A 2 1/2" hose with no nozzle attached and flowing at 25 psi discharges how many GPM?

To determine the discharge flow rate in gallons per minute (GPM) for a 2 1/2-inch hose at a pressure of 25 psi without a nozzle attached, we can use the flow rate formula for fire hoses. The flow rate for a straight hose can be approximated with the formula:

[ GPM = \frac{(diameter^2 \times pressure)}{2.3} ]

In this case, the diameter of the hose is 2.5 inches, which we convert to an area:

1. Square the diameter:

( (2.5)^2 = 6.25 )

2. Multiply by the pressure (in psi):

( 6.25 \times 25 = 156.25 )

3. Now, divide by 2.3 to find the GPM:

( \frac{156.25}{2.3} \approx 68.0 )

However, the factors in the standard fire flow formula actually lead us to a common multiplication factor used in the industry for direct calculations. As per fire hose flow tables, a 2 1/2-inch hose flowing at 25 psi is generally accepted to yield approximately 835 GPM