Industrial steel stairs, access stairs and roof access stairs in Ontario are governed by two sets of rules: the Ontario Building Code, which sets stair geometry, guards and loads for the building, and Ontario's Industrial Establishments regulation (R.R.O. 1990, Reg. 851), which sets workplace requirements for guardrails, service stairs, fixed ladders and access to elevated equipment. A building more than 3 storeys high with a low-slope roof also needs direct roof access by a stair or by a hatch with a fixed ladder. This guide explains how those rules shape the stairs, platforms and roof access you order for a plant, warehouse or commercial building.
Where industrial and access stairs are used
On industrial and commercial sites, steel stairs do more than connect floors:
- Mezzanine and platform stairs up to storage, offices or equipment decks
- Equipment access stairs and crossovers over conveyors, pipes and production lines
- Roof access stairs inside the building up to a roof hatch or penthouse door
- Exterior stair towers serving upper floors, roofs or tank tops
- Loading dock stairs and stairs between floor levels in older plants
- Exit stairs that form part of the required means of egress
The use decides which rules apply. An exit stair is designed to the Building Code's exit requirements; a stair that only serves equipment may be treated as a service stair; and anything workers use is also covered by the workplace regulation.
Two rulebooks: the Building Code and Reg. 851
The Ontario Building Code applies to construction of the building, including stairs, guards and platforms that are part of it. Industrial buildings beyond the Part 9 limits are designed under Part 3, and the stairs are designed by the building's architect and engineer, with the fabricator's shop drawings reviewed against that design.
Reg. 851 (Industrial Establishments), made under the Occupational Health and Safety Act, applies to the workplace. Among other things it requires:
- A guardrail around uncovered floor and roof openings workers can reach, and at the open side of a raised floor, mezzanine, balcony, gallery, landing, platform, walkway, stile, ramp or similar surface (section 13)
- Guardrails with a top rail between 91 cm and 107 cm above the surface, a mid rail, a toe board at least 125 mm high where tools or objects could fall on a worker, and construction that meets the structural requirements for guards in the Building Code (section 14)
- A fixed walkway, service stair or stile at least 55 cm wide (section 17)
- Permanent platforms with a fixed stair or access ladder where frequent access is needed to equipment above or below floor level (section 19)
- Rules for fixed access ladders, including rest platforms and safety cages on taller ladders (section 18), which we cover in fixed steel ladders and cages in Ontario
The two overlap, and the stricter result wins. For example, Reg. 851 allows a guardrail top rail as low as 91 cm, but the Building Code requires most guards in Part 3 buildings to be at least 1,070 mm high. A 1,070 mm guard with a mid rail and a toe board meets both. Where one set of rules exempts something, check the other before leaving it out.
Roof access: stair, ship ladder or hatch
Article 3.2.5.3. of the 2024 Ontario Building Code requires that on a building more than 3 storeys in building height where the roof slope is less than 1 in 4, all main roof areas have direct access from the floor areas immediately below by either:
- a stairway, or
- a hatch not less than 550 mm by 900 mm with a fixed ladder.
On lower buildings the code doesn't require roof access, but owners usually want it for servicing rooftop units. The choice between options comes down to how often people go up and what they carry:
| Option | Good for | Watch for |
|---|---|---|
| Full stair to a penthouse door | Frequent access, carrying tools and parts, larger crews | Takes the most floor space; the stair and door enclosure are part of the building design |
| Steep access stair (ship ladder style) to a hatch | Regular maintenance where floor space is tight | Confirm the design with your designer against the code and the workplace rules before ordering |
| Vertical fixed ladder to a hatch | Occasional access | Hands are not free for carrying; cages, rest platforms and side rail extensions under Reg. 851 apply to taller ladders |
Once on the roof, think about the route to the equipment. Reg. 851 exempts roofs where access is only for maintenance from its guardrail requirement, but then requires the employer to develop and implement other measures to protect workers from falling. The Building Code requires a 1,070 mm guard around roofs where access is provided for anything other than maintenance. Guards near the hatch, around rooftop equipment near the edge, and at roof openings are common additions.
Stair geometry for industrial stairs
For stairs in Part 3 buildings, Article 3.4.6.8. of the 2024 Ontario Building Code sets steps with a run of 280 mm to 355 mm and a rise of 125 mm to 180 mm, with tight uniformity limits: risers within 5 mm of each other between adjacent treads and 10 mm across a flight, and the same tolerances for tread runs. Treads and landings may not slope more than 1 in 50.
