Sprinkler System Design & Hydraulic Calculation – Quick Guide (Parts 1–4)

We put together a 4-part quick guide to sprinkler design, from the basic formulas to a fully worked hydraulic calculation, based on NFPA 13 (2022). Every number in our worked example has been checked with a script.

• Part 1 – Fundamentals: hazard classes LH to EH2, density/area, coverage and spacing, K-factors, Q = K√P and the 7 psi minimum

• Part 2 – Layout & pipe sizing: head selection, a spacing layout, Hazen–Williams, C-factors, fitting equivalent lengths and velocity

• Part 3 – Remote area & pump: operating sprinklers, hose allowance and duration, elevation, NFPA 20 pump curve and tank sizing

• Part 4 – Worked example: an OH1 remote area with 12 K-5.6 heads, section-by-section flow and pressure through to a 750 gpm @ 60 psi pump and a 173 m³ tank

Save it for your next design review. This is a summary only; always refer to NFPA 13 and the AHJ.

Part 1 – Fundamentals

Part 2 – Layout & Pipe Sizing

Part 3 – Remote Area & Pump

Part 4 – Worked Example

Download the full guide (PDF)