When it comes to cleanroom ratings, There are several doubts regarding some concepts and categorizations of controlled environments.

These questions often concern how to determine whether a cleanroom is Grade A, B, C or D. What is class 100 cleanroom? How to define each of them?

Continue reading and clear all your doubts.

There are numerous standards, GMP guides and legislation that are used for cleanroom classifications.

This material will clarify and clarify doubts regarding the classifications of clean areas. Check out each of the controlled environment categorizations below:

Classification of clean rooms according to ISO 14644

A NBR ISO 14644 classifies air purity levels into classes 1 to 9. It is applicable in clean rooms, in bulk, such as: pharmaceutical, veterinary, microelectronics industries, etc.

To classify this type of clean room, it is also necessary follow criteria regarding particle size in a given room volume. Check out how this classification works below:

Class 1 to 5 clean room

Class 1 to 5 cleanrooms operate under a laminar (unidirectional) airflow regime and are characterized by:

• Total air replacement every six seconds;
• Air flows uniformly from the ceiling at a rate of 0,45 meters per second;
• Filters throughout the ceiling;
• There are no drafts within the controlled environment;
• There is a uniform air flow through the environment without transversal dispersion of particles;
• Air is only removed from the room by exhausting the floor.

Class 6 to 9 clean room

Class 6 to 9 clean rooms operate under turbulent air flow and are characterized by:

• Air flowing from diffusers in the ceiling at a rate of 0,45 meters per second;
• Air currents within the controlled environment;
• Existence of transversal dispersion of particles within the controlled environment;
• Air is removed from the environment by exhaustion through the floor or ceiling.

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Classification of Cleanrooms: Grade A, B, C or D areas

In addition to the classifications noted above, there are other designations that are defined as grade A, B, C or D, based on EU GMP. They establish the limits for particles suspended in the air, in the occupational states “at rest” and “in operation” and also the limits for microbiological contamination during “in operation” monitoring.

To be clearer, when it is determined that a cleanroom is grade C, consequently it is understood that the maximum particle limits ≥ 0,5 µm and ≥ 5,0 µm are determined for this environment, in the “at rest” and “in operation” condition.

The same occurs in the case of particles suspended in the air, the maximum permissible limits of microbiological contamination during operation are also defined for each room grade.

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Class 100, 10.000 and 100.000 clean rooms

This type of classification was extremely common in Brazil before the publication of the ISO 14644-1 standard in 1999. It was created by US Federal Standard 209, which defined maximum numbers of particles suspended in the air = 0,5 µm per cubic foot.

Por exemplo, One Standard class 100 cleanroom must never exceed 100 particles greater than or equal to 0,5 µm per cubic foot. As for class 10.000, the maximum number of particles must be precisely 10.000 particles/ft³.

To be clearer, when it is determined that a clean room is grade C, consequently it is understood that the maximum particle limits ≥ 0,5 µm and ≥ 5,0 µm are determined for this environment, in the “at rest” and “in operation” condition.

An American standard, the FS 209, in its first versions, was only used with English units. Later, in revision E, it already pointed out the other corresponding metric units. In 2001, FS 209-E was canceled and replaced by parts 1 and 2 of the ISO 14644 standard.

In 2004, the FDA Guidance for Industry – Sterile Drug Products Produced by Aseptic Processing – Current Good Manufacturing Practice – was published. After the publication of this document, the 100, 10.000 and 100.000 class designation remains in effect despite the fact that FS 209 is cancelled. According to the FDA, once the cleanroom classification is defined, the boundary of this environment is automatically defined as follows:

• Airborne particles ≥ 0,5 µm;
• Viable particles obtained from active sampling of air and sedimentation plates.

The FDA document established limits only for particles ≥ 0,5 µm. The limits for particles ≥ 5,0 µm have no determinations established by the FDA.

It is very important to make it clear that when someone says that a certainwing is belonging to class 10.000, For example, for the specification to be complete, it is necessary Complement with the occupational status of this room. This, in practice, means that the room is class 10.000 at rest or in operation. After all, the FDA document does not specify the occupational status of the room.

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Critical, semi-critical and non-critical areas

The level of air purity required in a controlled environment is what determines what the rating will be. This is achieved according to each room's application and site needs. Quality levels are deferred for each clean area, with classes established for air purity.

critical area

Critical areas are environments that offer a high level of contamination development, as the place is intended for patients with infectious diseases, whose pathogenic agent is highly transmissible. Examples: laboratory, neonatal ICU, blood bank, material and sterilization center, isolation unit, burn patients and operating room, etc.

semi-critical area

It is classified as semi-critical area the environment that offers less risk of contamination development in relation to the critical area. Examples: pharmacy, restrooms, clinics, etc.

non-critical area

These are environments that offer no risk of contamination and are not occupied by any patient, in most cases. Examples: offices, warehouses, x-ray rooms, ultrasound, etc.

Well, it was clear in this material that there are several standards and documents that are used as a reference to determine the classification of a clean room. But it is important to note that they are all valid. The class designation of cleanrooms depends a lot on the legislation and the GMP guide that the company chooses to adopt.