Stair Construction

School Stairs

Speical consideration is required for school stairs.

Non Climbable Zones: Balustrades must be designed to prevent children from climbing them. This means no horizontal bars where chidren can get grip with their feet.

Dual Hand Rails: In primary schools it is common to install a second, lower handrails at approximate height of 600 to 700 mm specifically for small children in addtion to standard adult handrail (height 865-1000mm).

We usually see this handrails on long public bridiges, over passes.

Slip Resistance: School stairs are high traffic stairs.

Indoor stairs must have slip resistance rating of P3.

Contrasting nosing on every step. Width 50mm – 75 mm.

Outdoor stairs need a P4 or P5 rating.

Industrial Stairs

Industrial Stairs in invariable steel or cocrete.

Steel stair probably have edge over cocrete stairs, because generally industrial buildings are steel construction. Does not make much sense in building a concrete stair where everything else is steel.

Fire Escape Stairs

Minimum width reqirement: Must have an unobstructed width of at least 1 meter.

Width must increase as the number of occupants increases, buildings with more than 100 people need wider aggregate exit paths.

Also stair widths must be wider at lower floors.

Fire escape stairs cannot be timber. It must be steel or concrete.

Safety features: Handrails MUST be continous and must meet height and clearance standards.

Slip reisistance: Treads must comply to slip-resistance standards like AS4586.

Signage and lighting: Every exit must be clearly marked with emergency lighting and exit signs.

Also, even in residential, it would matter whether the stair is inside or outside the building.

Corrosion resistance

If the stair is installed outside the building, then corrossion reisistance become a prime consideration

Also attack by termites could another thing to be considered.

Choice of material

Should the stair be a steel stair or can it be timber.

I believe the most elegant staris are made from timber. The color and versatitlity of timber is hard to match with steel.

Types of Stair Configurations

• Straight Stairs: The most common and economical design, consisting of a single linear flight with no change in direction.
• L-Shaped (Quarter-Turn) Stairs: A straight flight that makes a 90-degree turn, typically at a landing, to save space or follow a building’s corner.
• U-Shaped (Switchback) Stairs: These feature two parallel flights of stairs joined by a landing that creates a 180-degree turn.
• Spiral Stairs: A very compact design where wedge-shaped treads radiate around a single central pole.
• Curved (Helical) Stairs: Similar to spiral stairs but with a larger radius and no central pole, creating a more elegant “sweeping” effect.
• Winder Stairs: A variation of L-shaped or U-shaped stairs that uses pie-shaped steps instead of a flat landing to turn corners, saving even more floor space.
• Bifurcated (Split) Stairs: A grand design starting with one wide flight that splits into two narrower flights heading in opposite directions from a central landing

Stair Terminolgy

• Tread: The horizontal part of the step that you actually walk on.
• Riser: The vertical portion between each tread.
• Stringer: The structural side or middle members that support the treads and risers.
• Nosing: The edge of the tread that protrudes over the riser below.
• Balustrade: The entire railing system, including the handrail, balusters, and newel posts.
• Baluster (Spindle): The vertical posts that support the handrail.
• Newel Post: The sturdy vertical post at the start, end, or turn of a flight that anchors the handrail.

Balustrading

Even for a timber stair, many a times the balustrading is out steel. The reason being the workability of steel and the strength the steel balustrade provides with smaller sections.

However, the elegance of a high end timber balustrde is hard to match with steel.

We also

Stair Codes for Australian Buildings

1. Residential Stairs (Private)

Governed by NCC Volume Two (Housing Provisions), these rules apply to Class 1 (houses) and Class 10 (non-habitable) buildings

• Risers and Goings:
  • Riser (R): Max 190 mm / Min 115 mm.
  • Going (G): Max 355 mm / Min 240 mm.
  • Slope Relationship: The value of () must be between 550 mm and 700 mm.

• Dimensions
  • Width: There is no mandatory minimum width in the NCC for private residential stairs, though 900 mm is a common industry recommendation for comfort.
  • Headroom: Minimum 2,000 mm measured vertically from the nosing line.

• Flights: Single fligth must have between 2 and 18. Not more than 18 without a landing.
• Safety: Open risers must not allow a 125 mm sphere to pass through. The 125 sphere is considered as the size of the head of a child.

2. Public Access Stairs (Commercial)

Governed by NCC Volume one, these apply to Class 2 to 9 building, such as offices, shops apartment common areas

• Risers and Goings:
  • Riser (R): Max 190 mm / Min 115 mm.
  • Going (G): Max 355 mm / Min 240 mm.
  • Slope Relationship: The value of () must be between 550 mm and 700 mm.

• Flights: Single fligth must have between 2 and 18. Not more than 18 without a landing.
• Safety: Open risers must not allow a 125 mm sphere to pass through. The 125 sphere is considered as the size of the head of a child.

• Dimensions
  • Width: Generally minimum of 1000 between hand rails. Stairs used for required exists may need wider depending upon buildings occupancy.
  • Lower flights cannot be narrower than upper flights
  • Hand rail: Required on both sides if stairway width is more than 1000.
  • Headroom: Minimum 2,000 mm measured vertically from the nosing line.
  • Accessability If stairs are part of accessible path, they must comply with AS 1428.1 which includes specific requirements for tactile ground surface indicators (TGSIs) and handrail extensions.

1. Industrial Stairs

Governed by AS 1657:2018, this standard applies to stairs used for access to plant, machinery, or maintenance areas

• Angle and Slope: ypically between 20° and 45°, with  to  being the preferred range.
• Risers and Goings:
  • Riser (R): Max 225 mm / Min 215 mm.
  • Going (G): Max 355 mm / Min 240 mm.
  • Slope Relationship: The value of () must be between 550 mm and 700 mm.
• Dimensions
  • Width: Generally minimum of 600 between stiles/hand rails
  • Head Room: Minimum 2000 mm, may need to increase if worker wears helmets.
  • Landings: Required at intervals of no more than 18 risers
  • Loading: Must support miniumum of 2.5 kpa