Fan Filter Unit

Self-ventilating units that generate the unidirectional ceiling flow: they draw from the plenum, filter with an high-efficiency filter and deliver air into the room at uniform velocity. They are the technical heart of cleanrooms, softwall and hardwall, and the number fitted decides the class.

  • Filtration HEPA H14 or ULPA U15 — 99.995 % at the MPPS or 99.9995 % at the MPPS: below ISO 5 the first is no longer enough
  • Electronically commutated motor — reduced consumption and the ability to compensate for the drop in airflow as the filter gets dirty, instead of suffering it
  • Three catalogue modules: three units with nominal airflows of 330, 570 and 1,150 m³/h. The choice depends on the available footprint, integration in the ceiling and the required airflow
  • Single or centralised control — continuously variable speed, driven via BUS, with the management software that monitors every single unit
Request a quote See the three models
Section · modular ceiling Plenum above, diffusion grille below
Each unit draws air from the plenum above the ceiling, pushes it through its own filter pack and delivers it into the room through the diffusion grille. Placing them side by side turns island flow into unidirectional flow across the whole floor plan.
  • 3Configurations
  • H14 · U15Filter classes
  • 330–1,150 m³/hAirflow per unit
  • 0.45 m/sNominal flow velocity
They chose us

Pharmaceutical, semiconductors, electronics, medical

Units integrated in the ceilings we build, and also supplied as spares for systems built by others.

  • L’Oréal Paris
  • Fratelli Beretta
  • Bill & Melinda Gates Foundation
  • PharmaJet
  • University of Pisa
  • Fiat Aviazione
  • Solvay
  • Epson
  • Actavis
  • Kolektor
  • PAN Compositi
  • Ansaldo Energia
  • University of Milan
  • Spes Medica
Images

The filter modules, up close

The complete unit, the same view with the transparent casing, and the ECM fan inside it.

  • Stand-alone FFU filter unit with sheet-metal plenum and high-efficiency filter on the supply side, three-quarter view
    Stand-alone FFU filter unit with sheet-metal plenum and high-efficiency filter on the supply side, three-quarter view.
  • Stand-alone FFU filter unit with sheet-metal plenum and high-efficiency filter on the supply side, technical view with the transparent casing
    Stand-alone FFU filter unit with sheet-metal plenum and high-efficiency filter on the supply side, technical view with the transparent casing.
  • ECM fan with aluminium backward-curved blades, mounted on the filter unit plate, three-quarter view
    ECM fan with aluminium backward-curved blades, mounted on the filter unit plate, three-quarter view.
The range

Three catalogue modules,
and the ceiling grid pitch decides

The three units share the same architecture — radial electric fan with EC motor and aluminium backward-curved impeller, continuously variable speed driven via BUS — and differ in size and airflow. The filter is chosen separately: HEPA H14 or ULPA U15 on the same casing.

  • 550×550330 m3/h

    Where the grid is tight

    Footprint 550×550×390 mm with 457×457 mm filter: the module for single workstations, hoods and tight-pitch grids, where a 700 will not fit. Same EC motor and same filter choice as the other two.

    550×550×390 mm
  • 700×700570 m3/h

    The standard module

    Module 700×700×320 mm with 610×610 mm filter, power draw from 72 to 115 W, noise level around 58 dB(A). It is the size on which most plenums are designed.

    72–115 W · ~58 dB(A)
  • 1310×7001150 m3/h

    The long module

    Module 1310×700×530 mm with 1220×610 mm filter, from 110 to 220 W, around 61 dB(A). It covers twice the surface with a single unit: fewer parts to power and maintain.

    110–220 W · ~61 dB(A)

Power supply 220–240 V 50 Hz, operating conditions between 25 and 40 °C with relative humidity below 70 %. The EC motor delivers over 30 % savings compared with an asynchronous one, allows speed and airflow monitoring and includes protection. The units comply with the Machinery Directive 2006/42/EC, the Electromagnetic Compatibility and Low Voltage directives, and with ISO 14644-7 on separative devices. Data are subject to change and improvement.

Challenges and solutions

Six things to know
before counting the units

The first question we get is how many are needed. The answer depends on six things, and none of them is the unit price.

  • Filter coverage is the class

    The ratio between the area covered by units and the total ceiling area decides whether the flow is unidirectional across the whole floor plan or only under the units. For a true ISO 5 the coverage tends towards the total above the critical zone; for an ISO 7 distributed units are enough. This is the calculation that decides the project, and it is not written in any product data sheet.

  • HEPA or ULPA is not a nuance

    An H14 retains 99.995 % at the MPPS, the most penetrating particle diameter; a U15 99.9995 % at the same MPPS. For H14 and U15 the efficiency refers to the MPPS according to EN 1822: penetration goes from 0.005% to 0.0005%, a tenfold reduction. Down to ISO 5 the H14 is the right choice; below that, it is not an alternative but a requirement.

