Qba/gal) % WL ^ttr % wt. Exempt soivt D«n«Hy
1 " ^100 x D«n«tty Water * 100 x Density of Exmpt Solvt ) X «J
Coating
[ (100 - % Wt Solid* - % Wt WM»r - % Wt Ex»mpi 8ofv9 x Density of Cottlng ]
%WtWt>r %WtExompt8oM DonoHy
* tt of Exmt Solvt I * °» J
-------
CALCULATION OF VOC OF A WATER-BORNE COATING
AS APPLIED. LESS WATER AND EXEMPT SOLVENT
PROBLEM:
CALCULATE THE VOC, AS APPLIED, LESS WATER AND EXEMPT SOLVENT.
FOR A WATER-BORNE COATING, GIVEN THE FOLLOWING:
DENSITY OF COATING
% WEIGHT SOLIDS
X WEIGHT WATER
* WEIGHT 1,1,1 TRICHLOROETHANE
DENSITY OF WATER
DENSITY OF 1,1,1 TCA
10.35 LBS/GAL
25.3
41 .2
12.3
8.33 LBS/GAL
11.06 LBS/GAL
15
-------
Solution to Problem:
[100-25.3-41.2-12.3] x 10.35
VOC, as applied, less water, =
less exempt solvent 100 - |7 41'2 . 12-3 \ x 10.35]
LV 8.33 * 11.06 '
21.2 x 10.35
100 - [(4.94 + 1.12) x 10.35]
219.42
37.3
VOC, as applied, less water, = 5.88 Ibs/gal
less exempt solvent
To convert to G/L = 5.88 x 119.8
704.4 G/L
-------
TO CALCULATE VOC, AS APPLIED, OF A WATER-BORNE COATING, LESS WATER, TO WHICH
A SOLVENT IS ADDED PRIOR TO COATING APPLICATION
Water
VOC A
Solids
VOCB
Given: Density of Coating Qbs/gal) or W.P.G.
% Weight Solids
% Weight Water
% Weight Exempt Solvent
Density of Water = 8.33 Ibs/gal.
Coaling
Solvent Added
Wt. of VOC A + Wt. of VOCB
VOC. as applied, less water = (Vol of VOC A + Solids) + Vol of VOC B
Wt. of VOC A = Wt. of total volatlles In coating - Wt. of Water
= (1-
% Wt. Solids
100
) x Density of Coating -
% Wt. Water Density of
X Coating
Wt. of VOC B = Vol of VOC B x Density of VOC B
Volume of VOC A + Solids = Total Volume of Coating - Volume of Water
-------
Assume total volume of coating = 1 gallon.
Then:
V^VOCA+SO,,,. = i-<•"%«*.
Combining these into one equation:
Density %WL
i. as applied, (1 - ,00 >* " -C io5 'x coaL Vo° B
COB lino
less water
. / % Wt. Water Density of Coating x m
1'( ^3: x n»noi»» ^i wot^r )"*• Vol VOC B
155 - * Density of Water
DamRy of DeraHy of /
= ( 100 -% Wt. Solids) x c^,,^ -(% Wt. Water) x CfMUn +\100x voi voc B x DtraRy voc B )
[ (100 - % Wt. Solids - % Wt. Water) x Density of Coating + (100 x Vol VOC B x Density VOC B)]
m % WL Water x Penally of Coating t Hnn ... f ur|^ „.
100 -( benslty oi Water 1 + (100 X Vol Of VOC B)
-------
CALCULATION OF VOC FOR A WATER-BORNE COATING,
AS APPLIED. LESS WATER. TO WHICH A SOLVENT
IS ADDED PRIOR TO COATING APPLICATION
PROBLEM;
CALCULATE THE VOC OF A WATER-BORNE DIPPING ENAMEL TO WHICH
PRECURSOR SOLVENTS ARE ADDED PRIOR TO COATING APPLICATION. THE
FOLLOWING INFORMATION IS PROVIDED:
DENSITY OF COATING
% WEIGHT SOLIDS
% WEIGHT WATER
VOLUME OF SOLVENT ADDED
DENSITY OF SOLVENT
DENSITY OF WATER
Note: 1 PINT - 0.125 GALLONS
10.1 Ibs/gal
28.0
48.0
•• 1 PINT PER GALLON
' 6.67 Ibs/gal
• 8.33 Ibs/gal
-------
Solution to Problem:
£100-26.0-48.0) x 10.1 + (100 X 0.126 X 6.67)]
VOC, as applied, lesa water =
100 ' )* (iooxo.125)
242.4 + 83.4
100 - 58.2 + 12.5
325.8
54.3
VOC, leae water = 6.0 Iba/gal
To convert to G/L = e.O x 119.8
718.8 G/L
22
-------
TO CALCULATE VOC OF A COATING
FROM A MATERIAL SAFETY DATA
SHEET - 1 SOLVENT
VOC(#/gaO = % Wt. Solvent x Density of Getting
100
TO CALCULATE VOC OF A COATING FROM
A MATERIAL SAFETY DATA SHEET
FOR SOLVENT BLEND
%WL8oM1 %WL8oM2 % WL SoM a
VOC(*/gaO - ( +——+ ——*
K Wl_ fta^tff ife
___I_-__ ) x Density of Coating
too
23
-------
PROBLEM:
CALCULATE THE VOC OF A COATING GIVEN THE FOLLOWING:
X WEIGHT OF SOLVENT = 16
DENSITY OF COATING (WPG) = 9.3 (LBS/GAL)
-------
SOLUTION TO PROBLEM:
VOC = * WEIGHT OF SOLVT X DENSITY OF COATING
100
= 16 X 9.3
100
VOC = 1.67 (LBS/GAL)
TO CONVERT TO G/L:
= 1.67 X 119.8
VOC = 200 (G /L)
-------
CALCULATION OF VOC FROM
MATERIAL SAFETY DATA SHEET
PROBLEM:
CALCULATE THE VOC FOR A COATING FOR WHICH THE MATERIAL SAFETY
DATA SHEET (MSDS) PROVIDES THE FOLLOWING INFORMATION:
PERCENT BY WEIGHT
INGREDIENT
MINERAL SPIRITS
VM&P NAPHTHA
TOLUENE
XYLENE
KEROSENE
WEIGHT PER GALLON OF THE COATING = 9.65 Ibs/gal
-------
Solution to Problem:
Simply add the % Wt. of all solvents. And multiply by the
coating density.
%Wt. = 28.76
Coating Density = 9.65
Therefore:
VOC(#/gal) = 28.76
100
= 2.78 (#/gal)
27
-------
Chapter XIII
-------
1
CHAPTER XIII
CALCULATING EMISSIONS OF VOCS EXPRESSED
IN LBS/GAL SOLIDS, AS APPLIED
-------
CALCULATING EMISSIONS OF VOCs
EXPRESSED IN (LBS/GAL SOLIDS), AS APPLIED
Summary
Participants will learn the concept of calculating emission of VOCs from coating
operations, expressed in terms of (Ibs/gal solids), as applied.
These calculations incorporate the transfer efficiency of the coating application.
The units (Ibs/gal solids), as applied, are consistent with several EPA surface coating
regulations.
Chapter XIII
-------
CHAPTER XIII
CALCULATING EMISSIONS OF VOC IN (LBS/GAL SOLIDS)
Concept for Calculating Emissions of VOC per
Volume Solids, as Applied (Ibs/gal Solids) 1
Equation for Calculating Emissions of VOC From
one Gallon of Solids, as Applied (Ibs/gal Solids) 2
Equation for Calculating Emissions of VOC, as Applied
(Ibs/gal Solids) if Actual Weights and Volumes of
Components are not Known 3
Equation for Calculating Emissions of VOC (Ibs/gal
Solids as Applied) when only the VOC (Ibs/gal) and
Density of the Solvent are Known 5
Problem: Calculating Emissions (Ibs/gal Solids)
With Weight of VOC and % Volume Solids 6
Problem: Calculating Emissions (Ibs/gal Solids)
Using Density of Coating,% Wt. VOC
and % Volume Solids 8
Problem: Calculating Emissions (Ibs/gal Solids), Less Water,
for a Water-Borne Coating Using Coating Density, %
Weight Water, Percent Weight Solids.Percent Volume Solids 10
Problem: Calculating Emissions (Ibs/gal Solids) for Same as
Previous Problem, but Using % Weight Total Volatiles 12
Problem: Calculating emissions (Ibs/gal Solids), less Exempt
Solvent, for a Solvent-Borne Coating that Contains Exempt Solvent 14
Problem: Caluclating Emissions (Ibs/gal Solids), as Applied,
Less Water, for a Water-Borne Coating, Given Density of
Coating, % Weight Solids, % Weight Water, % Volume Solids,
and Transfer Efficiency 16
Problem: Calculating Approximate Emissions (Ibs/gal Solids),
Given only the VOC (Ibs/gal) 18
Problem: Calculating Emissions (Ibs/gal Solids), Given
VOC (Ibs/gal), Density of VOC and Transfer Efficiency 20
Problem: Calculating Approximate Emissions (Ibs/gal Solids),
Given Only % Volume Solids 23
-------
CHAPTER XIII
TABLE OF CONTENTS
(Continued)
Problem: Calculating a Simple Alternative Emission Control
Plan by Incorporating a Non-Compliant Coating with high
Transfer Efficiency 25
Problem: Calculating Transfer Efficiency of an Operation
Given the Allowable Emissions (Ibs/gal Solids Applied)
for the Coating 27
-------
EXPLAINING THE CONCEPT OF EMISSIONS OF VOC
PER VOLUME OF SOLIDS APPLIED
1 GALLON
VOC
1 GALLON
VOC
VOC
SOLIDS
SOLIDS
SOLIDS
EMISSIONS
(LBS OF VOC/
GAL OF COATING)
EMISSIONS
(LBS OF VOC/
GAL OF SOLIDS)
T.E = 10036
EMISSIONS
(LBS OF VOC/
GAL OF SOLIDS)
T.E. < 10096
FIG. 1
FIG. 2
FIG. 3
-------
EMISSIONS FROM 1 GALLON LIQUID COATING
(LBS/GAL)
EMISSIONS FROM ONE GALLON OF SOLIDS
(LBS/GAL OF SOLIDS)
= WEIGHT OF SOLVENT (VOC) (1)
W T i_0 F _SO L V E NJ_A VQC J._
"~ VOLUME OF SOLIDS
(2)
EMISSIONS FROM ONE GALLON OF SOLIDS
AS APPLIED (LBS/GAL OF SOLIDS,APPLIED) = WEIGHT OF SOLVENT(VOC) X 1QO
VOLUME OF SOLIDS X T.E.
