PHEL curves indicate stay times for different workload conditions.

• A. Indicate stay times for different workload conditions.
• B. Predict fuel consumption during shifts.
• C. Measure radiation exposure in spaces.
• D. Determine noise levels in engine rooms.

Answer: (A)

PHEL curves map how long a task or operation remains under various workload levels. They plot stay times for each workload condition, so you can see how long the system or operator stays in light, moderate, or heavy workload during a given period. This makes them useful for planning staffing, pacing work, and scheduling rests, because you’re dealing with the duration in each workload state rather than predicting other quantities. Fuel consumption, radiation exposure, and noise levels are separate factors; they may vary with workload but aren’t what the curve directly measures.