Engineering Calculations & Airflow Assessment

During a fire, hot smoke rises and accumulates beneath the roof, forming a smoke layer that can spread throughout the building.

Without effective smoke exhaust, this layer can deepen, reducing visibility, increasing heat exposure and creating hazardous conditions for occupants and emergency responders.

Building geometry, smoke movement and the availability of suitable exhaust paths all influence how quickly conditions deteriorate

Engineering calculations help assess how wind pressure, thermal buoyancy and building geometry influence natural ventilation performance.

By evaluating inlet and outlet areas, pressure differences and anticipated operating conditions, engineers can estimate airflow rates and assess alternative ventilation configurations.

These calculations provide supporting evidence for a proposed Performance Solution, helping determine whether the design can meet the project's agreed ventilation performance criteria.

Consider five standard roller doors open on the windward face of an industrial building, providing approximately 25 m² of inlet area, together with ridge-mounted natural ventilators.

At a moderate wind speed of 4 m/s, this configuration can generate approximately 40–50 m³/s of airflow through the building.

That's equivalent to the airflow of approximately 20 × 500 mm axial fans running at full speed, based on the engineers' illustrative comparison.