Lab Factory Dust Free Cleanroom iso 7 level prefabricated clean room

Cleanrooms are classified by how many particles are in the air, as well as how big those particles are, within one cubic meter of air. The smaller the classification is, then the more sterile the clean room. These standards are used amongst different industries, some requiring a higher level of cleanliness.

ISO 14644-1 addresses the cleanroom classification in regards to cleanliness and particle sizes, ranging from 0.1 µm to 5.0 µm. Prior to introduction of ISO 14644-1 (Nov. 2001), Federal standard 209E (FED STD 209E) was main reference used to classify cleanroom cleanliness. Small numbers refer to ISO 14644-1, which indicates the number of particles 0.1 µm or larger allowed per cubic meter of air.
To comply with ISO standard, each classification requires a different air changes/hour, room velocity and filter coverage, ranging from ISO 3 (class1) having the highest air changes per hour.

ISO Class 7, (Class 10,000 FED STD 209E)

This particular class is often called class 10,000, and for particles smaller than 0.5 µm, there can be up to 352,000 cubic meters. For larger particles that still fall under 1.0 µm, there can be up to 8,320 particles. In addition, particles in this class can be up to 5 µm but are limited to 2,930 particles per square cubic meter.

In addition, ISO Class 7 is typically classified as Grade C. This means that at rest, 352,000 particles smaller than 0.5 µm can be present at any given time. During operation, this number multiplies to 3,500,000 particles. Most of these are generated due to the use of equipment and movement that occur.

What is measured in the air?

Class 3, 4, and 5 are based on the maximum number of 0.1 and 0.5 micron particles that are permitted in a cubic foot of air approaching any work operation within the room. Class 6, 7, and 8 are based on the number 0.5 micron particles.

What is a micron?

To give you an idea of what is being measured, one micron is one-hundredth the width of a human hair. The smallest particle seen with the naked eye is a 10 micron particle.

Where do these particles come from?

The clean room is under positive pressure, keeping out new particles from coming in. So where do they come from? We shed our outermost layer of skin every 24 hours, that is 1 billion flakes every 24 hours! One flake is about 35 microns.

What are the clean room classifications?

The ISO 14644-1 has changed these numbers to simple classes: