Technical Booklet H Stairs Ramps Guarding and Protection from Impact·Page 23·3.7
Rise measurement on sloping landings
Where a landing slopes across the width of the flight, the step rise must be measured at the midpoint of the flight width.
Where the landing of a stair is formed by the ground and slopes across the width of the flight, then the rise of the step should be measured at the mid-point of the width of the flight. See paragraph 3.11.
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