Parapet height, infill openings and handrail details are usually set by local regulations and the owner's requirements. Screens over railways or highways may have additional rules. Agreeing these details early avoids late changes to the main structure.
Final member sizes, details and specifications are determined by the engineer of record for each project. This page describes general practice and does not replace project-specific engineering.
This content is general technical information. It does not replace project-specific structural design, which must be carried out or approved by a qualified engineer under the applicable codes and the requirements of the authority having jurisdiction.