ISO 14644 is an International Organization for Standardization standard that specifies a methodology for cleanroom design, classification, and operation. The ISO 14644 international standard specifies a cleanroom classification scale from 1 to 9. 

A cleanroom’s cleanliness is measured in regards to the amount of airborne particulate per cubic meter and the average particle size, with a rating of 1 indicating the cleanest possible environment. To put it another way, the number should be lower if the air quality should be higher.

These extremely controlled environments are utilized in a wide variety of different industries, including the manufacturing of pharmaceuticals, biotechnology products, medical devices, and batteries, to name a few. 

In order to lessen the risk of contamination and maintain control over other aspects of the surrounding environment, including temperature, pressure, and humidity, precautions have been taken.

It is important to ask yourself the following three questions before deciding which cleanroom ISO standards are ideal for your needs:

  • What is the size of the particles that need to be removed from the mixture?
  • Who or what might have been responsible for the contamination?
  • How much air does the room need to have to circulate in order to clear it of the contaminated particles?

Before you make a decision about getting a cleanroom for your manufacturing, it is important to know these aspects in depth and determine what makes a difference in the cleanroom standards.

Particle Size

One of the most important pieces of information needed when planning a cleanroom is the particle size range that will have to be filtered out. To help with the huge percentage of the “greater than” calculations, see the table at the end of this piece.

For instance, the number of particles per cubic meter that are less than 0.5 microns in size must be less than 35,200 in an ISO 6 cleanroom. These are so small that they are indiscernible to the naked eye. To give you an idea of their size, one human hair is 100 microns in width, whereas the smallest particles that the human eye can detect are at least 50 microns across.

Cleanrooms that meet the stringent standards of ISO 1 are exceedingly uncommon because the surrounding atmosphere can never have more than 0.23 particles measuring 0.1 microns each and every square meter. Making this kind of controlled environment is extremely challenging, and only a handful of locations in the world can satisfy these requirements.


The two most common causes of contamination in a cleanroom are human activity and the nature of the procedure being carried out there. This means that you should anticipate these challenges before you begin planning your cleanroom. Ventilation grills and filtration systems, when placed strategically, can help keep a space clean.

Cleanrooms that have an ISO class of 7 or lower are needed to have a different room for dressing or gowning, which will keep the dirt from the outside from getting into the main cleanroom. Maintaining environmental control is essential in any manufacturing setting, whether it be for the production of pharmaceuticals or e-liquid, in order to eliminate the risk of cross-contamination.

Circulation of the Air

The HVAC (heating, ventilation, and air conditioning) system is one of the essential components that play an important role in maintaining order in this environment. Air filtration by means of HEPA (high-efficiency particulate air) filters, which are installed into the ceiling of a cleanroom and can remove particles as small as 0.3 microns, is an essential component of this system. 

This process results in the creation of an environment with positive pressure, which is defined as an internal pressure that is higher than the pressure of the surrounding environment. The air is forced to move toward the room’s lower half, where it is then expelled through vents that have been installed at the base of the cleanroom’s walls. This calls for an increase in the amount of air conditioning, as well as additional filters and space for circulation.

Changes in air flow contribute to the process of air dilution. As a result, the air is diluted to an acceptable concentration to a greater degree the more frequently it is changed.

The classification system was developed in order to assist with the classification of ISO 9. It is essential to construct a cleanroom that satisfies your requirements at a price that is affordable as compared to other options.