21 Mar ISO 7 Cleanrooms Explained: What You Need to Know

Understanding cleanrooms and their classifications can be confusing. Simply put, cleanrooms limit air particles to prevent contamination. Each class only differs in the number and size of particles allowed. In this guide, we’ll focus on ISO 7 cleanrooms and their key features.

What is an ISO 7 Cleanroom?

An ISO 7 cleanroom, as defined under the ISO 14644-1 standards, limits the number of air particles (think dust, microbes, and vapors) to maintain cleanliness. Per cubic meter, it allows a maximum of the following:

• 352,000 particles 0.5 micrometers or larger
• 83,200 particles 1 micrometer or larger
• 2,930 particles 5 micrometers or larger

As you can see from the chart above, ISO Class 7 cleanrooms only target particles that are 0.5 micrometers or bigger. They do not focus on smaller particles, such as those between 0.1 and 0.3 micrometers. This is because the smaller particles have less impact on the work done in these rooms.

Are ISO Class 7 Cleanrooms the Same as Class 10,000 Cleanrooms?

ISO 7 cleanrooms correspond to Class 10,000 under the older Federal Standard 209E. This older standard used particles per cubic feet for measurement. The ISO 14644-1 standard, on the other hand, uses particles per cubic meter, and has replaced Fed Standard 209E, making ISO the current global standard.

Although the Federal Standard 209E is no longer in use, the terms “Class 10,000,” “Class 1,000,” etc., are still commonly used for ease of reference.

Both ISO 7 and Class 10,000 standards require cleanrooms to have less than 352,000 particles bigger than 0.5 microns in each cubic meter of air.

ISO 7 Cleanroom Requirements

ISO Class 7 cleanrooms need to stay clean to keep the air particles at the right levels. They do this by changing the air often and using efficient filters to remove remaining particles. They also make sure the airflow is just right to stop contamination. In this section, we’ll go over some of the main requirements that keep the air in these cleanrooms pristine.

Air Changes per Hour

A high number of air changes per hour (ACPH) helps cleanrooms stay clean. ACPH tells us how often the air in a room is completely changed with new air in one hour.

ISO 7 cleanrooms replace their air 60 times each hour. This means that every minute, the air inside is completely replaced.

For some perspective, the American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE) suggests that a typical home should have a minimum of 0.35 ACPH to ensure good indoor air quality.

In other words, ISO Class 7 cleanrooms are much cleaner than the average house. To keep the air clear of particles, they use a special system. Let’s look at how that system works.

HEPA Filtration

A high-efficiency particulate air (HEPA) filtration system is crucial for filtering out particles in an ISO 7 cleanroom.

These filters trap 99.97% of particles 0.3 micrometers or larger. Their high efficiency ensures the air meets ISO 7 standards by capturing almost all airborne particles. This effectiveness is key for controlling contamination.

Optimizing Airflow for Cleanliness

In ISO Class 7 cleanrooms, how airflow is designed is just as important as filtration.

In most cases, turbulent air flow is sufficient to meet the standard. However, in special cases, you may need unidirectional or laminar flow, where air moves in a single direction at a consistent speed.

This ensures that particles are swept away from critical areas and towards the air returns, without creating turbulence that might push particles back up into the air.

The combination of high efficiency filtration and carefully designed airflow patterns minimizes the risk of contamination for sensitive processes.

How are ISO 7 Cleanrooms Used?

ISO Class 7 cleanrooms are used in many industries. They are important both for making safe products and for meeting regulations.

For example, in making medicines, they stop contamination during important steps like filling products. These cleanrooms also serve in making sterile drugs, building parts for spacecraft, and preparing food cleanly.

Other industries that commonly use these cleanrooms include:

• Biotechnology
• Electronics
• Optical manufacturing
• Medical devices manufacturing
• Automotive manufacturing

Understanding ISO 7 Cleanroom Variability

While ISO 7 cleanrooms are designed to meet strict standards, factors such as size, layout, specific industry requirements, and individual customer needs can greatly influence their design. Given this variability, it’s important to tailor each cleanroom to its intended use.

If you’re considering an ISO 7 cleanroom, we recommend contacting our engineers at Allied Cleanrooms. They can guide you through the options and help design a cleanroom that perfectly fits your requirements.