... assemble,2 unit steel reinforcements,4 units cross beamsIntake& exhaust systemIntake system1 set, with quadrate steel frameDouble layer ... wool panel to reduce noise.Intake fansQuantity- 2 sets fans, each fan- 5.5KW double intake centrifugal fan, ... for intake systemPre filter,high efficiency ceiling filterFilter for exhaust systemFiber glass filter,activated carbon filter for environmental ...