Which of the following is a type of copper tube joint?

• A. Soldered
• B. Flared
• C. Compression
• D. All of the above

Answer: (D)

When joining copper tubes, there are several valid methods, and each one is used to create a watertight connection. Soldered joints fuse the tube and fitting together with molten solder after cleaning and fluxing the surfaces, producing a durable, permanent bond often used in potable water and heating systems. Flared joints form a flare on the tube end and connect to a fitting with a flare nut, providing a secure seal without soldering and is common in certain plumbing and appliance applications. Compression joints rely on a nut and ferrule that press the tube against the fitting to seal, making them easy to assemble and serviceable without heat. Because soldered, flared, and compression joints are all recognized methods for copper tubing connections, all of the above is the best choice.