Identity

A passive aerodynamic steering device and curtain system installed at mechanical air inlets or along ceilings to physically direct and pressurize incoming cold air flows.

Overview

Inlet Deflector Curtains are a high-priority passive ventilation control component used in both minimum-pressure sidewall setups and longitudinal tunnel environments. During winter brooding, the system precisely directs incoming cold air high up toward the shed ceiling. This forces the heavy cold air to aggressively mix with warm stratified ceiling air before it drops to bird level, preventing deadly direct cold drafts and managing hazardous internal ammonia concentrations.

Structured Facts

Classification

Heating & Cooling Infrastructure / Curtain System

Purpose

To manage the direction, trajectory, and velocity of incoming fresh air, forcing a high-velocity air jet along the ceiling to mix with thermal layers before striking the bird zone. Also restricts truss cross-sections to increase local tunnel velocities.

Design & Construction

Manufactured from heavy fabric or passive plastics. In minimum ventilation modes, they restrict inlet openings. In open-truss, high-ceiling tunnel houses, baffle curtains are hung vertically directly from the ceiling across the full width of the building at regular longitudinal intervals of 30 to 50 feet (typically 40 feet on-center).

Environmental Controls

• Temperature: Prevents cold shock; forces thermal mixing.
• Ventilation: Operates via the vena-contracta fluid effect.
• Air Speed: Designed to generate a localized incoming jet at 4.0 to 5.0 m/s (800 to 1,000 ft/min). Increases local tunnel wind speed up to 25 feet downstream of the baffle.
• Air Quality: Helps regulate shed ammonia concentrations by preventing stagnant cold air pockets.

Capacity & Layout

Installed across the width of the structure. For a 500-foot long house, requires upwards of 15 curtains spaced 25 to 40 feet apart.

Equipment Integration

Aerodynamically interlocked with Minimum Ventilation Fans and 50-inch Exhaust Fans.

Advantages

Safely introduces fresh air in sub-zero winter setups without causing mass flock cold stress. Forces fast cooling air directly into the bird zone during summer tunnel mode.

Limitations

Significantly increases static pressure resistance. If baffles are hung too low towards the floor, cumulative static pressure drops between the pad and fan spike rapidly above 0.12 inches H₂O, severely overworking exhaust fans and crashing volumetric air exchange.

Maintenance

The bottom clearance height of the baffles must be monitored and adjusted. Raising baffles by 1.0 foot reduces systemic static pressure resistance and eases fan workload.

Quantitative Data

• Ventilation Rate: Requires 1.7 square feet of inlet opening per 1,000 CFM of active exhaust capacity (1.67 square feet if factoring vena-contracta effect of 60-80%).
• Air Speed: Target inlet velocity of 4.0 to 5.0 m/s (800 to 1,000 ft/min)
• Energy Requirement: Passive system
• Dimensions: Hung vertically at intervals of 30 to 50 feet (40 ft on-center).

Relationships

• Equipment: Minimum Ventilation Fan, Exhaust Fan (50-inch)
• Environmental Parameters: Shed Ammonia Concentration, Static Pressure, Vena-contracta effect
• Diseases: Respiratory disease, Cold Draft Shock
• Production Systems: Semi-EC House, Tunnel Ventilated House
• Calculators: 1.7 sq ft inlet / 1,000 CFM rule