Technical Booklet H Stairs Ramps Guarding and Protection from Impact·Page 27·3.14
Construction of steps in private stairs with open rises
Private stairs with open rises must have treads that overlap by at least 16 mm, and the stair must be constructed so that a 100 mm diameter sphere cannot pass through the open rises.
A private stair may have steps with open rises, but the treads should then overlap each other by at least 16 mm. See Diagram 1.1.
A private stair which has open rises, should be constructed so that a 100 mm diameter sphere cannot pass through the open rises.
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