A cleanroom does not achieve its required particle condition because one HEPA filter has a high efficiency rating. The entire air path must control contamination, pressure, airflow distribution and filter integrity from the AHU to the room.
Coordinate primary pre-filters (CG, CCB, CY, CNL, CJS), medium-efficiency filters (ZF bag 600mm, ZZH V-bank 295mm, ZDZ mini-pleat), scan-tested HEPA/ULPA filters, GFK passive supply diffusers (500–3,000 m³/h), GCFK ultra-thin 150mm terminals, distributed FFU fan filter units (900 m³/h, ≤54 dB(A)), and pressure relief dampers.
Omitting medium-efficiency filtration dumps coarse dust directly onto expensive terminal HEPA filters, rapidly consuming pressure budget.
Selecting the central fan based only on clean-filter resistance results in starved room airflow as dust loads the filter bank.
Installing passive HEPA boxes without sufficient AHU static pressure, or installing FFUs where central ducted pressure was already available.
Unsealed terminal housing joints, damaged gel seals, or negative room pressure pulling untreated air through wall/ceiling penetrations.
Stops coarse dust, lint, and large particles at the AHU fresh-air intake. Available in washable synthetic media, metal mesh, disposable pleated panels, and compact cartridge formats. Protects downstream medium and HEPA stages from rapid loading.
The critical intermediate filtration stage. Includes ZF5–ZF9 synthetic bag filters (600 mm depth), ZZH compact V-bank filters (295 mm depth for tight AHUs), ZDZ mini-pleat panels, and ZYG separator box filters, capturing 1–10 µm dust before it reaches terminal HEPA stages.
Final high-efficiency particle barrier. Scan-tested individually for pinhole leaks and frame-seal integrity per EN 1822 / ISO 29463. Available with polyurethane seamless endless gaskets, liquid gel seals for knife-edge grids, and mini-pleat fiberglass media.
Passive ceiling-mounted HEPA terminal housing (500–3,000 m³/h). Relies on central AHU fan pressure. Available in casing depths of 69, 80, 150, and 220 mm; fabricated from cold-rolled steel (powder coated), galvanized, stainless steel (-S), or aluzinc (-AZ) with top or side inlet connections.
Low-profile HEPA diffuser engineered for shallow ceiling voids (150 mm overall depth). GCFK-6 (610×610 mm, 600 m³/h), GCFK-9 (915×610 mm, 900 m³/h), and GCFK-12 (1220×610 mm, 1,200 m³/h) with ≤120 Pa initial DP and ≥99.99% MPPS efficiency (max 80 °C / 80% RH).
Integrates an internal backward-curved fan and H14 HEPA filter into one modular ceiling unit. Delivers 900 m³/h airflow, ≤54 dB(A) sound level, ≥99.99% @ 0.3 µm efficiency, ~180 VA power consumption on single-phase AC 220 V 50 Hz. Enables distributed fan power without high-pressure central ductwork.
Counterweighted residual-pressure relief valves maintain positive room pressure by relieving excess air at set ΔP. YFVAV-S-T100 pressure-independent terminals (Ø125–Ø400, 122–6,232 m³/h) and YF-MOA plenums provide variable airflow control where cleanroom designs require dynamic zoning.
| Selection Question | GFK / GCFK Passive Terminal | FFU Fan Filter Unit |
|---|---|---|
| Fan location | Central AHU / upstream plant room | Integrated local fan at ceiling module |
| Main pressure source | Central AHU fan carries terminal resistance | Local FFU fan plus room return air path |
| Ceiling electrical load | Primarily controls / BMS sensors only | Individual fan power required at every module |
| Central duct pressure | Must carry full terminal HEPA resistance (~250–500 Pa) | Ductwork operates at low/neutral pressure |
| Maintenance scope | Filter replacement & terminal housing wipe-down | Fan motor, speed control & filter servicing |
| Best first use case | Ducted cleanrooms with central plant air handlers | Large modular ceiling grids & flexible cleanrooms |
| Key sizing input | Airflow (m³/h) + available central static pressure | Airflow (m³/h) + ceiling coverage % + power |
Define ISO 14644 target class, room dimensions (L×W×H), and calculated air changes per hour (ACH).
Select Passive GFK/GCFK (central AHU static pressure) or Distributed FFU (fan-powered ceiling).
Choose G4 pre-filter, F7/F8 medium bags/V-banks, and H14/U15 terminal HEPA filter elements.
Define positive/negative room pressure differentials and size residual-pressure relief dampers.
YONGFAN cleanroom engineers will verify filter face velocities, calculate loaded-system pressure drops, model ceiling grid coverage, and supply scan-test certificates.
Every H13–U16 filter is individual scan-tested with automated probe arrays to verify zero media or frame leaks per EN 1822.
GFK and GCFK diffuser housings are leakage-tested to ensure zero bypass between duct connection and ceiling grid.
FFU fan assemblies are bench-tested for 900 m³/h airflow, ≤54 dB(A) noise level, and dynamic impeller balance.
Filters and cleanroom terminals are double-polyethylene sealed in a Class 100 environment before crating.
No. The filter removes particles from the air passing through it. Final room performance also depends on airflow volume, ACH, terminal sealing, room leakage, airflow pattern, and commissioning.
They capture coarse dust and sub-micron particles before they reach the high-efficiency terminal filter, extending expensive HEPA life and saving fan static pressure.
GFK is a passive HEPA diffuser box that relies on upstream AHU fan pressure. FFU integrates its own fan and HEPA filter into the ceiling module.
Use GCFK when ceiling void clearance is very tight. It has an ultra-thin 150 mm depth and delivers 600 to 1,200 m³/h at ≤120 Pa initial resistance.
The standard FFU module delivers 900 m³/h airflow with noise ≤54 dB(A) and ≥99.99% efficiency at 0.3 µm on AC 220 V 50 Hz.
Yes, where variable zone airflow is needed and the room pressure control sequence is specifically engineered to maintain positive pressure under all part-load conditions.
By supplying more treated air than is exhausted/returned plus room leakage. A counterweighted residual-pressure relief damper relieves excess air to maintain the set ΔP.
Only if your process has Airborne Molecular Contamination (AMC) risks from corrosive gases or VOCs. Particulate HEPA filters do not remove molecular gases.
No. Rated airflow, initial DP, dirty DP budget, face velocity, dimensions, sealing method (gel vs gasket), and AHU fan pressure all matter.
Monitor differential pressure across each filter stage. Replace pre-filters at 2× initial DP, medium filters per schedule, and HEPA filters before fan static limits are reached.
A YONGFAN HEPA filter, GFK, GCFK, or FFU does not independently guarantee an ISO 14644 cleanroom class without full room qualification.
GFK is a passive diffuser requiring external AHU pressure; do not specify GFK where localized ceiling fan power is required.
HEPA and ULPA filters capture suspended particles only; specify gas-phase chemical filtration where molecular gases must be removed.
Factory scan testing certifies the filter; on-site aerosol challenge testing (DOP/PAO) is required after installation to verify ceiling grid integrity.
Send your cleanroom dimensions, target cleanliness class, available ceiling void height, and AHU static pressure. YONGFAN application engineers will verify filter stages, size GFK/FFU ceiling grids, and supply certified submittals.
