Chapter NR 463

NR 463.02(1) (1) “Add-on air pollution control device” means equipment installed in the ventilation system of chromium electroplating and anodizing tanks for the purposes of collecting and containing chromium emissions from the tanks.

NR 463.02(2) (2) “Air pollution control technique” means any method, such as an add-on air pollution control device or a chemical fume suppressant, that is used to reduce chromium emissions from chromium electroplating and chromium anodizing tanks.

NR 463.02(3) (3) “Base metal” means the metal or metal alloy that comprises the workpiece.

NR 463.02(4) (4) “Bath component” means the trade, brand or chemical name of each component in trivalent chromium plating baths.

NR 463.02 Note Note: Since for trivalent chromium baths, the bath composition is proprietary in most cases, the trade or brand name for each component may be used. However, ss. NR 463.103 (2) (n) and 463.106 (9) (a) 3. require identification by chemical name of the wetting agent contained in that component.

NR 463.02(5) (5) “Chemical fume suppressant” means any chemical agent that reduces or suppresses fumes or mists at the surface of an electroplating or anodizing bath.

NR 463.02 Note Note: Another term for fume suppressant is mist suppressant.

NR 463.02(6) (6) “Chromic acid” means the common name for chromium anhydride (CrO3).

NR 463.02(7) (7) “Chromium anodizing” means the electrolytic process by which an oxide layer is produced on the surface of a base metal for functional purposes, such as corrosion resistance or electrical insulation, using a chromic acid solution. In chromium anodizing, the part to be anodized acts as the anode in the electrical circuit, and the chromic acid solution, with a concentration typically ranging from 50 to 100 grams per liter (g/L), serves as the electrolyte.

NR 463.02(8) (8) “Chromium anodizing tank” means the receptacle or container along with the following accompanying internal and external components needed for chromium anodizing: rectifiers fitted with controls to allow for voltage adjustments, heat exchanger equipment, circulation pumps and air agitation systems.

NR 463.02(8m) (8m) “Chromium electroplating tank” means the receptacle or container along with the following accompanying internal and external components needed for chromium electroplating: rectifiers, anodes, heat exchanger equipment, circulation pumps and air agitation systems.

NR 463.02(9) (9) “Composite mesh-pad system” means an add-on air pollution control device typically consisting of several mesh-pad stages. The purpose of the first stage is to remove large particles. Smaller particles are removed in the second stage, which consists of the composite mesh pad. A final stage may remove any reentrained particles not collected by the composite mesh pad.

NR 463.02(10) (10) “Decorative chromium electroplating” means the process by which a thin layer of chromium (typically 0.003 to 2.5 µm) is electrodeposited on a base metal, plastic or undercoating to provide a bright surface with wear and tarnish resistance. In this process, the part serves as the cathode in the electrolytic cell and the solution serves as the electrolyte. Typical current density applied during this process ranges from 540 to 2,400 amperes per square meter (A/m2) for total plating times ranging between 0.5 to 5 minutes.

NR 463.02(11) (11) “Electroplating or anodizing bath” means the electrolytic solution used as the conducting medium in which the flow of current is accompanied by movement of metal ions for the purposes of electroplating metal out of the solution onto a workpiece or for oxidizing the base material.

NR 463.02(12) (12) “Emission limitation” means the concentration of total chromium allowed to be emitted expressed in milligrams per dry standard cubic meter (mg/dscm), or the allowable surface tension expressed in dynes per centimeter (dynes/cm).

NR 463.02(12m) (12m) “Enclosed hard chromium electroplating tank” means a chromium electroplating tank that is equipped with an enclosing hood and ventilated at half the rate or less than that of an open surface tank of the same surface area.

NR 463.02(13) (13) “Existing” means any hard chromium electroplating tank, decorative chromium electroplating tank or chromium anodizing tank the construction or reconstruction of which was commenced on or before December 16, 1993.

NR 463.02(14) (14) “Facility” means the major or area source at which chromium electroplating or chromium anodizing is performed.

NR 463.02(15) (15) “Fiber-bed mist eliminator” means an add-on air pollution control device that removes contaminants from a gas stream through the mechanisms of inertial impaction and Brownian diffusion. These devices are typically installed downstream of another control device, which serves to prevent plugging, and consist of one or more fiber beds. Each bed consists of a hollow cylinder formed from 2 concentric screens; the fiber between the screens may be fabricated from glass, ceramic plastic or metal.

