Verified Mathematical Model & Formulation
Head Loss (ft) = 0.002083 × L × (100 / C)^1.852 × (GPM^1.852 / d^4.8655) Pressure Drop (PSI) = Head Loss (ft) × 0.4335
Uses the empirical Hazen-Williams hydraulic equation for water flow in circular pipes, relating pipe internal diameter, length, flow velocity, and surface roughness factor C.
Configurable Parameters & Standard Units
- Flow Rate (GPM): (Default: 20 count)
- Internal Pipe Diameter (Inches): (Default: 1.25 in)
- Pipe Length (Feet): (Default: 150 ft)
- Roughness C (150=PVC, 130=Copper, 100=Iron): (Default: 140 count)
Standard Worked Example & Practical Verification
Scenario: Pumping 25 GPM through a 200-foot run of 1.25" PVC pipe (C=150).
Calculated Solution
7.11 PSI Pressure Drop (16.4 ft Head Loss)
Practical Takeaway: Flow velocity is near the recommended 5 to 7 ft/sec water velocity ceiling to avoid water hammer.
Frequently Asked Questions
What is the recommended maximum water velocity in pipes?
Industry standards generally recommend keeping water flow velocity between 4 and 7 feet per second (fps) to prevent pipe erosion and noisy hydraulic water hammer.