Stair Regulations for Commercial Buildings
13 Sept 2022 Shane Barker, Business Development Manager
If you’re building a commercial structure with a mezzanine, or a steel structure that has two distinct levels, you’ll obviously need stairs to travel from one level to another.
When it comes to including stairs in your commercial building design, there are several regulations that you’ll need to adhere to as per the National Construction Code. Stairs present a real risk of slips, trips and falls, potentially leading to serious injuries. To combat this, stairs need to be well-designed and compliant with the Code.
Here, Shane offers some tips on requirements for stairs in commercial buildings.
CONTENTS
Commercial Stairs: Regulations
THE BRIEF
- Stairs in commercial buildings are subject to Building Code requirements and must be slip-resistant with suitable handrails and landings
- Your stairs need to have specific dimensional geometry to meet the Code
- Having your commercial structure designed by a qualified structural engineer or architect is the best way to ensure your project is compliant
What Does the Building Code Say?
The NCC stipulates that buildings take into account compliant and safe stairway design. This means that the stairway needs to be slip-resistant, highly visible, have suitable handrails and landings, and have correct dimensional geometry.
- The NCC requires a flight of stairs to include no more than 18 risers
- Risers should be constant throughout a single flight of stairs, meaning the dimensions shouldn’t vary more than a few mm
- Risers shouldn’t have any openings bigger than 125 mm in diameter
- Treads should be slip-resistant when tested in accordance with AS4586 or have a slip-resistant nosing strip
- If the stairway is more than 10m high the treads should be solid and not made from metal mesh or a similar perforated material
- Each riser must measure between 130mm and 225mm
- Each going must measure between 215mm and 355mm
- The angle of stairways should be between 20 and 45 degrees to the horizontal tread. It is recommended the angle be between 30 and 38 degrees.
Nosings, Goings, Commercial Stair Treads and Risers
It helps to understand the different terminology used for stairways when designing stairs in a commercial building.
What is a Riser?
The riser is the measurement between the surface of one tread and the next step up. It is the vertical distance between two stairs.
What is a Tread?
As the name suggests, the tread is the flat horizontal space you step on, however in construction, the tread is considered more of a surface treatment, whereas the going is a dimensional measurement. Treads should extend across the full width of the stairway.
What is a Going?
Different to a tread (the flat surface that you step on), the going of each step is the distance measured from one nosing to the next.
What is a Nosing?
Nosing is the protruding ‘lip’ of a tread that hangs over the top of a riser. Not all stairs have nosing. Nosings should be slip-resistant and made of contrasting material so they are easy to see.
Flights and Landings
Commercial stair landing requirements are another consideration: a single flight of stairs should have a minimum of two risers and a maximum of 18 risers, with any adjacent flights connected by a landing. Landings should be at least the width of the stairway and allow a standing space of at least 600 mm that is clear from cross-traffic or door swings.
Handrails
Each stairway should have at least one handrail, and any stairway wider than 1 metre should have a handrail on each side. Handrails should be positioned between 900mm and 1100mm above the floor or the nosing of a stair tread and provide continuous movement of your hand on the upper surface along the length of the handrail.
Ensure Your Stairs Are Designed Safely with Steelcorp
This information is prepared as a guide only and there are several other factors to take into account when designing stairways. The best way to ensure your stairs are compliant is to consult the Building Code and have your commercial structure designed by a qualified structural engineer or architect.
Steelcorp can offer advice and support in designing a compliant structure – get in touch with us for more information.
