A：
①First determine the location of the outlet, and then determine the location of the return air outlet.
②The height of return air outlet ≤ (+50cm above the ground) is preferred.
③The wind speed at return air outlet ≤3m/s is preferred.
④In addition to setup of return air outlet beneath appropriate wall surface in large-are clean room, setup of return air column in middle part of the plane is recommended to improve the imperfection of poor return air in middle area.
⑤Setup of adjusting damper on the riser of each return air outlet close to the ceiling is recommended for use during trial run. Note: If adjusting damper is located on return air outlet, when the damper is closed to a smaller opening, annoying 「gasp！gasp！」 noise will sound from return air outlet next to AHU.