(3)
NOTE: ALTHOUGH UNITS ARE GIVEN IN LBS/GAL, THE EQUATIONS ARE THE SAME IF THE UNITS
WERE TO BE IN GRAMS/LITRE.
-------
TO CALCULATE EMISSIONS OF VOCs PER VOLUME OF SOLIDS, AS APPLIED
IF ACTUAL WEIGHTS AND VOLUMES OF COMPONENTS ARE NOT KNOWN
FROM EQUATION (3):
EMISSIONS FROM ONE GALLON OF SOLIDS
AS APPLIED (LBS/GAL OF SOLIDS .APPLIED) = WEIG|±T_jDF_SpLy_ENT(VpCJL__X 100
VOLUME OF SOLIDS X I.E.
IF THE ACTUAL WEIGHT OF VOC IS NOT KNOWN:
WT. OF VOC = XWT. OF VOC X DENSITY OF COATING
"100
ALSO, IF ACTUAL VOLUME SOLIDS IS NOT KNOWN:
VOLUME SOLIDS -
* VOLUME, SOL IDS
100
THEREFORE:
EMISSIONS FROM ONE GALLON SOLIDS
AS APPLIED (LDS/GAL OF SOLIDS)
= *WT_._pF_VpC X COATING DENSITY X 1.0_Q
l"6o" XVQL,-_SQL IDS T.E
-------
THEREFORE:
EMISSIONS FROM ONE GALLON OF SOLIDS
AS APPLIED (LBS/GAL OF SOLIDS) :
XWT. OF VOC X COATING DENSITY X 100
XVOLUME SOLIDS X T.E.
(4)
TO CALCULATE THE EMISSIONS FOR A WATER-BORNE COATING, OR ONE CONTAINING EXEMPT
SOLVENT, IN LBS/GALLONS OF SOLIDS, AS APPLIED, LESS WATER, LESS EXEMPT SOLVENT
WT. OF VOC = (100 - %WT. WATER
%WT. SOLIDS)
THEREFORE:
EMISSIONS OF VOC (LBS/GALLON SOLIDS, LESS WATER)
= (100 - %WT. WATFR - *WT. SOLIDS) X COATING_DENSITY__X 1_P_Q
X VOLUME SOLIDS X T.E.
NOTE- USE THE SAME EQUATION FOR COATINGS WITH EXEMPT SOLVENTS. REPLACE
*WT. WATER, IN EQUATION (5), WITH XWT. EXEMPT SOLVENT.
...(5)
-------
TO CALCULATE EMISSIONS OF VOC (LBS/GAL SOLIDS APPLIED) WHEN ONLY THE VOC
AND THE DENSITY OF THE SOLVENT (VOC) ARE KNOWN
FROM EQUATION (3):
EMISSIONS FROM ONE GALLON OF SOLIDS
AS APPLIED (LBS/GAL OF SOLIDS)
VOLUME OF SOLIDS =
VOLUME OF SOLVENT =
WT. OF VOC X 1 00_,
VOLUME OF SOLIDS T.E,
(3)
THEREFORE:
THEREFORE:
VOLUME OF SOLIDS
EMISSIONS FROM ONE GALLON OF SOLIDS
AS APPLIED (LBS/GAL OF SOLIDS)
1 (GAL) - VOLUME OF SOLVENT (VOC)
WT. OF SOLVENT CVQCJ X 1.00
DENSITY 0~F SOLVENT (VOC) T.E
WT. OF SOLVE N_T_( VQCJ.
DENSITY OF SOLVENT (VOC)
WT_._QF_SQLV.ENJ_(_VOC_) ._
- WL-_QE_VQC ..
DENSITY OF SOLVENT (VOC)
EMISSIONS FROM ONE GALLON OF SOLIDS
AS APPLIED (LBS/GAL OF SOLIDS)
VOC
100
( 1 -
VOC
) X T.E.
DENSITY OF VOC
100
T.E"
(6)
PAGE 5
-------
PROBLEM: CALCULATE THE EMISSIONS OF A COATING, IN
LBS/GALLON OF SOLIDS, FOR THE FOLLOWING COATING:
WT. OF VOC = 3.5 LBS/GAL
XVOLUME SOLIDS = 52
PACE 6>
-------
SOLUTION TO PROBLEM:
USE EQUATION (2) TO SOLVE THE PROBLEM
THEREFORE:
EMISSIONS OF VOC (LBS/GAL OF SOLIDS
3.5
0.52
EMISSIONS OF VOC (LBS/GAL OF SOLIDS) = 6.7;
TO CONVERT TO G/L:
EMISSIONS OF VOC (G/L)
= 6.72 X 119.6
= 806 G/L
-------
PROBLEM: Calculate the emissions, less
water, (Ibs VOC/gal solids) for a solvent
based coating given the following.
Density of Coating = 8.96 (Ibs/gal)
% Wt. of VOC's = 32.0
% Volume Solids = 61.0
(% Wt. Water = 0)
PACES
-------
Solution:
_ . . 32 x 8.96
Emissions = —
61
= 4.70 Ibs/gal of solids
To convert to g/L = 4.7 x 119.8
= 563.1 g/L
PACE 9
-------
PROBLEM: calculate the emissions, less
water, (Ibs VOC/gallon of solids) for a
water-based coating given the following.
Coating Density = 9.0 (Ibs/gal)
% Wt. Water =30
% Wt. Solids = 30
% Volume Solids = 19.6
PACE 10
-------
Solution to Problem:
(100 - 30 - 30) x 9.0
Emissions, less water = -g ~
40 x 9.0
19.6
= 18.36 Ibs VOC/gal of solids
To convert to g/L = 18.36 x 119.8
= 2,200 gms VOC/L of Solids
PACE 11
-------
PROBLEM: Perform the same calculation
as the previous one, if the information
provided is as follows:
Coating Density = 9.0 (Ibs/gal)
% Wt. Water =30
% Wt. Total Volatiles = 70
% Volume Solids = 19.6
PACE 12
-------
Solution to Problem:
"Total Volitiles" Implies VOC's and water.
If you know the % Wt. Water and the % Total Volatiles, then:
% Wt. VOC's = % Wt. Total Volatlles - % Wt. Water
= 70-30
= 40
Then the solution to the problem Is:
_ . , 40 x 9.0
Emissions =
= 16.36 (Ibs VOC per gallon of solid)
To convert to g/L = 18.36 x 119.8
= 2199.5 g of VOCper L of solids
PACE 13
-------
PROBLEM: Calculate the emissions (Ibs
of VOC per gallon of solids) for a solvent-
borne coating which contains an exempt
solvent, given the following:
Coating Density = 9.34 (Ibs/gal)
% Wt. Exempt Solvent = 33.5
% Wt. Solids = 30.3
% Volume Solids = 28.0
PACE 14
-------
Solution to Problem:
Emissions, less exempt solvent (Ibs VOC per gallon of solids)
(100 - 33.5 - 30.3) x 9.34
28.0
36.2 x 9.34
28.0
12.1 Ibs VOC/gallon of solids
To convert to g/L = 12.1 x 119.8
= 1447 g of VOC per L of solids.
PACE 15
-------
PROBLEM: Calculate the emissions of
VOC, less water, per gallon of solids applied,
for the following coating:
Density of Coating = 10.4 (Ibs/gal)
% Wt. Solids = 25.3
% Wt. Water = 55.0
% Volume Solids = 23.4
Transfer efficiency = 45.0 %
PACE 16
-------
Solution to Problem:
Emissions of VOC, less water, as applied
_ (100 - 55.0 - 25.3) x 10.4 x 100
23.4 x 45.0
20488
1053
- 19.46 Ibs VOC per gallon of solids applied
PACE 17
-------
PROBLEM:
A COATING HAS A VOC OF 2.8 LBS/GAL. WHAT ARE THE APPROXIMATE
EMISSIONS FOR THIS COATING, EXPRESSED IN (LBS/GAL SOLIDS)?
