What is the flow rate from a 2.5-inch fire hydrant outlet with a pitot reading of 42 psi?

To determine the flow rate from a fire hydrant outlet based on a pitot reading, the formula that relates the pitot pressure to flow rate can be applied. The flow rate (GPM) can be estimated using the formula:

[ Q = 29.7 \times d^2 \times \sqrt{P} ]

where:

• ( Q ) is the flow rate in gallons per minute (GPM),
• ( d ) is the diameter of the outlet in inches,
• ( P ) is the pitot pressure in psi.

For a 2.5-inch outlet and a pitot reading of 42 psi, we can plug in the values:

1. Calculate ( d^2 ): ( 2.5^2 = 6.25 )

2. Calculate ( \sqrt{P} ): ( \sqrt{42} \approx 6.48 )

3. Now, apply these values into the flow rate formula: [ Q = 29.7 \times 6.25 \times 6.48 ]

Calculating that gives: [ Q \approx 29.7 \times 6