Friction Loss Fire Hose Calculator

Friction Loss Fire Hose Calculator

Calculate Pressure Loss for Fire Suppression Systems

1.5″ Hose (C=24) 1.75″ Hose (C=15.5) 2.0″ Hose (C=8) 2.5″ Hose (C=2) 3.0″ Hose (C=0.8) 4.0″ Hose (C=0.2) 5.0″ Hose (C=0.08) 6.0″ Hose (C=0.05)

Friction Loss (FL): 0 PSI

Pressure Per 100ft: 0 PSI

Pump Discharge Pressure (PDP): 0 PSI

Understanding Fire Hose Friction Loss

In fire suppression, Friction Loss (FL) refers to the part of total pressure that is lost while water moves through a hose line. This loss is caused by the turbulence of the water and the resistance from the inner lining of the hose. To ensure the correct pressure reaches the nozzle (Nozzle Pressure), the pump operator must calculate the friction loss and add it to the required nozzle pressure to determine the Pump Discharge Pressure (PDP).

The Friction Loss Formula

The industry-standard formula used for these calculations is:

FL = C × (Q / 100)² × (L / 100)

• FL: Total Friction Loss in PSI.
• C: Friction Loss Coefficient for the hose diameter.
• Q: Flow rate in Gallons Per Minute (GPM).
• L: Total length of the hose in feet.

Friction Loss Coefficients (C)

Hose Diameter	Coefficient (C)
1.5″ Hose	24
1.75″ Hose	15.5
2.5″ Hose	2
5″ (Large Diameter Hose)	0.08

Example Calculation

Suppose you are flowing 150 GPM through 200 feet of 1.75-inch hose with a nozzle pressure requirement of 100 PSI.

1. Identify Coefficient (C): For 1.75″, C = 15.5.
2. Square the GPM/100: (150 / 100)² = 1.5² = 2.25.
3. Identify Length/100: 200 / 100 = 2.
4. Multiply: 15.5 × 2.25 × 2 = 69.75 PSI (Total Friction Loss).
5. Add Nozzle Pressure: 100 + 69.75 = 169.75 PSI (Pump Discharge Pressure).

function calculateFrictionLoss() { var C = parseFloat(document.getElementById("hoseDiameter").value); var Q = parseFloat(document.getElementById("flowRate").value); var L = parseFloat(document.getElementById("hoseLength").value); var NP = parseFloat(document.getElementById("nozzlePressure").value); if (isNaN(Q) || isNaN(L) || isNaN(NP) || Q <= 0 || L <= 0) { alert("Please enter valid positive numbers for Flow Rate, Length, and Nozzle Pressure."); return; } // Calculation: FL = C * (Q/100)^2 * (L/100) var gpmFactor = Math.pow((Q / 100), 2); var lengthFactor = L / 100; var frictionLossTotal = C * gpmFactor * lengthFactor; // Per 100 ft loss var per100Loss = C * gpmFactor; // PDP = NP + FL (Simplified – excluding appliance loss and elevation) var pdp = NP + frictionLossTotal; // Display Results document.getElementById("flResult").innerText = frictionLossTotal.toFixed(2) + " PSI"; document.getElementById("per100Result").innerText = per100Loss.toFixed(2) + " PSI"; document.getElementById("pdpResult").innerText = pdp.toFixed(2) + " PSI"; document.getElementById("resultsArea").style.display = "block"; }