Wind Influence
Calculations assume stagnant atmospheric conditions. High external wind pressure on single elevations may counteract buoyancy forces.
Natural Smoke Exhaust: Mass Flow Rate Tool
Evaluate the performance of automated vents and natural openings. Support for Milke & Klote (AUS) and Morgan et al. (UK) calculation matrices.
Professional Notice: This tool assumes buoyant-driven flow and does not explicitly model external wind pressure impacts or sprinkler-induced smoke cooling.
Dual-Standard Analytical Analysis
Natural smoke exhaust relies on the buoyancy of hot gases to clear smoke from a compartment. This calculator allows engineers to rapidly determine the mass flow rate (kg/s) based on vent geometry, smoke layer depth, and temperature differentials.
Our implementation follows validated design guides, providing two distinct calculation paths to suit regional requirements and standard practices.
Milke & Klote (AUS Methodology):
m = C Av ฯ0 [ 2 g db (Ts-T0) T0 / (Tsยฒ + (C Av / Ci Ai)ยฒ Ts T0) ]โฐ.โต
Critical Variables:
Av = Vent Area
Ai = Inlet Area
db = Smoke Layer Depth
Ts = Smoke Temperature (K)Technical Constraints
Sprinkler Cooling
The model assumes thermally buoyany smoke. Sprinkler activation can cool the layer, reducing buoyancy and potentially causing smoke log-down.
Inlet Balancing
Natural exhaust is "air-bound" if makeup air is restricted. Ensure Ai is sufficiently large to prevent excessive pressure drops.
Validated References
- Klote & MilkePrinciples of Smoke Management (2002) โ The definitive reference for the Australian methodology.
- Morgan et al.Design methodologies for smoke and heat exhaust ventilation (1999) โ Foundation of the UK methodology.
- Arup/Morgan CodeInternal Design Guide for Natural Smoke Exhaust โ Version 3.0 / Rev 15.0 alignment.
Ready to calculate smoke exhaust?
Verify your design assumptions using our validated natural exhaust engine. Instant toggling between AUS and UK standards for global compliance.