Chapter NR 421

NR 421.05   Synthetic resin manufacturing.

NR 421.06   Coatings manufacturing.

NR 421.07   Synthetic organic chemical manufacturing industry.

NR 421.01 NR 421.01 Applicability; purpose.

NR 421.01(1) (1) Applicability. This chapter applies to all chemical, coatings and rubber products manufacturing air contaminant sources and to their owners and operators.

NR 421.01(2) (2) Purpose. This chapter is adopted under ss. 285.11, 285.13, and 285.17, Stats., to categorize organic compound emissions from chemical, coatings and rubber products manufacturing sources into separate organic compound air contaminant source categories and to establish emission limitations for these categories of sources in order to protect air quality.

NR 421.01 History History: Cr. Register, September, 1986, No. 369, eff. 10-1-86; am. Register, February, 1990, No. 410, eff. 3-1-90; corrections made in (2) made under s. 13.93 (2m) (b) 7., Stats., Register, December, 1996, No. 492.

NR 421.02 NR 421.02 Definitions. Except when another definition is specifically made applicable, the definitions contained in chs. NR 400, 419, and 420 apply to the terms used in this chapter. In addition, except when another definition is specifically made applicable, in this chapter and in chs. NR 422 to 425:

NR 421.02(1) (1) “Bead dipping” means the dipping of an assembled tire bead into a solvent based cement.

NR 421.02(2) (2) “Blending tank” means any vessel in which resin, coating or other materials, or any combination thereof, are added to produce product blend.

NR 421.02(3) (3) “Coatings manufacturing facility” means any facility which mixes, blends or compounds paints, varnishes, lacquers, enamels, shellacs or sealers, and which is classified under standard industrial classification code 2851, as described in the Standard Industrial Classification Manual, 1987, incorporated by reference in s. NR 484.05.

NR 421.02(4) (4) “Completed resin” is any resin which has completed its processing and is available for use in the basic components of plastics or as a component of surface coating formulations.

NR 421.02(5) (5) “Green tires” means assembled tires before molding and curing have occurred.

NR 421.02(6) (6) “Green tire spraying” means the spraying of green tires, both inside and outside, with release compounds which help remove air from the tire during molding and prevent the tire from sticking to the mold after curing.

NR 421.02(7) (7) “Grinding mill” means any mill with cylindrical chambers containing grinding media such as balls, pebbles, or sand which grind and disperse coating solids.

NR 421.02(8) (8) “High speed dispersion mill” means any mixer with one or more blades that rotate at high speed in order to disperse coating solids.

NR 421.02(9) (9) “Passenger type tire” means agricultural, airplane, industrial, mobile home, light and medium duty truck, and passenger vehicle tires with a bead diameter up to 50.8 cm (20 inches) and cross section dimension up to 32.5 cm (12.8 inches).

NR 421.02(10) (10) “Pneumatic rubber tire manufacture” means the production of pneumatic rubber passenger type tires on a mass production basis.

NR 421.02(11) (11) “Production equipment exhaust system” means a device for collecting and directing out of the work area fugitive emissions from reactor openings, centrifuge openings, and other vessel openings at a pharmaceutical manufacturing plant.

NR 421.02(12) (12) “Reaction tank” means any piece of equipment in which organic or other materials are reacted to produce a resin. A reaction tank may include a stripping column, condensers, and a water separator, which return the evaporated solvent to the reaction vessel.

NR 421.02(13) (13) “Reactor” means a vat or vessel, which may be jacketed to permit temperature control, designed to contain chemical reactions.

NR 421.02(14) (14) “Resin” means a solid or semi-solid, water-insoluble, organic material with little or no tendency to crystallize and which is used as the basic components of plastics or as a component of surface-coating formulations.

NR 421.02(15) (15) “Roller mill” means any mill with horizontal rollers that grind and disperse coating solids.

NR 421.02(16) (16) “Synthesized pharmaceutical manufacturing” means manufacture of pharmaceutical products by chemical synthesis.

NR 421.02(17) (17) “Synthetic resin manufacturing facility” means any facility which reacts organic compounds to produce a synthetic resin and which is classified under standard industrial classification code 2821, as described in the Standard Industrial Classification Manual, 1987, incorporated by reference in s. NR 484.05.

NR 421.02(18) (18) “Thinning tank” means any vessel in which resin, coating, or other products are combined with solvents to thin the product.

NR 421.02(18m) (18m) “Tote tank” means any transportable container used to convey coatings, inks, adhesives, or any other related materials, with a capacity equal to or greater than 209 liters (55 gallons).

