How Cleanroom Technology Developed

What a cleanroom is

Clean technology emerged to meet the demands of research and manufacturing for precision, miniaturisation, high purity, quality and reliability. A cleanroom is a room in which air filtration, air distribution, construction materials and operating procedures together keep the concentration of airborne particles at a specified level — and keep it there consistently.

From surgical hygiene to laminar flow

The idea of controlling contamination began in medicine, with antiseptic practice in operating rooms in the nineteenth century. The modern cleanroom arrived in the early 1960s, when the laminar-flow principle — filtered air moving in a uniform stream to sweep particles away — was developed in the United States. Cleanrooms spread rapidly through electronics and precision engineering and became a foundation of the semiconductor industry.

The technology was then carried from industrial cleanrooms (ICR) to biological cleanrooms (BCR), where the aim is to control viable microorganisms as well as particles. From the 1970s, cleanroom construction expanded into healthcare, pharmaceuticals, food and biochemistry.

Standards: from FED-STD-209 to ISO 14644

Early cleanrooms were classified under the US Federal Standard 209, with classes such as Class 100 and Class 10,000. It was withdrawn in 2001 in favour of ISO 14644-1, which defines classes ISO 1 to ISO 9 by particle concentration per cubic metre and is used worldwide today.

Pharmaceutical GMP raises the bar

Regulators have steadily tightened good manufacturing practice (GMP) for sterile and biological products, and with it the requirements for the production environment:

• The US FDA issued its guidance on sterile drug products produced by aseptic processing in 2004.
• The EU revised GMP Annex 1 on sterile manufacturing in 2008, and again in a major revision in 2022.
• China revised its GMP in 2010, bringing it closer to international practice and raising requirements for clean production environments.

These revisions pushed manufacturers towards better-designed cleanrooms, validated filtration and routine monitoring.

What it means for filtration

Stricter rules and more sensitive products mean more demand for documented performance: classified HEPA filters, in-place leak testing, reliable pre-filtration and chemical filtration where molecular contamination matters. For suppliers, the emphasis has moved from simply supplying filters to supporting validation, testing and maintenance over the life of the facility.