Final answer:
The requirement for the number of fire guards needed for a 275,000 square feet area during an 8-hour fire watch depends on local fire codes and other factors such as occupancy, combustibles, and layout.
Step-by-step explanation:
The number of fire guards required for a fire watch in an area of approximately 275,000 square feet, during an 8-hour period when a fire protection system is impaired, largely depends on the regulations and standards set by local fire codes.
These codes will specify the ratio of fire guards to the area being watched and the nature of the impairment to the fire protection system.
Additionally, the type of occupancy, amount of combustible materials present, and layout of the area can also influence the number of fire guards needed.
For an accurate determination, one would need to consult the applicable fire code or the authority having jurisdiction (AHJ) which typically might be the local fire department or fire marshal's office.