PACE 1«
-------
SOLUTION TO PROBLEM:
THE EQUATION TO BE USED IS EQUATION (6)
EMISSIONS OF VOC
(LBS/GAL SOLIDS) =
VOC
100
VOC
) X T.E
DENSITY OF VOC
SINCE WE HAVE NOT BEEN GIVEN THE DENSITY OF THE VOC, ASSUME
IT TO BE 7.36 LBS/GAL. THIS IS THE DENSITY ASSUMED BY THE
EPA TO BE AN AVERAGE.
I NOTE: ONLY ASSUME THE DENSITY OF THE VOC =7.36 LBS/GAL !
| WHEN APPROXIMATE CALCULATION'S ARE ADEQUATE! !
ALSO, SINCE THE TRANSFER EFFICIENCY HAS NOT BEEN GIVEN,
ASSUME IT TO BE 100X
EMISSIONS OF VOC
(LBS/GAL SOLIDS)
2.8 X 100
(1 - 2.8 ) X 100
7.36
EMISSIONS OF VOC
(LBS/GAL SOLIDS) = 4.52
-------
PROBLEM:
CALCULATE THE EMISSIONS OF VOC (LBS/GAL SOLIDS, AS APPLIED)
FOR A COATING WITH THE FOLLOWING INFORMATION:
VOC (LBS/GAL) = 3.5
DENSITY OF VOC (LBS/GAL) = 6.8
TRANSFER EFFICIENCY (56) = 47
f«
-------
SOLUTION TO PROBLEM:
USING EQUATION (6) AND SUBSTITUTING THE RELEVANT VALUES:
EMISSIONS OF VOC
(LBS/GAL SOLIDS, APPLIED)
3.5 X 100
( 1 - 3.5 ) X 47
6.8
EMISSIONS OF VOC
(LBS/GAL SOLIDS, APPLIED) = 15.3
PACE
-------
PROBLEM:
A PRODUCT DATA SHEET GIVES THE PERCENTAGE VOLUME SOLIDS OF A
COATING AS 42* UNFORTUNATELY, NO OTHER DATA IS AVAILABLE.
CAN YOU ESTIMATE WHAT THE VDC OF THE COATING MIGHT BE,
EXPRESSED IN LBS/BAL? AND EXPRESSED IN LBS/GAL SOLIDS?
-------
SOLUTION TO PROBLEM:
PERCENT VOLUME SOLIDS
PERCENT VOLUME SOLVENT
THEREFORE:
VOC (LBS/GAL)
VOC (LBS/GAL)
= (100 - Sb VOLUME SOLVENT)
= WT.OF SOLVENT (VOC) X 100
DENSITY OF SOLVENT (VOC)
VOC
100
DENSITY OF VOC
= % VOL. SOLVENT X DENSITY OF VOC
100
= (100 - XVOL SOLIDS) X DENSITY VOC
100
= (100 - 42) X 7.36
100
= 4^27
EMISSIONS OF VOC
APPLIED (LBS/GAL SOLIDS)
VOC
X 100
(1 -
VOC
DENSITY OF VOC
.) X T.E,
4.27 X 100
0.42 X 100
EMISSIONS OF VOC
APPLIED (LBS/GAL SOLIDS)
10.17
PAGE 24
-------
PROBLEM:
A LOCAL AIR POLLUTION CONTROL DISTRICT REQUIRES A COATING TO
HAVE A VOC OF 3.5 LBS/GAL AND A MINIMUM TRANSFER EFFICIENCY
OF 65*
A CUSTOM COATER WISHES TO USE A COATING WITH A VOC OF 4 $
LBS/GAL, BUT HIS DIPPING OPERATION YIELDS A TRANSFER
EFFICIENCY OF 90*.
WOULD THE CUSTOM COATER'S COATING APPLICATION BE EQUIVALENT
TO THE REQUIREMENTS OF THE DISTRICT?
:- /a -2C
PACE 25,
-------
SOLUTION TO PROBLEM:
USE EQUATION (6) TO SOLVE THIS PROBLEM.
ONCE AGAIN, SINCE THE DENSITY OF THE VOC HAS NOT BEEN GIVEN,
ASSUME IT TO BE 7.36 LBS/GAL
STEP 1:
CALCULATE THE EMISSIONS (LBS/GAL SOLIDS) REQUIRED BY THE
DISTRICT.
EMISSIONS OF VOC
(LBS/GAL SOLIDS, APPLIED) =
3.5
X 100
(1 - 3.5 ) X 65
7.36
10.
STEP 2:
CALCULATE THE EMISSIONS (LBS/GAL SOLIDS) PROPOSED BY THE
CUSTOM COATER.
EMISSIONS OF VOC
(LBS/GAL SOLIDS, APPLIED) =
4.3
X 100
(1 - 4.3 ) X 90
7.36
= 11.49
STEP 3:
COMPARISON BETWEEN WHAT THE DISTRICT REQUIRES AND WHAT THE
CUSTOM COATER PROPOSES, SHOWS THAT THE COATER WOULD EXCEED
THE EMISSIONS REQUIRED BY THE DISTRICT.
-------
Problem: A state rule requires that the
emissions, less water, of a coating shall be less
than 11.3 Ibs of VOC per gallon of solids applied.
If a sheet metal surface coater wishes to use a
coating with a VOC of 2.8 Ibs/gal, what transfer
efficiency must he achieve to comply with the
rule? The solvent density = 6.9 Ibs/gal.
PACE 27
-------
Solution to Problem:
Emissions (Ibs VOC per gallon of solids applied) =
VOC x 100
( 1 - VOC ) x T.E.
Density
2.8 x 100
11.3 =
/ 2.8 x
( 1 - -£5- ) x T.E.
2.8 x 100
11.3 =
0.59 x T.E.
Therefore:
T.E. = 2-6 x 100
11.3 X 0.59
= 42 %
Therefore, provided that the surface coater demonstrates
a transfer efficiency equal to or greater than 42%, he
will be In compliance with the state rule.
PAGE 28
-------
Chapter XIV
-------
CHAPTER XIV
CALCULATING % VOLUME SOLIDS FOR A
COATING OR COATING MIXTURE
J
-------
1
CALCULATIONS USING % VOLUME SOUDS OF
A COATING OR A COATING MIXTURE
Summary
Participants are provided with equations to calculate percent (%) volume solids for
single and two-component coatings, as well as for coatings that a re reduced prior to
coating application.
Several problems are discussed to demonstrate how these equations can be used to
calculate percent (%) volume solids and VOC contents from Material Safety Data
Sheets.
These equations are extremely important in order to carry out an Alternative Emissions
Control Plan (Bubble), or to calculate the costs of coating application.
Separate sessions have been compiled to calculate Alternative Emission Control Plans
(Bubbles) and costs of coating application.
Chapter XIV
-------
CHAPTER XIV
CALCULATIONS USING % VOLUME SOLIDS OF A
COATING OR A COATING MIXTURE
Equation to Calculate % Volume Solids of a Mixture 1
Problem: To Calculate % Volume Solids of a Reduced Coating 2
Problem: To Calculate % Volume Solids of a Two-Component Coating 4
Problem: To Calculate % Volume Solids of a Two-Component,
Reduced Coating 6
Equation to Calculate % Volume Solids Given the % Weight
or VOC Content of the Coating 8
Problem: To Calculate % Volume Solids of a Two-Component,
Reduced Coating, Given the VOC of its Components 9
Equation: To Calculate % Volume Solids, Given the % Weight
of Several Solvents in the Coating 11
Problem: To Calculate % Volume Solids of a Coating From
a Material Safety Data Sheet 12
Problem: To Calculate % Volume Solids and the VOC Content
of a Coating from a Material Safety Data Sheet 14
-------
TO CALCULATE PERCENT VOLUME SOLIDS
OF A COATING MIXTURE
1 LIQUID GALLON OF COATING
FRACTION VOLUME SOLIDS = SOLID GALLONS
LIQUID GALLONS
RE-ARRANGING THE EQUATION:
SOLVENT
SOLIDS
SOLID GALLONS = LIQUID GALLONS X FRACTION VOLUME SOLIDS
ALSO:
PERCENT VOLUME SOLIDS = FRACTION VOLUME SOLIDS X 100
USING THESE BASIC EQUATIONS, WE CAN CONSIDER A MIXTURE OF COATINGS AS FOLLOWS:
PERCENT VOL. SOLIDS OF MIX. = TOTAL SOLIDS GALLONS IN MIXTURE X 100
TOTAL LIQUID GALLONS IN MIXTURE
= SOLID GALS (1) + SOLID GALS (2) + SOLID GALS (3) +
x 100
LIQ GALS (1) + LIQ GALS (2) + LIQ GALS (3)
LIQ GALSd) x FRACT. SOLIDS (1) + LIQ CALS(2) X FRACT. SOLIDS(2) + ... x 100
TOTAL LIQUID GALLONS IN MIXTURE
-------
TO CALCULATE THE PERCENT VOLUME SOLIDS
OF A COATING THAT IS REDUCED
PRIOR TO APPLICATION
PROBLEM:
A COATING HAS A PERCENTAGE VOLUME SOLIDS OF 40%. IT IS REDUCED
FOR SPRAY APPLICATION WITH SOLVENT IN THE RATIO:
1 PART COATING : 0.25 PARTS REDUCER
WHAT IS THE PERCENT VOLUME SOLIDS OF THE MIXED COATING?