NR 421.02(19) (19) “Tread end cementing” means the application of a solvent based cement to tire tread ends.

NR 421.02(20) (20) “Undertread cementing” means the application of a solvent based cement to the underside of a tire tread.

NR 421.02(21) (21) “VOC emission leak” means a fugitive emission of volatile organic compounds from any valve, pump, sealed agitator, compressor, flange or relief valve for which the fugitive VOC concentration is measured to exceed 10,000 ppm when tested according to Method 21 in Appendix A of 40 CFR part 60, incorporated by reference in s. NR 484.04.

NR 421.02(22) (22) “Water based sprays” means release compounds, sprayed on the inside and outside of green tires, in which solids, water, and emulsifiers have been substituted for all organic solvents.

NR 421.02(23) (23) “Wipe cleaning” means cleaning which utilizes a material such as a rag wetted with a solvent, prior to a physical rubbing process to remove contaminants from surfaces.

NR 421.02 History History: Renum. from NR 154.01, cr. (1m), (2e), (2s), (4e), (4s), (9m), (10e), (10s), (11e) and (11s), Register, September, 1986, No. 369, eff. 10-1-86; renum. (2) and (5) to be NR 400.02 (22) and (51m), cr. (12m), Register, February, 1990, No. 410, eff. 3-1-90; renum. (10) and (11) to be (10w) and (11w) under s. 13.93 (2m) (b) 1., Stats., Register, August, 1990, No. 416; renum. (1m) to be (2), Register, May, 1992, No. 437, eff. 6-1-92; am. (2e) and (11e), Register, December, 1993, No. 456, eff. 1-1-94; am. (intro.), renum. (2e) to (13) to be (3) to (22) and am. (3), (17) and (21), Register, December, 1995, No. 480, eff. 1-1-96; CR 11-005: cr. (18m), (23) Register January 2012 No. 673, eff. 2-1-12; CR 20-088: am. (intro.) Register May 2022 No. 797, eff. 6-1-22.

NR 421.03 NR 421.03 Chemical manufacture.

NR 421.03(1) (1) Pharmaceutical manufacture.

NR 421.03(1)(a) (a) Applicability. This subsection applies, subject to the provisions of s. NR 425.03, to all operations at pharmaceutical manufacturing facilities involved in the manufacture of pharmaceutical products by chemical synthesis, with the exception of any reactor, distillation unit, dryer, filter, crystallizer, centrifuge, or other individual operation that has an actual emission rate of less than 6.8 kilograms per day (15 pounds per day) with all emission control equipment inoperative.

NR 421.03(1)(b) (b) Emission control requirements. Except as provided under par. (a), the owner or operator of a synthesized pharmaceutical manufacturing facility shall:

NR 421.03(1)(b)1. 1. Equip each vent from reactors, distillation operations, crystallizers, centrifuges, or vacuum dryers with surface condensers or an equally effective control device as approved by the department. If a surface condenser is used, the condenser outlet gas temperature may not exceed:

NR 421.03(1)(b)1.a. a. -25°C (-13°F) for VOCs with vapor pressure greater than 40 kPa (5.8 psia) as measured at 20°C (68°F).

NR 421.03(1)(b)1.b. b. - 15°C (5°F) for VOCs with vapor pressure between 20 kPa (2.9 psia) and 40 kPa (5.8 psia) as measured at 20°C (68°F).

NR 421.03(1)(b)1.c. c. 0°C (32°F) for VOCs with vapor pressure between 10 kPa (1.5 psia) and 20 kPa (2.9 psia) as measured at 20°C (68°F).

NR 421.03(1)(b)1.d. d. 10°C (50°F) for VOCs with vapor pressure between 7 kPa (1.0 psia) and 10 kPa (1.5 psia) as measured at 20°C (68°F).

NR 421.03(1)(b)1.e. e. 25°C (77°F) for VOCs with vapor pressure between 3.5 kPa (0.5 psia) and 7 kPa (1.0 psia) as measured at 20°C (68°F).

NR 421.03(1)(b)2. 2. Limit the VOC emissions from air dryer exhaust systems and production equipment exhaust systems to 15.0 kilograms per day (33 pounds per day) or to 10% of the uncontrolled emission rate of the system, whichever is less stringent.

NR 421.03(1)(b)3. 3. Enclose all centrifuges, rotary vacuum filters, and any other filters having an exposed liquid surface, where the liquid contains VOCs and exerts a total VOC vapor pressure of 3.5 kPa (0.5 psia) or more at 20°C (68°F).

