The formula to convert GPM to pipe size is:
\(D = \sqrt{\frac{4 \times (GPM / 7.481)}{V \times \pi}}\)
Where:
Example 1:
Calculation:
\(D = \sqrt{\frac{4 \times (500 / 7.481)}{10 \times \pi}} = \sqrt{\frac{4 \times 66.85}{31.42}} \approx 2.91 \text{ ft}\)
Example 2:
Calculation:
\(D = \sqrt{\frac{4 \times (1000 / 7.481)}{15 \times \pi}} = \sqrt{\frac{4 \times 133.69}{47.12}} \approx 3.36 \text{ ft}\)