This standard specifies the advanced handrails used on scaffolds with a work floor height of over 2 m and scaffolds used with support. Note: Preliminary handrails are designed to allow workers to work with handrails always in place to prevent them from falling, falling, or falling from the scaffolding. This equipment can be installed in advance and is used when dismantling the top layer of scaffolding, and is also used when working with scaffolding.