What is the effective number of threads for a 1" diameter screwed steel pipe?

The effective number of threads for a 1" diameter screwed steel pipe is calculated based on standard practices in pipe threading. For a 1” nominal pipe size, the number of threads per inch is typically standardized, and the effective number of threads takes into account the depth and pitch of the threads.

In this case, for a 1" diameter pipe, the common standard is approximately 11.5 effective threads when considering the pitch and the actual usable threaded length of the pipe. This number represents the threads that effectively contribute to the sealing or connection capacity when the pipe is joined.

Understanding the significance of the effective number of threads is crucial, especially in applications related to pipe fittings and how they carry loads or resist leakage. This specific information, combined with standards used in engineering, confirms why the answer is recognized as 11.5. The other options either round up or down incorrectly based on the standard threading formulas.