What type of joint is commonly used for joining metal pipes in pipefitting?

• A. Soldered joints
• B. Welded joints
• C. Mechanical joints
• D. All of the above

Answer: (D)

The correct answer is all of the above because each type of joint mentioned—soldered joints, welded joints, and mechanical joints—plays a significant role in pipefitting and is commonly used to join metal pipes.

Soldered joints are often utilized for joining smaller diameter pipes, typically in plumbing applications involving copper tubing. They create a strong connection through the melting of solder, filling the gap between the pipes.

Welded joints are fundamental in pipefitting and construction, particularly for large diameter pipes and systems that require a robust and permanent connection. Welding involves fusing the edges of the metals together by applying heat, making it suitable for high-pressure applications.

Mechanical joints are another method of connecting pipes without the need for heat, using fittings that can be tightened or otherwise connected to create a secure connection. This type offers adaptability and ease of assembly, making it widely used in various installations.

Since all these methods are valid and commonly practiced in joining metal pipes, selecting all of the above accurately reflects the range of techniques available to pipefitters.