Metal Painting and Coating Operations

Table of Contents  Background  Regulatory Overview  Planning P2 Programs  Overview of P2  Surface Preparation
Alternatives to Solvent-Borne Coatings  Application Techniques  Curing Methods  Equipment Cleaning

Table of Contents

Overview of Manual

Acknowledgments

Background

Definition of Terms
Uses for Paint and Coatings
Paint Composition
Description of Coatings Processes
Examples of Typical Systems
Sources of Wastes
Summary

Regulatory Overview

Clean Air Act
Resource Conservation and Recovery Act
Clean Water Act

Planning Pollution Prevention Programs at Coating Facilities

Characterizing a Facility
Planning
Identify Pollution Prevention Opportunities
Analyze and Select Options
Pilot Test or Validate Preferred Options
Procure and Implement New System
Evaluate and Keep the Program Going

Overview of Pollution Prevention in Coatings Application Processes

   Rigid Inventory Control
   Good Housekeeping
   Paint Mixing
   Operator Training
   High Transfer Efficiency Equipment
   Alternative Coatings
   Proper Cleaning Methods
   Filters
   On-Site Solvent Recycling

Surface Preparation

General Description
Pollution Problem
Mechanical Cleaning
Chemically-Assisted Cleaning
Conversion Coatings
Stripping
General P2 Options for Surface Preparation
Cleaning
   Solvent Vapor Degreasing
   Degreasing with Liquid Solvents (Cold Cleaning)
Alternative Cleaning Methods
Conversion Coatings
Stripping

Alternatives to Solvent-Borne Coatings

Conventional Paint Composition
Switch to Surface-Free Coating
Alternative Coatings
High-Solids Coatings
Waterborne Coatings
Powder Coating
Radiation Curing
Emerging Technologies
   Advantages and Disadvantages
   Cost and Implementation Issues

Application Techniques

General Description of Spray Systems
Pollution Problem
General P2 Options
   Transfer Efficiency and Paint Application
Strategies to Improve Transfer Efficiency
Conventional Air Spray (LVHP)
High-Volume/Low-Pressure (HVLP) Air Spray
Low-Pressure/Low-Volume (LPLV)
   General Description
Airless Spray
Electrostatic Spray
Other Methods
   Advantages and Disadvantages
   Cost and Implementation Issues
Paint Booths

Curing Methods

Equipment Cleaning

General Description
Pollution Problem
P2 Options

References
Appendix A
Appendix B
Appendix C
Appendix D
Appendix E
Appendix F
Appendix G

List of Tables

Table 1. Common Solvents, Federal Regulatory Status
Table 2. Scheduled Date for MACT Standards for Surface Coating
Table 3. EPA Guidelines for Maximum VOC Content of Coatings
Table 4. Hazardous Wastes Generated from Coatings Operations
Table 5. Overview of Assessment Information
Table 6. Opportunities for Improved Housekeeping in Coating Operations
Table 7. P2 Options for Coatings Processes
Table 8. Alternatives to Chlorinated Solvent Cleaning
Table 9. Advantages and Disadvantages of Plastic Media Blasting
Table 10. Advantages and Disadvantages of Vacuum Sanding Systems
Table 11. Advantages and Disadvantages of Sodium Bicarbonate
Table 12. Advantages and Disadvantages of Wheat Starch Blasting
Table 13. Advantages and Disadvantages of Carbon Dioxide Blasting
Table 14. Advantages and Disadvantages of Sponge Blasting Systems
Table 15. Advantages and Disadvantages of Water Blasting Systems
Table 16. Advantages and Disadvantages of Fluidized Bed Stripping
Table 17. Overview of Alternative Surface Preparation Technologies
Table 18. Health Effects of Solvents Used in Paint Formulations
Table 19. Overview of Alternatives to Solvent-Borne Coatings
Table 20. Advantages and Disadvantages of High-Solids Coatings
Table 21. Advantages and Disadvantages of Waterborne Coatings
Table 22. Characteristics of Powder Coating Techniques
Table 23. Advantages and Disadvantages of Powder Coatings
Table 24. Summary of Powder Coating Resin Properties
Table 25. Advantages and Disadvantages of Radiation-Cured Coatings
Table 26. Advantages and Disadvantages of VIC
Table 27. Advantages and Disadvantages of Unicoat Paint Technology
Table 28. Cost/Benefit Summary for Spray Application Methods
Table 29. Advantages and Disadvantages of HVLP Spray Guns
Table 30. Advantages and Disadvantages of LPLV Spray Guns
Table 31. Advantages and Disadvantages of Airless Spray Systems
Table 32. Advantages and Disadvantages of Electrostatic Spray Guns
Table 33. Advantages and Disadvantages of E-Coat Systems
Table 34. Advantages and Disadvantages of Autodeposition Systems
Table 35. Advantages and Disadvantages of Dip Coating Systems
Table 36. Advantages and Disadvantages of Flow Coating Systems
Table 37. Advantages and Disadvantages of Curtain Coating Systems
Table 38. Advantages and Disadvantages of Roll Coating Systems
Table 39. Advantages and Disadvantages of Plural Component Proportioning Systems
Table 40. Advantages and Disadvantages of Supercritical Carbon Dioxide
Table 41. Tansfer Efficiencies of Various Application Technologies
Table 42. Overview of Application Technologies
Table 43. Advantages and Disadvantages of Dry Filter Booths
Table 44. Air/Force Dry Vs. Bake
Table 45. Typical RACT Limits for Miscellaneous Metal Parts Coating

