Spray painting puts solvent vapour and atomised paint droplets in the air. The exhaust fan moves them through the filter bank — paint stop, cardboard, activated carbon — and out, while holding the booth cross-section velocity in the 0.3–0.6 m/s band that keeps overspray on the workpiece, not on the operator. ATEX Zone 2 by default for solvent vapour; Zone 22 for powder-coat combustible dust. We build them for automotive, engineering, furniture, appliance and aerospace paint shops.
A sample of units we've engineered, built and dispatched — each to a customer's duty point. Customer names and identifying marks are withheld. Click any photo to enlarge.
A paint-booth exhaust fan sits at the booth wall: pulling solvent-laden air off the workpiece, holding the booth under slight negative pressure, and pushing it through the filter bank (paint stop, cardboard, activated carbon) to the stack — all in a flammable atmosphere.
Enough air to hold booth cross-section velocity in the 0.3–0.6 m/s band that captures overspray — higher, 0.5–1.0 m/s, for powder coat.
Through the whole filter-train resistance — paint stops, cardboard, activated carbon, ducting — which loads progressively from clean to dirty and can reach 1,200 mmWC.
The atmosphere itself — solvent vapour (ATEX Zone 2) and sticky atomised paint, sometimes combustible powder (Zone 22), at ambient to 60 °C.
Flammable vapour + sticky overspray + filters that load as they fill drive the three things that destroy paint-booth fans. Design for them, and the fan holds rated velocity and stays safe between wash-downs. Design only for free-air flow, and overspray buildup throws the rotor out of balance within weeks.
Solvent vapour evaporates off the workpiece during application and flash-off, so the fan runs in an explosive atmosphere. A ferrous-on-ferrous spark or a hot surface above the solvent auto-ignition point ignites it.
How we engineer it outATEX Zone 2 configuration: aluminium (non-sparking) impeller, bronze rub rings, bonded earthing across the assembly, anti-static coatings and a T3 temperature class (max surface 200 °C) — Ex II 3G, self-declared per 2014/34/EU.
Fine paint droplets pass the in-booth paint stops and cardboard, then accumulate on the impeller blade. Over weeks the film builds, throws the rotor out of balance and corrodes the metal underneath.
How we engineer it outRadial-tipped self-cleaning impeller geometry, anti-stick PTFE-based coatings on impeller and casing interior, and gasketed access doors at the volute throat and wheel-cover for routine wash-down — typically a weekly schedule.
Booth capture depends on a fixed face velocity. As paint stops, cardboard and carbon fill, system resistance climbs — and a fixed-curve fan loses flow, so overspray drifts onto the operator instead of the workpiece.
How we engineer it outSized to hold rated velocity at 100% filter loading, with VFD speed control as standard on new installations so the fan ramps up as the filters fill rather than coasting down.
We don't sell a catalogue near-fit. The fan is engineered to your booth chemistry, ATEX class, target velocity and filter-train resistance.
No catalogue fan forced onto your booth. Your operating point — rated velocity against a fully loaded filter train — is engineered onto the best-efficiency region of the selected wheel, then verified on the 200 HP VFD test rig before dispatch.
| Parameter | Standard | On application |
|---|---|---|
| Volume flow | 10,000–1,00,000 CMH | up to 2,25,000 CMH for large automotive multi-zone booths |
| Static pressure | 200–800 mmWC | up to 1,200 mmWC for high-resistance filter + carbon banks |
| Operating temperature | ambient to 60 °C (bake-oven downstream excluded) | up to 80 °C |
| ATEX classification | Zone 2 (Cat 3G) self-declared for solvent service; Zone 22 (Cat 3D) for powder coat | — |
| Drive power | up to 150 HP | up to 250 HP for large multi-zone systems |
| Speed | 600–1,800 RPM typical | per duty + sound limits |
| Balance quality | ISO 21940 G6.3 | G2.5 / G1.0 on application |
| Bearing life (design target) | L10h ≥ 40,000 h continuous | longer L10 on application |
The envelope above covers the great majority of paint-booth exhaust duty. For duty beyond it, we engineer to spec and quote on enquiry. Booth face velocity is set by your booth design — typically 0.3–0.6 m/s for solvent paint and 0.5–1.0 m/s for powder coat — and the fan is sized to hold it at 100% filter loading, not just clean.
