To limit the probability that the variations in the height of step risers will be excessively high, which could lead to difficulties in moving in an emergency situation, which could lead to delays in the evacuation or movement of persons to a safe place, which could lead to harm to persons.
To limit the probability that the variations in the height of step risers will be excessively high, which could lead to persons tripping or falling, which could lead to harm to persons.
To supersede the requirements of Sentence 3.3.1.14.(1), which would otherwise require stair riser height variations to conform to Section 3.4. for exit stairways [specifically Sentence 3.4.6.8.(4)].