NR 463.02(16) (16) “Foam blanket” means the type of chemical fume suppressant that generates a layer of foam across the surface of a solution when current is applied to that solution.

NR 463.02(17) (17) “Fresh water” means water, such as tap water, that has not been previously used in a process operation or, if the water has been recycled from a process operation, it has been treated and meets the effluent guidelines for chromium wastewater.

NR 463.02(18) (18) “Hard chromium electroplating” or “industrial chromium electroplating” means a process by which a thick layer of chromium (typically 1.3 to 760 µm) is electrodeposited on a base material to provide a surface with functional properties such as wear resistance, a low coefficient of friction, hardness and corrosion resistance. In this process, the part serves as the cathode in the electrolytic cell and the solution serves as the electrolyte. The hard chromium electroplating process is performed at current densities typically ranging from 1,600 to 6,500 A/m2 for total plating times ranging from 20 minutes to 36 hours depending upon the desired plate thickness.

NR 463.02(19) (19) “Hexavalent chromium” means the form of chromium in a valence state of +6.

NR 463.02(20) (20) “Large, hard chromium electroplating facility” means a facility that performs hard chromium electroplating and has a maximum cumulative potential rectifier capacity greater than or equal to 60 million ampere-hours per year (A-hr/yr).

NR 463.02(21) (21) “Maximum cumulative potential rectifier capacity” means the summation of the total installed rectifier capacity associated with the hard chromium electroplating tanks at a facility, expressed in amperes, multiplied by the maximum potential operating schedule of 8,400 hours per year and 0.7, which assumes that electrodes are energized 70% of the total operating time. The maximum potential operating schedule is based on operating 24 hours per day, 7 days per week, 50 weeks per year.

NR 463.02(22) (22) “New source” or “new tank” means any hard chromium electroplating, decorative chromium electroplating or chromium anodizing source or tank the construction or reconstruction of which is commenced after December 16, 1993.

NR 463.02(22m) (22m) “Open surface hard chromium electroplating tank” means a chromium electroplating tank that is ventilated at a rate consistent with good ventilation practices for open tanks.

NR 463.02(23) (23) “Operating parameter value” means a minimum or maximum value established for a control device or process parameter which, if achieved by itself or in combination with one or more other operating parameter values, determines that an owner or operator is in continual compliance with the applicable emission limitation or standard.

NR 463.02(24) (24) “Packed-bed scrubber” means an add-on air pollution control device consisting of a single or double packed bed that contains packing media on which the chromic acid droplets impinge. The packed-bed section of the scrubber is followed by a mist eliminator to remove any water entrained from the packed-bed section.

NR 463.02(25) (25) “Research or laboratory operation” means an operation whose primary purpose is for research and development of new processes and products, that is conducted under the close supervision of technically trained personnel, and that is not involved in the manufacture of products for commercial sale, except in a de minimis manner.

NR 463.02(26) (26) “Small, hard chromium electroplating facility” means a facility that performs hard chromium electroplating and has a maximum cumulative potential rectifier capacity less than 60 million A-hr/yr.

NR 463.02(27) (27) “Stalagmometer” means an instrument used to measure the surface tension of a solution by determining the mass of a drop of liquid by weighing a known number of drops or by counting the number of drops obtained from a given volume of liquid.

NR 463.02(28) (28) “Surface tension” means the property, due to molecular forces, that exists in the surface film of all liquids and tends to prevent liquid from spreading.

NR 463.02(29) (29) “Tank operation” means the use of a tank for chromium electroplating or a chromium anodizing through the application of current or voltage. Tank operation ceases when the current or voltage is turned off.

NR 463.02(30) (30) “Tensiometer” means an instrument used to measure the surface tension of a solution by determining the amount of force needed to pull a ring from the liquid surface. The amount of force is proportional to the surface tension.

NR 463.02(31) (31) “Trivalent chromium” means the form of chromium in a valence state of +3.

NR 463.02(32) (32) “Trivalent chromium process” means the process used for electrodeposition of a thin layer of chromium onto a base material using a trivalent chromium solution instead of a chromic acid solution.

NR 463.02(33) (33) “Wetting agent” means the type of chemical fume suppressant that reduces the surface tension of a liquid.

