Kleanlabs’s Guide To Clean Room Standards And Classifications

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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The oldest, US FED STD 209E standard is no longer valid.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
Class	≥ 0,1 µm	≥ 0,2 µm	≥ 0,3 µm	≥ 0,5 µm	≥ 5 µm	ISO equivalent
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
Class	≥ 0,1 µm	≥ 0,2 µm	≥ 0,3 µm	≥ 0,5 µm	≥ 1 µm	≥ 5 µm	FED STD 209E equivalent
ISO 1	10^b	^d	^d	^d	^d	^e
ISO 2	100	24^b	10^b	^d	^d	^e
ISO 3	1 000	237	102	35^b	^d	^e	1
ISO 4	10 000	2 370	1 020	352	83^b	^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.