Update on designing for cleanrooms

Considering all the moving and static sources that contribute to particle generation, it’s no wonder that many designers cringe when they find out that a motion system will be operating in a cleanroom. But motion doesn’t have to be the enemy of the cleanroom. With an understanding of the particle sources and corresponding design adaptations, it’s possible to design cleanroom-friendly motion systems for various automation tasks.

Note that an on-demand webinar on this cleanroom topic can be found at this gateway.on24.com deep link.

What are today’s cleanroom standards for semiconductor, pharmaceutical, and aerospace environments — and how have they recently changed? How can design engineers achieve regulatory compliance while optimizing system performance?

Finally what cleanroom and vacuum-compatible actuators, low-friction bearings, and non-outgassing lubricants lead today? How does the integration of these components into cleanrooms differ from that for other settings?

Let’s start with basic definitions and requirements that became applicable in 2025.

According to the International Standards Organization’s ISO 14644-1, cleanrooms and peripheral environments control the air and surfaces if applicable to levels appropriate for executing contamination-sensitive activities.

Cleanrooms are most commonly associated semiconductor, electronics, and medical-device industries but aerospace, pharmaceuticals, and food and beverage also use cleanroom environments.

ISO 14644-1 rates cleanrooms from 1 (best) to 9 (worst) based on the number of particles in six size ranges present in a cubic meter of air.

Besides this ISO standard, the U.S. Federal Standard 209E is referenced though it was revoked in 2001. FS 209E ratings cross-reference to ISO ratings though class numbers don’t perfectly align. For example, a cleanroom rated as class 1 under FS 209E is rated as class three under ISO 14644-1.

ISO classes 1 and 2 are higher (better) than the highest FS 209E classification, and ISO class 9 is lower (worse) than the lowest FS 209E classification. In fact, Class 9 is just typical room air — like that found in a normal office setting. 209E Class-10 (ISO Class 4) cleanrooms are particularly common.

After 20 years with no major changes, in August 2025 the ISO published a refresh of 14644-5. The revision tightens expectations for personnel competency, material flows, documentation, and day-to-day operations yet keeps the familiar particle thresholds of 14644-1 and 14644-2.

For machine builders, the refreshed standard requires explicit installation, startup, maintenance, and change controls for equipment going in clean zones. OEMs must now demonstrate that (among other things) motion elements, lubricants, and materials (including those of cables, for example) support contamination-control strategies.

In addition, ISO 14644-5 now clarifies expectations for managing workforces, materials, and anything entering or exiting the cleanroom environment. Included are procedures for garbing, hand hygiene, and training.

Cleaning and disinfection mandates routines must be done with a given frequency and to verified levels of effectiveness. Residues should be minimized. In addition, new risk assessments inform controls … and any exceptions must be supported by documented rationale.

All these mandates leverage how much more digitalized the world has become over the last 20 years. Validating and safeguarding electronic records and data along with automation of environmental monitoring and processes control are encouraged. Digitized systems are also meant to inform continual cleanroom-operations improvement.

Particle counters or so-called sniffers verify automation components for these spaces are in fact suitable by counting particles shed as moving mechanical components wear against one other. In a typical arrangement, laminar not turbulent airflow is directed over a system element such as an actuator towards the sniffer below. A counter anywhere else won’t quantify worst-case scenario for a given arrangement.

Some industry-specific regulations complement the ISO foundation by adding stringent requirements. Consider one industry-specific regulation — the 2023 EU GMP Annex 1 for sterile manufacturing of medicinal products. This sets a Contamination Control Strategy (for microbial, particle, and endotoxin contamination) to a governing framework. In fact, Annex 1 also forces equipment-integration re-engineering to ensure cleanability of actuated designs that enter and exit clean areas.

Other standards often complement cleanroom requirements to prevent adulteration of end product or machinery. Just like that for the medical-device industry, the aerospace industry got an updated standard in 2023 with NAS412 from the Aerospace Industries Association or AIA.

The Fraunhofer IPA Institute tests many components to ensure they satisfy 14644. When there is an EN prefix on the standard, it confirms the European Committee for Standardization or CEN adopts it as a European standard sans change. Deutsches Institut für Normung or DIN prefixes indicate the same adoption by Germany’s standards body.

The British Standards BS prefix is used in the UK and NF in France to indicate formal recognition. Fraunhofer IPA Institute conducts copious tests of components’ outgassing tendencies.

To satisfy ISO 14644-5, cleaning regimens and documentation should be made easy to understand for end users. Validation data for particle emission at design speeds and duty cycles should detail the ISO Class satisfied.

Where integrated machine modules and robots are specified, products should have published cleanroom ratings or third-party certifications (ideally complemented by condition-monitoring capabilities).

Components that support cleanrooms include fanless motors — to avoid disturbing or dispersing particles; brushless motors — to avoid the introduction of brush-dislodged commutator debris; gear reducers with cleanroom-ready sealing for isolation; various other housings with smooth surfaces for cleanability; mechanical components lubricated with low-outgassing formulas; and cables with FEP/PFA jackets — just to give some examples.

Case in point: Some brushless servomotors for cleanroom environments feature high-grade stainless-steel housings and specialized materials help them maintain integrity in cleanrooms to ISO Class 1.