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Clean Room Classifications

Cleanroom with exterior gowning room

Clean Room Classifications

(ISO 8, ISO 7, ISO 6, ISO 5)

Cleanrooms are classified based on how clean the air is inside the environment, specifically by the number and size of airborne particles per cubic meter. The most widely used standard in the U.S. and Canada is ISO 14644-1, which defines cleanroom classes from ISO 1 (the cleanest) to ISO 9 (the dirtiest).

Even ISO 9 is significantly cleaner than a typical indoor space. The most commonly used classes for manufacturing are ISO 7 and ISO 8, which roughly align with the older Federal Standard 209E classes 10,000 and 100,000.

While Federal Standard 209E was officially replaced by ISO standards in 1999 (and withdrawn in 2001), many still reference its classifications. Additional industry-specific standards also apply. For example:

  • EU GMP Grades A–D for pharmaceuticals

  • USP 795, 797, and 800 for compounding pharmacies

Cleanroom Classes Defined

ISO cleanroom classifications are determined by the cleanliness of the air within the controlled environment. With your cleanroom manufactured to your needs, we can produce a modular solution meeting ISO cleanroom standards from Class 9 to Class 5. Our capabilities can offer the following ISO classifications:

  • ISO 5 cleanrooms: This classification is exceptionally clean, featuring less than 3,520 particles >0.5 microns per cubic meter and requiring 250-300 HEPA-filtered air changes per hour. ISO 5 cleanrooms are ideal for semiconductor manufacturing and pharmaceutical production.
  • ISO 6 cleanrooms: Cleanrooms with this classification are cleaner than ISO 7 and 8. They require less than 35,200 particles >0.5 microns per cubic meter and 180 HEPA-filtered air changes per hour.
  • ISO 7 cleanrooms: A common cleanroom classification, ISO 7 calls for less than 352,000 particles >0.5 microns per cubic meter and 60 HEPA-filtered air changes. This classification supports electronics and medical device manufacturing.
  • ISO 8 cleanrooms: Offering the least strict requirements, this classification must have less than 35,200,000 particles >0.5 microns per cubic meter and 20 HEPA-filtered air changes per hour. ISO 8 cleanrooms are well suited for medical device plastic extrusion, e-liquid manufacturing, and nutraceutical packaging.

ISO 14644-1 Modular Clean Room Particle Concentrations

Cleanroom standards are based on particle size, measured in micrometers (µm). Classifications are determined by the number and size of particles allowed per cubic meter of air.

This cleanroom classification table outlines the maximum allowable particle concentrations for each class. In some cases, certain particle sizes aren’t tested because their concentrations are either too low or too high to measure reliably, but this doesn’t mean the count is zero.

Class Maximum
Particles/m³		 FED STD 209E equivalent
>0.1
um		 >0.2
um		 >0.3
um		 >0.5
um		 >1
um		 >5
um
ISO 5 100,000 23,7000 102,000 3,520 8,320  293 Class 100
ISO 6 1,000,000 237,000 102,000 35,200 8,320 2,930 Class1,000
ISO 7       352,000 83,200 2,930 Class 10,000
ISO 8       3,520,000 832,000 29,300 Class 100,000
ISO 9       35,200,000 8,320,000 293,000 Room Air

What are the ISO Cleanroom Standards?

Criteria Class 100
ISO5		 Class 1000
ISO6		 Class 10,000
ISO7		 Class 100,000
ISO8
Air changes per HR/Min 300 to 480 / 5 to 8 180 / 3 60 /1 20 /0.33
Filter coverage % 60 – 70 20 – 30 7 – 15 4  – 5
CFM per square foot 36 – 65 18 – 32 9 – 16 4 – 8
Filter Efficiency 99.997% HEPAs 99.997% HEPAs 99.997% HEPAs 99.97% HEPAs
Ceiling Type Aluminum T-bar grid Aluminum T-bar grid Conventional T-bar grid Conventional T-bar grid
Light Fixture type Tear drop or 2’x4’ cleanroom fixture 2’x4’ cleanroom fixture 2’x4’ cleanroom fixture 2’x4’ standard fixture
Ceiling Panel FRP, Vinyl rock or Mylar Vinyl rock or Mylar Vinyl rock or Mylar Vinyl rock or Mylar
Wall System Modular Modular Modular Modular
Flooring cover Welded sheet vinyl or Epoxy Welded Sheet vinyl or Epoxy Sheet vinyl or VCT Sheet vinyl or VCT
Flooring base Cove or Aluminum base channel Cove or Aluminum base channel Cove or Aluminum base channel Cove or Aluminum base channel
Air Returns Low wall on long axis Low wall at perimeter Low wall Low wall or ceiling

What ISO Cleanroom Classification Do I Need?

Determining the required ISO cleanroom classification is essential in selecting the right solution for your facility. Key considerations when deciding the ISO cleanroom standards for your application include:

  • What are the sources of contamination in my location?
  • How small are the smallest particles I need to remove from the air?
  • How much air do I need to circulate to remove contaminants

What are Cleanrooms Used For?

Customized modular cleanrooms can be manufactured to fit any dimensions and with unique special features that deliver the required performance. Since they are entirely customizable, modular cleanrooms provide more design flexibility than standard drywall-constructed cleanrooms. Some of the industries that regularly utilize prefab cleanrooms include:

Iso 7 Cleanroom with Technicians

Common Modular Cleanroom Options

We can produce various modular cleanroom solutions to your exact specifications. Learn more about our prefabricated modular cleanroom configurations, including:

What is the Difference Between a Cleanroom and a Controlled Environment?

Although the two are very similar, a cleanroom and a controlled environment differ. In a controlled environment, certain parameters must be carefully controlled, such as temperature, pressure, humidity, and physical separation from non-controlled environments. However, unlike a cleanroom, a controlled environment generally doesn’t have to meet any specific particle contamination standards.

Therefore, a cleanroom is a controlled environment that must meet far stricter criteria. It also requires a specific temperature, pressure, and humidity, along with separation from outside environments and careful management of airborne particulates. All these factors must be monitored and controlled to maintain specific standards and conditions.

Contact Cleanrooms by United for High-Quality Modular Cleanroom Solutions

Cleanrooms by United is your trusted ISO cleanroom manufacturer, offering advanced quality in your prefab cleanroom solutions. Contact us today for more information regarding our portable cleanroom solutions and your design requirements, or request a quote to begin.