If you have a pipeline and need to find the OD (outside diameter) it makes sense to use a pipe diameter tape measure. Even a chimp could be trained to use one. (I think). All you do is
- Wrap the tape around the pipe.
- Read the marking where the zero mark touches the tape.
- Even though the tape is wrapped around the circumference, it is marked by a factor of pi, so it gives you the diameter.
- You’re done.
Now it’s time to enjoy the rest of the day in the shade.