PACE 2
-------
SOLUTION TO PROBLEM:
GALS LIQUID COATING X FRACTION SOLIDS •= GALS SOLIDS
COATING 1 0.40 0.40
REDUCER 0.25 0 0
FRACTION SOLIDS
% VOLUME SOLIDS
-------
L
PROBLEM:
A TWO-COMPONENT COATING CONSISTS OF COMPONENT A AND
COMPONENT B. THE DATA SHEET PROVIDES THE PERCENTAGE VOLUME
SOLIDS AS FOLLOWS:
COMPONENT A = 52%
COMPONENT B = 90%
THE COATING IS MIXED IN THE RATIO:
4 PARTS COMPONENT A: 1 PART COMPONENT B
WHAT IS THE PERCENTAGE VOLUME SOLIDS OF THE MIXTURE?
PACE 4
-------
SOLUTION TO PROBLEM:
GALS LIQUID COATING X FRACTION SOLIDS = GALS SOLIDS
COMPT. A
COMPT. B
4.0
1.0
5.0 (GALS)
0.52
0.90
2.08
0.90
2.98 (GALS)
FRACTION SOLIDS
% VOLUME SOLIDS
ft VOLUME SOLIDS
2.98
0.596
0.596 X 100
59.6 ft
PAGES
J
-------
PROBLEM;
THE TWO-COMPONENT COATING IN THE PREVIOUS PROBLEM WAS
FURTHER REDUCED WITH SOLVENT SO THAT THE ACTUAL MIXED COATING
COULD BE SPRAY APPLIED. THE COATING WAS MIXED AS FOLLOWS:
4 PARTS COMPT. A : 1 PART COMPT. B : 0.15 PARTS REDUCER
WHAT IS THE PERCENTAGE VOLUME SOLIDS OF THE MIXED COATING,
READY FOR SPRAY APPLICATION?
I PACE6 J
-------
SOLUTION TO PROBLEM:
GALS LIQUID COATING X FRACTION SOLIDS = GALS SOLIDS
COMPT. A 4.0 0.52 •= 2.08
COMPT. B 1.0 0.90 = 0.90
REDUCER 0.15 0.0 = 0.00
!7i5 (GALS) ^98 (GALS)
FRACTION SOLIDS = 2.98
T15
0.579
% VOLUME SOLIDS = 0.579 X 100
% VOLUME SOLIDS = 57.9%
L
PAGE 7
-------
TO CALCULATE PERCENT VOLUME SOLIDS OF ONE SOLVENT
GIVEN ITS PERCENT WEIGHT OR ITS VOC CONTENT
(VOC)
SOLVENT
SOLIDS
100X
VOL. SOLVENT + XVOL. SOLIDS = 100
% VOL.SOLIDS
BUT:
FRACTION VOL. SOLVENT
= (100 - X VOL. SOLVENT)
WT. SOLVENT (VOC)
DENSITY OF SOLVENT
56 VOL. SOLVENT
= WT. SOLVENT (VOC^ X 100
DENSITY OF SOLVENT
THEREFORE:
X VOL. SOLIDS
(100 - WT. SOLVENT (VOC) X 100 )
DENSITY OF SOLVENT
X VOL. SOLIDS
( 1 -
WT. SOLVENT (VOC) ) X ICO
DENSITY OF SOLVENT 1
% VOL. SOLIDS = ( 1 -
VOC
DENSITY OF VOC
) X 100
1
NOTE- IF THE DENSITY OF THE SOLVENT (VOC) IS NOT KNOWN YOU
MAY ASSUME IT TO BE = 7.36 LBS/GAL. ONYL USE THIS VALUE FOR
PURPOSES OF APPROXIMATION.
PACES
-------
CALCULATION OF
VOLUME SOLIDS
PROBLEM:
THE DEFT WATER-REDUCIBLE EPOXY PRIMER HAS A VOC CONTENT OF 2.8
#/GAL WHEN COMPONENTS A & B ARE MIXED AS PACKAGED. THE MIXED
COATING IS FURTHER REDUCED WITH WATER IN THE FOLLOWING RATIO:
1 PART MIXED EPOXY :
1.75 PARTS WATER
WHAT IS THE RESULTING PERCENT VOLUME SOLIDS OF THE MIXED AND
REDUCED COATING?
ASSUMPTIONS;
ALL SOLVENTS IN THE COATING ARE VOCs.
DENSITY OF SOLVENTS = 7.36 0/GAL
PAGE 9
-------
Solution to Problem:
To calculate % volume sollda of mixed A & B:
VOC of coating «= 2.8 #/gal (given)
Density of VOC = 7.36 #/gal (assumed)
mt i« i M ii j i* Wt. Of Solvent „
% Volume Solid. « (1 - of *
62.0%
To Calculate % Volume Solids of Reduced Coating:
1.0 gallon mixed A A B e 0.62 gal eollde
1.76 gallon of water • ° »•' •olldt
2.75 gallona of mixed, reduced coating B ^^ Oal •olld8
% Volume Sollda •= ~ x 100
22.5%
PAGE 10
-------
CALCULATION OF PERCENT VOLUME SOLIDS
FOR A BLEND OF SOLVENTS IN COATING
% Vol Solids -I- % VoL Solvt - 100
Alao, % Vol. Solvt - % Vol. Solvt 1 + % Vol. Solvt 2 +...
% Vol. Solvt n
THEREFORE: m ^QQ _ (% y<)I 8o|yt 1 +
% Vol. Solids
% Vol Solvt n)]
REMEMBER. VOL OF SOLVENT -
AND, WT OF SOLVT - % WT SOLVT x DENSITY OF COATING
VOL OF SOLVT - % Wt. of Solvt. x Density of Dotting
Density of Solvt.
% Vol. Solids - r1QQ . f%wi.s»Mi ^ %ma»M2
L1OO - (D
% Wl. 8>M n
. ..•.». i
) x Density of Coating ]
PACE 11
-------
Problem:
Calculate the % volume solids of a coating for which the
material safety data sheet provides the following:
Ingredient % Wt Solvent
XYLENE 20
MIBK 15
MEK 13
ACETONE <5
DENSITY OF COATING (WPG) = 9.8 #/gal
Tables of solvent densities give the densities of these
solvents as:
Density (*/gal)
XYLENE 7.35
MIBK 6.67
MEK 6.72
ACETONE 6.61
ASSUME % WT OF ACETONE = 5%
PAGE 12
-------
Solution to Problem:
Perform this calculation in a table.
Density (#/gal) % wt. $0|vt
INGREDIENT
XYLENE
MIBK
MEK
ACETONE
% WT. SOLVENT
20
15
13
<5
of Solvent
7.35
6.67
6.72
6.61
Total:
Density
2.72
2.25
1.93
0.76
7.66
% Volume Solids = [100 - (7.66 x 9.8)]
% Volume Solids = 100 - 75.07
= 24.93
PAGE 13
-------
Problem:
Calculate the % volume solids of a coating, and the VOC of
the coating (less exempt solvent), based on the following
information:
ingredient %wr
METHYLISOAMYL KETONE 2.77
BUTYL ACETATE 2.77
ETHANOL 0.15
XYLENE 5.54
1,1,1 TRICHLOROETHANE (TCA) 44.35
Weight per gallon of Coating = H.58#/gal
Tables of solvent densities provide the following:
Density (#/gal)
MIAK 6.76
BUTYL ACETATE 7.36
ETHANOL 6.58
XYLENE 7.35
1,1,1 TRICHLOROETHANE (TCA) 11.06
PAGE 14
-------
Solution to Problem:
(a) Find the % Volume Solids
INGREDIENT
MIAK
Butyl Acetate
Ethanol
Xylene
1,1.1 TCA
% WT. SOLVENT
2.77
2.77
0.15
5.54
44.35
of Solvent
6.76
7.36
6.58
7.35
11.06
Density of Solvent
0.41
0.38
0.02
0.75
4.01
Total:
5.57
% Volume Solids = [100 - (5.57 x 11.58)]
= 100 - 64.50
% Volume Solids = 35.50
(b) Find VOC, less exempt solvent
The equation for this is:
voc =
_
[100 - % Wt. Solids - % Exempt Solvt] x
100 - ( * wt- of Exempt Solvt x Density of Coating \
Density of Exempt Solvt.
Density of
PACE 15
-------
Simplifying, the numerator becomes:
_ % wt- voc x Density of Coating
_ . % Wt. of Exempt Solvt x Density of Coating .
Density of Exempt Solvent
From the MSDS, the % Wt. of VOC
= (2.77 + 2.77 + 0.15 + 5.54)
= 11.23
Therefore, VOC = 11'23 X 1t58
100 . , 44.35 x 11.58 )
11.06
130.04
53.56
VOC = 2.43 #/gal, less exempt solvent
To convert to G/L = 2.43 x 119.8
= 291.1 G/L
PAGE 16
-------
Chapter XV
-------
r
CHAPTER XV
CALCULATING ALTERNATIVE EMISSION
CONTROL PLANS ("BUBBLES")
-------
CALCULATING AN ALTERNATIVE EMISSIONS CONTROL PLAN
Summary
Participants will learn how to calculate Alternative Emission Control Plans under dif-
ferent circumstances:
• Based on mass per unit volume solids applied
(example: Ibs/gallon solids applied)
• Using emissions factors that take volume of solids into account
Chapter XV
-------
CHAPTER XV
CALCULATING AN ALTERNATE EMISSIONS CONTROL PLAN
Equation to Calculate Excess Emissions 1
Problem: To Calculate Excess Emissions (Basic Problem) 2
Problem: to Calculate Excess Emissions (More Complex Problem) 4
Concept Explanation: To Calculate an AECP Using a
Ibs/gal Solids Basis 7
Example: To Calculate an AECP using a Ibs/gal Solids Basis 12
Calculating an AECP Using an Emissions Factor as Basis 21
Equations for Calculating an AECP Using an Emissions
Factor as Basis 22
Graphs of Emissions Factors for Air Dry Coatings 25
Graphs of Emissions Factors for Bake Coatings 26
Problem: Calculating Emissions Factor and Excess Emissions 27
Problem: Calculating an AECP Using Emissions Factors as a
Basis (Solvent-Borne Coatings) 28
Problem: Calculating an AECP Using Emissions Factors as a
Basis (Solvent and Water-Based Coatings) 31
-------
Alternate Emission Control Plans
'Bubbles"
To calculate Excess Emissions:
Excess Emissions (Ibs) = Emissions from actual coatings and
processes - theoretical emissions from
compliant coating and methods (Ibs).
ii?M?osltiXS (+)Athen th* Proposed alternate
"
/»o
control plan ("Bubble") would not be acceptable!