List of Figures 

Figure 1. Overview of the Coating Process
Figure 2. Coating Process and Waste Generation
Figure 3. Emissions vs. VOC Content
Figure 4. Major Resin Fluidization Methods
Figure 5. HVLP System

 

Overview of Manual

This manual is broken down into nine chapters as described below. Supporting case studies, tables, figures and appendices are also provided. 

  • Chapter 1 provides background information on paints and coatings, including a discussion of the coatings process and wastes generated. 
  • Chapter 2 presents an overview of federal regulations that affect coatings processes. 
  • Chapter 3 provides specific information on the role of technical assistance providers in promoting pollution prevention. 
  • Chapter 4 is an overview of pollution prevention options for surface preparation, coatings applica- tion/curing and equipment cleaning. 
  • Chapter 5 discusses surface preparation methods with an emphasis on reducing solvent use. 
  • Chapter 6 presents alternatives to solvent-borne coatings, including high-solids, waterborne and powder coatings. 
  • Chapter 7 provides an overview of application techniques (i.e., spray painting and other methods) along with a discussion of transfer efficiency. 
  • Chapter 8 presents information on curing methods. 
  • Chapter 9 discusses alternatives to traditional equipment cleaning methods. 
  • Appendix A presents information resources for coatings. 
  • Appendix B presents information on how to calculate VOC/HAP emissions. 
  • Appendix C provides information on conducting an economic analysis of paint costs. 
  • Appendix D presents purchasing guidelines for HVLP spray guns. 
  • Appendix E presents information on coatings testing. 
  • Appendix F provides a glossary of terms pertaining to the coatings process. 
  • Appendix G provides information on calculating transfer efficiency.

Audience

NEWMOA designed this manual for individuals who are involved in providing technical assistance to firms seeking information on P2 for paint and coating processes. NEWMOA believes that the information in this manual also would be useful for environmental inspectors and permit writers who are involved in regulatory compliance activities. Comments and suggestions from manual users on content and format are welcomed. Please take a moment and complete the evaluation form included with this document to help us with future versions of this manual and related manuals, or call NEWMOA at (617) 367-8558 to speak with us directly. 

Using This Manual

This manual is designed to serve as a complete reference on P2 methods for paint and coating processes, however, it alone should not be used to advise companies on the selection of a particular coating system. The selection of a coating system depends on a number of application-specific factors, including the type of surface to be coated as well as the required performance characteristics of the coating. Companies that decide to adopt an alternative system should do so only after consultation with the appropriate coating and equipment vendors, and careful in-house analyses of the costs and benefits as well as technical feasibility of the alternative system.

Disclaimer

The views expressed in this report do not necessarily reflect those of NEWMOA, NEWMOA member states, Waste Management and Research Center (WMRC), or U.S. EPA. Mention of any company, process, or product name should not be considered an endorsement by NEWMOA, NEWMOA member states, WMRC, or U.S. EPA. 

Acknowledgments

NEWMOA is indebted to the U.S. Environmental Protection Agency's Office of Pollution Prevention for its support for this project. The Northeast states provided additional in-kind support. 

NEWMOA would also like to thank those who provided advice and assistance, especially those who volunteered on the peer review committee: 

Alan Buckley, Massachusetts Office of Technical Assistance 
Mike Callahan, Jacobs Engineering Group Inc 
Dean Cornstubble, Research Triangle Institute 
Lynn Corson, Ph.D., Purdue University 
Mike Eck, U.S. Army Environmental Center 
Tim Greiner, Greiner Environmental 
Paul Pagel, MnTAP 
Jeff Palmer, The Powder Coating Institute 
Alice Pincus, Pincus Associates 
Paul Randall, U.S. EPA 
Alexander Ross, RadTech 
Mike Simek, Rutgers 
Rodger Talbert, Chemical Coaters Association International 
David Liebl, Solid and Hazardous Waste Education Center 
Kathy Blake, New Hampshire Department of Environmental Services

Project Staff/Contributors

Terri Goldberg, NEWMOA P2 Program Manager—Editor/Manager 
Lisa Regenstein, NEWMOA P2 Project Manager—Research/Writer 
Jennifer Shearman, NEWMOA Technical Staff—Research/Writer 
Beth Anderson, EPA—EPA Project Manager 
Laurie Case, WMRC—Layout and Desktop Publishing 

 


NEWMOA welcomes users of this manual to cite and reproduce sections of it for use in providing assistance to companies. However, the Association requests that users cite the document whenever reproducing or quoting so that appropriate credit is give to original authors, NEWMOA and U.S. EPA. NEWMOA thanks you for cooperating with this request. 