NR 463.02 History History: Cr. Register, September, 1997, No. 501, eff. 10-1-97; CR 05-039: am. (intro.), (8), (27) and (30), cr. (8m), (12m) and (22m) Register February 2006 No. 602, eff. 3-1-06.

NR 463.03 NR 463.03 Nomenclature, units and abbreviations. The definitions contained in s. NR 400.03 apply to the abbreviations and symbols of units of measure used in this subchapter. In addition, the nomenclature used in this subchapter has the following meaning:

NR 463.03(1) (1) AMR is the allowable mass emission rate from each type of affected source subject to the same emission limitation in milligrams per hour (mg/hr).

NR 463.03(2) (2) AMRsys is the allowable mass emission rate from affected sources controlled by an add-on air pollution control device controlling emissions from multiple sources in mg/hr.

NR 463.03(3) (3) CMP is composite mesh-pad, a control technique.

NR 463.03(4) (4) EL is the applicable emission limitation from s. NR 463.04 in milligrams per dry standard cubic meter (mg/dscm).

NR 463.03(5) (5) IAtotal is the sum of all inlet duct areas from both affected sources and sources not affected by this subchapter in meters squared.

NR 463.03(6) (6) IDAi is the total inlet area for all ducts associated with affected sources in meters squared.

NR 463.03(7) (7) IDAi,a is the total inlet duct area for all ducts conveying chromic acid from each type of affected source performing the same operation, or each type of affected source subject to the same emission limitation in meters squared.

NR 463.03(8) (8) lbf is pound-force, the unit of force in the English system.

NR 463.03(9) (9) PBS is packed-bed scrubber, a control technique.

NR 463.03(10) (10) VR is the total of ventilation rates for each type of affected source subject to the same emission limitation in dry standard cubic meters per minute (dscm/min).

NR 463.03(11) (11) VRinlet is the total ventilation rate from all inlet ducts associated with affected sources in dscm/min.

NR 463.03(12) (12) VRinlet,a is the total ventilation rate from all inlet ducts conveying chromic acid from each type of affected source performing the same operation, or each type of affected source subject to the same emission limitation in dscm/min.

NR 463.03(13) (13) VRtot is the average total ventilation rate for the 3 test runs as determined at the outlet by testing using Method 306 of Appendix A of 40 CFR part 63, incorporated by reference in s. NR 484.04, in dscm/min.

NR 463.03 History History: Cr. Register, September, 1997, No. 501, eff. 10-1-97; CR 04-023: am. (intro.) and (5) Register December 2008 No. 636, eff. 1-1-09.

NR 463.04 NR 463.04 Emission limits.

NR 463.04(1) (1) MACT requirements. Each owner or operator of an affected source subject to the provisions of this subchapter shall comply with these requirements on and after the compliance dates specified in s. NR 463.06 (1). All affected sources are regulated by applying maximum achievable control technology.

NR 463.04(2) (2) Applicability of emission limits.

NR 463.04(2)(a) (a) The emission limitations in this section apply during tank operation as well as during periods of startup and shutdown as these are routine occurrences for affected sources subject to this subchapter. The emission limitations do not apply during periods of malfunction. However, the work practice standards that address operation and maintenance and that are required by s. NR 463.05 shall be followed during malfunctions.

NR 463.04(2)(b) (b) If an owner or operator is controlling a group of tanks with a common add-on air pollution control device, the emission limitations of subs. (3), (4) and (5) apply whenever any one affected source is operated. The emission limitation that applies to the group of affected sources is as follows:

NR 463.04(2)(b)1. 1. The emission limitation identified in subs. (3), (4) and (5) if the affected sources are performing the same type of operation, such as hard chromium electroplating, are subject to the same emission limitation, and are not controlled by an add-on air pollution control device also controlling sources not affected by this subchapter.

NR 463.04(2)(b)2. 2. The emission limitation calculated according to s. NR 463.09 (5) (c) if affected sources are performing the same type of operation, are subject to the same emission limitation, and are controlled with an add-on air pollution control device that is also controlling sources not affected by this subchapter.

NR 463.04(2)(b)3. 3. The emission limitation calculated according to s. NR 463.09 (5) (d) if affected sources are performing different types of operations, or affected sources are performing the same operations but subject to different emission limitations, and are controlled with an add-on air pollution control device that may also be controlling emissions from sources not affected by this subchapter.