If the Excess Emission < 0 (or negative (-)), then the proposed alternate
emission control plan ("Bubble") ywM be potentially acceptable
PAGE 1
-------
Problem:
The actual total emissions from a coating process is 132
Ibs/day. If the coating facility were to use strictly
complying coatings and processes, the emissions would
be 87 Ibs/day. What are the excess emissions (Ibs/day)?
PAGE 2
-------
Solution to Problem:
Excess Emissions = 132 - 87
= +45lbs/day
This actual coating line does not comply with the regulated
requirements.
PAGE 3
-------
Problem:
A coating line utilizes a combination of non-compliant
coatings and powder coatings. The total daily emissions
from the operation is 320 Ibs. If all of the coatings used in
the operation strictly met the regulated requirements, then
on a theoretical basis, the daily emission would be 402 Ibs.
Is this coating line able to demonstrate that it is in
compliance with the regulation, via an alternate emission
control plan?
PAGE 4
-------
Solution to Problem:
Excess Emissions = 320 - 402
= -82 Ibs/day
Since the answer Is negative (-) this coating line emits less
VOC than would be emitted if ail of the coatings strictly met
the regulation. Clearly, this coating line would satisfy the
regulation.
PAGE 6
-------
To calculate an alternate emission plan. ("Bubble")
The purpose of this exercise is to demonstrate that the
emissions of the proposed plan are less than the
emissions which would be generated If the coating and
processes strictly met the requirements of the regulation.
It is vital to ensure that all the data used in the calculations
have the same basis. For instance, If solvent and water-
base coatings are used, the usage of the water-base
coatings must be calculated by eliminating the water
content.
After all the data has been standardized, the following
steps can be followed:
PAGE 7
-------
Step 1 Calculate the actual emissions from the coatings being used.
Gals used, VOC of coating,
less water (gals) x less water (Ibs/gal)
Actual
Emissions (Ibs)
Coating A
Coating B
Coating C
Total Actual Emissions (Ibs)
Step 2 Calculate the volume solids of coatings used.
Uq. Coating used % Vol Solids T.E.
less water (gals) x 100 x 100
Solid Coating
used (gals)
Coating A
Coating B
Coating C
Total solid coating deposited (gals)
Step 3 Calculate the gals of liquid compliant coating that would be
required to deposit the same volume of aoJifl coating. If the
regulation requires a minimum transfer efficiency then this must
be Included In the calculation. If the transfer efficiency Is not a
consideration, then:
T.E. =
IflQ * 1
100
PAGE 8
-------
Vol. of Liquid Vol. Solids Coating deposited (gals) x 100 x 100
Compliant =
Coating (gals) % Vol. Solids off Compliant Coating x % T.E.
Step 4 Calculate the theoretical emissions from the theoretical compliant
coating process.
Emissions (Ibs of VOC) = Vol. of Liq. Compliant Coatino (gals) x
of Compliant Process VOC of Compliant Coating (ibs/gal)
Step 5 Calculate the Excess Emission of the proposed plan by comparing
the emissions of these coatings and processes with the theoretical
•missions which w£uld be generated if only a compliant coating
rocesses with the theoretical
e enerated
and process were used.
Excess Emissions (Ibs of VOC) = Emissions from Actual or Proposed
Coatings and Processes • Emissions
from Theoretical Compliant Coatings and
' Processes.
PAGE 9
-------
If the resulting excess emission > 0 (positive (+)), then the
proposed plan would_not be acceptable.
If the resulting excess emissions < 0 (negative (-)), then
the proposed plan will be potentially acceptable.
Step 6 If the proposed plan still does not reduce the emission to a level
rocesses,
emissions
equivalent to the use of compliant coatings and processes, then
you may wish to calculate the additional percent e
reductions necessary to comply.
*, ~ . . - -. « % Excess Emissions x 100
% Emission Reduction =
Actual Emissions
PAGE 10
-------
The excess emissions are positive (+). In other words, the
actual emissions from coatings A, B, C, and D exceed the
theoretical emissions from the compliant coating.
Therefore, the proposed alternate emissions control plan
"Bubble" would not be acceptable.
The percentage additional emissions reductions required
to make this plan work are:
% Emission Reductions = % Excess Emissions x 100
Actual Emissions
20.35x100
773
26.3
PAGE 11
-------
Alternative emission control plans using
as basis: Emissions of VOC per volume
solids applied
Problem 1 A custom coater utilizes two solvent-based coatings on his
conveyor line. One coating is non-complying, the other is over-
complying. Can the custom coater get into compliance by
averaging the emissions from both coatings?
The following information is provided:
Coating A Coating B Compliant Coating
Gals used
VOC of Coating (Ibs/gal)
% Volume Solids
6.0
5.0
32.1
10.0
2.0
72.8
?
3.5
52.4
Hints:
Fraction volume solids = % Volume Solids
100
PAGE 12
-------
Solution to Problem 1
Approach to solving problem:
1. We need to calculate the total actual emissions from both coatings, A
and B, respectively.
2. We need to calculate the volume of solids (gals) deposited by coatings
A and B, respectively.
3. We need to calculate the total theoretical emissions that would be
generated if the VOC-compliant coating, with a VOC-content of 3.5
Ibs/gal, were utilized to apply the same amount of solid coating that
was used for coating A and B, respectively.
4. We will compare the actual amount of total emissions generated by A
and B, and compare them with the theoretical emissions that would be
generated if only the compliant coating (3.5 Ibs/gal) were used in the
coating operation.
PAGE 13
-------
Step 1 Calculate actual emissions (Ibs of VOC)
Gals used, VOC of coating, Actual
less water (gals) x less water (Ibs/gal) = Emissions (Ibs)
Coating A 6.0
Coating B 10.0
5.0
2.0
6.0x5.0 = 30.0
10.0x2.0 = 20.0
Total Actual Emissions (Ibs) = 50.0 Ibs of VOC
Step 2 Calculate volume solids (gals) of coatings A and B
Liq. Coating used % Vol Solids T.E. Solid Coating
less water (gals) x 100 x 100 = used (gals)
Coating A 6.0 0.321 1.0 1.93
Coating B 10.0 0.728 1.0 7.28
Total solid deposited (gals) = 9.21 (gals)
Step 3 Calculate the volume of liquid compliant coating required in order
to deposit 9.21 solid gallons, and calculate the resulting emissions
(Ibs)
c^mplair.^ating = Voi of Solids Coatinfl **** x 100 x 100
% Volume Solids of Compliant Coating x T.E.
9.21x100x100
52.4x100
17.6 gals liquid coating
PAGE 14
-------
Step 4 Calculate the theoretical emissions from the theoretical complaint
coating process.
VOC emissions from compliant coating (Ibs) = VOC (Ibs/gal) x Gals, used
3.5x17.6
61.6 Ibs
Step 5 Compare the total actual emission generated by Coatings A and B
with theoretical emissions generated by the compliant coating.
Excess Emissions (Ibs of VOC) = Emissions from the actual Coatings -
Emissions from Compliant Coatings
50.0-61.6
-11.6 Ibs.
Since the excess emissions are negative (•), in other words the average
emissions from coatings A and B are less than the theoretical emissions from
a compliant coating, the proposed alternative emission control plan
("Bubble") would be acceptable!
PAGE 15
-------
Problem 2 A large manufacturing facility utilizes 4 coatings on its lines.
Some of the coatings comply with the regulation, others do not.
Determine whether the coating facility would qualify for an
alternative emission control plan, given the following
Information:
Compliant
Coating Coating Coating Coating Coating Per
A B C D Regulation
Avg. Coating Usage
(gals/day)
VOC of Coating,
less water (Ibs/gal)
T.E.%
%Vol Solids,
It known
%Wt. of Water
Density of Solvent
(VOC)
Density of Coating
(Ibs/gal)
Density of Water
(Ibs/gal)
3.0
5.4
40.0
?
0
6.67
N/A
9.5
3.7
90.0
45.5
0
N/A
N/A
14.0
1.8
65.0
20.2
58.2
N/A
9.34
8.33
6.5
2.3
25.0
21.5
51.2
N/A
10.15
8.33
3.5
3.5
65.0
?
N/A
7.36*
N/A
N/A
•Assumptions If the density of the VOC Is not known, assume
density = 7.36 Ibs/gal.
