Frequently Asked Questions

  1. What is a cleanroom?
  2. What is worn in a cleanroom?
  3. What are sterile environments?
  4. How are cleanrooms classified?
1.What is a cleanroom?

A cleanroom is a room in which the concentration of airborne particles is controlled. Particles are controlled by the filters that surround the room. These filters cause the air to move in a vertical direction, laminar air flow, through the room. Cleanrooms are used for manufacturing computer chips, semiconductors, drugs, and much more. These products are manufactured in this type of environment to prevent small airborne particles or lint from getting on the surface of a computer chip and destroying it. This is called particle contamination.


The key objective in a cleanroom is to prevent particles shedding into the air and/or onto the surface of a product.

Sources of contamination

  • people and their activities
  • apparel and/or accessories
  • supplies
  • filters


To prevent contamination from personnel, the correct gowning system should be in place. The room and the filters should also be monitored on a periodic basis.

2.What is worn in a cleanroom?

Cleanroom clothing is primarily worn to contain particles inside the suit which are shed by workers during activity. Clothing may also be worn to protect the wearer from substances that are being handled. Cleanroom garments consist of both reusable and limited-use clothing.

Reusable garments are made from:

  • polyester
  • taffeta
  • herringbone

Limited-use clothing consists of apparel made from:

  • Tyvek®
  • Microporous membrane fabrics such as ProClean® 2
  • SMS

Cleanroom garments are specially designed and constructed for particle containment:

  • Garments should cover the entire body
  • Closures at the wrists and ankles should be tight with tunnelized elastic
  • Garment should allow for excess movement and stretch in arms and legs to prevent ripouts and exposure of skin, both of which lead to particle contamination

DuPont Personal Protection Product Line

DuPont Personal Protection offers two choices for your cleanroom apparel needs. The first is ProClean®, a line of different styles made from microporous membrane fabric. The second is IsoClean®, apparel made from Tyvek®.

3.What are sterile environments?

In addition to cleanrooms that control particles, some cleanroom environments also try to eliminate bacteria. These environments are called sterile cleanrooms, and there are two types. One type is a room where sterility is the main issue. Another type is a room where sterility and particle containment are the key concerns. Pharmaceutical, biotechnology, and medical devices are industries where sterile environments are used.

Sterilization is a process where all organic material and/or bacteria is eliminated. This process is independent and not a function of "cleaning" or the particle removal process. The following are three methods of sterilization:

  • Autoclaving (steam)
  • ETO (ethylene oxide)
  • Gamma irradiation (cobalt 60).

The food and drug administration (FDA) regulates the standards for each sterilization process.

4.How are cleanrooms classified?

Cleanrooms are classified based on the number of particles that flow through the room. The classification is based upon particles .5 microns and larger per cubic foot of air. Table I illustrates the different classes of cleanrooms.

Table I

The standard for cleanrooms does not correlate with standards for cleanroom apparel. Testing for apparel is conducted with a Helmke Drum Test. Table II (reference IEST RP-CC003.4) illustrates the results of this test. Another standard that regulates manufacturers is ISO (International Standards Organization). The ISO 9000 series is a set of generic standards that provide quality management guidance and identify generic quality system elements necessary to achieve quality manufacturing.

Table II