A malleable iron coupling with 4 ribs indicates what?

A malleable iron coupling with 4 ribs indicates that it has right/left hand threads, which is important for ensuring a secure connection in various piping systems. The design of the coupling with 4 ribs serves as a visual marker to signify that it is a reversible coupling, allowing it to connect pipes with both right-hand and left-hand threads. This versatility is crucial for systems where pipe orientations may vary, providing flexibility in installation.

Understanding the threading is essential for maintenance and repair work, particularly when disassembling plumbing systems, as using the wrong type of threading could lead to leaks or failures. The presence of ribs on the coupling not only informs about the threading type but also enhances grip and ease of installation. Consequently, the 4-rib design is a reliable indicator of the coupling's threading capabilities.