1. Toxic gases: Some gases are toxic, such as ammonia, hydrogen sulfide and hydrogen cyanide. These gases will cause harm to human body at high concentration, including respiratory system damage, poisoning and even death. Therefore, when operating these gases, they must be operated in a fume hood to protect the operator from toxic gases.
2. Combustible gas: Some substances in gas, such as methane, propane and hydrogen, are combustible. They form a flammable gas mixture in the air, and once they reach the flammable limit, they may explode or catch fire when they encounter a fire source. Operating in a fume hood can reduce the invasion of fire sources and reduce the risk of fire or explosion.
3. Corrosive gases: Some gases are very corrosive, such as chlorine and fluorine. These gases will corrode metals, damage equipment and cause serious harm to human skin and respiratory tract. Operating in a fume hood can reduce the corrosive effects of these gases on equipment and personnel.
4. Radioactive gas: Radioactive gas, such as radon, has radioactive radiation and is harmful to human tissues and cells. Operating in a fume hood can limit the diffusion of radioactive gas, reduce radiation exposure and protect the health of operators.
5. Unstable gas: Some gases will become unstable under certain conditions, such as hydrogen peroxide and hydrogen chloride. Under certain conditions, they may decompose or produce other dangerous substances. Operating in a fume hood can control environmental conditions and reduce the risk of unstable gas decomposition.
6. Volatile organic compounds (VOCs): VOCs are a class of volatile organic compounds, including various solvents and chemicals. These compounds volatilize in the air, which may cause harm to health, and may also react with other gases or chemicals to produce toxic substances. Operating in a fume hood can effectively control the volatilization of these compounds and reduce their harm to the environment and people.