NR 421.03(1)(b)4. 4. Install covers on all in-process tanks that contain a VOC at any time. Covers are to be closed except for necessary operator access during production, sampling, maintenance or inspection.

NR 421.03(1)(b)5. 5. Repair all visually detectable leaks of liquid VOCs the first time the equipment is off-line for a period long enough to complete the repair.

NR 421.03(2) (2) Transfer of VOCs at pharmaceutical manufacturing facilities.

NR 421.03(2)(a) (a) Applicability. Subject to the provisions of s. NR 425.03, this subsection applies to all storage vessels for VOCs of more than 7,751 liter (2,000 gallon) capacity at a synthetic pharmaceutical manufacturing facility.

NR 421.03(2)(b) (b) Emission reduction requirements. No owner or operator of a synthetic pharmaceutical manufacturing facility may permit the delivery of VOCs with vapor pressure in excess of 28.0 kPa (4.1 psia) at 20°C from a truck or railcar to the storage vessel unless a vapor balance or equivalent control system is provided. The system must be at least 90% effective in reducing emissions from transfer operations.

NR 421.03(3) (3) Storage of VOCs at pharmaceutical manufacturing facilities.

NR 421.03(3)(a) (a) Applicability. This subsection applies, subject to the provisions of s. NR 425.03, to all storage vessels for VOCs of more than 3,785 liters (1,000 gallon) capacity at synthetic pharmaceutical manufacturing facilities.

NR 421.03(3)(b) (b) Storage requirements. The owner or operator of any storage vessel shall install pressure-vacuum conservation vents set at ±0.2 kPa, or an equally effective control device approved by the department, on all storage vessels that store VOCs with vapor pressures in excess of 10.5 kPa (1.52 psia) at 21°C (70°F).

NR 421.03 History History: Renum. from NR 154.13 (2) (b), (3) (e) and (9) and am., Register, September, 1986, No. 369, eff. 10-1-86; am. (1) (b) 1. and (2) (b), Register, February, 1990, No. 410, eff. 3-1-90; am. (1) (a), Register, December, 1993, No. 456, eff. 1-1-94.

NR 421.04 NR 421.04 Pneumatic rubber tire manufacture.

NR 421.04(1) (1) Applicability. This section applies, subject to the provisions of s. NR 425.03, to all pneumatic rubber tire manufacturing facilities involved in undertread cementing, tread end cementing, bead dipping, or green tire spraying operations.

NR 421.04(2) (2) Exemptions.

NR 421.04(2)(a) (a) This section does not apply to the production of specialty tires for antique or other vehicles when produced on an irregular basis or with short production runs. This exemption applies only to tires produced on equipment separate from normal production lines for passenger type tires.

NR 421.04(2)(b) (b) The requirements of sub. (3) do not apply provided the combined total VOC emissions from all undertread cementing, tread end cementing, bead dipping and green tire spraying operations are less than or equal to 57 grams per tire produced and the emission rates are determined and certified by August 31, 1981.

NR 421.04(3) (3) Emission control requirements. The owner or operator of a pneumatic rubber tire manufacturing facility shall:

NR 421.04(3)(a) (a) For all undertread cementing, tread end cementing and bead dipping operations install and operate one of the following:

NR 421.04(3)(a)1. 1. A carbon adsorption system which reduces the VOC emissions from the capture system by at least 90% by weight.

NR 421.04(3)(a)2. 2. An incineration or catalytic oxidation system which oxidizes at least 90% of the nonmethane VOCs (measured as total combustible carbon) which enter the incineration or oxidation unit, to nonorganic compounds.

NR 421.04(3)(a)3. 3. An alternative VOC emission reduction system demonstrated to have at least 90% reduction efficiency measured across the control system, as approved by the department.

NR 421.04(3)(b) (b) For green tire spraying operations, implement one of following control strategies:

NR 421.04(3)(b)1. 1. Utilize water-based mold release compound sprays with a volatile fraction containing, at a minimum, 90% water.

NR 421.04(3)(b)2. 2. Install and operate a carbon adsorption system which reduces the VOC emission from the capture system by at least 90% by weight.

NR 421.04(3)(b)3. 3. Install and operate an incineration or catalytic oxidation system which oxidizes at least 90% of the nonmethane VOCs (VOC measured as total combustible carbon) which enter the incinerator or oxidation unit to nonorganic compounds.

