The Ontario Building Code | Manholes
(2) A manhole shall be provided with,
(a) a cover which shall provide an airtight seal if located within a building,
(b) a rigid ladder of a corrosion-resistant material where the depth exceeds 1 000 mm, and
(3) A manhole shall have a minimum horizontal dimension of 1 200 mm, except that the top 1 500 mm may be tapered from 1 200 mm down to a minimum of 600 mm at the top.
(4) A manhole in a sanitary drainage systemshall be channelled to direct the flow of effluent.