(1) Subject to the provisions of subsection (3), all gullies, grease-traps and stable-traps shall be located in the open air or, if beneath a roof, in a place permanently exposed to the open air, and shall be at all times readily accessible for the purposes of cleaning or maintenance.

(2) Every floor in a factory, stable or other premises upon which liquid is discharged continuously or intermittently shall have a hard, smooth, durable surface, and shall be graded and drained to a gully or other approved trapped receptacle.

(3) Notwithstanding the provisions of subsection (1), a gully referred to in subsection (2) may be located within a building.