The safety signs are classified into four categories: prohibition signs, warning signs, instruction signs, and prompt signs, as well as supplementary signs. The geometric figure of the prohibition sign has a slashed ring, in which the ring is connected to the slash, with red; the graphic symbol is black and the background is white. The geometric figures of the warning signs are black regular triangles, black symbols and yellow background. The geometry of the instruction sign is round, blue background, white graphic symbol.

Hazard and warning signs should be set far enough in front of the hazard source to ensure that the observer has sufficient time when the sign is first seen and noticed the danger, and this distance varies with different circumstances.

Requirements for the use of safety signs:

1. In order to effectively play the role of the sign, it should be checked regularly, cleaned regularly, and it is found that there are deformation, damage, discoloration, falling off graphic symbols, and brightness aging, etc. The safety management department should do a good job of supervision and inspection, find problems and correct them in time.

2. It is necessary to regularly publicize the procedures for the use of safety signs to the staff, especially those who need to abide by preventive measures.