Cleanroom Classifications Explained

A cleanroom classification basically tells you how clean a cleanroom is. While we typically consider cleanrooms to use HEPA filters and multiple layers of protection, cleanrooms can really be any room where precautions are taken to ensure that the product stays clean from contaminants.

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But if that&#;s the case, then what makes one cleanroom stand above the other? That&#;s where cleanroom classifications come into play.

Who Sets Cleanroom Classifications?

Cleanroom classifications are set by the International Organization for Standardization (ISO). They are an independent, non-governmental agency dedicated to providing world standards in a variety of industries. ISO offers international standards, but there is an additional standard for companies wanting a USA certification.

The Federal Standard 209 (FS 209) is an American classification that was established in by the Institute of Environmental Sciences and Technology (IEST). Similar to ISO, there are a number of classifications available through the IEST &#; ranging from FS209A through FS209E. The most recent update was FS209E establishing the maximum number of particles present if a room is to be officially classified as a cleanroom.

Whether you choose to go with the FS 209 classifications or the ISO classification, FS 209 E and ISO -1 reflect the same measurements to classify a cleanroom at certain levels. While being classified with either is a good idea (and, often, required), we typically side with ISO as the international aspect allows for more flexibility.

What Are Cleanroom Classifications?

Since we typically use the ISO standard, today we&#;ll be talking about how these classifications work.

There are 9 ISO classifications of cleanrooms:

• ISO 1
• ISO 2
• ISO 3 (FS 209 E class 1 equivalent)
• ISO 4 (FS 209 E class 10 equivalent)
• ISO 5 (FS 209 E class 100 equivalent)
• ISO 6 (FS 209 E class 1,000 equivalent)
• ISO 7 (FS 209 E class 10,000 equivalent)
• ISO 8 (FS 209 E class 100,000 equivalent)
• ISO 9 (room air)

If you want to be the cleanest cleanroom, you&#;ll need an ISO 1 classification. To attain this classification, you&#;ll need to prove a known sample that has 10 or fewer particles measuring 0.1 microns and only 2 or fewer particles at 0.2 microns.

From there, the scale allows for more and larger particles. ISO 9 is considered normal room air. These rooms have a known sampling with 35,200,000 or fewer particles measuring 0.5 microns, 8,320,000 or fewer particles measuring 1 micron, and 293,000 or fewer particles measuring 5 microns.

Basically, there are a lot of particles and they can be pretty big!

Your classification really depends on what you&#;re producing and how sterile the environment needs to be. But once you determine what classification is required for your industry and production, there are steps you can take to certify your cleanroom and conduct regular maintenance.

How Can You Certify Your Cleanroom Classification?

If you&#;re ready to get your cleanroom classification, there are a few steps you can follow.

1. Determine your cleanroom size and the number of areas that need to have their particles measured.
   Depending on the size of your cleanroom and entry and exit locations, you will need to measure your cleanroom&#;s particle size and count in different areas. Your particle counter can help with this determination.
2. Determine what level of cleanliness you need for your desired classification.
   This will help you figure out what size and concentration of particles you need to achieve to secure your classification. Make sure your particle counter can correctly and accurately measure particles in the size and concentration you need.
3. Measure the required areas.
   When going through your annual or semi-annual testing to verify your cleanroom classification, we recommend conducting 4 tests. While the Non-Viable Particle Counting is the one that will determine how clean your cleanroom is, all 4 tests give you valuable information for your classification and general cleanroom maintenance. The tests are:
   Airflow Volume/Velocity Readings: This test makes sure the airflow is in the correct amount and direction.
   HEPA Filter Integrity Testing: While not required by ISO standards, this test is often required by other organizations such as the FDA. This test makes sure there are no leaks in your HEPA filter.
   Non-Viable Particle Counting: In this process, this is the most important test, as it tells you how many particles are in a certain area as well as what size they are. This is the test that will determine your classifications.
   Room Pressurization Testing: This test verifies the desired room pressure is correct.
4. Take the averages.
   Average the number and size of particles in each location. Then take your location averages and find their average, so you have the overall average size and number of particles for the cleanroom.
5. Find your cleanroom classification!
   Use a particle counter that will automatically find the Upper Confidence Limit to determine where your statistically significant particle size and number. Then determine which ISO classification you fall under.

Let Us Help You Keep Your Cleanroom Clean!

What industry are you in? How clean does your cleanroom need to be? What&#;s your ideal cleanroom classification?

Whatever your ideal is, we know we can get you there.

As the world&#;s clean air experts and industry leaders, we are always putting our best foot forward when it comes to optimizing your cleanroom and preventing yield loss. We perfected real-time particle monitoring technology and are always striving for more ergonomic and practical advances. For example, our Apex Z has set industry records for the longest battery life and shortest recharge time. Just one more thing you don&#;t have to worry about.

Here at Lighthouse Worldwide Solutions, we&#;re all about just that: solutions. Solutions for your particle counting needs, solutions for helping you achieve your cleanroom classification, and solutions for the ups and downs that come with working in a cleanroom.

For more information, please visit clean room standard.

And we do it so you don&#;t have to think about it.

Want to find out which one of our particle counters will optimize your cleanroom contamination strategy and improve your production? Find out today.

