Final answer:
Open-sided floors or platforms that are 4 feet or above the adjacent floor must have standard railings on all open sides, excluding entrances for ramps, stairways, or ladders.
Step-by-step explanation:
The requirement for guarding open-sided floors or platforms is that they must be guarded by a standard railing on all open sides if they are 4 feet or more above the adjacent floor or ground level. The only exception to this rule is where there is an entrance to a ramp, stairway, or ladder. In such cases, the open side with the entrance would not require a railing. This is to ensure the safety of workers by preventing falls from elevated work areas, which is an important hazard addressed by the Occupational Safety and Health Administration (OSHA) standards.