Intake side. Downdraft physics are the same in every generation: air enters through a ceiling plenum, passes through diffusion media, and falls as an even column over the vehicle. On the Classic that means a ceiling diffusion fill whose exact panel or pad format needs to come off your booth, because the Classic's ceiling geometry is not carried in the catalog records we cross-reference. A tape measure and a photo of the plenum from inside the cabin are enough to lock it in.

Exhaust side. Overspray leaves through floor-level arrestor media in a downdraft. Fiberglass arrestor is the default recommendation for solvent collision work; polyester arrestor earns its premium where waterborne or high-solids coatings load fiberglass too fast. Which format and quantity the Classic takes in your installation gets confirmed in the same fitment pass as the ceiling.

Why the one-time check pays. Undocumented does not mean unsupportable. The first order carries a confirmation step, cross-referenced against distributor and manufacturer catalogs and verified by the WERCS service team, after which the Classic is as routine to supply as any current booth. What you avoid is a pallet of media cut for the wrong generation.

A Classic-era booth still has to meet current rules. EPA 6H (NESHAP Subpart HHHHHH) does not grandfather old cabins: collision spraying belongs in a ventilated booth fitted with filter technology and maintained per its design, whatever its vintage. OSHA 1910.94(c) holds the ventilation requirement for spray finishing regardless of booth age, and an older booth with tired media is precisely where face velocity quietly drops below what the standard expects. NFPA 33's concern with combustible overspray accumulation also bites harder on older installations, where exhaust plenums may carry decades of deposit history; fresh arrestor media on a real schedule is the cheap half of that control.