No person shall cause, suffer, allow or permit particles to be emitted from any stack or chimney into the outdoor air the shade or appearance of which is greater than twenty-percent opacity, exclusive of water vapor.
The provisions of this chapter shall not apply to:
A. 
Particles the shade or appearance of which is greater than twenty-percent opacity, exclusive of water vapor, for a period of not longer than three minutes in any consecutive thirty-minute period.
B. 
Source operations issued a variance by the New Jersey Department of Environmental Protection in accordance with N.J.A.C. 7:27-6.5 of the New Jersey Administrative Code.
C. 
Indirect heat exchangers.
D. 
Incinerators.