NR 463.04(3) (3) Standards for hard chromium electroplating.

NR 463.04(3)(a) (a) Open surface tanks. During tank operation, each owner or operator of an existing, new or reconstructed affected source shall control chromium emissions discharged to the atmosphere from that affected source by doing any of the following:

NR 463.04(3)(a)1. 1. Not allowing the concentration of total chromium in the exhaust gas stream discharged to the atmosphere to exceed 0.015 milligrams of total chromium per dry standard cubic meter (mg/dscm) of ventilation air (6.6 x 10-6 grains per dry standard cubic foot (gr/dscf)) for all open surface hard chromium electroplating tanks that are affected sources other than those that are existing affected sources located at small hard chromium electroplating facilities.

NR 463.04(3)(a)2. 2. Not allowing the concentration of total chromium in the exhaust gas stream discharged to the atmosphere to exceed 0.03 mg/dscm (1.3 x 10-5 gr/dscf) if the open surface hard chromium electroplating tank is an existing affected source and is located at a small, hard chromium electroplating facility.

NR 463.04(3)(a)3. 3. If a chemical fume suppressant containing a wetting agent is used, not allowing the surface tension of the electroplating or anodizing bath contained within the affected tank to exceed 45 dynes per centimeter (dynes/cm) (3.1 x 10-3 pound-force per foot (lbf /ft)) as measured by a stalagmometer or 35 dynes/cm (2.4 x 10-3 lbf /ft) as measured by a tensiometer at any time during tank operation.

NR 463.04(3)(b) (b) Enclosed tanks. During tank operation, each owner or operator of an existing, new or reconstructed affected source shall control chromium emissions discharged to the atmosphere from that affected source by doing any of the following:

NR 463.04(3)(b)1. 1. Not allowing the concentration of total chromium in the exhaust gas stream discharged to the atmosphere to exceed 0.015 mg/dscm (6.6 x 10-6 gr/dscf) for all enclosed hard chromium electroplating tanks that are affected sources other than those that are existing affected sources at small, hard chromium electroplating facilities.

NR 463.04(3)(b)2. 2. Not allowing the concentration of total chromium in the exhaust gas stream discharged to the atmosphere to exceed 0.03 mg/dscm (1.3 x 10-5 gr/dscf) if the enclosed hard chromium electroplating tank is an existing affected source and is located at a small, hard chromium electroplating facility.

NR 463.04(3)(b)3. 3. If a chemical fume suppressant containing a wetting agent is used, not allowing the surface tension of the electroplating or anodizing bath contained within the affect tank to exceed 45 dynes/cm (3.1 x 10-3 lbf /ft) as measured by a stalagmometer or 35 dynes/cm (2.4 x 10-3 lbf /ft) as measured by a tensiometer at any time during tank operation.

NR 463.04(3)(b)4. 4. Not allowing the mass rate of total chromium in the exhaust gas stream discharged to the atmosphere to exceed the maximum allowable mass emission rate determined by using the calculation procedure in s. NR 463.09 (6) (b) for all enclosed hard electroplating tanks that are affected sources other than those that are existing affected sources located at small, hard chromium electroplating facilities.

NR 463.04(3)(b)5. 5. Not allowing the mass rate of total chromium in the exhaust gas stream discharged to the atmosphere to exceed the maximum allowable mass emission rate determined by using the calculation procedure in s. NR 463.09 (6) (d) if the enclosed hard chromium electroplating tank is an existing affected source and is located at a small, hard chromium electroplating facility.

NR 463.04(3)(c) (c) Facility size.

NR 463.04(3)(c)1. 1. An owner or operator may demonstrate the size of a hard chromium electroplating facility by meeting the criteria of s. NR 463.02 (20) or (26). Alternatively, an owner or operator of a facility with a maximum cumulative potential rectifier capacity of 60 million A-hr/yr or more may be considered small if the actual cumulative rectifier capacity is less than 60 million A-hr/yr as demonstrated using one of the following procedures:

NR 463.04(3)(c)1.a. a. If records show that the facility’s previous annual actual rectifier capacity was less than 60 million A-hr/yr, by using nonresettable ampere-hour meters and keeping monthly records of actual ampere-hour usage for each 12-month rolling period following the compliance date in accordance with s. NR 463.103 (2) (L). The actual cumulative rectifier capacity for the previous 12-month rolling period shall be tabulated monthly by adding the capacity for the current month to the capacities for the previous 11 months.

