What characteristic of hard-drawn, seamless copper tubes makes them suitable for use in Category 3 positive pressure systems?

The suitability of hard-drawn, seamless copper tubes for use in Category 3 positive pressure systems primarily stems from their high tensile strength. This characteristic allows the copper tubes to withstand the increased stresses and pressures associated with positive pressure systems, ensuring that they maintain their structural integrity and do not fail under operational conditions. In addition to being able to handle the pressure, high tensile strength also contributes to the durability and longevity of the tubes, making them a reliable choice for conveying fluids in such systems.

While flexibility, corrosion resistance, and low thermal conductivity are beneficial properties of copper, they do not directly address the critical requirement of withstanding high pressure. Flexibility might even be a disadvantage in high-pressure applications where rigidity and strength are preferred. Corrosion resistance is also important, but in the context of positive pressure systems, having a material that can withstand mechanical stresses is paramount. Low thermal conductivity is generally a favorable trait for temperature control but does not significantly influence its application in positive pressure contexts.