Excerpt from the ONTARIO BUILDING CODES
This is from an older version of the Code - which one of the Municipalities actually offered online as downloadable PDF. I have pulled together a number of the sections which appear to define the requirements for railings. I have highlighted portions of special interest in terms limits to residential designs.
NOTE: This information should be considered a rough guide line ONLY - as the Ontario Building Codes are under almost constant revision!
3.3.1. All Floor Areas
3.3.1.15. Curved or Spiral Stairs
(1) A curved or spiral stair is permitted in a stairway not required as an exit provided the stair has
(a) treads with
(i) a minimum run not less than 150 mm, and
(ii) an average run not less than 200 mm, and
3.3.1.17. Guards
(1) Except for the front edges of stages, floor pits in repair garages and loading docks, a guard not less than 1 070 mm high shall be provided (42")
(c) at each raised floor, mezzanine, balcony, gallery, interior or exterior vehicular ramp, and at other locations where the difference in level is more than 600 mm (24").
(2) Except as provided in Sentence (3) and Sentence 3.3.2.8.(4), openings through any guard which is required by Sentence (1) shall be of a size which will prevent the passage of a sphere having a diameter more than 100 mm (4") unless it can be shown that the location and size of openings which exceed this limit do not represent a hazard.
(3) Openings through any guard which is required by Sentence (1) and which is installed in a building of industrial occupancy shall be of a size which will prevent the passage of a sphere having a diameter more than 200 mm unless it can be shown that the location and size of openings which exceed this limit do not represent a hazard.
(4) Openings through any guard which is not required by Sentence (1) and which serves a building of other than industrial occupancy, shall be of a size which
(a) will prevent the passage of a sphere having a diameter more 100 mm, or
(b) will permit the passage of a sphere having a diameter more than 200 mm unless it can be shown that the location and size of openings which exceed these limits do not represent a hazard.
(5) Unless it can be shown that the location and size of openings do not present a hazard, a guard shall be designed so that no member, attachment or opening located between 140 mm and 900 mm above the level protected by the guard will facilitate climbing. (between 5 1/2" and 35 1/2")
3.3.4. Residential Occupancy
3.3.4.7. Stairs, Handrails and Guards for Dwelling Units
(1) Stairs, handrails and guards within a dwelling unit shall conform to the appropriate requirements in Section 9.8.
3.4.6. Types of Exit Facilities
3.4.6.3. Landings and Maximum Vertical Rise of Stair Flights
(1) No flight of stairs shall have a vertical rise of more than 3.7 m between floors or landings, except that a flight of stairs serving as an exit in a Group B, Division 2 or 3 occupancy shall have a vertical rise not more than 2 400 mm between floors or landings.
(2) Except as provided in Sentence (6), the length and width of a landing shall be at least the width of the stairway in which it occurs, except that in a straight run the length of the landing need not be more than 1 100 mm.
(3) Where a doorway or stairway empties onto a ramp through a side wall, there shall be a level area extending across the full width of the ramp, and for a distance of 300 mm on either side of the wall opening, or on one side if the opening abuts on an end wall.
(4) Where a doorway or stairway empties onto a ramp through an end wall, there shall be a level area extending across the full width of the ramp and along its length for not less than 900 mm.
(5) A landing shall be provided at the top and bottom of every flight of stairs.
(6) Where the direction of exit travel changes at a landing, the landing is permitted to be chamfered or curved in plan, provided the required width of the stair is maintained where measured perpendicular to the direction of exit travel across the landing.
3.4.6.4. Handrails
(1) An exit ramp or stairway shall have a handrail on at least one side, and if 1 100 mm or more in width, shall have handrails on both sides (43")
(2) If the required width of a ramp or flight of stairs is more than 2 200 mm, one or more intermediate handrails continuous between landings shall be provided, and located so that there will be not more than 1 650 mm between handrails.
(3) Handrails shall be continuously graspable along their entire length and shall have
(a) a circular cross-section with an outside diameter not less than 30 mm and not more than 50 mm, (minimum 1 1/8' - maximum 2") or
(b) any non-circular shape with a graspable portion that has a perimeter not less than 100 mm and not more than 155 mm and whose largest cross-sectional dimension is not more than 57 mm.
