[preventive measures against thing-like crashes]
A. I establish a strong work floor having strength fixed to a building, facilities permanently
B. I lay stairs (more than handrail 900mm in height) for the going up and down to be able to go to the work floor for
C. On the work floor, I prevent the crashes such as the walls such as walls with the strength or the fence (less than crosspiece gap 300mm more than 1,100mm in height)