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