How can you identify right/left hand threaded 150# malleable couplings?

The identification of right and left hand threaded 150# malleable couplings can be accurately done by looking for specific features on the coupling itself. The presence of four or more ribs on the coupling, along with a stamp indicating "L" for left hand, serves as a definitive marker for left hand threads. This method relies on manufacturers' standards where specific markings and designs are utilized to differentiate between right and left handed threads, ensuring that users can easily identify them during installation or maintenance.

In contrast, other methods mentioned might not reliably indicate the thread direction. For instance, thread color coding is not a universally adopted standard in the industry and can lead to confusion. Measuring the diameter provides information about the size of the coupling rather than the threading direction. Visual inspection of the flange could help in identifying general characteristics of a coupling but does not provide accurate information regarding whether the threads are right or left hand. Therefore, the most reliable method for identifying the thread type in this case is through the features of the coupling itself, specifically the ribs and the stamped designation.