The same engineering language carries from your enquiry to the GA drawing to the nameplate — expressed in the standard AMCA conventions, with the ATEX marking alongside.
| Specification field | Options |
|---|---|
| Arrangement (AMCA 99) | Arr. 1 (overhung, fan bearings) / Arr. 4 (direct, motor on base) / Arr. 8 (overhung on common base) / Arr. 9 (overhung, motor side) / Arr. 10 (overhung, motor inside base) — selected by drive, access and ATEX motor location. |
| Width / inlet | SWSI (single width, single inlet) default for paint-booth exhaust; DWDI (double width, double inlet) for high flow on large multi-zone booths. |
| Wheel type | Radial-tipped self-cleaning (default, overspray-tolerant) / backward-curved (clean after-filter, post-carbon, high-efficiency duty only). |
| ATEX marking | Ex II 3G (gas — solvent vapour, Zone 2) standard; Ex II 3D (dust — powder coat, Zone 22) added for powder lines; T3 temperature class (max surface 200 °C); Module A self-declaration per 2014/34/EU. |
| Materials of construction | Aluminium non-sparking impeller (ATEX, per booth chemistry) / 304 SS casing with epoxy exterior (solvent-only) / 316L SS for water-wash-down booths / PTFE anti-stick coatings on impeller and casing interior. |
| Drive | Direct-coupled / V-belt / VFD (default for velocity control as filters load). ATEX-rated motor (Ex e or Ex nA) from a CE-marked manufacturer. Drive up to 150 HP standard; speed typically 600-1,800 RPM. |
| Discharge & rotation (AMCA orientation) | Rotation CW or CCW (viewed from drive side) with discharge angle per AMCA — e.g. TH/BH/UB/DB — set to match your booth take-off, stack run and installed footprint. |
| Accessories & ATEX scope | VFD velocity control; bronze rub rings and bonded earthing; anti-static coatings (resistivity <10^9 ohm-sq, <10^8 ohm-sq for powder dust); gasketed wash-down access doors at volute throat and wheel-cover; mounting flange + transition to the booth filter bank; acoustic enclosure for <75 dB(A) on application. |
Every job's performance is verified at our works on the 200 HP VFD test rig, to the IS 4894 / ISO 5801 / AMCA 210 method, before dispatch.
Assembly-plant paint booths (basecoat, clearcoat, anti-chip), touch-up booths, body-shop spray booths.
Tier-1 / Tier-2 supplier paint lines for plastic trim, metal stampings, engine components.
Fan, pump, valve and motor-enclosure paint operations.
Spray-finish booths for wood furniture, cabinetry and kitchenware — often water-based, still ATEX-classified.
Refrigerator, washing-machine, water-heater and air-conditioner paint booths.
Aircraft component painting — small batch, high precision, demanding finish.
Powder-coat lines for aluminium extrusions, steel windows, fences and gates.
45 application/duty types engineered. Tell us yours.
What our marks mean, in the words that survive an audit.
Tested to the IS 4894 / ISO 5801 / AMCA 210 method, in-house on our 200 HP VFD rig. Tested-to-method — not AMCA-certified.
ISO 9001:2015 — third-party certified. Our only third-party certification.
Self-declared per 2006/42/EC + 2014/35/EU. A self-declaration, not a notified-body certificate.
Self-declared, Zone 2/22, Category 3, per 2014/34/EU, where the area classification calls for it.
Designed and built to API 673 as project-specific scope.
ASME Sec IX qualified welders + WPS for every joint.
ISO 21940 — G6.3 minimum, G2.5 / G1.0 on application.
ISO 14694 fan-specific limits; ISO 20816 general evaluation method.
| Stage | Standard duty | CE / ATEX / API / AMCA |
|---|---|---|
| Offer / quotation | 3 working days | 5 to 7 working days |
| GA drawing for approval | 3 days from customer PO | 5 to 7 days from customer PO |
| Manufacture + balance + paint | 2 to 3 weeks from PO + PI + approved GAD | 4 to 5 weeks from PO + PI + approved GAD |
| Performance test + witnessed FAT | ~1 week | ~1 week |
| Order-to-dispatch (total) | 4 to 6 weeks | 7 – 9 weeks |
Shutdown-driven replacements: we have shipped fans within 3 weeks of a clean PO. Tell us your shutdown window and we commit to a dated plan.
The same engineering, viewed three ways — by fan family, by duty, and by industry. Follow the cross-references.
You do not need us to get to a first number. Booth extract volume is the open face area times the velocity you have to hold across it — that is the whole sum.
Figures in m³/h. The face velocity is yours, not ours — it is set by the coating process and by whatever local rule applies to your plant. The 0.3–0.6 m/s band above is what we see in practice; specify your own and the arithmetic is unchanged.
Flow is the easy term. The static is where booth fans are undersized, because the filter bank does not stay where it started: a clean-to-dirty run through paint arrestor, bag or carbon and the ducting can reach 1,200 mmWC. Size the fan on the dirty figure, not the clean one — a fan selected on clean filters holds its face velocity for a fortnight and then quietly stops capturing overspray, which is the failure nobody notices until the finish does.
Send us the two numbers — opening size and the velocity you must hold — and we will come back with the fan, the motor and the static it is selected against. Or send the flow you just calculated; it is the same conversation one step further on.
Flow, static, gas temperature, application — or attach a spec, GA drawing or a multi-fan schedule. Engineer to engineer.
ISO 9001:2015 quality system · performance-tested to IS 4894 / ISO 5801 / AMCA 210 method · witnessed FAT on request, at no cost.
*For our standard range, additional days required for special projects
