The Fan Filter Unit (FFU) offers specific advantages for cleanroom users. Rob Flaherty, international sales manager at Trion, takes a look at its evolution in cleanroom applications and why new, low-energy FFUs promise an exciting future ahead.
Since their initial introduction in 1984, fan filter units (FFUs) have proved a popular choice for cleanrooms and continue to be so today. Initially used in ISO Class 5 cleanrooms and above, with a negative plenum design, FFU sales soon grew and matured into a global market that saw a range of manufacturers and brands emerging in the sector. These were followed by new FFU products to meet changing cleanroom requirements.
The technology is undeniably simple – little more than a HEPA or ULPA filter attached to a ‘plug’ fan installed within a standard suspended ceiling grid on 1,200 x 600mm centrelines to offer high efficiency filtration for the space.
The attraction of this simplicity of operation and installation is compelling; so too are the significant additional benefits the FFU provides. Fundamentally, it offers a low capital cost, low noise filtration solution that is easy to service and maintain.
But there are other advantages too. Most obviously, incorporating FFUs within negative plenum designs enables smaller air handling units (AHUs) to be specified for a particular cleanroom installation, saving space and cost. In such an application, the plenum becomes a mixing chamber for the conditioned make up air that is needed for exhaust, pressurisation and to satisfy temperature and humidity demands, as well as for the recirculated air from the cleanroom.