The Real Requirements Behind Cleanroom Classification

Passing particle counts isn't the same as staying compliant. See the parameters, pitfalls, and processes that separate a certified cleanroom from a vulnerable one.
July 24, 2026

Cleanroom compliance is often reduced to an ISO classification, but that number tells only part of the story. 

This guide walks through the parameters that actually keep a cleanroom validated between audits: particle counts, pressure differentials, temperature, humidity, and the testing cadence regulators expect to see documented. It also covers the classification scale itself, how to certify your space step-by-step, and the common blind spots that trip up teams relying on periodic testing or building systems alone. 

If you're responsible for keeping a cleanroom audit-ready year-round, this is a resource to keep close.