A. Smoke control.
(1) No smoke shall be emitted from any chimney or other source with visible gray greater than No. 1 on the Ringelmann Chart as published by the U.S. Bureau of Mines.
(2) Smoke of a shade not darker than No. 2 on the Ringelmann Smoke Chart may be emitted for not more than four minutes in any 30 minutes.
(3) These provisions, applicable to visible gray smoke, shall also apply to visible smoke of a different color, but with an equivalent apparent opacity.
B. Control of dust and dirt, fly ash and fumes, vapors and gases.
(1) No emission shall be made which can cause any damage to health, to animals or vegetation or other form of property or which can cause any excessive soiling at any point.
(2) No emission of liquid or solid particles from any chimney or otherwise shall exceed 0.3 grains per cubic foot of the covering gas at any point.
(3) For measurement of the amount of particles in gases resulting from combustion, standard correction shall be applied to a stack temperature of 500ºF. and 50% excess air.