DOES THIS REGULATION APPLY TO ME?

TABLE 3-1. FUNCTIONS AND PROCESS PARAMETERS OF THE TYPES OF OPERATIONS

Type of operation	Functions	Process Parameters
Hard (or "industrial") chromium electroplating	Provides a surface with functional properties such as: · Wear resistance· A low coefficient of friction· Hardness· Corrosion resistance.	Specified in regulation:Plate thickness of 1.3 to 760 micronsCurrent density of 150 to 600 A/ft2Plating time of 20 minutes to 36 hoursOthers: Chromic acid concentration of 30 to 50 oz/gal Sulfuric acid concentration of 0.3 to 0.5 oz/galSolution temperature of 120° to 150°F
Decorative chromium electroplating	Provides a bright surface with wear- and-tarnish resistance.	Specified in regulation:Plate thickness of 0.003 to 2.5 microns (chromicacid bath) or 0.13 to 25 microns (trivalentchromium bath)Current density of 50 to 220 A/ft2 Plating time of 0.5 to 5 minutes Others: Chromic acid concentration of 30 to 50 oz/gal Sulfuric acid concentration of 0.3 to 0.5 oz/galSolution temperature of 100° to 115°F
Chromium anodizing	Provides corrosion resistance or electrical insulation.	Specified in regulation:Chromic acid concentration of 6.67 to 13.3 oz/galOthers:Film thickness of 0.02 to 0.05 micronsCurrent density of 144 to 720 A/ft2 Anodizing time of 30 to 60 minutes Solution temperature of 90° to 95°F pH of 0.5 to 0.85Voltage of 20 or 40 volts

APPLICABILITY OF THE REGULATION

The regulation applies to virtually all hard and decorative chromium electroplaters and chromium anodizers as defined in the regulation, regardless of size (see exemptions listed below). Both major and area sources are covered by the regulation. (Major sources are sources emitting 10 tons per year or more of any hazardous air pollutant or 25 tons per year or more of any combination of hazardous air pollutants. Area sources, also referred to as "nonmajor sources," are sources that do not qualify as major.) The EPA believes that the high toxicity of chromium compounds and the close proximity of many small shops to residential areas warrant regulation of all sources, even small businesses.

Hard chromium electroplating operations deposit a thick layer of chromium directly on a base metal to provide wear and corrosion resistance, low friction, and hardness (for hydraulic cylinders, industrial rolls, etc.).

Decorative chromium electroplating operations deposit a thin layer of chromium on a base material to provide a bright finish and wear and tarnish resistance (for bicycles, auto trim, tools, etc.). Decorative chromium electroplating tanks may use a chromic acid bath or a trivalent chromium bath.

Chromium anodizing operations form a chromium oxide layer on aluminum to provide corrosion resistance (for aircraft parts, architectural structures, etc.).

See Appendix B of this guidebook for complete definitions of these terms as they appear in the regulation.

Are any sources exempt? The regulation specifically exempts certain types of sources. These sources are:

• Process tanks that may contain low concentrations of chromium but neither chromium electroplating nor chromium anodizing is taking place in the tank (e.g., rinse tanks, etch tanks, and cleaning tanks);
• Tanks that contain a chromium solution, but in which no electrolytic process occurs (e.g., chrome conversion coating tank); and
• Tanks that are used for research and laboratory operations.
  

How many facilities are affected and where are they located? The EPA estimates that there are about 5,020 affected facilities nationwide. Of the estimated 5,020 facilities, an estimated 1,540 are hard chromium electroplaters, 2,800 are decorative chromium electroplaters, and 680 are chromium anodizers. Figure 3­1 shows the approximate distribution of the facilities by State. Appendix C of this

guidebook lists the known facilities that are affected by this regulation.

How do you determine what type of facility you have? The terms "hard chromium electroplating," "decorative chromium electroplating," and "chromium anodizing" are defined by typical process parameters, as well as by function. Therefore, regardless of what name you assign to your process, you will be regulated according to the functions and process parameters of your tank. Process parameters include the plating thickness, the current density applied, and the plating time. Table 3­1 summarizes the functions and process parameters associated with the three types of facilities.

Some facilities may have operations that do not fit exactly into one of the definitions in the regulation. In this case, judgement and communication between the facility and its State or local air pollution control agency is required.

For example... A facility that operates a "black chromium electroplating process" may qualify as either a decorative or a hard chromium electroplater, depending on the process parameters at the particular source. In one case, a black chromium electroplating process that calls for a current density of 40 to 90 amperes per square foot (A/ft²), a plating time of 30 to 45 minutes (min), and a plate thickness of 5 microns (mm) would best fit the description of a hard chromium plating process. However, another black chromium electroplating operation that uses 144 to 288 A/ft², a plating time of 5 min, and a plate thickness of 0.13 to 0.51 mm would best fit the description of a decorative plating process. If you are unsure about which definition fits your operation, contact your State or local air pollution control agency.

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