Ventilation is designed and built so that air cannot move from contaminated to clean areas, and it can be reached for cleaning, filter changes and maintenance. Natural or mechanical ventilation is enough to remove unwanted steam, dust and odours, and where appropriate the quality of air supplied to rooms is controlled to prevent airborne microbiological contamination. Requirements for air that directly touches food or a food-contact surface are set and monitored.
The graph holds this control, the 0 it maps to, and the evidence behind each claim, over MCP and REST.