CPC Subgroup
E04F 17/06 Light shafts, e.g. for cellars
Full Title
Vertical ducts; Channels, e.g. for drainage (pipes in general F16L; pipe-line systems F17D ) > Light shafts, e.g. for cellars
E04F 17/06 Vertical ducts; Channels, e.g. for drainage (pipes in general F16L; pipe-line systems F17D ) > Light shafts, e.g. for cellars