Refrigerant pipe joints located in air ducts carrying air to occupied spaces must withstand what temperature without leakage?

The correct answer indicates that refrigerant pipe joints located in air ducts carrying air to occupied spaces must withstand a temperature of 700 degrees without leakage. This requirement is important for ensuring the safety and integrity of the refrigeration system and the surrounding environment.

When refrigerant pipes are installed in air ducts, they are exposed to high temperatures that can arise during normal operation or fire situations. The ability of pipe joints to withstand elevated temperatures is crucial to prevent leaks, which can compromise the refrigerant's effectiveness and potentially create safety hazards. If the joints cannot endure these conditions, they may fail, leading to refrigerant loss and possible damage to the air quality in the occupied spaces.

While the other temperature thresholds presented are higher, they do not align with the requirements specified for air ducts in occupied areas. The choice of 700 degrees represents a balance between safety, performance, and system design guidelines established in codes and standards that govern refrigeration systems.