Airports present some of the most demanding environments for air handling units. Terminals packed with thousands of passengers, airside facilities operating around the clock, and security requirements that make access and installation logistically complex. It’s a sector we know well — we’ve delivered bespoke AHUs for Heathrow and completed a full AHU replacement at a major London airport within a live operational facility.
Here’s what makes airport ventilation different and why it demands specialist expertise.
The Scale Challenge
Airport terminals are vast open spaces with high ceilings, massive glazed facades, and occupancy levels that fluctuate wildly — from a handful of staff at 4am to thousands of passengers during peak departure times. The thermal loads are equally variable: solar gain through glass roofs in summer, body heat from crowded departure lounges, heat from retail kitchens and equipment.
Sizing AHUs for airport terminals means designing for peak loads while running efficiently at part load for the majority of operating hours. Oversized systems waste energy. Undersized systems can’t cope with peak conditions. The engineering requires careful load modelling and flexible system design.
We design our airport AHUs with variable speed drives and demand-responsive controls as standard. The system adjusts output continuously based on actual conditions — temperature, CO2 levels, occupancy — rather than running at fixed capacity.
24/7 Operation
Most airport facilities operate continuously. Terminals may reduce activity overnight but never fully close. Airside facilities — baggage handling, maintenance hangars, cargo processing — often run around the clock.
This means AHUs can’t simply be switched off for maintenance or replacement. When we replaced the units at the major London airport project, we had to work around continuous operations — phasing the work so that ventilation was maintained throughout, with temporary provisions where necessary.
Redundancy is essential. Standby capacity, N+1 fan configurations, and automatic failover controls ensure that a single component failure doesn’t compromise ventilation to an occupied terminal. We design these failsafe measures into every airport installation.
Security and Access
Working in airports means navigating security protocols that don’t apply to other construction sites. Personnel vetting, airside access restrictions, tool and material controls, and escorted access requirements all add complexity and time to installation programmes.
Delivery logistics are equally challenging. Large AHU sections need to reach plant rooms that may be accessed through restricted zones, with deliveries coordinated around flight operations and ground vehicle movements.
We factor these constraints into project planning from the outset. Our experience at Heathrow and other airport sites means we understand the protocols and can programme works realistically rather than discovering access restrictions after mobilisation.
Air Quality in High-Occupancy Spaces
Airports concentrate large numbers of people in enclosed spaces — departure lounges, security halls, baggage reclaim, immigration queues. Ventilation must maintain adequate air quality to prevent stuffiness, manage odours, and — increasingly post-pandemic — reduce airborne pathogen risk.
Enhanced filtration, higher fresh air rates, and CO2-responsive controls are becoming standard requirements for airport terminal ventilation. We specify filtration grades and air change rates based on the specific zone — a crowded departure lounge has very different requirements to a low-occupancy office area within the same terminal complex.
Noise Control
Airports are already noisy environments, but within terminal buildings, acoustic comfort matters. Passengers waiting, shopping, or eating don’t want to be overwhelmed by HVAC noise. AHUs serving terminal areas need careful acoustic treatment — attenuators, low-noise fan selection, and vibration isolation — to maintain acceptable background noise levels.
Our bespoke AHU designs incorporate acoustic modelling to ensure noise criteria are met without oversizing attenuators or restricting airflow.
Corrosion and Durability
Airside AHUs — those serving hangars, maintenance facilities, and ground-level plant — may be exposed to aviation fuel vapours, de-icing chemicals, and salt-laden air at coastal airports. Standard casing materials won’t last in these conditions.
We specify appropriate materials and coatings for the operating environment — stainless steel drain pans, coated coils, marine-grade fixings — based on the specific exposure conditions at each installation.
Working With Us
i-Flow Technologies has proven experience delivering air handling solutions for the aviation sector. From bespoke terminal AHUs to live-environment replacements, we understand the unique demands of airport projects.
If you’re planning an airport ventilation project — whether new terminal construction, system replacement, or efficiency upgrade — contact us to discuss your requirements. We’ll bring the experience and engineering expertise your project needs.
