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Head clearance above a nosing line and width of flights

Simple questions like this crop up surprisingly often, causing architects, builders and designers to reach for the relevent code.
The relevant code is AS 1428.1-2009 Design for access and mobility - General requirements for access - New building work. Often the constraints imposed by the surrounding space mean that designers can be tempted to make these clearances as small as possible, so it's worth while being aware of the minimums specified by the Australian Standards.

  • The minimum head-height (measured with respect to the nosing line) must be at least 2000mm.
  • The width of the the stairway, measured from the inside of handrail to inside of handrail, must be at least 1000mm
  • These measurements are not strictly specified in the stair sections of the code, but because stairs are normally considered one of the fire-egress routes, they fall within its scope.
  • The measurements are primarily applicable to commercial buildings.
Arden recommends that a reasonable tolerance above these absolute minimums are to specified by architects. Obviously, no form of obstruction can be incorporayed anywhere within these bounds in order to comply with code.

Published on: 25-Mar-2011. Topic/s: Stair safety, compliance, and regulations