PAGE 16
-------
Solution to Problem 2
Since we have a combination of solvent-borne and water-base coatings, we
will need to eliminate all water from coatings C and D. Moreover, we will need
to establish the % volume solids of coatings A and the theoretical compliant
coating. Once we have this data, we can continue to calculate the "Bubble."
Preliminary Steps: For coatings C and D, the coating usage, less water, is
as follows:
Coating Usage (gal),
less water
= Actual Coating Usage x % Volume Water
% Volume Water
% Wt. Water x Density of Coating
Density of Water
For Coating C:
% Volume Water
58.2 x 9.34
ifss
65.3
For Coating D:
% Vol. Water
51.2x10.15
8.33
62.4
PAGE 17
-------
Calculate the average usage of coatings C and D, assuming that there were
no. water in the coatings.
Avg. Coating Usage (gals) = Actual Coating Usage x
(less water) % Volume Water
For Coating C:
65 3
Coating usage, less water (gals) = 14.0 x 1_
100
= 9.14 gals
For Coating D:
Coating usage, less water (gals) = 6.5 x _
100
= 4.10 gals
Calculate the % Volume Solids for Coating A and for the theoretical compliant
coating.
% Volume Solids = (1 - VOC ) x 100
Density of VOC
For Coating A. % Vol. Solids = (1- _) x 100
6.67
= 19.0
For Compliant Coating. « e *
%VoL Solids = (1- r±__)
x 100
7.36
52.4
PAGE 18
-------
Finally! We can now calculate the alternate emission control plan "Bubble."
Step 1 Calculate the Actual total emissions from Coatings A, B, C, and D.
Gals used, VOC of coating, Actual
less water (gals) x less water (Ibs/gal) = Emissions (Ibs)
Coating A
Coating B
Coating C
Coating D
3.0
9.5
9.14
4.10
5.4
3.7
1.8
2.3
3.0x5.4 = 16.2
9.5 x 3.7 = 35.2
9.14x1.8 = 16.5
4.1x2.3 = 9.4
Total Actual Emissions
= 77.3 Ibs of VOC
Step 2 Calculate the volume of solid coatings utilized on the coating line.
Llq. Coating used
less water (gals)
% Vol Solids
x 100 x
100 =
Solid Coating
used (gals)
Coating A
Coating B
Coating C
Coating D
3.0
9.5
9.14
4.10
0.190
0.455
0.202
0.215
0.40
0.90
0.65
0.25
0.23
3.89
1.20
0.22
Total Volume of Solid Coating (gals) = 5.54
PAGE 19
-------
Step 3 Calculate the liquid compliant coating required to deposit 5.54
gallons of solids, and calculate the resulting emissions (Ibs).
ColmplalntllqUld J/olume Solid of Coating (gals) x 100 x 100
Coating (gals) % Vol. Solids of Compl. Coating x T.E.
5.54 x 100 x10&
52.4 x 65.0
= 16.27 gals
Step 4 Calculate the theoretical VOC emission from the use of the
compliant coating:
Emissions of VOC (Ibs) = Gals of Compliant Coating used x
VOC(lbs/gal)
16.27x3.5
56.95 (Ibs)
Step 5 Compare total actual emissions generated by coatings A, B, C,
and D, with the theoretical emissions generated by the compliant
coating. r
„._ ,..~~i = Emissions from Actual Coatings -
(Ibs of VOC) Emissions from Compliant Coating
77.3-56.95
i
+20.35 Ibs
PAGE 20
-------
CALCULATING AN ALTERNATIVE EMISSIONS CONTROL PLAN
(b) Using Emissions Factors which take volume of solids into
account.
PAGE 21
-------
0-20
APPENDIX «-2
TO CALCULATE EMISSION FACTORS FOR NON-COMPLYING
OR OVER-COMPLYING COATINGS
Definition: The Emission Factor for a non-complying coating is the excess
emissions that are emitted, per gallon of coating used when compared with the
emissions that would result if the same amount of solids we're used with a VOC-
compliant coating.
Conversely: the Emission Factor for an over-complying coating is the credit in
emissions that are available, per gallon of coating used, when compared against the
emissions that would result if the same amount of solids were applied, using a
VOC-compliant coating.
Emission Factor (E.F.) is expressed in Ibs/gal.
If E.F. is positive (+), then a credit is available.
If E.F. is negative (-), then the emissions are in excess of those
allowable.
Calculations
Emission Factor (E.F.)
= VOC emitted from complying coating (B) -
VOC emitted from 1 gallon of non-complying
or over-complying coating (A)
Let A = Non-complying or over-complying coating
B = Complying coating
G = Gallons of liquid coating used
VOC = Volatile Organic Compound emissions in Ibs/gal
VS r Fraction of solids per gallon of coating
= % Volume Solids
100
TEA = Transfer efficiency of coating A
TEjj = Transfer efficiency of coating B
In these calculations, coating "A" will always be referred to as "non-complying."
t
VOC emitted from coating "A" = GA x VO^A
Amount of solid coating used = GA x VSA x TEA
-------
0-21
Amount of complying coating used to spray the same amount of parts:
Amount of liquid coating
used (gals)
Therefore, amount of liquid
coating B used
But the number of solid
gallons of B used
And amount of solid coating
A used
Therefore, GB
VOC emitted from coating B
Therefore, E.F.
Amount of solid coating used (gals)
Volume solids x transfer efficiency
Amount of solid coating B used (gals)
VSB x TEB
= Number of solid gallons of A used,
= GA x VSA x TEA
a GA x VSA x TEA
VSB x TEB
= GBxVOCB
= GA x VSA x TEA x VOCB
VSBx TEB
= CA x vsA x TEA x vocB - (GA x VOCA)
VSB x TEB
But, by definition, E.F. is per gallon of coating "A."
Therefore, GA = 1 gallon
(1)... Therefore, E.F. = V^ x TEA x VOCB - (VOCA)
VSB x TEB
In many cases, the fraction volume solids of a coating isn't known. One can
approximate the fraction volume solids if the VOC content is known. This is
done as follows:
Fraction volume solvent
VOC
Density of Solvent
Assuming a density of 7.3 Ibs/gal (accepted by the EPA):
VOC
^^••^^^^H
7.36
Fraction volume solvent
-------
Also: Fraction Volume Solids = 1 - Fraction volume solvent
) 7.36 -
VSB
Thus, substituting for
V$B equation (1) gives: E.F.
7.36
(1 -
7.36
xVSA x
7.36
x VOCB -
(2)... " 7.36 - VOCB
II VSA is also not known with any accuracy, then one
can also assume its solvent to have a density = 7.36 Ibs/gal.
(1 - VOCA) . (7.36 - VOCA)
Then, VSA = 7.35 = 7.36
Equation (2) then gives: E.F.
7.36 x (7.36 - VOCA) x VOCB x
- (VOCA)
' (7.36-VOCB)x
This simplifies to E.F.: = (7.36 x VOCB) -J
(3) 7.36 - VOCB
TEB
If the transfer efficiency
is to be ignored, then:
-------
+6.0
+5.0
+4.0
+3.0
+2.0
+1.0
•1.0
-2.0
-3.0
-4.0
-5.0
-6.0
I
-£3
s
_L_X
^
—1:±
--•-r
-t-
..J.J.
t~
'l1
ill
^
rzn.
:ti±
H^--
-r-i
^
-
!.
r-r
i H
•"'fl
, i
8
-H-
EMISSION FACTOR
FOR
AIR DRY COATINGS
FIGURE 4-2
iTTt
ICompll
I i
:J.L
m
_u_
u.
+-H
iant'Cpiting-1
O.
3E
S
.VIP
«^
s
1- t
oc;
iw» >-
_u_
i\ \
1.0
!.0 3.0 4.0 5.0
VOC OF COATING (fcs/pat)
6.0
7.0
-------
CALCULATION OF EMISSIONS FACTOR
AND EXCESS EMISSIONS
PROBLEM:
COATING 'A" HAS A VOC OF 5.0 Ibs/gal AND A DEMONSTRATED TRANSFER
EFFICIENCY OF 90%. WHAT IS THE EMISSIONS FACTOR IF THE COATING MUST
COMPLY WITH A REGULATED LIMIT OF 2.3 Ibs/gal AND THE MANDATED
TRANSFER EFFICIENCY IS 65% ?
IF 6 GALLONS OF COATING A ARE USED EVERY DAY, THEN WHAT ARE THE
DAILY EXCESS EMISSIONS FOR THE FACILITY?
ASSUME AVERAGE DENSITY OF VOC = 7.36 Ibs/gal
-------
Solution to Problem:
Emission Factor = ((7.36 x 2.3) - (2.3 x 5.0) x 90_
7.36-2.3 65
,[(16.93-11.5 )X1.38].5.0
5.06
1.5-5.0
Emission Factor = -3.5 Ibs VOC per gallon off Coating A
Thus for every 1 gallon of coating A used, the excess emissions emitted into
the air, when compared with the use of complying coating, are 3.5 Ibs.
Iff 6 gallons of coating were used, the excess emissions would be:
6 x (-3.5) = -21.0 Ibs off VOC
PAGE 28
-------
CALCULATION OF APPROXIMATE EXCESS EMISSIONS
FROM THE FOLLOWING PROPOSED ALTERNATE EMISSIONS
CONTROL PLAN
PROBLEM:
A COATING FACILITY PROPOSES TO "BUBBLE" A VARIETY OF COATINGS,
DETAILS OF WHICH ARE GIVEN BELOW.
