ISO-5 cleanroom classification is a common high level of the cleanroom classes. The ISO cleanroom standards are set by the International Organization for Standardization. They are a private international organization with a membership of 167 national standards bodies.
ISO-5 cleanrooms are required to have 300-480 air changes per hour of HEPA filtered air and less than 29particles/meter3 greater or equal to 5 microns. By comparison, a conditioned office space (non-cleanroom space) would have more than 10,000X as many particles per meter3. ISO-5 cleanroom classification also has requirements for >0.5 micron and >1 micron size particles (see figure 2).
There is a separate FED 209E cleanroom classification system that has been historically used in United States for industrial cleanrooms such as semiconductor cleanrooms and printed circuit board cleanrooms. The ISO cleanroom classification is on metric system (particles per meter3). The FED 209E cleanroom classification system is based on imperial system (particles per feet3). There are comparable ISO and FED 209E cleanroom classes for each level of cleanliness. An ISO-5 cleanroom classification corresponds to FED 209E class 100 cleanroom classification (see figure 3).
Common applications for ISO-5 cleanroom classification rooms
- Semiconductor manufacturing cleanroom (photolithography)
- Medical device manufacturing cleanroom (final clean and packaging)
- Pharmaceutical cleanroom - Aseptic filling
- Aerospace – NASA satellite assembly, component manufacturing
- R&D cleanroom (Universities and Federal National Laboratories)
- Hard disk manufacturing and repair
- Pharmaceutical compounding
There are three different types of ISO-5 classification cleanrooms. They can be modular cleanroom, stick built (gypboard on studs) cleanroom or softwall cleanroom. A modular cleanroom has advantage of a fast install, easily modified or disassembled and moved to alternative site and can be upgraded to higher cleanroom classification. A stick-built ISO-5 classification cleanroom requires the gypboard walls to be painted with epoxy paint. The cost can be slightly cheaper than modular but it takes significantly longer to build and is difficult to modify. A softwall ISO-5 classification cleanroom must be one pass so it cannot incorporate air conditioning. The stick-built cleanroom cost is similar to a modular cleanroom.
Filtration for ISO-5 classification cleanrooms is done with HEPA filters or ULPA filters. The best modular cleanroom design uses a negative pressure plenum with HEPA fan filter units in the ceiling and incorporated low wall air returns to achieve laminar air flow. The HEPA filtered air sweeps dirt down to the floor and horizontally to the low wall air returns.
Special lighting for ISO-5 cleanrooms. Semiconductor cleanrooms typically have photolithography rooms which require special amber lighting to not expose the photoresist. Often ISO-5 cleanrooms have 100% HEPA ceiling coverage so there is no room for lights. In that situation tear drop cleanroom lighting that mounts on t-grid between the HEPA filters is used.
Special flooring for ISO-5 cleanrooms. Often ISO-5 cleanrooms have very tight temperature and humidity requirements. In that case it is common to use raised floors to ensure the HEPA filter air only flows vertically and can return from beneath the floor. The flooring is perforated to allow air to pass thru. The tiles are mounted on aluminum pedestals to create 2’ space beneath flooring for the air to flow. Heat welded vinyl and epoxy flooring are also used for ISO-5 cleanrooms.
Cleanroom gowning for ISO-5 classification cleanrooms. Typically, cleanroom personnel wear full bunny suits that cover staff from head to toe along with goggles and face masks. All the garments are manufactured from special non particulating cleanroom approved materials. Options include disposable or washable (you send back to cleanroom laundry) garments. It is critical the personnel wear cleanroom garments if user wants to maintain ISO-5 cleanroom classification.
Why gown room/airlock for ISO-5 classification cleanroom. Because an ISO-5 classification cleanroom does 300 air changes per hour, if a door is even briefly opened to the dirty exterior it can let in millions of particles to the cleanroom which is supposed to only have 29 particles per cubic meter. The gown room/airlock will have ISO-7 HEPA filtration so less than 2930 particles per cubic meter are present when opening door between gown room and cleanroom. Gown room / airlocks are critical part of your ISO-5 classification cleanroom.