Power Flue System Sizing
Overcome structural constraints and natural draught failures. Accurately calculate required fan capacities (L/s), minimum duct sizing, and safe discharge limits for complex power flue systems per AS/NZS 5601.1.
Demo Video Coming Soon
Why Professionals Use This Tool
Stop risking compliance failures on manual math and generic approximations. GasCalc transforms complex AS/NZS 5601 regulatory requirements into a rapid, error-free digital workflow. Bring absolute certainty, unprecedented speed, and audit-ready documentation to every gas fitting project.
Instant Volume Calculation
Enter the total gas consumption (MJ/h) and your target CO2 percentage. GasCalc instantly processes the Q = T/R formula to determine the exact fan volume (L/s) required.
Automated Duct Sizing
Beyond fan capacity, the tool automatically calculates the minimum duct diameter required to maintain a safe 3 m/s velocity, minimizing system noise and friction losses.
Motor Temp Ratings
By calculating the target dilution ratio, GasCalc predicts the continuous flue temperature (e.g., 140°C), ensuring you specify a fan motor capable of handling the heat.
How the Calculator Works
Designing a power flue requires precise balancing of gas input against dilution air to prevent hazardous CO2 concentrations. GasCalc automates this critical math.
Enter Gas Load
Input the total gas consumption (T) in MJ/h for all appliances connected to the power flue system.
Set Target CO2 (R)
Define your target CO2 concentration. GasCalc provides guidance (e.g., max 1.0% for low-level discharge, 4.0%-8.0% for roof discharges).
Specify Your Fan
Instantly receive the required fan volume (L/s), the exact dilution air required for the room, and the safe duct diameter.
Compliance & Standards
AS/NZS 5601.1:2022 Appendix H.2: This tool strictly applies the formulas required for power flues, ensuring accurate calculations for challenging installations where natural draught is unsuitable.
Mandatory Safety Rules: The calculator outputs critical compliance reminders, such as the requirement for flow failure interlocks (pressure switches) and weatherproof motor specifications.
GasCalc acts as your digital reference for Table H.9, eliminating manual interpolation errors.
Ready to Streamline Your Gas Calculations?
Join modern gas professionals who have traded error-prone manual math for GasCalc's precise, standardized toolkit.
Subscribe NowInstant access to all calculators and reporting tools.