NR 421.04(3)(b)4. 4. Install and operate an alternate VOC emission reduction system demonstrated to have at least a 90% reduction efficiency, measured across the control system, as approved by the department.

NR 421.04(3)(c) (c) For any control device required by this section, install and operate a capture system, as approved by the department, which is designed to provide maximum reasonable capture and transfer of VOCs to the control device. Maximum reasonable capture and transfer shall be in accord with guidance provided by:

NR 421.04(3)(c)1. 1. Industrial Ventilation: A Manual of Recommended Practice, 20th ed., incorporated by reference in s. NR 484.11.

NR 421.04(3)(c)2. 2. Recommended Industrial Ventilation Guidelines, incorporated by reference in s. NR 484.05.

NR 421.04 History History: Renum. from NR 154.13 (8) and am. (1), Register, September, 1986, No. 369, eff. 10-1-86; am. (4) (intro.), Register, February, 1990, No. 410, eff. 3-1-90; am. (3) (c) 1. and 2., Register, May, 1992, No. 437, eff. 6-1-92; am. (3) (c) 1. and 2., r. (4), Register, December, 1995, No. 480, eff. 1-1-96; correction in (2) (b) made under s. 13.93 (2m) (b) 7., Stats., Register, December, 1995, No. 480; am. (3) (a) (intro.), (c) 1., Register, December, 1996, No. 492, eff. 1-1-97; am. (3) (a) 2., Register, October, 1999, No. 526, eff. 11-1-99.

NR 421.05 NR 421.05 Synthetic resin manufacturing.

NR 421.05(1) (1) Applicability.

NR 421.05(1)(a) (a) Effective October 1, 1986, subs. (2) and (3) (a) and (b) apply to reaction tanks, thinning tanks, blending tanks, and other process vessels used in any synthetic resin manufacturing facility which has maximum theoretical emissions of VOCs from the processes greater than or equal to 100 tons per year and which is located in the county of Kenosha, Milwaukee, Ozaukee, Racine, Washington, or Waukesha.

NR 421.05(1)(b) (b) Effective January 1, 1994, subs. (2) and (3) (a) and (b) apply to reaction tanks, thinning tanks, blending tanks, and other process vessels used in any synthetic resin manufacturing facility which has maximum theoretical emissions of VOCs from the processes greater than or equal to one of the following:

NR 421.05(1)(b)1. 1. 25 tons per year for a facility located in the county of Kenosha, Milwaukee, Ozaukee, Racine, Washington, or Waukesha.

NR 421.05(1)(b)2. 2. 100 tons per year for a facility located in the county of Door, Kewaunee, Manitowoc, Sheboygan, or Walworth.

NR 421.05(1)(c) (c) Subsections (2m), (3) (c), and (4) apply to facilities with synthetic resin manufacturing operations as described in par. (a) located in the county of Kenosha, Milwaukee, Ozaukee, Racine, Sheboygan, Washington, or Waukesha if VOC emissions from all industrial cleaning operations, before consideration of controls, equal or exceed 3 tons per year on a 12 consecutive month rolling basis.

NR 421.05 Note Note: “Maximum theoretical emissions” has the meaning given in s. NR 419.02 (11).

NR 421.05(2) (2) Emission control requirements. The owner or operator of a synthetic resin manufacturing facility shall:

NR 421.05(2)(a) (a) Equip each vent from reaction tanks, and all blending tanks and thinning tanks, with an emission control system which meets one of the conditions listed in this paragraph. Any equally effective control method or equivalent system approved by the department under this paragraph shall be submitted to, and will not become effective for federal purposes until approved by, the administrator or designee as a source-specific revision to the department’s state implementation plan for ozone. The emission control system shall be one of the following:

NR 421.05(2)(a)1. 1. A surface condenser, or equally effective control device approved by the department, and a vapor recovery or control system that reduces emissions from the surface condenser or equally effective device by 85%.

NR 421.05(2)(a)2. 2. An equivalent system or approach demonstrated to reliably control emissions from a process that does not include a condenser by not less than 90% as approved by the department.

NR 421.05(2)(b) (b) If a surface condenser is used, continuously record the condenser outlet gas temperature, and prevent the condenser outlet gas temperature from exceeding 32°C (90°F).

NR 421.05(2)(c) (c) Enclose all centrifuges, rotary vacuum filters, and any other filters having an exposed liquid surface, where the liquid contains VOCs.

NR 421.05(2)(d) (d) Install covers on all in-process tanks that contain a VOC at any time. Covers shall be closed except for necessary operator access during production, sampling, maintenance or inspection.