DIFF Subgroup
E04F 17/04 Air-ducts or air channels
Introduced: September 1968
Full Title
Full titles differ between systems:
IPC:
Vertical ducts; Channels, e.g. for drainage > Air-ducts or air channels
CPC:
Vertical ducts; Channels, e.g. for drainage (pipes in general F16L; pipe-line systems F17D ) > Air-ducts or air channels
No child classifications to compare. This is a leaf node in both IPC and CPC.