According to the U.S. Occupational Safety and Health Administration, falls are one of the leading causes of death in the construction industry. Although construction workers have a dangerous job to do, OSHA provides employers with information on how to make their jobs safer. Fall protection systems, such as safety railings, offer a way to secure the safety of workers who perform duties in elevated locations.
OSHA says that whenever workers are exposed to a drop of six feet or more, side openings and holes must be blocked off by a guardrail system. Top rails must have a top-edge height of between 39 and 45 inches above the walking or working surface level. An exception to this requirement results when workers use stilts, at which case the top edge height must be increased to meet the equivalent height of the stilts.
If railings are left open, they will not serve much of a purpose. For that reason, OSHA requires railings to be filled in by installing midrails. A midrail, such as a screen, mesh material or other intermediate structures, must be added to the guardrail system when walls are absent or no other surrounding structures are at least 21 inches high. Midrails have to fit from between the walking or working surface up to the top edge. When using screens or mesh, the material must run for the entire length of the rail. If another type of intermediate structure is used, such as a balaster, then the posts must be set 19 inches apart, or less. Gaps that are larger than 19 inches pose a safety hazard.
According to OSHA, a proper railing system is able to withstand 200 pounds of applied force in all directions, and midrails, mesh, screens or intermediate structures have to be strong enough to withstand 150 pounds of applied force in all directions.
Railings can be made out of wood, piping or structural steel. For railings made out of wood, the top and intermediate rails must be comprised of wood that is at least 2-inch by 4-inch. Pipe railings require at least 1 1/2 inches nominal diameter for top and intermediate railings. When constructing railings out of structural steel, top and intermediate rails must be of 2-inch by 2-inch by 3/8-inch angles.
The guardrails themselves must not pose safety hazards to workers. For instance, guardrails must not be jagged or have rough spots or sharp edges that could potentially cause injuries, such as lacerations and punctures. Additionally, the top and midrails are not to protrude out causing a projection hazard.