How Is Aircraft Hangar HVAC Designed for Huge Open Bays?

The heating load calculation follows standard practice, but the delivery method does not. In a bay with 30-to-50-foot ceilings, heating the air means heating a vast volume the occupants never touch, and warm air's buoyancy parks it at the roof. Gas-fired infrared tube heaters or low-intensity radiant panels mounted in the upper third of the bay radiate directly to the floor, aircraft, and people, producing comfortable conditions at lower air temperatures and recovering in minutes after the doors close. The engineer spaces heaters for uniform coverage, verifies clearances to structure, sprinklers, and stored combustibles, and zones controls by bay so heating follows the work. Destratification fans — large slow-turning ceiling fans or axial destrat units — mix the stratified layer back down, cutting the roof-to-floor temperature spread and trimming heater runtime. The two systems are controlled together, not as strangers.

The ventilation design starts from an inventory of what burns fuel or emits fumes inside: APUs run during maintenance, tugs and fuel trucks come and go, and paint, solvent, and battery areas each have their own contaminants. General exhaust is sized to dilute vehicle exhaust to safe levels during the expected operating schedule, with carbon monoxide sensing that ramps ventilation on demand rather than running full-time. Makeup air is provided in equal measure — a hangar exhausted without makeup goes negative, pulls in dust through every gap, and makes doors hard to operate. Local exhaust serves welding stations, parts washers, and battery rooms directly at the source. Intake louvers are placed away from exhaust discharge, APU blast zones, and fueling areas so the building does not re-breathe its own contaminants, and the engineer coordinates louver locations with the architect's envelope and the structural engineer's bracing.

Use this checklist before the mechanical drawings are finalized: • Heating load calculated per standard practice; radiant system selected for the bay height and duty cycle • Radiant heaters laid out for uniform floor-level coverage with listing-required clearances verified • Destratification fans sized and controlled on temperature differential to break up the stratified layer • Exhaust ventilation sized for APU, tug, and vehicle exhaust with CO-based demand control • Makeup air provided to match exhaust; intakes located away from exhaust, blast, and fueling zones • Local exhaust at welding, battery, paint, and parts-washing stations • Door-switch setback logic so heating does not fire at full rate through long open-door periods • Every device coordinated in 3D against aircraft tails, wingtips, cranes, and fall-protection systems