Which pipe size range has approximately 11 threads?

Which pipe size range has approximately 11 threads?

• A. 1/2 inch to 1 inch
• B. 1 1/4 inch to 2 inch
• C. 2 1/2 inch to 3 inch
• D. 4 inch

Answer: (B)

In NPT pipe threading, the number of threads per inch varies with the nominal size: smaller pipes have more threads per inch, while larger pipes use fewer. For common sizes, about 11 TPI appears around the 1 1/4" to 2" range, whereas smaller sizes like 1/2" to 3/4" run around 14 TPI, and larger sizes such as 2 1/2"–3" and 4" drop to around 8 TPI or 7 TPI. So the range that has approximately 11 threads is 1 1/4" to 2".

In NPT pipe threading, the number of threads per inch varies with the nominal size: smaller pipes have more threads per inch, while larger pipes use fewer. For common sizes, about 11 TPI appears around the 1 1/4" to 2" range, whereas smaller sizes like 1/2" to 3/4" run around 14 TPI, and larger sizes such as 2 1/2"–3" and 4" drop to around 8 TPI or 7 TPI. So the range that has approximately 11 threads is 1 1/4" to 2".