ISO 7 Cleanrooms (Class 10,000 Cleanrooms)
Cleanrooms are modular or soft-sided structures that provide a clean and protected environment by using filtration systems and cleanliness protocols to minimize contamination from airborne and surface particles, gases or liquids, or static electricity. Classification for cleanrooms ranges from ISO 1 to ISO 9, with ISO 9 being the “dirtiest” and ISO 1 being the “cleanest.” These classifications are assigned based on the maximum allowable concentration of particles per cubic foot or meter of air.
ISO 7 cleanrooms, also known as Class 10,000 cleanrooms, have hard-sided walls and use HEPA filtration systems to maintain air cleanliness levels of a maximum of 10,000 particles (≥0.5µm) per cubic foot. Class 10,000 cleanroom filtration systems must provide filter coverage of 15-25% and – a minimum of 60 air changes per hour. The standard air flow rate for an ISO 7 filtration system is 9-16 CFM per square foot.
ISO 7 Cleanroom Standards
Contaminant levels for cleanrooms are measured in microns and were previously defined under US Federal Standard 209E. Filtration requirements and particle count for Class 10,000 cleanrooms are now defined under ISO 14644-1, though many manufacturers and industries use both sets of requirements as a reference point.
- US Federal Standard 209E: denotes the number of particles (≥0.5 µm or larger) per cubic foot (f³) of air.
- ISO 14644-1: replaced federal standard 209E in 2001 but is still used as a reference. It denotes the number of particles (≥0.1µm to ≥5µm or more) per cubic meter (m³) of air.
ISO 14644-1 Standard for Maximum Number of Particles Permitted/m³ for ISO 7 Cleanrooms
(FED STD 209E Equivalent: Class 10,000)
US FED Standard 209E Maximum Number of Particles Permitted/ft³ for Class 10,000 Cleanrooms
(ISO 14644-1 Equivalent ISO 7)
Preventing Contamination in ISO 7 Cleanrooms
Class 10,000 cleanrooms require workers to wear fewer protective garments than cleanrooms with a lower classification but still require the use of cleanroom clothing such as face masks, hair and beard covers, and lab coats or other frocks to cover street clothing. In some ISO7 cleanrooms, coveralls and gloves may also be required. Cleanroom clothing is made from nonwoven fabrics to prevent contamination from shedding material fibers. Gloves are sterile and made from latex, nitrile or other synthetic materials.
Depending on industry and application requirements, other precautionary measures may be taken to control particle count in an ISO 7 cleanroom environment. Sticky mats are often placed outside of cleanroom entrances to remove dirt and other contaminants from shoes. Pass-thru cabinets fitted with filtration systems may also be used to safely transfer products while limiting the number of people entering and exiting the room.
Cleanroom requirements vary widely based on industry standards and the type of processes being performed. Always consult with a cleanroom professional for assistance in selecting the design and classification that are best suited for your application.