§ 251.54 Ringelmann Chart
   “Ringelmann Chart” means the chart published and described in the U.S. Bureau of Mine Information Circular 8333, and on which are illustrated graduated shades of grey to black for use in estimating the light obscuring capacity of smoke.
(Ord. No. 857-A-76. Passed 6-27-77, eff. 6-30-77)