Nowadays, laboratory hoods are among the most important equipments suitable for laboratory locations, which disinfect the air flow without any fine and suspended particles with the help of suction system, and always protect the laboratory environment, operators and laboratory personnel against Factors such as acid vapors, microbial and chemical agents, and so on. At present, these hoods are offered in different types of chemical hoods, microbial hoods (laminar) as well as arm hoods. In this article, we try to examine the difference between microbial hoods and chemical hoods, as well as the difference between laminar and microbial hoods. Chemical hoods are one of the laboratory equipments suitable for chemical environments that transfer gases and vapors caused by the use of chemicals and solvents to the outside space. In fact, these hoods prevent the entry of toxic and polluted vapors due to their chamber. They are taken to the laboratory environment and the evaporated vapors and gases are directed to the outside environment through implanted channels and a centrifuge fan.