The vertical column. Everything about downdraft filtration follows from the air column. Clean, heated air enters through the full-ceiling media, washes down over the vehicle, and carries overspray into floor-level exhaust arrestor. If either end of that column is starved (a blinded ceiling blanket or a loaded exhaust pad), velocity drops, the column breaks up, and you get the classic complaints: dust in finish, fog hanging at bumper height, doors hard to open.

Ceiling stage. The 9 Series ceiling runs diffusion media whose job is fine filtration plus even air distribution. Since the dossier for this model does not record ceiling dimensions or panel counts, we hold ceiling sizes for a fitment confirmation: one measured panel or a clear grid photo is enough to lock the record for all future orders.

Exhaust and AMU stages. Floor exhaust takes fiberglass or polyester arrestor sized to the pit or grid layout, chosen by the coatings you spray and how fast you want to be changing pads. Ahead of the fan and heat source, AMU pre-filter media keeps shop dust out of the air handling package. Cycle math worth internalizing: exhaust arrestor turns over fastest, ceiling media slowest, and the pre-filter rides in between, so a single "change everything together" habit wastes money on one stage and starves another.

A 9 Series spraying automotive refinish coatings almost always sits under EPA 6H (NESHAP Subpart HHHHHH), which obligates filtered exhaust and maintenance records regardless of how premium the booth is. OSHA 1910.94(c) sets the ventilation baseline for spray finishing, and it is enforced against measured performance, so filter neglect can turn a compliant booth into a citation. NFPA 33 adds the fire marshal's view: accumulated overspray in exhaust media is combustible loading, and a dated change log is the cheapest evidence of control you can hold during an inspection.