Which surface areas are targeted by the 'Other critical barriers' approach?

• A. Doors, windows, ventilation, drains or wall penetrations.
• B. Floors and ceilings only.
• C. Roof only.
• D. Interiors of pipes only.

Answer: (A)

The idea is to identify surface-level gaps that allow air or contaminants to move between spaces. The areas targeted are doors, windows, and ventilation pathways, because these are direct openings and conduits that connect indoor spaces with the outside or with other zones. Drains and wall penetrations are included too since they create gaps in the building envelope through which air or liquids can pass and contaminants can travel. These surface spots are prioritized because they’re practical to inspect and seal or manage—weatherstripping doors and windows, securing or filtering ventilation, sealing wall penetrations, and properly draining systems all help block contaminant pathways.

Other surface areas like floors and ceilings don’t capture the same breadth of common transfer routes, a roof alone misses mid-building connections, and concentrating only on interiors of pipes overlooks the gaps around those pipes that also serve as entry points for contaminants.