The most predominant method used to join steel pipe and fittings is?

• A. threaded
• B. welded
• C. soldered
• D. glued

Answer: (A)

Threaded joints are the most common way to connect steel pipe and fittings because they provide a reliable, leak‑tight connection that can be assembled on site with basic hand tools and easily disassembled for maintenance. Steel pipe is produced with standard threads that match fittings, allowing quick, interchangeable, and cost‑effective connections across many sizes and applications. This method doesn’t require heat or special equipment, unlike welding, and it’s compatible with typical steel piping used in plumbing systems, including black steel and galvanized variations. Soldering isn’t used for steel pipes, and glue is reserved for plastics, so those options aren’t suitable for standard steel installations. While welding is used in some high‑stress or permanent industrial setups, threaded connections remain the predominant choice for everyday steel piping due to simplicity, cost, and field practicality.