CPC Subgroup
E04H 12/28 Chimney stacks, e.g. free-standing, or similar ducts (chimneys as part of buildings E04F17/02)
Full Title
Towers; Masts or poles; Chimney stacks; Water-towers; Methods of erecting such structures (cooling towers E04H5/12; derricks for oil drilling E21B15/00) > Chimney stacks, e.g. free-standing, or similar ducts (chimneys as part of buildings E04F17/02)