Handrail graspability to be either type i or ii with a minimum 1 1 2 inch clearance from a wall.
Standard stair rise and tread dimensions.
Application this section covers all stairways including standard spiral ship and alternating tread type stairs except for articulated stairs stairs that change pitch due to change in height at the point of attachment such as those serving floating roof tanks stairs on scaffolds stairs designed into machines or equipment and stairs on self propelled motorized equipment.
The tread depth td is to be 185mm and it should not be more than 30mm shorter than the going g.
If the stairs have open risers the open space between the steps cannot be large enough to allow a 4 inch sphere to pass through.
The greatest riser height within a flight of stairs cannot exceed the smallest by more than 3 8 inch.
These dimensions may be useful when laying out a staircase or if you have general questions about the size and shape of a traditional tread or a retro tread.
All risers and all goings in the same flight of stairs shall be of uniform dimensions within a tolerance of 5 mm.
Maximum 12 3 vertical height rise for a flight of stairs.
Standard stair tread dimensions.
Maximum 7 3 4 inch stair riser height.
Stair details refer to the standard requirements for each of the various components of a flight of stairs.
Here is a drawing detailing our standard stair tread and riser dimensions.
Minimum 10 inch stair tread depth with nosing or minimum 11 inches with no nosing.