A cleanroom is a controlled environment where products are packed, manufactured, and assembled. The room eliminates sub-micron airborne contamination generated from people, processes, facilities and equipment. The higher the level of cleanliness, the lower the likeliness of particles or microbes damaging or corrupting production processes by tainting sterile and non-sterile products.

Cleanroom Manufacturing

Cleanroom design and construction requires tight controls over contamination, air flow rate, pressure, temperature, and humidity. As a manufacturing asset, the ability to produce, assemble, preserve and inspect a clean end product is paramount before delivery. While most cleanrooms function in similar fashion, the levels of control and particulate levels vary widely. The dirtiest cleanrooms may contain 1,000,000 micron sized particles per cubic meter, while one of the cleanest cleanrooms (ISO Class 3) may contain just 1000 particles or less. The ISO class system provides an industry-wide standard for cleanliness and particles counts, therefore helping facilities measure and test their contamination levels against established benchmarks.

What’s the Difference Between ISO 14644 Cleanroom Standards and US Fed Standard 209E Cleanroom Standards?

ISO 14644 replaced the previous cleanroom standard, Federal Standard 209E in 2001. The federal standard provides an imperial measure of units (particles per cubic ft.), while ISO standards use metric units (particles per square meter). ISO Class standards outline a higher degree of micron level particulates starting at 0.1 micron, while FS 209E references a standard particle diameter of 0.5 micron.

It should be noted that these standards are easily confused, sometimes even in manufacturer spec sheets — a “Class 1” (Fed. Standard) cleanroom has a particle threshold equivalent of an “ISO Class 3” (ISO Standard). Unless specifically noted as an “ISO” standard, one could assume that the US Fed. Standard 209E is being referenced, which was officially canceled by the General Services Administration of the US Dept. of Commerce November 29, 2001, but is still widely used.

Particle Counts

The impact of particles on a production process is not always predicated by volume, but instead by specific sizes of problematic particles based on the application. The increased specificity of ISO class cleanroom standards provides a more accurate and translatable picture of cleanliness, because it defines allowable particle counts in stages of 0.1 micron – 5 microns. The 0.5 micron standard of the FS 209E systems is continually growing outdated; as the rush for smaller components and more sensitive devices grows and cleanrooms become cleaner, particle thresholds require increased sensitivity. Likewise, particle counting technology has improved the ability to detect and differentiate aerosol (airborne) particles with impressive accuracy. Learn more about cleanroom standards, and additional standards such as British standard or GMP EU (e.g. Class A) standards.