This Standard for cast iron threaded drainage fittings covers: (a) size and method of designating openings in reducing fittings (b) marking (c) materials (d) dimensions and tolerances (e) threading (f) ribs (g) coatings (h) face bevel. This standard covers fittings intended for use in gravity drainage systems subject only to the gravity head of waste liquids at temperatures from ambient to approximately 100 deg. C (212 deg. F). This standard includes metric dimensions as the primary units while U.S. Customary units are secondary and shown in parenthetical or separate forms.