Staircases, ladders, grating and checkered plate

Access elements in a steel building

Every mezzanine, platform and roof needs a safe way up. In pre-engineered buildings the access elements are usually supplied in steel with the structure: staircases to mezzanines and offices, fixed ladders to roofs and crane platforms, and floor surfaces of grating or checkered plate. They are small in tonnage but closely regulated, because they are where people walk, climb and can fall.

Steel staircase with stringers and treads, a fixed ladder with cage, a grating panel and a checkered plate panel — Staircase, ladder with cage, grating and checkered plate.

Staircases

Steel stairs consist of two stringers – channels, plates or hollow sections – with treads of grating, checkered plate or folded plate for a concrete or tile infill, plus landings, guards and handrails. The choice between a general building stair and an industrial stair depends on who uses it: stairs used by the public or office staff follow the building code, while stairs serving plant and equipment may follow industrial access rules.

Typical stair geometry and guard limits (indicative – confirm locally)
Requirement	Building stairs (e.g. IBC 2021/2024)	Industrial access (e.g. OSHA, AS 1657, EN ISO 14122-3)
Riser height	Max about 178 mm (7 in)	Max about 240 mm (OSHA 9.5 in); AS 1657 130–225 mm
Tread depth	Min about 279 mm (11 in)	Min about 240 mm (OSHA 9.5 in)
Stair angle	About 30–35°	About 30–50° (OSHA); 20–45° (AS 1657)
Handrail height	865–965 mm (34–38 in)	About 860–1,100 mm depending on code
Guard height	Min 1,067 mm (42 in)	About 1,070 mm (OSHA), 900–1,100 mm (AS 1657), 1,100 mm (EN ISO 14122-3)

Guards typically need intermediate rails or infill so that a 100 mm (4 in) sphere cannot pass in public areas, and toe boards on industrial platforms. Mezzanine stair layouts and egress are discussed in mezzanine floors.

Fixed ladders and fall protection

Fixed ladders are used where a stair is impractical – roof access, crane cabins, tanks and high platforms. Rungs are usually round or square bars at about 250–300 mm spacing between flat or channel stringers, with a clear width of around 400–600 mm.

United States: under OSHA 29 CFR 1910.28, new fixed ladders over 7.3 m (24 ft) need a personal fall arrest or ladder safety system; cages and wells alone are no longer accepted for new installations.
Australia: AS 1657:2018 limits ladder heights between landings and specifies cages or fall-arrest systems above set heights.
Europe: EN ISO 14122-4 covers fixed ladders, safety cages and landing intervals for machinery access.
Canada: provincial OHS regulations apply, alongside the NBC 2020 for building access.

Ladder fall-protection rules have changed in recent years. Always check the current local regulation rather than reusing an older standard detail.

Grating and checkered plate

Floor plate options
Type	Typical form	Best use
Welded steel bar grating	Bearing bars 25–50 mm deep at about 30 mm centres, cross bars at about 100 mm; often hot-dip galvanized	Platforms, catwalks, stair treads, outdoor areas
Serrated grating	Notched bearing bars for extra slip resistance	Wet, oily or sloping surfaces
Checkered (tread) plate	Raised-pattern plate, about 4.5–10 mm thick	Covers, landings, areas where items must not fall through
Expanded or perforated plank	Pressed slip-resistant planks	Light walkways, roof access

Grating panels are fixed with saddle clips or welded, and must be supported at the bearing-bar ends with the span checked for the design load and deflection. Checkered plate needs stiffeners for larger spans. For platform applications see roof platforms and catwalks.

Stairs and access steel from World Steel

World Steel designs and fabricates stairs, landings, ladders, handrails, grating and checkered plate as part of its accessories and mezzanine floor systems, hot-dip galvanized or painted per coating system requirements, and detailed to the access code of the destination market.

Normas por región

Región	Norma	Alcance
United States	IBC 2024 Ch. 10 / OSHA 29 CFR 1910.23–.29	Means of egress, stairs, guards; ladders and fall protection
United States	ANSI/NAAMM MBG 531 / ASTM A786	Metal bar grating; rolled steel floor plates
Canada	NBC 2020 Parts 3 and 9	Stairs, handrails and guards
Australia / NZ	AS 1657:2018	Fixed platforms, walkways, stairways and ladders
Europe	EN ISO 14122-1 to -4	Permanent means of access to machinery

Preguntas frecuentes

Are ladder cages still allowed?

It depends on the country. In the US, new fixed ladders over 24 ft require a fall arrest or ladder safety system rather than a cage alone; other markets still accept cages under set conditions.

Should stair treads be grating or checkered plate?

Grating treads with a nosing are common for industrial stairs because they drain and resist slipping. Checkered plate or concrete-filled pans are used where a solid surface is preferred.

What guard height is required on a mezzanine?

Typically 1,067 mm (42 in) under the IBC and NBC, 900–1,100 mm under AS 1657 for industrial platforms, and 1,100 mm under EN ISO 14122-3.