Having the proper level of cleanroom control is essential for the quality of your product/s as well as the safety of your customers and employees.  

There are differing cleanroom standards that operations need to abide by for various reasons.  The international classifications for these rooms may determine whether there is an appropriate level of filtration to assure the safe production of a product.

Although cleanrooms are required in several manufacturing applications, not all are created equal.


  • Internal Surfaces
    • Every surface in a cleanroom must be smooth and impervious to microorganisms.
    • They should be simple to clean and strong enough not to crack or shatter easily.
    • Important that their materials do not create dust or flakes.
  • Air Flow
    • The air handling system employed must be effective at circulating particles out of the room.
    • Filters typically are used to clean any contaminants such as moisture, vapors, or particulates.
    • After it is cleaned, the air may recirculate into the space or fresh air can be pumped into replace it.
  • Employee Access
    • Only specially trained personnel should be allowed inside the room, and the number of people should be strictly controlled.
    • People are the largest source of contamination; managing those who come in our out should be high priority.


Cleanrooms are classified according to ISO (International Standards Organization) guidelines.  The nine classes are based on the level of particulates in the air.  Class 1 is the cleanest, while Class 9 allows for the highest level of contaminants.

Contamination is measured in terms of particles per cubic meter.  These measurements include particles as small as .1 microns in size.  As classifications increase, the concentration of particles allowed decreases.   EXAMPLE:   A Class 4 cleanroom can only allow 350 particles per cubic meter of contamination, whereas a Class 3 room can only have 35 particles per cubic meter.   The smaller a particle is, the higher the allowable concentration in the air.


  • When should you test your cleanroom: The most current version of ISO specifies that testing should be performed based on risk assessment of the intended use.
    • Evident of cleanroom performance related to particle concentration is the metric used to determine this.
  • How often should your cleanroom be inspected: The rule of thumb is that the more stringent the standards of the classification, the more frequent inspections need to be.
    • These inspections typically are connected to compliance testing, which can occur once or twice per year.
  • How clean does your cleanroom need to be: The level of cleanliness required by your facility will depend on the standards of your industry.
    • Based on what you produce, there also may be government regulation s you need to observe.
    • If there are no mandated requirements, you may need to consider your specific product tolerances and internal quality control standards.

If you have questions about cleanroom requirements and what they could mean for your operations, contact us, or give us a call at (614) 771-4700.  At Scientific Equipment Calibration in Ohio, we are here to answer any questions you may have.