The Ontario Building Code | Doors
3.4.6.11. doors
(1) The distance between a stair riser and the leading edge of a door during its swing shall be not less than 300 mm.
(2) No exit door shall open directly onto a step except that, if there is danger of blockage from ice or snow, an exit door is permitted to open onto not more than one step which shall be not more than 150 mm high.
(3) Exit doors shall be clearly identifiable.
(4) No door leaf in an exit doorway ="http://thehandyforce.com/doors/" title ="Toronto Door installer">doorway with more than one leaf shall be less than 600 mm wide.