Which statement describes Class 3 Expedient sheltering?

• A. Selected Portions of the Building Are Sealed by Temporary Measures Such as Plastic Sheeting and Tape
• B. The Building Is Not Airtight Enough to Maintain Pressurization
• C. Transportable Filter Units Are Permanently Mounted to the Building
• D. The System Allows Use of the Existing HVAC or Alternate System

Answer: (A)

Class 3 Expedient sheltering focuses on quickly creating a protected zone inside an existing building by sealing off selected portions with temporary barriers like plastic sheeting and tape. This approach reduces air exchange with the outside or contaminated areas, giving occupants a safer space without requiring the whole building to be airtight or to rely on the HVAC system. It’s about isolating a portion of the structure to maintain a cleaner, more controllable indoor environment in an emergency, rather than designing for pressurization or permanent filtration.

The other options describe approaches that aren’t the defining feature of Class 3. Relying on the building being too unsealed to maintain any pressurization isn’t the goal here, since the emphasis is on creating a sealed zone within the building rather than maintaining pressurization. Using permanently mounted transportable filter units implies a long-term or fixed installation rather than a quick, temporary expedient sheltering measure. And depending on the existing HVAC or another system would involve using the building’s air handling, which is not the core idea of expedient sheltering, where the emphasis is on isolating space with temporary barriers.