1. What is Friction Loss in Firefighting?

Definition: Friction loss is the pressure lost due to the friction between water and the hose lining as water flows through the fire hose.

Purpose: Calculating friction loss helps firefighters determine the required pump pressure to deliver adequate water flow at the nozzle.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( FL \) — Friction loss (psi per 100 feet of hose)
• \( Q \) — Flow rate (gallons per minute)

Explanation: This formula is specific to 2.5" diameter fire hose. The friction loss increases with the square of the flow rate.

3. Importance of Friction Loss Calculation

Details: Proper friction loss calculation ensures adequate water pressure at the nozzle for effective firefighting while preventing excessive pressure that could damage equipment.

4. Using the Calculator

Tips: Enter the flow rate in gallons per minute (gpm). The value must be > 0. The calculator will compute the friction loss in psi per 100 feet of 2.5" hose.

5. Frequently Asked Questions (FAQ)

Q1: Why is the formula Q squared?
A: Friction loss increases exponentially with flow rate because higher flows create more turbulence and friction against the hose walls.

Q2: Does this apply to all hose sizes?
A: No, this formula is specific to 2.5" hose. Other sizes have different coefficients (e.g., 1.5" hose uses FL = 24 × Q²).

Q3: How does hose length affect friction loss?
A: Friction loss is proportional to hose length. For 200 ft of hose, multiply the result by 2; for 50 ft, multiply by 0.5.

Q4: What about elevation changes?
A: This calculator doesn't account for elevation. Add 0.434 psi per foot of elevation gain, or subtract for elevation loss.

Q5: What's a typical flow rate for 2.5" hose?
A: Common flows range from 100-300 gpm, with 250 gpm being a standard flow for many firefighting operations.