Q Source Guide to Cleanroom Classifications & Standards

Cleanrooms are controlled, contaminant-free environments used in industries such as biotechnology, pharmaceutical research, medical-device production, and other critical-process manufacturing in which airborne particulates and chemical vapors can compromise operations. Q Source is a global distributor of industry-leading, electrostatic-discharge-dissipating equipment, garments, and operational tools for every type of cleanroom.
Our selection includes testing-meter kits, wrist-strap, and heel-strap grounding, static-dissipative blow-off guns, cleanroom wipes, rubber table mats, and other safety items, and we have provided the following guide to cleanroom classifications and standards for your reference.

An overview of cleanrooms

In general terms, a cleanroom can be any contained space where steps have been taken to control environmental factors such as air pressure, temperature, and humidity to reduce the potential for contamination by airborne particles, particulates, and vapors. This is achieved through the use of high-efficiency particulate air (HEPA) filters designed to trap particles of sizes 0.3 microns and larger. Ultra-low particulate air (ULPA) filters are used in cleanrooms that require the absence of particulates as miniscule as 0.12 microns.

The air in a typical outdoor urban or suburban environment will contain approximately 35.2 million particles per cubic meter at a size of 0.5 microns and larger in diameter, none of which will pass through the filtration system of even the lowest classification of cleanroom standards. Because of these rigid standards, employees who work in cleanrooms undergo extensive contamination-control training and are required to wear specially designed garments that trap the contaminants naturally produced by our skin and bodies.
The garments required for employees will depend on the classification of the cleanroom, with the lowest classifications perhaps requiring only shoe covers and the highest classifications requiring fully sealed space suits with a breathing device. Typically, cleanroom garments may include boots, shoes, shoe covers, lab jackets, face masks, gloves, finger cots, hoods, hairnets, and more depending on the classification.

Cleanroom classifications and standards

Cleanroom classifications are determined by the air’s cleanliness based on federal and international standards. The current standard used in the U.S. is Federal Standard (FS) 209E, while the International Standards Organization (ISO) is ISO 14644-1. Both standards classify cleanrooms by the number of particles 0.5 millimeters and larger found in the room’s air and measures the results in terms of number of particles per cubic foot.

Thus, today’s cleanrooms in the U.S. are classified by the number of particles size 0.5 millimeters or bigger found per cubic foot of air. Classifications in the U.S. have larger reference numbers than their international equivalents, climbing exponentially from Class 1, to Class 10, to Class 100, to Class 1,000, to Class 10,000, to Class 100,000, compared to ISO 1 through ISO 9 in other parts of the world.

For example, a Class 10,000 cleanroom in compliance with standard FS 209E would be allowed a maximum of 10,000, particles at a minimum size of 0.5 millimeters per cubic foot and would be the equivalent of an ISO 7 classification under the international ISO 14666-1 standard. For comparison, the room in which you are reading this, or the air in any given “ordinary” room, has about 35.2 million 0.5-millimeter or greater particulates to give it a Class 1 million classification under the U.S. standard, which is equivalent to an international ISO 9 classification.

But let’s go back to the Class 10,000 cleanroom. Typical applications for such a classification might include the manufacturing of pharmaceuticals and aerospace products, or the bonding, testing, and metal-removal of semiconductors. Such a cleanroom would also probably require its employees to be fully suited in a non-particulating cleanroom garment, complete with shoe covers and hoods, would be temperature-controlled, equipped with HEPA filter-fan units, have heat-welded vinyl or epoxy floors with sticky mats at all entry and exit points, and may even have an air shower through which to enter the room.