McAleer&McGarrity Ltd required a detailed assessment of "Effects of wind on smoke ventilation from a large commercial carpark" in 2019. The work brought together computational fluid dynamics (CFD) and the project information supplied for this building and construction application. The central objective was to connect local flow, thermal, transport or process behaviour with system-level performance, risk and design decisions that the client could implement.

We evaluated how wind conditions interact with a car‑park smoke control strategy, using CFD to resolve buoyancy‑driven smoke movement, make‑up air supply and wind‑induced pressure fields across the openings and ductwork. Scenarios covered multiple wind directions and speeds, fan duty points and fire‑size assumptions that reflect realistic operational envelopes. The model mapped the balance between extraction, entrainment and recirculation to identify risks of smoke re‑entry or stratification loss, with attention to critical travel routes and refuge zones. We compared alternative louvre/orifice arrangements and control set‑points, including natural versus mechanical boosts at key portals. Mesh and solver choices balanced fidelity with turnaround; verification checks and targeted sensitivities supported robust option‑to‑option conclusions. Results were communicated via clear planmaps and section visualisations of velocity, temperature and smoke concentration, together with time histories at points of interest. Recommendations addressed opening configuration, fan logic and contingency actions that maintain tenability and visibility across a range of site winds, de‑risking design development and supporting discussions with stakeholders and regulators.

The methodology centred on a transient buoyant-flow and species-transport CFD model of the car park, smoke-control system and external wind environment. The representation retained the fire zone, extract and make-up air paths, openings, ducts, travel routes and external geometry influencing pressure and smoke re-entry. Boundary and operating conditions covered credible fire sizes, fan duties, natural and mechanical ventilation modes, and the wind directions and speeds relevant to the site, with material, fluid and equipment properties assigned from the available design information. Resolution was concentrated in regions where steep velocity, thermal, concentration or phase gradients were expected, while the overall model remained efficient enough to compare several credible configurations. This balance allowed system-level performance to be linked to the local mechanisms responsible for it.

The assessment compared opening arrangements, louvres, extraction strategy and control set-points. Performance was judged using smoke concentration, visibility and temperature proxies, layer stability, extraction effectiveness, re-entry risk, recirculation and conditions along critical routes. Results were reviewed through quantitative summaries and engineering visualisations, such as contours, vectors, streamlines, sections and time histories, selected to suit the physics. Important assumptions and operating uncertainties were considered so that the recommendations relied on repeatable comparative trends rather than a single nominal case.

For McAleer&McGarrity Ltd, the principal value was a more resilient smoke-control strategy and clear evidence for design and regulatory review. The final evidence linked each recommendation to the relevant model or process output, making it suitable for internal design reviews, supplier or contractor discussions and, where applicable, planning, safety or regulatory dialogue. The work also created a reusable baseline that can be updated as geometry, operating data or test results become available, reducing the cost and risk of later design iterations.