Fire Hydrant Flow Calculator GPM

Fire Hydrant Flow Formula:

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

Flow Rate (GPM):

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1. What is the Fire Hydrant Flow Formula?

The Fire Hydrant Flow Formula estimates the flow rate of water from a fire hydrant in gallons per minute (GPM) based on the diameter of the outlet and the water pressure. This calculation is essential for firefighting operations and hydrant testing.

2. How Does the Calculator Work?

The calculator uses the fire hydrant flow formula:

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

Where:

\( d \) — Diameter of the outlet (inches)
\( P \) — Pressure (psi)
\( GPM \) — Flow rate in gallons per minute

Explanation: The formula accounts for the relationship between outlet size, water pressure, and resulting flow rate.

3. Importance of GPM Calculation

Details: Accurate flow rate calculation is crucial for determining firefighting capabilities, hydrant testing, and water system design.

4. Using the Calculator

Tips: Enter the diameter in inches and pressure in psi. All values must be valid (diameter > 0, pressure > 0).

5. Frequently Asked Questions (FAQ)

Q1: What is the coefficient 29.7?
A: This is an empirical coefficient that accounts for unit conversions and flow characteristics in fire hydrants.

Q2: What are typical GPM values for fire hydrants?
A: Standard fire hydrants typically flow between 500-1,500 GPM, depending on size and pressure.

Q3: When should this calculation be performed?
A: During hydrant testing, fire flow testing, or when designing fire protection systems.

Q4: Are there limitations to this formula?
A: The formula assumes ideal conditions and may vary slightly based on hydrant design and water system characteristics.

Q5: How accurate is this calculation?
A: It provides a good estimate but actual flow measurements are more accurate for critical applications.