Sulphur hexafluoride (SF6) is a good gas insulator widely used in gas insulation of electronic and electrical equipment; Its typical application is used as gas insulation in high voltage switchgear of transmission and conversion plants and power plants in power supply departments. To protect sulfur hexafluoride, we should first understand the physical and chemical properties of sulfur hexafluoride. The pure sulfur hexafluoride has low toxicity and stable properties. However, after inhaling the mixture of 80% sulfur hexafluoride and 20% oxygen for a few minutes, the human body will be deaf and slightly agitated. There is a certain pressure when sulfur hexafluoride gas is loaded into the high voltage cabinet, so that the probability of gas leakage is high, and the oxygen content in the air is sufficient, whereby the conditions for sulfur hexafluoride gas are combined with oxygen to produce toxicity after leakage are sufficient. This is one of the situations that require protection.

When sulfur hexafluoride gas meets high heat and high temperatures (such as arc), it produces by-products sulfur oxide and hydrogen fluoride gas, which coexist with unresolved sulfur hexafluoride gas. At this time, there are three types of toxic gases.

Sulfur oxide is a kind of sulfur anhydride that is easily absorbed by the moist mucous membrane surface of the human body to produce sulfuric acid and sulfur, and has a strong irritating effect on the eyes and mucous membrane of the respiratory tract. The specific symptoms are tears, cough, sore throat, conjunctiva and tingling of the respiratory tract. The sweat of the human body makes the skin red and swollen. Hydrofluoric fluoride, water soluble. Hydrofluoric acid is also easily absorbed by the moist mucous membrane surface of the human body to produce hydrofluoric acid, which is as harmful to the human body as sulfur oxide contact eyes and respiratory tract, but more harmful. Hydrofluoric acid is often used for etching glass, which shows that it is extremely corrosive. When human sweat is encountered, hydrofluoric acid forms on the surface of human skin. It can penetrate the surface of the skin and penetrate into the deep layer, formation of ulcers and necrosis, and should not be cured. If skeletal damage causes fluorosis, it cannot be restored. The toxicity of hydrogen fluoride is worse than that of sulfur oxide and sulfur hexafluoride.