Which statement best describes space-by-space ventilation vs system-wide ventilation?

• A. Space-by-space ventilation applies rates to individual spaces; system-wide uses a central rate
• B. System-wide ventilation is always less efficient
• C. Space-by-space ventilation ignores occupancy
• D. System-wide ventilation uses only local exhaust

Answer: (A)

The distinction being tested is how outdoor-air requirements are allocated. In space-by-space ventilation, the outdoor-air rate is specified for and applied to each individual space, so different rooms can have different rates based on their use and occupancy. In system-wide ventilation, a single central outdoor-air rate is established for the whole building and distributed through the system to all spaces. So the statement that space-by-space ventilation applies rates to individual spaces while system-wide uses a central rate accurately describes the difference.

The other ideas don’t fit: system-wide is not inherently more or less efficient in all cases, and space-by-space ventilation does consider occupancy because those per-space rates often depend on how many people use the space. System-wide ventilation isn’t limited to local exhaust; it involves the central supply and distribution to the spaces, not just exhaust only.