Not just any wall panel works. ISO 14644-4 specifies:

Match materials to your cleaning agents (Clause 6). Size the HVAC for the required air changes per hour (typically 20–60 for ISO 7, 240–600 for ISO 5).

The design of cleanrooms and associated controlled environments shall take into account the following:

| Stage | Name | Objective | |-------|------|------------| | 1 | | Cleanroom built, equipment installed but not running. Verify airflow velocity, filter integrity, and particle counts per ISO 14644-1. | | 2 | Dynamic Testing | Equipment running (simulated process), but no personnel. Check that machinery does not generate excessive particles. | | 3 | Operational Testing | Personnel present, performing simulated tasks. This is the true test of gowning discipline and workflow design. |

Based on Clause 5.1, write a 2–3 page document stating:

The 2022 update removed outdated cleanroom classifications (e.g., ISO Class 2 and 3 are now covered differently) and added energy efficiency requirements. Auditors expect the current version.

While other parts of the ISO 14644 series focus on classification (Part 1) or testing (Part 3), Part 4 addresses the from conception to operational readiness. It bridges the gap between theoretical cleanliness standards (ISO Classes 1 through 9) and the physical facility that achieves them.