Wisconsin Administrative Code
Department of Natural Resources
NR 400-499 - Environmental Protection - Air Pollution Control
Chapter NR 431 - Control of visible emissions
Section NR 431.05 - Emission limitations after April 1, 1972
Current through August 26, 2024
No owner or operator of a direct or portable source on which construction or modification is commenced after April 1, 1972 may cause or allow emissions of shade or density greater than number 1 of the Ringlemann chart or 20% opacity with the following exceptions:
(1) When combustion equipment is being cleaned or a new fire started, emissions may exceed number 1 of the Ringlemann chart or 20% opacity but may not exceed number 4 of the Ringlemann chart or 80% opacity for 6 minutes in any one hour. Combustion equipment may not be cleaned nor a fire started more than 3 times per day.
(2) Emissions may exceed number 1 of the Ringlemann chart or 20% opacity for stated periods of time, as permitted by the department, for such purpose as an operating test, use of emergency equipment, or other good cause, provided no hazard or unsafe condition arises.
(3) For direct or portable sources in operation on or before February 1, 1975, where emission test data taken concurrently with opacity readings or continuous emission monitor data show the source to be in compliance with the applicable emission limits but not the opacity limits, an alternative opacity limit may be established according to methods and procedures in s. NR 431.07.
