Learn How FFUs Work and How To Select an Optimal Unit for Your Facility
Fan filter units (FFUs) are the unsung heroes for industries where air purity is essential and contamination can lead to product defects or health hazards. Industries that rely on these systems include healthcare, research laboratories, chip manufacturing, aerospace engineering, pharmaceutical manufacturing, and many others.
When choosing an FFU, your system requirements depend on your industry’s standards. For instance, higher cleanroom classifications demand more units and higher air-change rates to maintain air purity. Facility teams must also consider filter type, airflow rate, customizations, and even the OEMs they’ve chosen to work with.
This guide covers how these commercial air filtration units function, how to choose the right model, and how they can be customized for your facility.
How Fan Filter Units Work
The process begins when the FFU’s internal fan draws air into the unit from the room or a plenum, depending on the design. Air first passes through a pre-filter that captures larger particles and debris. This early stage both improves air quality and protects the primary ULPA or HEPA air filter from overload.
After pre-filtration, air passes through the HEPA or ULPA media, where the vast majority of particles are removed. Designed with precision, HEPA air filters remove 99.99% of particles ≥0.3 μm and ULPA filters capture up to 99.995% of particles ≥0.12 μm. Once filtration has occurred, filtered air exits the FFU in a uniform, low-turbulence (laminar) flow that helps sweep contaminants away from critical work zones and deliver clean air.
Choosing the Right FFU for Your Needs
- Airflow rate and CFM
A common 2 ft. x 4 ft. module at ~100 fpm delivers airflow at ~700 to 800 cubic feet per minute (CFM). Tighter classifications, such as those used in exceptionally stringent industries, call for higher air-change rates, which may require more FFUs or higher-output models. Some high-performance air filtration units deliver 800–1,000+ CFM, supporting demanding applications and higher-resistance filters. - Noise level and energy efficiency
Noise affects comfort and productivity. Electronically commutated (EC) fan filter units can reduce noise significantly, at about ~50 dB at 1 ft. EC-motor FFUs also cut energy consumption when compared with conventional motors. - Motor type
Today’s FFUs often leverage EC motors for their variable speed and higher efficiency, but alternating current (AC) FFUs are also available.
Why FFU Air Filtration Is Essential in Controlled Environments
- Ensuring product safety and compliance
FFUs may support ISO cleanroom benchmarks and Good Manufacturing Practice (GMP) expectations in life sciences, semiconductor manufacturing, aerospace, and more, reducing compliance risks. - Protecting workers from airborne contaminants
Continuous high-efficiency filtration limits exposure to particles in healthcare, labs, and high-sensitivity manufacturing. Effective use of fan filter units meets the American Society of Heating, Refrigerating and Air-Conditioning Engineers’ (ASHRAE) guidance for healthcare facilities, including ASHRAE Standard 170.
- Reducing operational costs with localized filtration
Modular FFUs place clean air exactly where it’s needed and scale to your process, often improving energy use versus conditioning the whole space with centralized systems. For example, a fan filter unit can be installed directly over an operating table in a surgical theater to ensure laminar flow of filtered air precisely where it is needed.
Learn About Types of Fan Filter Units
Facilities that rely on excellent indoor air quality (IAQ) for medical procedures, sensitive manufacturing, and other mission-critical environments understand the value of these commercial air filtration systems for infection prevention, contamination control, and business continuity.
Ceiling-Mounted FFUs
High-efficiency motors and industry-leading CFM outputs make these units a strong fit wherever overhead clean air is required, including:
- Operating rooms.
- Compounding pharmacies.
- Laboratories.
Reverse-flow
Reverse-flow FFUs draw contaminated room air and filter it through a plenum for containment, protecting occupants from hazardous bioaerosols and particles. These are effective for:
- Patient recovery rooms.
- Containment spaces.
Portable FFUs
This compact, mobile version of a ceiling-mounted unit is stackable, storable, and easy to wheel between locations on swivel casters with brakes. These are ideal for:
- Isolation rooms and patient recovery rooms.
- Compounding pharmacies and laboratories.
- Classrooms and commercial offices.
Benchtop & Top-Side-Access FFUs
Two common challenges, ceiling access and repositioning, are solved with benchtop and top-side-access designs. Service filters from the room side for faster changeouts and troubleshooting.
Determine Your Facility’s Needed Air Filtration Customizations
To tailor your estimate and build the best FFUs for your application, consider these options:
Ceiling-mounted FFU customizations
- Filter monitoring & overload indicators
- Networked controls
- Built-in LED lighting
- Antimicrobial finishes
- HEPA or ULPA filters
- Reverse-flow or circulating configurations
What To Look for in an FFU Manufacturer
- Innovation. Select a team that continually pushes the boundaries of fan filter unit performance specifications.
- Expertise. Consider the depth and breadth of the manufacturer’s experience in your industry and other relevant markets.
- Evolution. Determine whether their products are informed by the latest IAQ research, energy-efficiency best practices, and the business case for hazard prevention.
- Trust. Look for a team that delivers work for recognized organizations that expect a high standard of engineering.
Fan Filter Units Deliver Exceptional Air Filtration Results
Fan filter units are critical to achieving and maintaining pristine air quality across cleanrooms and other controlled environments. From airflow performance and noise to filter selection, motor control, and maintenance strategy, the right choices for your commercial air filtration system keep you compliant, protect people and products, and add measurable value.
Our Frequently Asked Questions About Fan Filter Units
Q1. What is a Fan Filter Unit (FFU) and how does it work?
A fan filter unit is a self-contained device that combines a fan, pre-filter, and ULPA/HEPA air filtration to remove airborne particulates. It delivers uniform, laminar flow back into the space.
Q2. What are the benefits of using FFUs in controlled environments?
They support compliance, protect products and occupants, and can lower operating costs through energy efficiency and risk protection.
Q3. How do I choose the right FFU?
Match your particular process needs with characteristics like CFM/velocity, air filtration (HEPA vs. ULPA), motor or control strategy (e.g., constant-flow EC), noise, and service features.
Q4. Are FFUs energy efficient?
Yes, especially with EC motors. Many facilities realize significant energy reductions versus fixed-speed alternatives.