  • The motor is paid for every hour for twenty years

    A unit works twenty-four hours a day for the life of the plant. The difference in consumption between a traditional motor and an electronically commutated one, multiplied by the number of units and by the hours, is almost always larger than the difference in purchase price. The calculation must be made over the life cycle.

  • Sizing and integration

    The choice of FFU must consider the footprint of the unit, the filter dimensions and the space available in the plenum. Installation dimensions must be defined on the working drawing of the chosen configuration.

  • Controlled, or endured

    A unit with only a switch runs at whatever speed it happens to while the filter gets dirty. With BUS control you adjust by zone, read the consumption, see the filter status and bring everything into the supervision system: it costs little at purchase and changes the management.

  • Reducible noise

    In applications where noise is a critical factor, FFU noise can be reduced by means of low particle-shedding insulating materials.

The calculation that decides

How many units are needed
is a question of geometry

Few units on a large ceiling produce islands of unidirectional flow and, between one island and the next, circulating air. Under the filter the class is there; two metres further on it is gone.

With the ceiling covered the flow is unidirectional across the whole floor plan and the class belongs to the room, not to a point. The ratio between filtering area and total area is the number that decides the project — and, along with it, the consumption of the next twenty years.

Talk to a technician Italy+39 02 8364 7535Spain+34 673 889 559
Same room, two ceilings Islands on the left, full coverage on the right
  • IslandsClass only under the filter
  • Full coverageClass across the whole floor plan
  • 0.45 m/sNominal velocity
How we work

Six steps, one point of contact

It is the same path as a plant, to scale: what is looked at changes at each step, not who answers.

  1. 01

    Analyse

    Process, standards and site constraints: from these come the class and the URS that fixes it.

  2. 02

    Design

    Layout, separate flows, pressure cascade and HVAC, verified on BIM and CFD models.

  3. 03

    Manufacture

    Panels, metalwork and control panels in our workshop, with factory acceptance testing (FAT).

  4. 04

    Install

    On-site assembly, systems and monitoring, on-site verification (SAT) and start-up.

  5. 05

    Qualify

    We carry out the tests and deliver audit-ready documentation, where required.

  6. 06

    Support

    Scheduled maintenance, filters and calibration, including on systems built by others.

Applications

Where our units end up

In the ceilings of the cleanrooms we build, in softwall and hardwall rooms, and as spares on systems built by others. Each card leads to the sector page.

Reference standards

The regulatory framework we apply

The filter class is declared according to EN 1822 and verified installed, in situ, according to ISO 14644-3. The resulting room classification follows ISO 14644-1.

  • EN 1822 · H13–U17
  • ISO 14644-1
  • ISO 14644-2
  • ISO 14644-3
  • ISO 14644-4
  • EU GMP Annex 1
  • ISO 29463
  • IEST-RP-CC034
  • CEI EN 60335-2-80
  • VDI 2083
Frequently asked questions

FFU: what we get asked

The questions that come back on every site survey, with the answer we would give in person.

How many do I need for my room?

The calculation starts from the class and the zone to be protected, not from the square metres. We establish the filter coverage needed above the critical zone — which for an ISO 5 tends towards the total — and verify the air changes per hour against volume and load. With the plan and the class of each zone we calculate the number ourselves, and put it in writing in the quote.

HEPA or ULPA?

Down to ISO 5 the right choice is theH14. Below ISO 5 you need a U15 or higher, and it is not a preference: the class cannot be reached otherwise. Mind the footprint — the ULPA pack is 30 mm taller — and the mounting, because at these efficiencies the leak is almost always in the frame.

How much do they consume?

It depends on airflow and filter condition, and the figure that matters is the one at the real operating point, not the nameplate one. Models with an electronically commutated motor and a read-out interface let you truly measure it, unit by unit: on a system with dozens of units it is the largest running cost after air treatment.

How often is the filter changed?

Not by calendar, but when the differential pressure says airflow is no longer guaranteed. On models with an indicator or interface the value can be read continuously; on the others it is measured during scheduled maintenance. After every replacement the in-situ integrity test must be repeated.

Can they all be controlled together?

Yes: the speed is continuously variable and driven via BUS, so you adjust by zone, read consumption and filter status and bring them into the building supervision system. It is how a large system is managed without climbing a ladder.

Do you also supply them as spares?

Yes, including on systems built by others. We need the ceiling grid dimensions, the height available in the plenum, the design airflow and the filter class in use: on these data we supply compatible units and, if needed, repeat the integrity test after installation.

Let’s talk

Send us the plan and the class,
we will calculate the number of units

Surface and height of each zone, required class, ceiling grid and height available in the plenum. With these elements the calculation arrives precise at the first pass, and the quote is built on your process.

Request a quote See the cleanrooms