What is Air Permeability?

Link to YouTube ChannelĀ 

Link to LinkedIn PageĀ 


Need help choosing the right clean room door for your factory? Check out the full range of suitable hygiene doors here.




Our question this week is about Air Permeability. What is it, and why is it important? Let’s break it down. The Latin origin of the word ‘permeability’ (or ‘permeable’) is ‘permeare’, meaning “to pass through.” Simply put, Air Permeability refers to how much air is able to pass through a material, or product, within a given period of time. The British Standard for testing air permeability of industrial doors is BS EN 12427. In this test, a sample is installed onto a rig and subjected to a positive air pressure of 50 pascals. The air leakage through the doorway is then measured over one hour. The results are shown as air leakage (m3/h) divided by the surface area of the sample door (m2). The results are split into 5 different classifications for comparison purposes, the lower the air leakage, the higher the class it achieves. Specialist industries like pharmaceuticals and battery manufacturing rely on being able to control the air quality of their production environments to extremely tight margins. Air permeability through doorways is one critical factor in enabling this control.

We’re now going to cover off 5 reasons why air permeability is critical for cleanroom doors:


  1. Particle Control: Cleanrooms aim to limit the presence of airborne particles, including dust, microbes, and other contaminants. Doors with an appropriate air permeability rating help to prevent the entry of particles from the surrounding environment into the cleanroom.
  2. Pressure Differentials: Cleanrooms are usually maintained at a very specific air pressure differentials to control the direction of air flow. Doors with controlled air permeability help to maintaining these pressures, preventing uncontrolled air exchange between cleanroom zones and adjacent areas.
  3. Airflow Control: In some cleanroom processes, maintaining specific airflow patterns is critical. Cleanroom doors with controlled air permeability help to manage the airflow within the cleanroom areas, preventing turbulence or unwanted air movements that could carry contaminants.
  4. Temperature and Humidity Control: Certain cleanroom processes require precise control over temperature and humidity levels. Doors with the correct air permeability rating contribute to maintaining these environmental conditions by preventing the influx of outside air that is likely to have different temperature or humidity characteristics.
  5. Energy Efficiency: In addition to cleanliness considerations, the air permeability in cleanroom doors can contribute to energy efficiency. Well-designed doors can minimize the loss of conditioned air, helping to maintaining stable temperature and humidity levels without excessive energy consumption.


In summary, air permeability of cleanroom doors is a critical aspect for controlling the required cleanliness and environmental conditions within cleanrooms.

If you found this video useful, consider subscribing to the Tekta YouTube Channel, or following our LinkedIn page where we’ll be answering more questions every week.