H = physical stack height (meters)
V = stack gas flow rate (m3/second)
T = exhaust temperature (°K)
The stack with the lowest value of K is the worst-case stack.
NR 666.106(2)(g)(g) Criteria for facilities not eligible for screening limits. If any of the following criteria are met, the Tier I and Tier II screening limits do not apply. Owners and operators of such facilities shall comply with either the Tier III standards provided by sub. (4) or with the adjusted Tier I feed rate screening limits provided by sub. (5). NR 666.106(2)(g)1.1. The device is located in a narrow valley less than one kilometer wide. NR 666.106(2)(g)2.2. The device has a stack taller than 20 meters and is located such that the terrain rises to the physical height within one kilometer of the facility. NR 666.106(2)(g)3.3. The device has a stack taller than 20 meters and is located within 5 kilometers of a shoreline of a large body of water such as an ocean or large lake. NR 666.106(2)(g)4.4. The physical stack height of any stack is less than 2.5 times the height of any building within 5 building heights or 5 projected building widths of the stack and the distance from the stack to the closest boundary is within 5 building heights or 5 projected building widths of the associated building. NR 666.106(2)(g)5.5. The department determines that standards based on site-specific dispersion modeling are required. NR 666.106(2)(h)(h) Implementation. The feed rate of metals in each feedstream shall be monitored to ensure that the feed rate screening limits are not exceeded. NR 666.106(3)(3) Tier II emission rate screening limits. Emission rate screening limits are specified in ch. NR 666 Appendix I as a function of terrain-adjusted effective stack height and terrain and land use in the vicinity of the facility. Criteria for facilities that are not eligible to comply with the screening limits are provided in sub. (2) (g). NR 666.106(3)(a)(a) Noncarcinogenic metals. The emission rates of antimony, barium, lead, mercury, thallium and silver may not exceed the screening limits specified in ch. NR 666 Appendix I. NR 666.106(3)(b)(b) Carcinogenic metals. The emission rates of arsenic, cadmium, beryllium and chromium may not exceed values derived from the screening limits specified in ch. NR 666 Appendix I. The emission rate of each of these metals is limited to a level such that the sum of the ratios of the actual emission rate to the emission rate screening limit specified in ch. NR 666 Appendix I may not exceed 1.0, as provided by the following equation: where:
n = number of carcinogenic metals
AER = actual emission rate for metal “i”
NR 666.106(3)(c)(c) Implementation. The emission rate limits shall be implemented by limiting feed rates of the individual metals to levels during the trial burn (for new facilities or an interim license facility applying for a license) or the compliance test (for interim license facilities). The feed rate averaging periods are the same as provided by sub. (2) (a) 1. and 2. and (b) 2. The feed rate of metals in each feedstream shall be monitored to ensure that the feed rate limits for the feedstreams specified under s. NR 666.102 or 666.103 are not exceeded. NR 666.106(3)(d)(d) Definitions and limitations. The definitions and limitations provided by sub. (2) for the following terms also apply to the Tier II emission rate screening limits provided by this subsection: terrain-adjusted effective stack height, good engineering practice stack height, terrain type, land use and criteria for facilities not eligible to use the screening limits. NR 666.106(3)(e)1.1. Owners and operators of facilities with more than one onsite stack from a boiler, industrial furnace, incinerator or other thermal treatment unit subject to controls on metals emissions under an operating license or interim license shall comply with the emissions screening limits for any such stacks assuming all hazardous waste is fed into the device with the worst-case stack based on dispersion characteristics. NR 666.106(3)(e)3.3. For each metal, the total emissions of the metal from those stacks may not exceed the screening limit for the worst-case stack. NR 666.106(4)(4) Tier III and adjusted Tier I site-specific risk assessment. The requirements of this subsection apply to facilities complying with either the Tier III or adjusted Tier I controls, except where specified otherwise. NR 666.106(4)(a)(a) General. Conformance with the Tier III metals controls shall be demonstrated by emissions testing to determine the emission rate for each metal. In addition, conformance with either the Tier III or adjusted Tier I metals controls shall be demonstrated by air dispersion modeling to predict the maximum annual average off-site ground level concentration for each dispersion modeling to predict the maximum annual average off-site ground level concentration for each metal, and a demonstration that acceptable ambient levels are not exceeded. NR 666.106(4)(b)(b) Acceptable ambient levels. Chapter NR 666 Appendix IV and ch. NR 666 Appendix V list the acceptable ambient levels for purposes of this rule. Reference air concentrations (RACs) are listed for the noncarcinogenic metals and 10–5 risk-specific doses (RSDs) are listed for the carcinogenic metals. The RSD for a metal is the acceptable ambient level for that metal if only one of the 4 carcinogenic metals is emitted. If more than one carcinogenic metal is emitted, the acceptable ambient level for the carcinogenic metals is a fraction of the RSD as described in par. (c). NR 666.106(4)(c)(c) Carcinogenic metals. For the carcinogenic metals, arsenic, cadmium, beryllium and chromium, the sum of the ratios of the predicted maximum annual average off-site ground level concentrations (except that on-site concentrations shall be considered if a person resides on site) to the risk-specific dose (RSD) for all carcinogenic metals emitted may not exceed 1.0 as determined by the following equation: