How many openings are allowed on each side of the horizontal guardrailing?

The correct number of openings allowed on each side of the horizontal guardrailing is one. This is primarily for safety reasons, as having a single opening helps ensure that the structural integrity of the guardrail is maintained while still providing necessary access for maintenance or inspection of the equipment or area it protects.

Having only one opening also minimizes the risk of accidents, as multiple openings can lead to confusion and may increase the chances of individuals inadvertently falling or accessing restricted areas. The design of guardrailing systems aims to provide adequate protection while balancing accessibility, and one opening is considered sufficient in most regulatory frameworks.

Other options suggesting two or more openings would compromise the safety function of the guardrail by creating additional potential hazards, so they do not align with standard safety practices and regulations concerning guardrailing systems.