American Cleanroom Systems

What is a cleanroom certification?

June 15, 2023
Figure 1. Cleanroom particle counter

Cleanroom certification is when users have their cleanroom periodically tested by 3rd party to ensure they meet ISO cleanroom classification. For medical device and pharmaceutical companies this may be to stay compliant with their CGMP or FDA validation. For semiconductor, aerospace and other industries, the cleanroom is essential to manufacturing yield and product quality.

Cleanroom classification standards include particle counts and air changes per hour. Other parameters that are often tested as part of cleanroom certification include: room pressure, temperature, humidity, viable particles, light and sound.

Particle tests can be non-viable or viable (living). For cleanroom classification the tests are for non-viable particles. For ISO 14644-1 each cleanroom classification has a maximum number of particles of a certain size per cubic meter. These measurements are taken using a laser particle counter (Figure 1).    

ISO 14644-1 Cleanroom Standards | Cleanroom Classifications
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 1 10 2
ISO 2 100 24 10 4
ISO 3 1,000 237 102 35 8 Class 1
ISO 4 10,000 2,370 1,020 352 83 Class 10
ISO 5 100,000 23,700 10,200 3,520 832  29 Class 100
ISO 6 1,000,000 237,000 102,000 35,200 8,320 293 Class 1,000
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
Figure 2. ISO-14644-1 cleanroom classes

There is also the US FED STD 209E cleanroom classes which measures particle per cubic foot but is very similar to the ISO-14644-1 classes.

US FED STD 209E Cleanroom Standards | Cleanroom Classifications
Class Maximum  Particles/ft³ ISO equivalent
>0.1 um >0.2 um >0.3 um >0.5 um >5 um
 1 35 7 3 1 ISO3
 10 350 75 30 10 ISO4
100 100 ISO5
1000 1000 7 ISO6
10,000 10,000 70 ISO7
100,000 100,000 700 ISO8
Figure 3. FED STD 209E cleanroom classification

Room air pressure testing is typically done with portable manometers. Most cleanrooms have permanent magnehelic gauges that display cleanroom pressure in inches of water or pascals.

Figure 4. Permanent cleanroom magnehelic gauge

Air flow testing: Another requirement for both ISO and FED STD cleanroom classification is HEPA filtered air changes per hour.

Design Requirements for Cleanroom Classifications
Criteria Class 10 ISO4 Class 100 ISO5 Class 1000 ISO6 Class 100,000 ISO8
Air changes per HR/Min 500-600 / 8 to 10 300 to 480 / 5 to 8 180 / 3 60 /1 20 /0.33
Filter coverage % 90 – 100 60 – 70 20 – 30 7 – 15 4  – 5
CFM per square foot 85 – 90 36 – 65 18 – 32 9 – 16 4 – 8
Filter Efficiency 99.9997% ULPAs 99.997% HEPAs 99.997% HEPAs 99.997% HEPAs 99.97% HEPAs
Figure 5. Cleanroom Classification - Air changes per hour

The individual air flow rate from each HEPA fan filter unit can be measured with air flow capture hood or Velgrid system.

Viable testing is for live organisms. Typically, samples are collected using settling plates with some type of media. The plates are placed in the cleanroom at specific locations for 4 hours and then are then sent off to analytical labs for incubation and measurement.

Figure 6. Cleanroom air flow testing
Figure 7. Cleanroom settling plate

Temperature testing is done with a NIST traceable digital thermometer. Humidity testing is done with NIST traceable humidity sensor.

Light testing is typically done with a light meter in grid pattern. The cleanroom test is lumens per square meter (LUX).

Figure 8. Cleanroom light map

Sound testing is done with sound level meter in grid pattern. The cleanroom test is in decibels.

Figure 9. Cleanroom test equipment

Frequency of cleanroom testing

Most companies do 3rd party cleanroom testing annually and do internal testing quarterly or monthly. How often depends on company manufacturing procedures, ISO-9001 procedures, customer requirements, or CGMP/FDA validation document.

Summary: Cleanroom certification is when a cleanroom is tested by 3rd party to ensure they meet cleanroom classification standards including particle counts and air changes per hour. Other parameters that are often tested include room pressure, temperature, humidity, viable particles, light and sound. The tests are required to meet FDA validation/CGMP requirements, ISO procedures or ensure manufacturing yield and product quality.

Property American Cleanroom Systems 2023

The author Anthony Chien has worked at American Cleanroom Systems for more than 10 years . He has more than 40 years of cleanroom experience. Anthony has a BS and MS in Electrical Engineering specializing in semiconductor manufacturing from the University of Illinois. American Cleanroom Systems is a design build modular cleanroom manufacturer based in Rancho Santa Margarita CA. It is expert in ISO-5 thru ISO-8 (class 100 to class 100k) modular cleanrooms for nutraceutical cleanrooms, pharmaceutical cleanrooms, medical device cleanrooms, and industrial cleanrooms.
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