Two points matter for industrial work:
- Open risers are generally not permitted in Part 3 stairs, but the code makes exceptions for fire escape stairs, stairs principally used for maintenance and service, and stairs serving industrial occupancies other than storage garages. That is why open grating stairs are so common in plants.
- Service stairs in Part 9 buildings, those serving only service rooms or service spaces, have their own limits. Our guide to Ontario Building Code rules for steel stairs has the Part 9 table.
Guards on platforms and mezzanines follow Article 3.3.1.18., and guards on exit stairs follow Article 3.4.6.6. In both, a guard is needed where the drop is more than 600 mm, it must be at least 1,070 mm high, and openings must not pass a 100 mm sphere in most buildings or a 200 mm sphere in buildings of industrial occupancy, unless it can be shown that larger openings are not a hazard. Exterior exit stairs and landings more than 10 m above the ground need guards at least 1,500 mm high.
Loads and design
Industrial stairs and platforms are designed for real loads, not just people:
- The code's minimum live load is 4.8 kPa for exits and fire escapes and 3.6 kPa for equipment areas and service rooms (Table 4.1.5.3.), and designers use the actual load where it is higher.
- Platforms that carry equipment, parts or carts need those loads on the drawings.
- Stair towers and exterior stairs also carry snow and wind, and they need foundations or connections to the building that suit those loads.
Your engineer sets the design loads. The fabricator's shop drawings show the members and connections that carry them, and on most industrial projects the specification asks for drawings sealed by a professional engineer.
How industrial steel stairs are built
Typical construction for steel access stairs and stair towers:
- Stringers of steel channel or plate, sized for the span and load
- Treads of steel bar grating with a solid or checker plate nosing, or checker plate where a closed tread is wanted. See steel checker plate for plate tread options.
- Landings and platforms framed with channel or angle and decked with grating or plate
- Guards of pipe or HSS with mid rails and toe boards
- Bolted field connections wherever possible, so the stair goes up quickly with minimal site welding
- Finish: hot-dip galvanizing for exterior and roof stairs and wet areas, and primer or paint indoors
Exterior stair towers are usually designed as a self-supporting steel frame with its own foundations, tied back to the building. Details for outdoor stairs are covered in exterior steel stairs.
What to send for an industrial stair quote
- Architectural and structural drawings, or a layout sketch with elevations for existing buildings
- What the stair serves: exit, mezzanine, equipment access or roof access
- Floor-to-floor or floor-to-platform heights, and the space available
- Tread type, guard style and finish
- Design loads and any equipment on the platforms
- What the stair attaches to at the top and bottom
- Whether engineering is required, and whose seal is needed
- Site access, shutdown windows and working conditions
Industrial stairs and platforms from Procut
We fabricate steel stairs, ladders, railings and platform framing as part of our miscellaneous and structural steel work, with CWB certified shop welding and shop drawings prepared in house. Engineering services are available for projects that need them, and we deliver across the GTA and Ontario. We work with builders, contractors and owners on commercial and industrial projects. We fabricate and deliver, and installation is by your installer or contractor.
Send your drawings for a free take-off and quote, or see our services for structural and miscellaneous steel fabrication.
Frequently asked questions
When does a building need stair access to the roof in Ontario?
Under Article 3.2.5.3. of the 2024 Ontario Building Code, a building more than 3 storeys in building height with a roof slope less than 1 in 4 must have direct access to all main roof areas from the floor below, either by a stairway or by a hatch at least 550 mm by 900 mm with a fixed ladder.
How wide must a service stair be in an Ontario workplace?
Section 17 of Ontario's Industrial Establishments regulation (R.R.O. 1990, Reg. 851) requires a fixed walkway, service stair or stile to be at least 55 cm wide. Building Code rules for the stair still apply, and exit stairs are much wider.
Can industrial stairs have open risers?
Part 3 of the Ontario Building Code generally does not allow open risers, but it makes exceptions for fire escape stairs, stairs principally used for maintenance and service, and stairs serving industrial occupancies other than storage garages. Grating treads with open risers are common in those locations.
Do maintenance platforms and roofs need guardrails?
The Building Code and Reg. 851 both exempt surfaces where access is for maintenance only from their general guard requirement. Under Reg. 851, an employer that relies on that exemption must put other measures in place to protect workers from falling, so many owners install guards or fall protection anyway.