ESTIMATE WHETHER THE FACILITY WILL FALL WITHIN THE "BUBBLE", AND
ASSUME THAT THE DATA PRESENTED BY THE FACILITY REPRESENTS THEIR
WORST CASE SCENARIO.
COATING
USAGE (GALS/DAY) VOC (Ibs/gal)
ALKYD AIR DRY
EPOXY AIR DRY
MELAMINE BAKING ENAMEL
5.0
10.0
21.5
4.0
2.2
1.5
ASSUME THAT TRANSFER EFFICIENCY IS NOT AN ISSUE IN THIS COMPLIANCE
PLAN.
FOR PURPOSES OF THE CALCULATION, ASSUME THAT THE REGULATED VOC
LIMITS ARE AS FOLLOWS:
AIR DRY
BAKE
2.8 Ibs/gal
2.3 Ibs/gal
PAGE
-------
Solution to Problem:
Coating
Usage VOC
(gals/day) (Ibs/gal)
(Ibs) Excess
E.F.* Emissions
Alky Air Dry
Epoxy Air Dry
Melamine Bake
5.0
10.0
21.5
4.0
2.2
1.5
-1.9
+ 1.0
+ 1.15
-9.5
+ 10.0
+24.7
+25.2
'Emission Factor
This coating facility will comply with its proposed plan. In
fact, It will generate 25.2 Ibs. of VOC less than if it were in
strict compliance with the regulated limits.
PAGE 30
-------
CALCULATION OF APPROXIMATE EXCESS EMISSIONS
FROM THE FOLLOWING PROPOSED ALTERNATE EMISSIONS
CONTROL PLAN
PROBLEM:
A COATING FACILITY USES A MIXTURE OF SOLVENT-BASED AND WATER-BORNE
COATINGS SOME OF THE SOLVENT-BASED COATINGS ARE OUT OF
COMPLIANCE, BUT THEIR WATER-BORNE COATINGS ARE WELL WITHIN THE
REGULATED VOC LIMITS. ESTIMATE WHETHER THE FACILITY WILL BE IN
COMPLIANCE IF IT UTILIZES AN ALTERNATIVE EMISSIONS CONTROL PLAN
("BUBBLE"). THE FOLLOWING REPRESENTS THE AVERAGE DAILY USAGE OF
EACH COATING.
COATING
USAGE
GALS/DAY
WATER-BORNE ALKYD AIR DRY 12.5
ALKYD ENAMEL BAKE 8 . 5
POLYURETHANE ENAMELS VARIOUS 14.8
48.5
0
0
VOC
(ibs/eal)
1.5
1.8
5.5
FOR PURPOSES OF THE CALCULATION ASSUME THAT TRANSFER EFFICIENCY
IS NOT A CONSIDERATION.
ALSO ASSUME THAT THE REGULATED LIMITS ARE AS FOLLOWS:
AIR DRY COATINGS 2.8 Ibs/gal
BAKE COATINGS 2.3 Ibs/gal
IP THE FACILITY DOES NOT COMPLY WITH THE PROPOSED PLAN, WHAT EXCESS
EMISSIONS WOULD BE EXPECTED?
-------
Solution to Problem:
Coating
Actual Usage
Usage Wt. less Water VOC
(gals/day) % Water (gals/day) (Ibs/gal)
Excess
Emissions
E.F.* (Ibs)
W/B Alkyd A.D
Alkyd Bake
Polyurethanes
12.5
8.5
14.8
48.5
0
0
6.1
8.5
14.8
1.5
1.8
5.5
+2.1
+0.75
-4.3
+ 12.81
+6.38
63.64
-44.45
*Emlsslon Factor
This facility will NOT comply with the plan. This is seen by the (-) negative
emission total. \/ »
Excess Emissions = 44.45 Ibs/day.
PAGE 32
-------
Chapter XVI
-------
CHAPTER XVI
INTRODUCTORY WORKSHOP FOR ENVIRONMENTAL
PAINTS AND COATINGS PROGRAM
-------
INTRODUCTORY WORKSHOP FOR
PAINTS AND COATINGS
TRAINING PROGRAM
Chapter XVI
-------
INTRODUCTORY WORKSHOP
TRUE FALSE
1. The acronym, •VOC,' stands
•Volatile Organic Carbons."
2. All organic solvents used in paints
and coatings are VOCs
3. Check True" for each of the follow-
ing solvents that are considered to
be VOCs:
Xylene
Toluene
1,1,1 Trichloroethane
Trichloroethylene
MIBK
MEK
Water
Isopropropyl Alcohol
Acetone
Methylene Chloride
4. Water-based coatings can be assumed
to comply with the air pollution regu-
lations controlling the use of surface
coatings.
5. Water-based coatings generally do
not contain organic solvents.
-------
TRUE
FALSE
To carry out an Alternative Emission
Control Plan ("Bubble"), you can
multiply the number of gallons of
coating used by the VOC of each
coating, and then average the
results.
Example:
3 gallons x 4.5 Ibs/gal
6 gallons x 1.5 Ibs/gal
=13.5 Ibs of VOC
: 9.0 IDS of VOC
9 gallons
Average VOC
22.5 Ibs of VOC
= 22.5
9
Average VOC = 2.5 Ibs/gal VOC
The VOC of the following water-based
coating is 0.8 Ibs/gal, less water
1 Gallon
-------
TRUE FALSE
8. Electrostatic spray guns areCcfesigr
always give a minimum transfer efficiency of
65%
9. The EPA encourages the use of water-based
coatings, rather than solvent-based coatings.
10. Which of the following statement is/are likely
to be true?
A solvent-based epoxy primer probably
has better corrosion resistance than
a water-based epoxy primer
A two-component polyurethane probably
out-performs an acrylic baking enamel
The new high-volume, low-pressure turbo
spray gun is approved by the EPA as
giving equivalent transfer efficiency
to an electrostatic spray gun
Water-based coatings take a longer time
to cure than solvent-based coatings.
-------
Chapter XVII
-------
CHAPTER XVII
SELECTION OF COATING APPLICATION EQUIPMENT
(SEVERAL SCENARIOS)
-------
SELECTION OF APPLICATION EQUIPMENT
Problem:
Thompson Landmovers is a foundry that makes large steel castings (ap-
proximate dimensions: 6 feet x 3 feet x 3 feet), which it sells to crane manufac-
turers.
The facility produces an average of 50 castings per day.
All of the castings weigh several hundred pounds, and some weigh several tons.
What low-labor-type of application would be economical
for this facility?
Chapter XVII Page 1
-------
SELECTION OF APPLICATION EQUIPMENT
Problem:
Clydesfiejd and Thomer provide the construction industry with, steel reinforcing
bars ano\heayy-gauge flat steel/tie-down brackets for steel columns.
The geometry of its products is simple: No difficult-to-reach corners, no welded-
on brackets, or other complications. Moreover, a common garden-variety Red
Oxide shop primer is applied for the sole purpose of providing the finished
product with a reasonable looking color. The customer is not concerned about
.appearance.
Clydesfield makes thousands of part each day. What would be
the most reasonable method for applying the Red Oxide coating?
Chapter XVII Page 2
-------
SELECTION OF APPLICATION EQUIPMENT
Problem:
Quadrant Contractors is a job shop for the petroleum refinery industry. Primari-
ly, it sandblasts and repaints large steel vessels, large-diameter pipes, etc. on-
site.
The coatings that the company uses are generally high-build expoxies, vinyls,
polyurethanes, etc.
What type of spray equipment should be considered?
Chapter XVII Page 3
-------
SELECTION OF APPLICATION EQUIPMENT
Problem:
The Zonarite Company supplies large communication shelters to the Military.
When fully assembled, these shelters will contain electronic communication
equipment, and an operator will sit at a desk inside the shelter to perform his/her
work.
The Zonarite Company makes the shelter only. It coats the outside with an epoxy
primer, followed by a camouflage topcoat. The inside is coated with the same
epoxy primer, followed by a semi-gloss enamel.
The primer is applied to the interior and exterior surfaces. The interior is top-
coated before the exterior.
The exterior of the shelter is relatively flat and resembles a large box; but on the
inside, the paint operator must work around wall brackets, lighting fixtures and
an air conditioning housing.
Although the military customer would like a good-looking finish, he/she does
not expect automotive quality.
One other point: The camouflage coating is supplied to the customer in only
one base color. After final assembly, the customer will apply the camouflage
pattern.
Approximately six shelters pass through the spray booth per day.
What spray equipment should be considered for Zonarite?
What equipment should the customer use when applying
the patterned camouflage topcoat?
Chapter XVII Page 4
-------
SELECTION OF APPLICATION EQUIPMENT
Problem
Hawthorne Industries of California makes wooden skate boards that are coated
with high-gloss wood lacquers.
The skateboards are painted front and rear, and must satisfy the consumer's
requirement for a high-quality finish.
In California, the Air Quality Rules require that transfer efficient application equip-
ment be used to coat wooden parts.
What type of spray equipment should be considered?
Chapter XVII Page 5
-------
SELECTION OF APPLICATION EQUIPMENT
Problem:
Fungames USA manufactures "Nautilus'-type exercising equipment such as
bicycles, arm and leg presses, rowing simulators, etc.
For the most part, the equipment is made from square and round aluminum ex-
trusions, although several steel castings are also coated.
The extrusions vary in length, but the average diameter is 11/2" square or round
tubing.
The company is small and must purchase relatively inexpensive and unsophis-
ticated spray equipment. .'.- •->
What equipment would you suggest for consideration?
