Achieving ISO Class 5 with Modular Construction: A Semiconductor Approach

Home› Technical› Achieving ISO Class 5 with Modular Construction Technical Analysis · Semiconductor Cleanrooms Achieving ISO Class 5 with Modular Construction: A Semiconductor Cleanroom Approach Can a cleanroom that is built in a factory and assembled on site really hit the cleanliness a semiconductor process demands? This is a technical look at how a modular clean room reaches — and holds — ISO Class 5. Topics modular clean room portable cleanroom prefabricated clean room ≤3,520 / m³ Max particles ≥0.5 µm allowed at ISO Class 5 Unidirectional The airflow regime ISO 5 requires Factory-built Sealing and QC done under controlled conditions Weeks Typical site time versus months for stick-built By the Wonclean technical team Updated June 2026 ~7 min read There is a lingering assumption that “modular” means “lower spec” — fine for a workshop or a softwall enclosure, but not for the clean end of semiconductor work. In practice the opposite is true: the qualities that define ISO Class 5 — airtight sealing, precise airflow, controlled surfaces — are exactly the things a factory-built, prefabricated system can deliver more consistently than a build assembled in the open. This article sets out what ISO Class 5 actually requires, why modular construction is well suited to meeting it, and how a semiconductor-grade modular clean room is put together to reach and hold that standard. Modular, not compromised. A high-classification cleanroom built from a modular envelope — a continuous filter-and-light ceiling, sealed wall panels and a controlled floor, delivered as one engineered system. 01 — The target What ISO Class 5 actually demands ISO Class 5, defined by ISO 14644-1 and equivalent to the older “Class 100” and to EU GMP Grade A/B, allows no more than 3,520 particles of 0.5 µm or larger per cubic metre — around a thousand times cleaner than ordinary indoor air. Hitting that number is not about one heroic component; it is about four things working together: Unidirectional airflow. A near-continuous sheet of filtered air moving top-to-bottom, so particles are swept away from the work plane rather than mixed around the room. High filter coverage and air change. A ceiling largely filled with HEPA or ULPA filters, delivering a high, steady air-change rate. An airtight envelope. Walls, ceiling and joints sealed so unfiltered air cannot leak in and the pressure cascade holds. Controlled surfaces. Smooth, non-shedding, cleanable materials throughout, with no dust-collecting corners. Every one of these is a property of how precisely the room is built and sealed — which is where construction method starts to matter. 02 — The case for modular Why prefabrication suits high-classification cleanrooms Traditional “stick-built” construction assembles a cleanroom in place, trade by trade, often in a dusty, weather-exposed shell. A modular clean room inverts that: the panels, ceiling system, filters and services are manufactured to precise tolerances in a factory and as...