Ventilation & Climate
Tunnel Ventilation
Tunnel ventilation moves air longitudinally through a poultry house at 2.5–3.5 m/s to deliver wind-chill cooling on hot days. It is the dominant ventilation strategy for broilers in hot climates above 25 °C ambient.
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Role within the project
Tunnel ventilation combined with evaporative cooling determines summer heat-stress mortality. Under-sized systems lose 3–8% of the flock in extreme heat events.
Typical applications
- Broiler houses in hot climates
- Breeder houses in hot climates
- Turkey grow-out (with adjusted velocities)
Selection criteria
- Guaranteed CFM at static pressure — not free-air rating
- Fan efficiency (CFM/W) and blade design
- Compatibility with evaporative pads and controller
- Belt vs direct-drive maintenance profile
Engineering considerations
- Cross-section sized for target tunnel velocity
- Pad area sized for target wet-bulb approach
- Fan static pressure at design condition
- Emergency drop-curtain override on power failure
Commercial considerations
- Fan cost dominated by efficient designs at high CFM/W
- OPEX savings on efficient fans measurable over 12–24 months
- Warranty on motor and bearing life
Procurement considerations
- Independent airflow test at commissioning
- AMCA-certified fan rating required in RFQ
- Standby power sized for full tunnel ventilation load
Common mistakes
- Sizing on free-air CFM instead of static-pressure CFM
- Fan spacing that leaves dead zones
- Pad system sized for average not design wet-bulb
- No emergency drop-curtain
Ask suppliers
Ask for AMCA-certified static-pressure CFM at your design operating point, with fan wattage measured.
Related resources
Frequently asked
What tunnel velocity should I target?
For broilers in hot climates, 2.5–3.0 m/s is standard; 3.0–3.5 m/s for extreme heat events. Above 3.5 m/s the wind-chill gain flattens and dust becomes a problem.
Do I need evaporative cooling with tunnel ventilation?
Above ambient design temperatures around 32 °C, yes — tunnel alone runs out of wind-chill capacity. See the cooling pads page for pad sizing.