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Rohner · Downdraft

Rohner Full Downdraft

Filter kit, alternatives, and current pricing for the Full Downdraft.

Rohner model • Full Downdraft

Rohner Full Downdraft Filter Fitments

This is Rohner's large-format liquid booth for work that will not fit in a collision bay: equipment frames, truck bodies, structural weldments, oversized fabrications. At 48 feet of representative depth (17'4" x 19'2" x 48'5" outside), the booth is closer to a building than an appliance. A full-downdraft layout at this size means a very large ceiling media area and an equally serious floor exhaust bank, which is why filter planning on these booths is a budget line, not an afterthought.

Quick answer

Air in a Rohner Full Downdraft moves one way: down. Filtered supply air enters through a full-ceiling plenum, washes vertically over the workpiece, and exits through floor-level exhaust media. Rohner builds this as a 16-variant industrial family, from 14' x 10' x 26' up to 20' x 16' x 60' working chambers, spanning roughly 18,200 to 60,000 CFM on 5 to 10 HP fan packages; the representative IDD-16-16-48 runs 38,400 CFM. The filter program is two big consumable surfaces: ceiling diffusion media on the intake and arrestor media at the floor. Sizes vary by variant, so confirm your configuration through a fitment check before setting up recurring orders.

By BoothFilterPro Editorial · Filter Fitment Desk · Updated Jul 15, 2026
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How Full Downdraft shops choose filters

Intake side. The ceiling plenum carries diffusion media across essentially the whole footprint of the working chamber, and on a booth up to 60 feet deep that is a lot of square footage. The ceiling media does two jobs at once: final-stage filtration of supply air so dirt never reaches the wet finish, and even diffusion so the downward air column stays laminar instead of streaking. Degraded or sagging ceiling media shows up directly as dirt-in-paint and uneven flow.

Exhaust side. Floor-level exhaust media catches overspray before the fan and stack. On a family spanning 18,200 to 60,000 CFM, exhaust media area scales with the variant, and the loading rate scales with spray volume. Fiberglass and polyester arrestor styles both serve here; the right choice depends on your coating solids and change-cycle preference, which a quote conversation settles quickly.

Cycle math. The two stages age at different rates and should never be forced onto one calendar. Exhaust arrestor loads with overspray in proportion to what you spray; ceiling media ages with total airflow hours and ambient dust. Run manometer readings across both banks and change on pressure rise.

Regulatory landscape

Liquid spray application in this booth carries the standard federal stack. If you spray coatings containing NESHAP 6H target HAPs, 40 CFR 63 Subpart HHHHHH requires spraying in a filtered booth, maintaining that filtration per manufacturer guidance, and keeping records that demonstrate it. OSHA 29 CFR 1910.94(c) governs the ventilation itself, including maintained airflow and clean, unobstructed exhaust media. NFPA 33 treats heavily loaded exhaust media as accumulated combustible residue. On a booth moving up to 60,000 CFM, neglected filters are not a paperwork problem first; they are a fan-load and fire-load problem.

Who runs the Full Downdraft

Heavy equipment manufacturers and refurbishers are the core population: ag machinery, construction attachments, trailers, and truck bodies that need the finish quality of downdraft airflow at industrial dimensions. Second, large fabrication shops that finish structural steel and weldments in-house rather than sending them out, where the booth runs long single-color sessions and floor media loads fast. Third, fleet and transit operations repainting full vehicles, where the long-chamber variants earn their depth. All three tend to buy filters by the pallet, which makes upfront fitment verification worth the five minutes it takes.

Full Downdraft filter FAQs

Why do downdraft booths hold the finish-quality reputation over crossdraft?

Because the air column moves down past the part instead of along it. Overspray and airborne dirt get pulled toward the floor immediately rather than traveling the length of the booth across freshly painted surfaces. The cost of that pattern is more filter area.

Which Rohner Full Downdraft variant do I have, and does it change my filter order?

It changes it substantially. The family runs 16 variants from 14' x 10' x 26' to 20' x 16' x 60', and ceiling and floor media quantities scale with the footprint. Check the nameplate or measure the working chamber, then run it through a fitment check so panel counts and sizes match your actual plenum layout.

Should ceiling and floor filters change on the same schedule?

No. Floor exhaust media loads with overspray, so spray volume sets its pace. Ceiling media degrades with total airflow hours and inbound dust regardless of how much you spray. Track differential pressure on each bank separately; pairing them on one schedule wastes one stage or overruns the other.

What does a loaded floor filter bank do to a booth this size?

It chokes the fan. As floor media plugs, static pressure rises, airflow drops, and the downward air wash weakens, which shows up as overspray hanging in the chamber and settling back onto parts. Pressure creep costs airflow, finish quality, and motor life together.

Your fitment data for this model says needs verification. What does that mean for my order?

It means our record is built from Rohner's published specification table rather than a field-measured install, so we confirm before you commit. Send booth dimensions or nameplate data with your quote request; the WERCS service team cross-checks it against distributor and manufacturer catalogs, and your first confirmed order locks the fitment.

Sources

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