What type of equipment uses refrigerant that boils below -58°F at atmospheric pressure?

The correct understanding lies in the relationship between refrigerants and their boiling points under different pressures. Refrigerants that boil below -58°F at atmospheric pressure are indicative of low-pressure systems. In refrigeration, the classification of equipment often corresponds to the pressures at which the refrigerants operate.

Low-pressure equipment is designed to handle refrigerants that have lower boiling points, which are typically in a vapor state at standard atmospheric conditions. Standard pressure equipment typically involves working with refrigerants that boil at higher temperatures, and high-temperature equipment is designed for refrigerants that operate efficiently at elevated temperatures.

Very high pressure equipment is not relevant in this context, as it generally pertain to refrigerants that require high pressures for their phase changes, which would not include those that boil below -58°F at standard atmospheric pressure.

Therefore, the classification of refrigerant operation at low pressures causes this equipment to use refrigerants that exhibit the characteristics defined in the question, demonstrating why this option is the most suitable answer.