When selecting, pay attention to key operational reference numbers, typically including temperature during work, wind size, etc. Ensure it can operate normally for a long period under the condition that the medium temperature is below 85℃. It should also comply with existing relevant standards. For the pressure values of the pressure control equipment in the smoke prevention and exhaust system of fresh air exchange machine manufacturers, the statistical analysis should be conducted according to the method of the circuit without the system's use. Additionally, the pressure value in the stairwell of the smoke prevention and exhaust system should be between 40~50Pa.