How to Calculate Pipe Sizes
There are several standards for pipe sizing worldwide. In the United States, NPS (Nominal Pipe Sizing) is the most common method of sizing pipes. The size carries two values: SCH (Schedule, or wall thickness) and NPS (roughly related to the actual diameter of the pipe).
Things You Will Need
- String
- Ruler or tape measure
The best method for calculating the pipe size is to measure the circumference and the wall thickness, then compare the values to a standardized chart.
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Wrap a piece of string around the outside of the pipe. For the most accurate measurement, press the string up against a fixture on the pipe or the very edge of the pipe.
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Mark the string where it crosses itself.
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Measure the length of the string between the marks in inches. Write down this value.
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Divide the circumference of the pipe by pi, or 3.14. This is the OD (outer diameter).
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Measure the thickness of the pipe. With the edge of the pipe exposed, place the ruler against the pipe and measure the width of the wall in inches.
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Compare the values with a standardized chart (see Resources). Find the OD from your measurement under OD on the chart. The number labeling the row for the OD is the NPS. Go across the row until you find the width of the pipe wall. The number labeling the column for the pipe wall width is the SCH. The values may not match exactly so use the closest match.
References
Resources
Writer Bio
Chris Hanson started writing music, lyrics, and poetry in 2001 and began writing fiction and nonfiction professionally in 2006. Hanson was first published in the "Grand Forks Herald" in 2004. Hanson is an experienced Web programmer with experience with several operating systems and Web protocols. He completed his Bachelor of Arts in anthropology at the University of Minnesota in just three years.
Photo Credits
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- Chris Stein/Digital Vision/Getty Images
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