What Is a Fan Filter Unit (FFU)?

A Fan Filter Unit (FFU) is a self-contained air delivery module that combines a fan, a prefilter and a HEPA or ULPA filter in one housing. FFUs are mounted in cleanroom ceilings (or used as standalone laminar-flow units) to supply a controlled, filtered flow of clean air to the workspace below. They are the most flexible way to build ISO 5–8 cleanrooms, especially where ductwork is impractical.

Onecleans manufactures FFUs for cleanrooms, mini-environments and process equipment, with a focus on low noise, high airflow and long filter life.

How an FFU Works

Room air is drawn into the FFU, passes through a prefilter to catch coarse particles, is pressurised by the fan, then pushed through a HEPA or ULPA final filter before entering the cleanroom as a uniform laminar or turbulent flow. A diffuser or screen evens the airflow across the ceiling area.

Our flagship Fan Filter Unit (FFU) is built for cleanroom ceiling grids and stand-alone laminar-flow applications.

Key FFU Specifications

Airflow — typically 500–1,500 m³/h, adjustable via speed control
Final filter — HEPA (H13/H14) or ULPA, matching the cleanroom class
Noise level — low-noise EC/DC motors for comfort and compliance
Housing — galvanised steel, aluminium or stainless steel
Control — manual speed control, or networked/EC motor control for large arrays

Benefits of FFUs

Modular — add or reposition units as your cleanroom grows
No ductwork required — ideal for retrofits and rented facilities
Localised control — tune airflow per zone or per process
Fast commissioning — plug-and-play compared to central AHU systems

Applications

Electronics & semiconductor cleanrooms and mini-environments
Pharmaceutical filling and compounding suites
Biotechnology and biosafety cabinets and isolators
Laboratories, optics assembly and food processing

For a field example, read how we delivered mirror-finished stainless steel FFU frames for a pharmaceutical cleanroom.

How to Choose an FFU

Calculate required airflow from room volume and target air changes per hour.
Select the final filter grade (HEPA vs ULPA) for your ISO class.
Choose housing material for cleanability and corrosion resistance.
Decide on control — manual, EC with speed control, or network control.

Frequently Asked Questions

What is the difference between an FFU and a central AHU?

An FFU is a self-contained ceiling module; an AHU is a central system feeding multiple rooms through ductwork. FFUs are more modular and faster to deploy; AHUs are more efficient for very large facilities.

Can I use an FFU without a cleanroom?

Yes — FFUs are also used as standalone laminar-flow hoods and local clean-air stations above individual processes.

What maintenance does an FFU need?

Regular prefilter replacement, periodic HEPA/ULPA filter replacement, and fan/motor inspection. Filter life depends on usage and ambient air quality.

Request an FFU quote — tell us your airflow and cleanroom class for a matched unit.

Fan Filter Units (FFU): Complete Guide for Cleanroom Air Supply