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Cleanroom Classification Requirements: Design, Redesign & Compliance

May 21,2018| by Patricia Kelly


Cleanroom classification is one of the most complex – yet essential – parts of designing and building a cleanroom. There are many important questions that need to be asked when planning for, designing and setting up your cleanroom.

Types of Cleanroom Classifications

Cleanroom Classifications follow strict Cleanroom Guidelines from the following independent and governmental organizations:

  • FDA - CFR: Code of Federal Regulations, ex.  21 CFR Part 11
  • ISO – International Organization for Standardization
  • USP – United States Pharmacopeia – compendia of monographs
  • cGMP - Current Global Manufacturing Process

The different cleanroom classifications are based on contaminants which are measured in microns. Microns, or micrometers are equal to 1 millionth of a meter. For comparison, a head of a pin is 2mm.

While, FED classes no longer used, they are still talked about frequently. The US FED-STD-209E was a United States federal standard, that was officially cancelled by the General Services Administration on November 29, 2001, but is also still widely used:


So what cleanroom guidelines do you need to follow? Unclear as to which cleanroom classification will work for you? Check out this post outlining the top 5 answers to the most common cleanroom classification questions.  


Top Sources of Cleanroom Contamination

Bioburden is the number one source of cleanroom contamination and is defined as the number of bacteria living on a non-sterilized surface. Over 80% of cleanroom contaminants are derived human body, with a cleanroom’s personnel being the primary source of bioburden.

At complete rest, individuals shed about 10,000 particles per cubic meter. The outer layer of skin hosts up to a million microorganisms per square cm. Even water can introduce contaminants to the environment during the gowning process in cleanrooms.

Because bioburden is the top source of cleanroom contamination, after determining the classification of cleanroom and the guidelines to follow, it is essential to research the necessary equipment that will help keep your cleanroom contaminant-free. Equipment should be designed to generate minimal air, water and employee contamination.

How Most Cleanrooms are Designed to Prevent Contamination


Air Contamination:

Most cleanrooms are designed so that the air entering a cleanroom is filtered to exclude dust, and the air inside is constantly recirculated through high-efficiency particulate air (HEPA) and/or ultra-low particulate air (ULPA) filters to remove internally generated contaminants.

Even the equipment inside the cleanroom is designed to generate minimal air contamination. Only special mops and wipes are used. Cleanroom furniture is designed to produce minimum particles and be easy to clean. Plus, common materials like paper towels and cardboard which are made from natural fibers are often excluded to reduce the presence of particles.

Many cleanrooms also have an air shower at their entrance to help prevent air contamination.


Staff Contamination:

Most cleanrooms use an anteroom, also known as a "gray room", to help prevent employee contaminants from entering the cleanroom. Staff enter and leave the anteroom and cleanroom through airlocks. Plus, tacky mats, air showers or both are also used to prevent contaminants from entering the anteroom and cleanroom from employee clothing and footwear.

Once in the anteroom, employees follow proper gowning procedures to put on protective clothing such as hoods, face masks, gloves, boots, and coveralls. These types of PPE or Personal Protective Equipment can vary depending on the classification of cleanroom. Garbing order is typically dirtiest to cleanest: Shoes/shoe covers, facial/hair covers, glasses – WASH HANDS – non-shedding gown, gloves (sanitizer).

Gowning methods and the materials used are critical to minimize contamination and provide a barrier between the individual and the at-risk product. Additionally, good gowning practices protect the cleanroom technician from the product.




CleanTech Automated Handwashing Stations Meet Cleanroom cGMP Requirements & Reduce Bioburden

Meritech’s Cleantech Automated Handwashing Stations are designed specifically for cleanrooms with all of these design elements and current cleanroom classification trends in mind. Cleantech handwashing systems are clinically-validated to remove pathogens and particulates. In an independent study from one of our Fortune100 med device accounts, a 3 log reduction in measurable bioburden was determined from using our fully-automated handwashing systems. To learn more about how Meritech can help reduce bioburden and improve employee hygiene practices, contact us today.