NR 463.04(3)(c)1.b. b. By accepting a federally-enforceable limit on the maximum cumulative potential rectifier capacity of a hard chromium electroplating facility and by maintaining monthly records in accordance with s. NR 463.103 (2) (L) to demonstrate that the limit has not been exceeded. The actual cumulative rectifier capacity for the previous 12-month rolling period shall be tabulated monthly by adding the capacity for the current month to the capacities for the previous 11 months.

NR 463.04(3)(c)2. 2. Once the monthly records required to be kept by s. NR 463.103 (2) (L) and by this paragraph show that the actual cumulative rectifier capacity over the previous 12-month rolling period corresponds to the large designation, the owner or operator is subject to the emission limitation identified in par. (a) 1. or 3. or (b) 1., 3. or 4., in accordance with the compliance schedule of s. NR 463.06 (1) (e).

NR 463.04(4) (4) Standards for decorative chromium electroplating tanks using a chromic acid bath and chromium anodizing tanks. During tank operation, each owner or operator of an existing, new or reconstructed decorative chromium electroplating tank using a chromic acid bath or chromium anodizing tank shall control chromium emissions discharged to the atmosphere from that affected source by one of the following:

NR 463.04(4)(a) (a) By not allowing the concentration of total chromium in the exhaust gas stream discharged to the atmosphere to exceed 0.01 mg/dscm (4.4×10-6 gr/dscf).

NR 463.04(4)(b) (b) If a chemical fume suppressant containing a wetting agent is used, by not allowing the surface tension of the electroplating or anodizing bath contained within the affected tank to exceed 45 dynes per centimeter (dynes/cm) (3.1 x 10-3 pound-force per foot (lbf /ft)) as measured by a stalagmometer or 35 dynes/cm (2.4 x 10-3 lbf /ft) as measured by a tensiometer at any time during operation of the tank.

NR 463.04(5) (5) Standards for decorative chromium electroplating tanks using a trivalent chromium bath.

NR 463.04(5)(a) (a) Each owner or operator of an existing, new or reconstructed decorative chromium electroplating tank that uses a trivalent chromium bath that incorporates a wetting agent as a bath ingredient is subject to the recordkeeping and reporting requirements of ss. NR 463.103 (2) (n) and 463.106 (9), but is not subject to the work practice requirements of s. NR 463.05, or the continuous compliance monitoring requirements in s. NR 463.07. The wetting agent shall be an ingredient in the trivalent chromium bath components purchased from vendors.

NR 463.04(5)(b) (b) Each owner or operator of an existing, new or reconstructed decorative chromium electroplating tank that uses a trivalent chromium bath that does not incorporate a wetting agent as a bath ingredient is subject to the standards of sub. (4).

NR 463.04(5)(c) (c) Each owner or operator of existing, new or reconstructed decorative chromium electroplating tank that had been using a trivalent chromium bath that incorporates a wetting agent and ceases using this type of bath shall fulfill the reporting requirements of s. NR 463.106 (9) (c) and comply with the applicable emission limitation within the timeframe specified in s. NR 463.06 (1) (f).

NR 463.04 History History: Cr. Register, September, 1997, No. 501, eff. 10-1-97; CR 05-039: am. (3) (a), (4) (b), (5) (a) and (c), cr. (3) (a) 3. and (b), renum. (3) (b) to be (3) (c) and am. (3) (c) 1. a., b. and 2. Register February 2006 No. 602, eff. 3-1-06; CR 04-023: am. (1), (2) (a) and (b) 1. to 3. Register December 2008 No. 636, eff. 1-1-09.

NR 463.05 NR 463.05 Operation and maintenance practices.

NR 463.05(1) (1) Work practice standards. All owners or operators subject to the standards in s. NR 463.04 (3) and (4) are subject to the following work practice standards:

NR 463.05(1)(a) (a) At all times, including periods of startup, shutdown and malfunction, owners or operators shall operate and maintain any affected source, including associated air pollution control devices and monitoring equipment, in a manner consistent with good air pollution control practices, consistent with the operation and maintenance plan required by sub. (2).