(a) No person shall cause or permit visible emissions (other than uncombined water vapor) from equipment identified hereunder and that was installed and in operation, or for which a permit had been issued by the Division of Environmental Quality prior to January 30, 1972, to exceed the following limitations:

1. (1) Emissions shall not exceed forty percent (40%) opacity, except that emissions greater than forty percent (40%) opacity will be allowed for not more than six (6) minutes in the aggregate in any consecutive sixty-minute period, provided such emissions will not be permitted more than three (3) times during any twenty-four-hour period.

(b) No person shall cause or permit visible emissions (other than uncombined water vapor) from new equipment identified hereunder that was installed or permitted by the division after January 30, 1972, to exceed the following limitations or to exceed any applicable visible emission limitations of the new source performance standards promulgated by the United States Environmental Protection Agency:

1. (1) For incinerators and fuel-burning equipment, exclusively, emissions shall not exceed twenty percent (20%) opacity except that emissions greater than twenty percent (20%) opacity but not exceeding sixty percent (60%) opacity will be allowed for not more than six (6) minutes in the aggregate in any consecutive sixty-minute period, provided such emissions will not be permitted more than three (3) times during any twenty-four-hour period; and
2. (2) For equipment used in a manufacturing process, emissions shall not exceed twenty percent (20%).