Intake side. The old style Accudraft runs a filtered ceiling in the classic downdraft arrangement, and the catalog record puts it at 18 to 21 panels of 37x45 media depending on the booth's configuration. Two booths under the same name can carry different ceiling counts, so count your grid before ordering rather than assuming the maximum. Plenum seals and panel frames age too; fresh media in a warped frame still leaks dirt onto the job.

Exhaust side. The exhaust position takes a cube-style overspray filter at 16x25x20. Cube media works by depth loading, holding overspray through the body of the filter rather than only at its face. Cube dimensions are unforgiving: an undersized cube bypasses around its edges and an oversized one will not seat, so the 16x25x20 spec is worth verifying against your frame once, then locking in.

Cycle math. Legacy booths rarely run legacy schedules well. Fans lose curve, ductwork gains resistance, and the original maintenance chart assumed a new machine. Set change intervals by manometer reading across each stage instead of by the old manual, and expect the exhaust cube to cycle faster than the ceiling set under collision-shop volume.

Age does not grandfather a booth out of anything. If the work sprayed inside involves NESHAP 6H target coatings, 40 CFR 63 Subpart HHHHHH applies to a decades-old booth exactly as it does to a new one: filtered exhaust, maintained per documented practice, with records to show it. OSHA 29 CFR 1910.94(c) likewise judges the ventilation as it performs today, not as it performed at commissioning. In practice, older downdrafts pass or fail on maintenance discipline: fresh ceiling media and a correctly seated exhaust cube make a compliant booth; blinded media is an airflow finding waiting to be written up. Keep the change log; on legacy equipment it is often the only documentation trail that exists.