Northeast Waste Management Officials' Association

The Northeast Waste Management Officials' Association (NEWMOA) is a non-profit, nonpartisan, interstate governmental association. The membership is composed of state environmental agency directors of the hazardous waste, solid waste, waste site cleanup and pollution prevention programs in Connecticut, Maine, Massachusetts, New Hampshire, New York, Rhode Island, and Vermont. 

NEWMOA's mission is to help states articulate, promote, and implement economically sound regional programs for the enhancement of environmental protection. The group fulfills this mission by providing a variety of support services that facilitate communication and cooperation among member states and between the states and EPA, and promote the efficient sharing of state and federal program resources. 

NEWMOA was established by the governors of the New England states as an official interstate regional organization, in accordance with Section 1005 of the Resource Conservation and Recovery Act (RCRA). The organization was formally recognized by the U.S. Environmental Protection Agency (EPA) in 1986. It is funded by state membership dues and EPA grants. 

NEWMOA established the Northeast States Pollution Prevention Roundtable (NE P2 Roundtable) in 1989 to enhance the capabilities of member state environmental officials to implement effective source reduction programs. The NE P2 Roundtable's program involves the following components: (1) managing a regional roundtable of state pollution prevention programs; (2) publishing a newsletter; (3) managing a resource center of books, reports, case studies, fact sheets, notices of upcoming meetings and conferences, and a list of P2 experts; (4) organizing training; and (5) conducting research and publishing reports and other documents. The resource center provides pollution prevention information to state and local government officials, the public, industry, and others. Funding for the NE P2 Roundtable is provided by the NEWMOA member states and the U.S. EPA. For more information contact: Terri Goldberg, NEWMOA, 129 Portland Street, 6th floor, Boston, MA 02114, (617) 367-8558 x302 (Phone); (617) 367-0449 (Fax); newmoa@aol.com (e-mail). 

About This Manual 

The Northeast Waste Management Officials' Association (NEWMOA) designed this manual to provide environmental assistance staff with a basic reference on the metal coatings process. The purpose of the manual is to enable assistance providers to rely on a single publication to jump start their research on pollution prevention for companies with which they are working. The manual is explicitly designed to be useful to assistance professionals with experience working with metal coating operations and those who have never before encountered this process. The U.S. Environmental Protection Agency Pollution Prevention Division funded this manual as a model of a comprehensive packet of pollution prevention (P2) information on a single industry. 

The Northeast Waste Management Officials' Association designed this manual to provide information on P2 methods for paints and coatings processes. Specifically, the manual focuses on P2 methods for reducing volatile organic compounds (VOCs) emitted during the coating of metal substrates. This manual stresses the use of low-VOC paints and coatings (i.e., high-solids, waterborne and powder coatings that contain lower solvent concentrations than conventional paints) as well as techniques that can increase transfer efficiency (i.e., the percentage of paints actually put on the part compared to the amount of paint used/sprayed). Methods for reducing the amount of solvents used during other stages of the coatings process, particularly surface preparation and equipment cleaning, also figure prominently. 

NEWMOA collaborates with state and local environmental assistance programs in the Northeast; these programs have requested this manual to help them provide more efficient and effective help to the numerous companies with metal coating operations. Assistance providers have reported frustration with having to search databases for materials only to obtain a list of citations and case studies that they have to spend considerable time finding in order to provide information to their client companies. In addition, these officials rarely have the opportunity to check the accuracy of the information they find in databases to determine whether the material is still current. To avoid duplicating efforts and to ensure that the information companies receive is up-to-date and accurate, NEWMOA developed this manual as a model "synthesized" information packet that includes an exhaustive compilation and synthesis of existing materials on P2 for the metal coatings process. 

To compile this manual, NEWMOA reviewed many books, articles, fact sheets, reports and guides on P2 for metal coatings operations. NEWMOA staff also sent a draft of the manual to more than 15 expert reviewers for their comments and suggestions. The result is an up-to-date compilation of information on P2 options for metal coatings. However, pollution prevention is a rapidly changing field, and all users should check with the various centers identified in Appendix A to determine whether any new information is available.