The Ontario Building Code | Underground Ducts

6.2.3.5. Underground Ducts

(1) Underground ducts shall,

(a) be constructed and installed with a slope to provide interior drainage to all low points,

(b) not be connected directly to a sewer, and

(c) be installed and constructed of materials in conformance with ASHRAE Handbooks, SMACNA Manuals and the HRAI Digest.

(2) A clean-out or pump-out connection shall be provided in an underground duct system at every low point of the duct system.