Chapter XVII Page 6
-------
SELECTION OF APPLICATION EQUIPMENT
Problem:
The Humdrum Shelving Company makes steel shelving for supermarkets.
Ninety percent of the shelving has dimensions of 2 feet x 6 feet. Both the front
and back edges of the shelving are bevelled to eliminate sharp edges and
prevent injuries.
The shelving receives one smooth basecoat of an acrylic baking enamel, fol-
lowed by a light-texture coating in the same color. The base coat is applied in
one spray booth and then shelves go to an oven for a quick flash-off. Next, the
shelves pass through a second booth where the texture pattern is applied.
A paint operator inspects each part as it leaves the second spray booth, and
the operator is equipped to touch up any areas that do not meet specification.
Please suggest the type(s) of spray equipment that should be considered
for each booth and for the spray operator.
Chapter XVII Page 7
-------
SELECTION OF APPLICATION EQUIPMENT
Problem:
Peabody Lawnmowers, Inc. manufactures snowblowers and lawnmowers for
the consumer market. A high-solids acrylic coating is applied directly over the
pretreated substrates.
Because of highly critical consumer requirements, Peabody must provide an ex-
tremely high-gloss automotive-quality finish at the most economical price.
The snowblowers and lawnmowers are intermixed on the conveyor line so there
is no pattern as to the number of each that will be loaded on the conveyor hooks.
It is entirely possible that one hook will suspend a snowblower housing, followed
by a lawnmower housing. It is also possible that several consecutive hooks will
suspend housings of either the snowblower or the lawnmower.
The snowblowers are painted in one of three standard colors, and the
lawnmowers in one of 10 standard colors.
What type of spray equipment would make sense for this facility?
Chapter XVII Page 8
-------
SELECTION OF APPLICATION EQUIPMENT
Problem:
The Martin Walnut Company manufactures super-high-quality metal office
desks for the top-executive market. All the desks have the same design. The
company has decided to coat all of its products with high-gloss, two-component
epoxy primers and two-component polyurethane topcoats.
The paint facility uses an average of 25 gallons of each color each day, and
these quantities are applied to several hundred individual desks.
What application equipment should they purchase?
Chapter XVII Page 9
-------
Chapter XVIII
-------
CHAPTER XVIII
SELECTION OF COMPLIANT COATING SYSTEMS
-------
PROBLEM-SOLVING WORKSHOP
HOW TO SELECT COMPLIANT COATING SYSTEMS
Summary
Participants will learn how to set up a decision chart based on weighting factors
in order to give important coating requirements more consideration than less
important requirements.
The class will be divided into groups of five to seven people. Several realistic
scenarios will be presented to each group. Using the decision-making charts,
the members of each group will select the most appropriate compliant coating
system(s) for each scenario.
The entire class will then discuss the preferred selections.
Chapter XVIII
J
-------
Problem:
A small fabricator makes boat trailers and roof racks for the low-priced con-
sumer automotive after market.
All of the products are made from hot rolled or cold rolled steel tubular stock.
Currently, these products are solvent-wiped prior to painting.
Finishing consists of one or two coats of non-compliant, medium-priced alkyd.
The coating is applied by conventional air-atomizing electrostatic spray.
Customers appear to be happy wrththe finished products, although a few have
complained about premature corrosion (rust) of the steel.
The existing coating air dries (at room temperature) in 1 to 2 hours.
The coatings are purchased in many colors, usually in small quantities, to suit
customer requirements.
The fabricator needs to convert to a VOC-compliant coating (2.8 Ibs/gal). He
wishes to make the change with as little disruption of his present operations as
possible, and he cannoit afford to purchase an oven or other sophisticated
equipment. At most, he is willing to spend up to $5,000 for new equipment, if
necessary.
What type(s) of compliant coatings should he consider?
Chapter XVIII Page 1
-------
Problem:
A lighting manufacturer makes a variety of flourescent and incandescent light-
ing fixtures for the Indoor consumer market. (Most of his products are sold
through hardware and chain stores such as K-Mart.)
For obvious reasons, the finished products must have an excellent appearance,
although they do not need to have an automotive-quality finish.
The fixtures are manufactured from cold rolled steel, light gauge aluminum sheet
stock, and zinc die castings.
Surface preparation is by means of a 3-stage, iron phosphate srpay washer,
and the coatings are applied using conventional air atomized spray guns.
The products are coated with up to 30 different standard colors, but the cus-
tomers often order their own custom colors, which must be specially matched.
The most commonly used colors-white, black, red, and blue-are purchased in
55-gallong drums, while the remaining standard colors are purchased in 1- or
5-gallon containers. The specially mixed custom colors are often ordered in
quantities of 1 or 2 quarts.
Many of the products are coated in two colors: a decorate color on the outside
of the lamp housing, and a white reflective, or dull black non-reflective color, on
the inside of the housing.
The common white fluorescent fixtures, which are coated on a separate line, are
coated in white, inside and outside.
The company currently uses a non-compliant alkyd enamel that is force-dried
in an oven at 150°F for 30 minutes.
The company desperately needs to convert to a VOC-compliant system (a2.8
Ibs/gal air or force dry; 2.3 Ibs/gal bake). The company can increase the
temperature of its oven to accommodate a baking system, if necessary. The
company is also willing to purchase other equipment is there is adequate jus-
tification. In addition, the company would like to improve its transfer efficiency
above what is currently being achieved.
What are the most likely coatings that this fabricator should consider?
Use a weighting chart to justify your choice.
Chapter XVIII Page 2
-------
ENVIRONMENTAL PAINTS AND COATINGS
TRAINING PROGRAM
Presented to: Environmental Protection Agency
Submitted by: Ron Joseph
•
July 1988
-------
AGENDA FOR
EPA ENVIRONMENTAL PAINTS AND COATINGS
TRAINING PROGRAM
DAY 1
8:00 - 8:30 REGISTRATION
8:30 - 9:00 INTRODUCTORY WORKSHOP. (Chapter 16J
9:00 - 10:00 AN OVERVIEW OF ENVIRONMENTAL REGULATIONS FOR
SURFACE COATING OPERATIONS. I STATE
IMPLEMENTATION PLANS; (Chapter 1)
10:00 - 10:15 COFFEE BREAK
10:15 - 11:15 WHAT ONE NEEDS TO KNOW ABOUT A COATING SYSTEM.
(Chapter 5)
11:15 - 12:00 WHY PAINTS AND COATINGS CAUSE AIR POLLUTION.
(Chapter 6)
12:00 - 1:00 LUNCH
1:00 - 2:45 BASIC CALCULATIONS OF VOCS FROM PRODUCT AND
MATERIAL SAFETY DATA SHEETS. (CALCULATORS ARE
REQUIRED). (Chapter 11 and 12)
2:45 - 3:00 COFFEE BREAK
3:00 - 4:30 CALCULATING EMISSIONS OF VOCs EXPRESSED IN
LBS/GAL SOLIDS, AS APPLIED. (Chapter 13)
(AGENDA21.900J
-------
DAY 2
8:00 - 9: 15
9:15 - 10:30
10:30
10:45
10:45
11 :30
11:30 - 12:00
12:00
1 :00
2:30
2:45
1 :00
2:30
2:45
4:30
BRIEF PROCESS DESCRIPTION OF SELECTED VOC SURFACE
COATING CATEGORIES (Chapter 7)
A COMPREHENSIVE REVIEW OF VOC COMPLIANT LIQUID
COATING TECHNOLOGIES. (Chapter 8)
COFFEE BREAK
A REVIEW OF POWDER COATING TECHNOLOGIES AND
APPLICATION METHODS. (Chapter 9)
WHAT TO EXPECT FROM A PAINT FACILITY AIR QUALITY
INSPECTION. (Chapter 2)
LUNCH
WORKSHOP41 SELECTION OF COMPLIANT COATING
SYSTEMS. (SEVERAL SCENARIOS) (Chapter 18)
COFFEE BREAK
CALCULATING % VOLUME SOLIDS OF COATINGS AND
COATING MIXTURES. (Chapter 14)
CALCULATING ALTERNATIVE EMISSION CONTROL PLANS
("BUBBLES"). (CALCULATORS REQUIRED).
(Chapter 15)
ZI .900)
-------
8:00 -
9:45 -
10:00 -
11 :00 -
9:45
10:00
1 1 :00
12:00
12:00
1 :00
1 :30
1 :00
1 :30
DAY 3
VOC PROCESS SAMPLING (Chapter 3)
COFFEE BREAK
SPRAY APPLICATION EQUIPMENT. (Chapter 10J
WORKSHOP*: SELECTION OF COATING APPLICATION
EQUIPMENT. (SEVERAL SCENARIOS). (Chapter 17)
LUNCH
HOW TO SET UP A COMPLIANCE PLAN AND SCHEDULE OF
INCREMENTS OF PROGRESS. (Chapter 4)
- 3:00 FINAL QUIZ ON MATERIAL COVERED DURING COURSE.
* NOTE:
During the workshops the participants are divided into groups of
approximately 5-7 people. Each group is required to solve the
problems presented to them. Thereafter, each group shares its
results with the entire class, and the instructor, in discussion
with the class, critiques the individual solutions and suggests
th'e most appropriate solution to each problem.
Each participant will be given a three ring binder containing all
of the course material. The binder is designed so that it can be
used as a reference manual.
(AGENDA21.900)
------- |