I, fan equipment, noise reduction target requirements fan used in factories, industrial factories on the fan noise reduction requirements are 8 hours within the factory noise were less than 85. For range hoods or roof ventilation fan, according to the use of environmental area, the second level of commercial offices require less than 50 dB at night, less than 60 dB during the day, the first level of residential hospitals and other areas require less than 45 dB at night, less than 55 dB during the day. Second, fan noise management technology program 1. fan mechanical noise processing: mechanical noise can be dealt with by improving the degree of lubrication between fan parts, assembly precision, replacement of new parts and other measures. 2. fan pneumatic noise processing; inlet and outlet muffler use: fan inlet and outlet noise is generally higher than the other location of more than 10 decibels, so the muffler can be effectively installed in the inlet and outlet to reduce the inlet and outlet of the pneumatic noise generated by the use of the muffler. Therefore, installing mufflers at the inlet and outlet can effectively reduce the pneumatic noise generated by the inlet and outlet. The type of muffler can be impedance composite muffler, and the muffling amount can reach more than 25 decibels. The use of fan soundproof enclosure: soundproof enclosure adopts composite soundproof board as the main body, enclosing a single fan or all fans, and becoming a fan soundproof enclosure or soundproof room. This way of fan noise reduction effect is good, but the site requirements are high. At the same time, the soundproof room should be equipped with soundproof doors and windows, ventilation and heat dissipation system. Fan room renovation:Soundproofing the original fan room, you can change the fan room into a completely soundproof room, or you can use soundproof doors and windows, soundproof walls, soundproof walls and so on. to block and shield the noise, which helps to reduce costs. Treatment of fan piping:Noise will also be generated in the fan piping, including internal airflow impact noise and pipe vibration noise. It can be wrapped with sound-absorbing cotton to isolate the airflow impact noise, and can also be used to isolate the vibration generated by the impact of the damping sound insulation blanket. Equipment vibration damping: fan work will produce local vibration. Treatment measures include laying floating ground on the foundation of the fan or installing a vibration-damping foundation to reduce the vibration of the solid structure of the sound transmission.