(a) No person shall cause, suffer, allow or permit smoke from any fuel-burning equipment, the shade or appearance of which smoke is darker than No. 1 of the Ringelmann Smoke Chart, to be emitted into the open air.
(b) This section does not apply to smoke emitted during the cleaning of a fire box or the building of a new fire, the shade or appearance of which smoke is not darker than No. 2 of the Ringelmann Smoke Chart, for a period or periods aggregating not more than three minutes in any fifteen consecutive minutes.
(1976 Code 16-5.)