Clean Room Classifications (ISO 8, ISO 7, ISO 6, ISO 5)
Clean rooms are classified according to the cleanliness level of the air inside the controlled environment. The clean room class is the level of cleanliness the room complies with, according to the quantity and size of particles per cubic meters of air. The primary authority in the US and Canada is the ISO classification system ISO 14644-1.
This ISO standard includes these clean room classes : ISO 1, ISO 2, ISO 3, ISO 4, ISO 5, ISO 6, ISO 7, ISO 8 and ISO 9. ISO 1 is the “cleanest” class and ISO 9 is the “dirtiest” class. Even if it’s classified as the “dirtiest” class, the ISO 9 clean room environment is cleaner than a regular room.
The most common ISO clean room classes are ISO 7 and ISO 8. The Federal Standard 209 ( FS 209E ) equivalent for these ISO classes are Class 10,000 and Class 100 000.
The old Federal Standard 209E ( FS 209E ) includes these clean room classes : Class 100,000; Class 10,000; Class 1,000; Class 100; Class 10; Class 1. This standard was replaced in 1999 by ISO-14644-1. It was withdrawn in 2001, but it is still widely used.
Clean rooms must also follow industry-specific and international standards. For example, EU GMP (A-B-C-D), applies to pharmaceutical products and USP (795, 797 and 800) to compounding pharmacies.
Cleanroom Classifications & Standards
In ISO Classes 4-9, air change rates are expressed as the rate per hour the air in the cleanroom is completely refreshed (ACH = air changes per hour). As cleanroom classifications become more stringent, the air change rate must increase to remove particles and keep the air cleaner. In Class 5 and below, the strictest cleanroom classifications, the air change rate is so rapid it is expressed instead as airflow velocity, either in meters per second or feet per minute. These cleanroom environments require air that is extremely clean, so the constant changing of contaminant-free air is vital to maintain classification standards.
When upgrading to a stricter cleanroom classification, an important step is to increase the filtration and air change rate to remove more particles of a smaller size from the air. For example, ISO Class 7 requires between 60-90 ACH and allows for 352,000 particles at 0.5 microns per cubic meter. To move to an ISO Class 6, the facility would need to increase to 150-240 ACH to filter all but 35,200 particles at 0.5 microns per cubic meter. The more stringent the classification, the more extreme the standards of cleanliness. Extremely clean cleanrooms require extensive filtration and powerful HVAC systems to maintain classification standards.
ISO 8 Clean Rooms
ISO 8 cleanrooms, also known as Class 100,000 cleanrooms, can be modular or soft-walled and have a maximum particle count of 100,000 particles (≥0.5 um) per cubic foot of interior air. They are required to have HEPA filtration coverage over 4-5% of the area and provide a minimum of 20 air exchanges per hour with air flow rates of 4-8 CFM per square foot.
ISO Clean Room Standards
Cleanroom classifications range 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. Contamination levels in ISO 8/Class 100,000 cleanrooms are measured by the concentration of particles in a cubic foot or meter of air. These levels are measured in microns and defined by the following standards:
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 8 Cleanrooms
(FED STD 209E Equivalent: Class 100,000)
≥0.1 µm ≥0.2 µm ≥0.3 µm ≥0.5µm ≥1µm ≥5 µm — — — 3,520,000 832,000 29,300
US FED Standard 209E Maximum Number of Particles Permitted/ft³ for Class 100,000 Cleanrooms
(ISO 14644-1 Equivalent ISO 8)
≥0.1 µm ≥0.2 µm ≥0.3 µm ≥0.5µm ≥5 µm — 750,000 300,000 100,000 70
ISO 8 Clean Room Particle Specifications
ISO 8 clean rooms do not require certain particle sizes to be tested, either because concentration levels are too high or low to be tested, but it cannot be zero. For ISO Class 8, particles smaller than 0.5 µm aren’t considered. The concentration of particles that are ≥0.5 µm should be below 3,520,000.
ISO 8 Clean Room Protective Requirements
There are different ISO 8 cleanroom designs, including modular cleanrooms and soft-sided cleanrooms. A modular cleanroom has hard-sided walls that provide complete floor-to-ceiling protection for a higher level of cleanliness. They are used for permanent and semi-permanent installations and can be configured to any size. Softwall cleanrooms are constructed of soft panels or strips and do not touch the floor. They are designed for portability and more temporary installations and are commonly used as a “spot clean” enclosure within an already controlled environment.
