Everything you need to know about cleanroom standards

Cleanrooms are special rooms or indoor environments where the number of particles and contaminants in the air, the temperature, humidity and pressure are all prescribed by strict standards, including the number of micron and tenthmicron particles. Cleanrooms are meant for controlling and maintaining the number of these particles on the same level.

Cleanrooms are used widely across several industries such as fine mechanics, pharmaceuticals, automotive and space technology. More and more industries have been discovering the benefits of using cleanrooms in their production. All these industries require a highly controlled environment provided by high-quality equipment.

Why control the air?

The reason is different in each industry. Mostly, the goal is to create products that are completely protected from airborne contamination. For example, no one wants to see a small particle or dust behind the display of a new phone. There are many other reasons apart from this, why cleanrooms should be used in manufacturing. For the pharmaceutical and microbiology industries, it is critical to maintain sterility and extreme hygiene, while in laboratories, the main goal is to keep the samples protected from the lab environment.

Cleanroom Standards

US FED STD 209E

The oldest, US FED STD 209E standard is no longer valid. However, several multinational companies still determine their requirements based on FED209E standards to this day.

Class maximum particles/ft3 ISO equivalent
≥ 0,1 µm ≥ 0,2 µm ≥ 0,3 µm ≥ 0,5 µm ≥ 5 µm
1 35 7,5 3 1 0,007 ISO 3
10 350 75 30 10 0,07 ISO 4
100 3 500 750 300 100 0,7 ISO 5
1 000 35 000 7 500 3 000 1 000 7 ISO 6
10 000 350 000 75 000 30 000 10 000 70 ISO 7
100 000 3.5×106 750 000 300 000 100 000 830 ISO 8

ISO 14644-1

ISO14644-1 is the most widespread modern cleanroom standard that not only defines the design of clean rooms, but also provides guidelines for implementation and use. Many manufacturers base their requirement system on ISO-14644:

Class maximum particles/m3 a FED STD 209E equivalent
≥ 0,1 µm ≥ 0,2 µm ≥ 0,3 µm ≥ 0,5 µm ≥ 1 µm ≥ 5 µm
ISO 1 10b d d d d e
ISO 2 100 24b 10b d d e
ISO 3 1 000 237 102 35b d e 1
ISO 4 10 000 2 370 1 020 352 83b e 10
ISO 5 100 000 23 700 10 200 3 520 832 d,e,f 100
ISO 6 1 000 000 237 000 102 000 35 200 8 320 293 1 000
ISO 7 c c c 352 000 83 200 2 930 10 000
ISO 8 c c c 3 520 000 832 000 29 300 100 000
ISO 9 c c c 35 200 000 8 320 000 293 000 Room air

a The following concentrations are cumulative measures, i.e. maximum permissible levels in a certain category refer to all particles of a given size or smaller.

b When testing these values, a large volume of air is required for sampling, which the standard makes specific recommendations for.

c This value is not specified by a certain class, since the limit would not be significant because of the very high concentration values.

d Measuring such small concentrations is not practical due to technical difficulties, therefore, these values are not specified by the standard.

e Measuring the low concentration of particles larger than 1 μm is problematic because the meter itself absorbs a fraction of the particle, which is difficult to control. Thus, these values are not specified.

EU GMP

The GMP guidelines may be the strictest standards for cleanrooms, as they require an in-service qualification process, i.e. the cleanroom is tested during normal operations.

Class maximum particles/m3
At Rest In Operation
≥ 0,5 µm ≥ 5 µm ≥ 0,5 µm ≥ 5 µm
Grade A 3 520 20 3 520 20
Grade B 3 520 29 352 000 2 900
Grade C 352 000 2 900 3 520 000 29 000
Grade D 3 520 000 29 000 Not defined Not defined

Nevertheless, cleanroom standards do not only include requirements referring to the number of particles in the controlled environment. Well-designed cleanrooms take into account the number of air exchanges required to stay within the boundaries, the required inflow and suction points, their positioning and coverage of the ceiling, and the direction of air flows.

Cleanroom standards therefore include complex technology guidelines that help you to create an environment with appropriate equipment that matches the specificities of your industry.

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