I need to have a “childsafe” railing, what does it mean?

A childsafe railing in a staircase should be minimum 900 mm high and not have any vertical openings that are bigger than 100 mm. Also, keep in mind that the railing should not consist of any horizontal parts that entails climbing. If you want a fully childsafe staircase you should not have more than 100 mm opening between the steps.