Which of the following is NOT considered part of fire protection systems?

The correct answer, indicating what is NOT considered part of fire protection systems, is fire-resistant walls. While fire-resistant walls are essential for limiting the spread of fire and protecting structural integrity, they are categorized under fire-resistant construction features rather than active fire protection systems. Fire protection systems generally refer to dynamic systems designed to detect, control, or extinguish fires, which include smoke detectors, sprinkler systems, and fire alarms.

Smoke detectors and fire alarms actively monitor for signs of fire and alert occupants, while sprinkler systems automatically suppress or extinguish fires. These systems work in tandem to provide immediate action during a fire incident, which is why they are classified as part of active fire protection. Fire-resistant walls, on the other hand, provide passive fire protection, serving as barriers to slow down or contain the fire's spread, but do not take action once a fire starts. This distinction clarifies why fire-resistant walls are not included in the definition of fire protection systems.