(4) Handrails on stairs and ramps shall be not less than 865 mm and not more than 965 mm high, measured vertically from a line drawn through the outside edges of the stair nosing ( minimum 33" maximum 38") or from the surface of the ramp, except that handrails not meeting these requirements are permitted provided they are installed in addition to the required handrail.
(5) Except as required by Sentence (10), at least one handrail shall be continuous throughout the length of the stairway, including landings, except where interrupted by doorways or newels at changes in direction.
(6) Handrails shall be terminated in a manner which will not obstruct pedestrian travel or create a hazard.
(7) At least one handrail at the side of a stairway or ramp shall extend horizontally not less than 300 mm beyond the top and bottom of the stairway or ramp (12').
(8) A clearance of not less than 40 mm shall be provided between a handrail and any wall to which it is fastened (1 1/2").
(9) Handrails and their supports shall be designed and constructed to withstand the loading values obtained from the non concurrent application of
(a) a concentrated load not less than 0.9 kN applied at any point and in any direction for all handrails, and
(b) a uniform load not less than 0.7 kN/m applied in any direction to handrails not located within dwelling units.
(10) In a nursing home, a home for the aged and a Group B, Division 3 occupancy, a continuous handrail shall be provided on both sides of a stairway throughout the length of the stairway, including landings, except where a handrail is interrupted by doorways or newels at changes in direction.
3.4.6.5. Guards
(1) Every exit shall have a wall or a well-secured guard on each side.
(2) Except as required by Sentence (4), the height of guards for exit stairs shall be not less than 920 mm measured vertically to the top of the guard from a line drawn through the outside edges of the stair nosings and 1 070 mm around landings.
(3) Exit ramps and their landings shall be protected with guards not less than 1 070 mm measured vertically to the top of the guard from the ramp surface where the difference in elevation between the adjacent ground or floor level and the ramp is more than 600 mm.
(4) The height of guards for exterior stairs and landings more than 10 m above adjacent ground level shall be not less than 1 500 mm measured vertically to the top of the guard from a line drawn through the outside edges of the stair nosings.
(5) Except as provided in Sentence (6), openings through any guard which is required by Sentence (1) shall be of a size which will prevent the passage of a sphere having a diameter more than 100 mm unless it can be shown that the location and size of openings which exceed this limit do not represent a hazard.
(6) Openings through any guard which is required by Sentence (1) and which is installed in a building of industrial occupancy shall be of a size which will prevent the passage of a sphere having a diameter more than 200 mm unless it can be shown that the location and size of openings which exceed this limit do not represent a hazard.
(7) In a stairway, a window for which the distance measured vertically between the bottom of the window and a line drawn through the outside edges of the stair nosings is less than 900 mm, or a window that extends to less than 1 070 mm above the landing, shall
(a) be protected by a guard that is
(i) located approximately 900 mm above a line drawn through the outside edges of the stair nosings, or
(ii) not less than 1 070 mm high measured to the top of the guard from the surface of the landing, or
(b) be fixed in position and designed to resist the lateral design loads specified for guards and walls in Articles 4.1.10.1. and 4.1.10.3.
(8) Unless it can be shown that the location and size of openings do not present a hazard, a guard shall be designed so that no member, attachment or opening located between 140 mm and 900 mm above the level being protected by the guard will facilitate climbing.
3.4.6.7. Treads and Risers
(1) Except as permitted for dwelling units and by Sentence 3.4.7.5.(1) for fire escapes, steps for stairs shall have a run of not less than 255 mm and not more than 355 mm between successive steps.
(2) Steps for stairs referred to in Sentence (1) shall have a rise between successive treads not less than 125 mm and not more than 200 mm.
(3) Treads and risers in every exit stair, except a fire escape stair, shall have uniform run and rise in any one flight, and shall not alter significantly in run and rise in successive flights in any stair system.
(4) The leading edge of a stair tread shall have either a radius or a bevel between 8 mm and 13 mm in horizontal dimension.
(5) The front edge of stair treads in exits and public access to exits shall be at right angles to the direction of exit travel.
3.4.6.8. Curved Stairs
(1) Except as permitted by Sentence (2), tapered treads shall not be used in an exit.
(2) A curved stair used as an exit shall have
(a) a handrail on each side,
(b) treads with a minimum run of 240 mm exclusive of nosings,
(c) treads that conform to Article 3.4.6.7. where they are measured 230 mm away from the handrail at the narrow end of the tread, and
(d) an inside radius that is not less than twice the stair width.