08 Jan ISO 6 vs ISO 7 Cleanrooms: Sorting Out the Differences

Confused about ISO 6 vs ISO 7 cleanrooms? You’re not alone, as many people get lost in the technical-sounding jargon. In truth, however, it’s not nearly as complicated as it seems. It’s important to know the difference, too, especially if you’ve been tasked with figuring out which classification your organization needs; the wrong choice can increase contamination risks, or else lead to unnecessary costs. In this article, we’ll compare and contrast ISO 6 vs ISO 7 cleanrooms, discuss their requirements, applications, and more.

An Overview of ISO 6 vs ISO 7 Cleanrooms

As most people already know, the International Organization for Standardization classifies cleanrooms from ISO 1 (the cleanest) to ISO 9 (the “dirtiest”). ISO 6 and ISO 7 cleanrooms appear to be nearer to the “dirtier” classes of cleanrooms, but for all practical purposes, they are considered mid-range. And because they differ by only one number, some may make the mistake of thinking they are very similar, so let’s take a  quick look at their main differences.

The main distinction between ISO 6 vs ISO 7 cleanrooms lies in the size and number of particles they allow. ISO 6 cleanrooms allow far fewer particles than ISO 7 spaces, and even place limits on smaller particles that aren’t relevant or counted in ISO 7.

The result of all this is that ISO 6 spaces require more air changes (an important metric marking cleanliness), are more expensive (all else being equal), and therefore have different applications than ISO 7 spaces.

Here’s a quick table showing the major differences, which we will explore in more detail in the following sections.

Particle Count Differences

As always, the primary difference between ISO cleanroom classifications are particle count differences.

To be specific, ISO 6 cleanrooms allow no more than 35,200 particles (0.5 micrometers or larger) per cubic meter, while ISO 7 cleanrooms can permit up to 352,000 particles of the same sizes.

However, as you can see in the representation above, ISO 6 cleanrooms put a cap on particles at sizes as low as 0.1 micrometer, while ISO 7 cleanrooms stop measuring at 0.5 micrometers.

This is because the work done in these cleanrooms can be affected by particles of small sizes such as these, while ISO 7 applications do not generally need to worry about them.

If only looking at particle counts, it is clear that ISO 6 cleanrooms are roughly ten times cleaner than ISO 7, which is no small difference, despite the fact that they are only one number apart.

Air Change Rate Requirements

Similarly, the air change change rates, or air changes per hour (ACH), are very different in ISO 6 vs ISO 7 spaces. To keep it simple, ACH is just an indication for how many times the air is replaced in one hour (at least, in theory). In other words, the higher the ACH, the cleaner the space will be.

The ACH required in each classification can vary widely, and depends on many factors, including the size of the cleanroom. However, speaking generally, we can say with some confidence that ISO 6 cleanrooms require 150 to 240 ACH, while ISO 7 cleanrooms only require 60 to 120 ACH.

The higher ACH in ISO 6 spaces means they are “cleaner,” but this also affects their costs.

Relative Costs

When trying to figure out the costs of cleanrooms, you have to keep in mind both the cost to build and the cost to operate. When considering ISO 6 vs ISO 7 spaces, ISO 6 will undoubtedly be more expensive, all else being equal.

This is because, as we have stated already, ISO 6 environments need more air changes, which requires more advanced HVAC systems, higher energy costs, and stricter monitoring.

Applications of ISO 6 Cleanrooms

ISO 6 cleanrooms are important in industries where particles tinier than 0.5 micrometers may cause damage to products or sensitive processes. Some common uses include:

• Semiconductor manufacturing.
• Pharmaceutical compounding.
• Biotechnology.
• Medical device manufacturing.
• Optical manufacturing.
• Aerospace.

Applications of ISO 7 Cleanrooms

ISO 7 cleanrooms are also important to many industries, but of course require much less control over particle limits and sizes. A few common applications include:

• Biotechnology.
• Electronics.
• Precision manufacturing.
• Automotive manufacturing.

Please note that while the applications for ISO 6 and ISO 7 cleanrooms seem to overlap, they will typically be used in different stages of the manufacturing or scientific process, namely ones that need to be more or less strict.

The Bottom Line

If you need to decide whether your organization needs an ISO 6 or ISO 7 cleanroom, it’s important to know that each has distinct applications, particle limits, HVAC requirements, and other differences. Though they are close in number, ISO 6 cleanrooms are roughly ten times cleaner than ISO 7 ones. Choosing the right classification will depend on your specific industry standards, budget considerations, and other factors.

Still confused? Reach out to the experts at Allied Cleanrooms to make sense of what you need and get a quote on new ISO 6/7 spaces.

FAQs About ISO 6 vs ISO 7 Cleanrooms

1. What is the main difference between ISO 6 and ISO 7 cleanrooms?

The main difference is that ISO 6 cleanrooms allow far fewer particles than ISO 7 ones.

2. Are ISO 7 cleanrooms good for food processing?

Yes, actually, both ISO 6 and ISO 7 cleanrooms are quite common in food processing.

3. How does airflow design differ between ISO 6 and ISO 7 cleanrooms?

Typically, ISO 6 and ISO 7 spaces do not need unidirectional or laminar airflow. However, they may need to use it in some smaller area of the cleanroom. All this will depend on exactly what the cleanroom is being used for.

If you’re interested in learning more about the differences between individual ISO classifications, check out our other articles on ISO 5 vs ISO 7, ISO 7 vs ISO 8, ISO 5 vs ISO 6, and ISO 5 vs ISO 8.