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Hydraulic Calculations – Fire Sprinkler & Hydrant System

Project: Proposed Building Plan – M/s DLYFT INDIA LLP
Location: VPO Kahni, District Rohtak, Haryana
Standards: NFPA 13 & NFPA 14

Scope of Work

  • Identified and modeled the most remote area (Mezzanine Floor) for sprinkler and hydrant demand analysis.

  • Classified the sprinkler system as Ordinary Hazard – Group 1 with a design density of 0.15 gpm/ft² over 1,500 ft².

  • Calculated:

    • Sprinkler discharge per head (K5.6, max. 130 ft² coverage).

    • Minimum required end-head pressure (12.12 psi).

    • Flow and friction loss in mains and branch lines using HASS software.

  • Included hose stream allowance (250 gpm) and hydrant demand in the total system sizing.

  • Performed hydrant demand analysis for 2 × 63 mm landing valves at ≥100 psi.

  • Prepared hydraulic demand curves and system supply graphs for both sprinkler and hydrant systems.

  • Verified water supply meets demand curve with a 10% safety margin.

Hydraulic Demand Results

Sprinkler System

  • Demand Flow: ~234 gpm

  • End Sprinkler Flow: 19.5 gpm @ 12.12 psi

  • Hose Stream Allowance: 250 gpm

Hydrant System

  • Demand Flow: 500 gpm (2 landing valves × 250 gpm)

  • Residual Pressure: >100 psi at remote outlets

Combined Maximum Demand:

  • Sprinkler: 234 gpm

  • Hose Stream: 250 gpm

  • Hydrant: 500 gpm

  • Total: 984 gpm

🚒 Fire Pump Sizing

  • Main Pump: 1,000 gpm @ 124 psi (8.5 bar)

  • Jockey Pump: 100 gpm @ 130 psi (9 bar) for pressure maintenance

Compliance & Outcome

  • System meets NFPA 13 & NFPA 14 requirements for flow, pressure, and duration (≥60 minutes).

  • Friction losses and velocities within acceptable limits.

  • Hydraulic graphs and calculation sheets prepared for submission to AHJ.

🛠 This hydraulic design ensures reliable water delivery to sprinklers and hydrants during fire scenarios, maintaining adequate residual pressures across the system while complying with international standards.

👉 View Design and Calculations.

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