HVAC Journeyman Practice Exam

What type of joints are required for hydronic copper tubes installed under a building?

1. Brazed

2. Soldered with 95 percent tin and 5 percent antimony

3. Soldered with 50 percent tin and 50 percent lead

4. Silver brazed or equal

The correct answer is: Soldered with 50 percent tin and 50 percent lead

The appropriate type of joint required for hydronic copper tubes installed under a building is typically brazed or soldered with an alloy that ensures high strength and durability, particularly given the potential pressures and temperatures these systems experience. In this context, the use of soldered connections with a composition of 95 percent tin and 5 percent antimony can be a valid choice, but is not the most commonly required method for hydronic installations. This combination provides corrosion resistance and good mechanical strength, making it suitable for certain applications; however, soldered joints may not be as robust as those created through brazing, especially in environments where joint integrity is critical. Silver brazed joints are preferred for critical applications due to their superior strength and higher melting points, reducing the risk of joint failure over time and under heat. Such methods provide greater reliability in hydronic systems, particularly when installed in locations subject to movement or vibration. Thus, understanding the specific requirements for hydronic copper tube installations involves evaluating the environmental conditions, temperature, and pressure capabilities. While the option selected presents a method for connecting the tubes, it is essential to recognize that military and industry standards might dictate the selection of silver brazing or equivalent methods to ensure the highest safety and performance in hydronic systems