EPA Self-Audit and Inspection Guide
Organic Finishing of Metals

Table of Contents

Infrared Radiation: Regulatory Requirements

Air
The Clean Air Act regulates the emission of volatile organic compounds (VOCs) (40 CFR Part 60) and hazardous air pollutants (HAPs) (40 CFR Part 61 and 40 CFR Part 63), and provides specific standards of performance to control emissions from various types of coating operations (40 CFR Part 60). Depending on the solvent content of the coating material applied, sufficient VOC and HAP emissions may develop in convection ovens to subject an operator to major source requirements and Title V permitting requirements.

Controlling VOC emissions can be accomplished in two ways. A coating material with a lower VOC content can be used. Otherwise, air pollution control equipment is required for infrared curing exhaust systems to recover or incinerate the VOCs and HAPs before they are released from the facility.

Self-Audit/Inspection

• Do exhaust air streams have air pollution control equipment attached? Is that air pollution control equipment working properly? Does the final exhaust air have concentrations of pollutants below required levels?

Infrared Radiation: Common Causes of Violation

• Emission of volatile organic compounds or hazardous air pollutants around infrared radiation systems may occur causing limits established in Clean Air Act Title V permits to be exceeded. The quantity of VOCs or HAPs released from the curing coating material depends on the amount of organic solvent in the coating formulation. The hazardous emissions in the exhaust air stream can be captured and treated to prevent their release to the atmosphere. Common air pollution control tactics include solvent recovery, solvent incineration, and solvent concentration.

Infrared Radiation: Sources of Pollution Volatized organic compounds and hazardous air pollutants (dependent on the coating material formulation). Parts which have been improperly cured (overcured or undercured) resulting in the need to strip and recoat.

Infrared Radiation: Pollution Prevention Alternatives
Volatile organic compound and hazardous air pollutant emissions can be reduced by using powder coating or waterborne coating formulations, rather than solvent-based coating materials. Proper curing can be achieved by optimizing the wavelength, exposure period, and part arrangement. Curing can be improved by introducing air into the system to distribute latent heat more evenly across part surfaces.