To limit the probability that steps for stairs will be designed with an improper rise dimension [i.e. rise is too high or too low], which could lead to difficulties in movement 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 steps for stairs will be designed with an improper rise dimension [i.e. rise is too high or too low], which could lead to persons tripping or falling, which could lead to harm to persons.