Figure 1. ISO-7 medical device cleanroom

To make cleanrooms clean the cleanroom are built using HEPA filtration, non-particulating materials, airlocks, and non-particulating flooring. In addition,  cleanroom personnel follow special rules such as wearing cleanroom garments, no eating or drinking, and wipe down the cleanroom on regular basis. Finally, cleanrooms monitor the cleanliness of the room using particle testing and biological settling plates.

1. Cleanroom design elements that make the cleanroom clean:

Cleanroom use HEPA filtration to remove particulates from the air. HEPA is &#;an acronym for "High Efficiency Particulate Air [filter]" (as officially defined by the U.S. Dept. of Energy). This type of air filter can theoretically remove at least 99.97% of dust, pollen, mold, bacteria, and any airborne particles with a size of 0.3 microns (µm).&#;   HEPA fan filter units have fan attached to HEPA filter assembly to push the air thru the filter (figure 2) . The HEPA fan filter units are placed in ceiling of cleanroom (figure 3) so the only air entering the cleanroom is clean air thru the HEPA fan filter units.

Higher class cleanrooms can also use ULPA filters. ULPA  stands for Ultra Low Particulate Air. ULPA filters are denser than HEPA filters, so they are 99.999% effective at removing particulates 0.12-micron diameter or larger.  The HEPA fan filter units are placed in ceiling of cleanroom (figure 2) so the only air entering the cleanroom is clean air thru the HEPA fan filter units.

Figure 2. HEPA fan filter unit Figure 3. Recirculating modular cleanroom with HEPA fan filter units in negative pressure plenum

Cleanroom have Air lock/Gown room to prevent particles from entering the cleanroom every time the door is opened. The airlock prevents 96% of particulates from entering the cleanroom. The room also provides a clean space for personnel to put on their cleanroom garments &#; which also stops particles from entering the cleanroom.

Figure 5. Cleanroom epoxy flooring

Only non-particulating materials used for cleanroom construction

1. Modular cleanroom walls have Melamine, vinyl, FRP, or painted aluminum surfaces. Standard construction gypboard walls must be painted with epoxy paint.

2. Only special vinyl coated cleanroom ceiling tiles are used in cleanroom ceilings. Standard commercial ceiling tiles will particulate.

3. Special sealed lights are used in cleanrooms to keep particulates from leaking into cleanroom from plenum.

4. Cleanrooms have special flooring requirements. Not only must the flooring be non-particulating, but it must be easily cleanable and durable since in medical device and pharmaceutical cleanrooms it is subject to frequent cleaning with harsh cleaning agents.  Acceptable flooring materials include Industrial VCT, epoxy, heat welded vinyl, heat welded vinyl with integral cove. The type of flooring selected depends on cleanroom classification, industry of user and expected cleaning regimen.

Figure 6. Cleanroom Air shower

5. Some cleanrooms use Air showers as last step before personnel enter cleanroom. The purpose of the air shower it to blow off any particulates on the outside of personnel cleanroom garments with HEPA filtered super clean air.

2. Cleanroom personnel rules to prevent them from introducing particulates into the cleanroom. These include:

1. Always wear cleanroom garments when inside cleanroom
2. No eating or drinking in cleanroom
3. Cleanroom doors always kept closed after entering cleanroom
4. Wipe down all cleanroom surfaces on regular basis
5. Wipe down all equipment before bringing into cleanroom
6. Do not bring cardboard or other particulating material into cleanroom.

3. Cleanrooms must be cleaned on a regular basis to keep them clean. 

Figure 7. Cleanroom garments for ISO-5 cleanroom

Daily or weekly cleaning is done to remove an particulates that may have settled on walls, work surfaces or floor.

1. Industrial cleanroom are typically wiped Isopropyl wipes or Simple Green.  
2. Pharmaceutical and medical device cleanrooms often use more aggressive cleaning  agents like bleach, spore-clean, De-ton, perchloric acid to attack microbial or mold contamination.

Figure 8. Cleaning tools

4. Regular Cleanroom Testing

Cleanroom are typically tested internally weekly or monthly with annual 3rd party testing. The cleanroom is tested to ensure it meets the ISO -1 cleanroom classification. Viable testing is also done to ensure cleanroom meets sterility requirements.  Regular testing is an important part of keeping a cleanroom clean. Testing will show if there are contamination problem and allow the cleanroom user to address the problem.

A. For cleanroom classification - the test is for non-viable particles. For ISO -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 10. Laser particle counter for cleanroom testing

B. Cleanroom 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 11 . Settling plates for cleanroom viable particle counts

Conclusion

The science of making cleanrooms include  using HEPA filtration, non-particulating materials, airlocks, and non-particulating flooring. In addition, cleanroom personnel follow special rules such as wearing cleanroom garments, no eating or drinking, and wipe down the cleanroom on regular basis. Finally, it is important monitor the cleanliness of the room using particle testing and biological settling plates to identify problems and address them. 

Property American Cleanroom Systems

The author Anthony Chien has worked at American Cleanroom Systems for past 11 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 pharmaceutical cleanrooms, medical device cleanrooms, and industrial cleanrooms.

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