Final answer:
Anterooms that open into positive pressure buffer rooms must be ISO 7 or cleaner.
Step-by-step explanation:
Anterooms that open only into positive pressure buffer rooms must be ISO <strong>7</strong> or cleaner. This means that the anteroom should have an air cleanliness level of ISO 7 or higher. ISO refers to the International Organization for Standardization, which sets standards for cleanroom environments. In this case, an ISO 7 cleanroom means that for every 1 cubic foot of air, there should be no more than 3520 particles with a size of 0.5 micrometers or larger.