In addition to structure, there are other important considerations for usability and to ensure effective control contaminant levels. Incorporating air showers, pass-through chambers and other additional cleanroom accessories into the cleanroom design may be required to help prevent contamination from entering the cleanroom environment. Lighting, filtration and temperature control are also extremely important.
Cleanroom design considerations and standard requirements vary depending on the industry and application. In general, primary considerations for designing a Class 100,000 cleanroom include:
ㆍHEPA filtration requirements
ㆍAir pressure requirements
ㆍHumidity or temperature control requirements
ㆍNumber of personnel working in the area
ㆍStatic control requirements
ㆍMaximum contaminant levels
ㆍSanitation requirements
ㆍNumber and type of windows and doorways
ㆍLighting and electrical needs
Hardwall Modular Cleanroom Advantages
Due to their ease of maintenance and simple installation methods, hard-walled modular cleanrooms are increasing in popularity in numerous industries across the globe. Since they can be installed quickly and easily and can be modified or even relocated with minimal expense and downtime. Many prefabricated modular cleanrooms are almost 100% reusable. Some additional benefits of a hard-walled modular cleanroom include:
ㆍLess expensive than sheetrock construction
ㆍEasily installed in days, not weeks
ㆍFactory-cut options, with numerous custom options
ㆍPre-wired UL Classified raceway installation capabilities
ㆍInsulated wall options for reduced energy costs
ㆍAnteroom and gowning room options for reduced contamination
ㆍAirlock, air shower, and pass-through box options for reduced contamination from personnel and materials
Flexible & Affordable Modular Cleanroom Systems
Since they are constructed of hard or soft panels with a hard ceiling, modular cleanroom systems are highly configurable. Soft panel cleanrooms have walls made from clear PVC and one small opening for entering and exiting the area. Hard panel systems consist of prefabricated panels that join to create a square or rectangular room. Hard-walled cleanrooms are fully enclosed and can be fitted with doors, windows, and transfer hatches, just like a permanent cleanroom.
Some of the advantages modular cleanroom systems provide over permanent clean rooms include:
ㆍVersatility: A modular cleanrooms can be readily assembled, disassembled, and relocated, often in just a few days or less
ㆍEasily reconfigurable: The layout of a modular cleanroom can be rearranged, expanded, retrofit, and/or upgraded.
ㆍCost-effective: Modular cleanrooms are designed and manufactured offsite for a fraction of the cost of permanent construction.
ㆍTime Saving: Modular cleanroom systems can be installed onsite in a fraction of the time as permanent construction.
ㆍReduced downtime: Modular cleanroom installation causes far less disruption to daily operations, allowing many users to keep some or all operations running without disruption.
ㆍLeasing: If you lease your space, the modular option allows you to uninstall the clean room you need and take it with you if your operation changes locations.
ㆍR.O.I.: Because it can be taken down, moved, and re-erected, a modular cleanroom is considered a piece of capital equipment and can be treated as such for taxation purposes.
ㆍCleanliness: A modular cleanroom is the better option for cleanroom requirements above ISO 6 classification. The materials used in these systems do not shed like drywall or metal studs, reducing the level of contamination.
What Cleanroom Classification do you Need?
A typical cleanroom is designed to keep outside contaminants and particles at a minimum based on the ISO clean room standards. Once fully built and operational, an isolated cleanroom is free from outside particles and contamination. However, the two things that can introduce particles and contamination into your cleanroom are people and processes.
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. The lower the ISO class the more stringent the requirements for keeping particles and contamination to the acceptable levels of the room class.
As an example, ISO 8 cleanrooms, also known as Class 100,000 cleanrooms, can be modular or soft-walled and have a maximum particle count of 100,000 particles (≥0.5 um) per cubic foot of interior air. They are required to have HEPA filtration coverage over 4-5% of the area and provide a minimum of 20 air exchanges per hour with air flow rates of 4-8 CFM per square foot. View Modular Cleanroom Systems to learn about the differences between types of of cleanrooms.
ISO 8 Cleanroom Applications
ISO 8 clean rooms provide air cleanliness levels of a maximum of 100,000 particles (≥0.5 um) per cubic foot of interior air and a minimum of 20 air exchanges per hour. Applications include:
