Designer Tools

Quick, copyable, printable reference calculations for sprinkler system design.

PQK Formula Solve for P, Q, or K

Flow (Q)

gpm

Pressure (P)

psi

K-factor (K)

gpm/√psi

Enter any two values.

Formula: Q = K · √P (consistent units). Enter any two values; FireCalc solves the third.

Friction Loss (Hazen–Williams) Pipe, schedule, length, flow

Pipe schedule Nominal pipe size C-factor

Flow

gpm

Length

Fittings equivalent length (optional)

Build fittings equivalent length automatically

90° elbows 45° elbows Tee (through run) Tee (branch) Gate valve (open) Swing check valve

Leq from fittings: 0 ft

Uses typical Le/D multipliers × selected pipe ID. Confirm against your project standard if required.

Uses Hazen–Williams with selected internal diameter for the chosen schedule.

Static Head Elevation → pressure

Elevation difference (positive = up)

Tip: Use negative elevation for downhill gains.

Pipe Volume Volume in pipe run

Pipe schedule Nominal pipe size Length

Pipe Weight (Empty & Full) Per length & total

Pipe schedule Nominal pipe size Length

Weights are typical values for steel pipe; always confirm final loads with project specs and supplier data.

Tip: Use the Print button to save a PDF from your browser. Each module output is formatted for easy copy/paste into emails or reports.