Kapa Corporation Guide: Proper Installation and Sizing of Ductwork for Compressed Air Systems

Guide: Proper Installation and Sizing of Ductwork for Compressed Air Systems

At Rotary Screw Air Compressor, we understand that the efficiency and reliability of compressed air systems depend heavily on the proper design and installation of exhaust ductwork. Improper installation can result in overheating, poor air quality, and increased maintenance—especially during warmer months. To help you avoid these common pitfalls, our experts have outlined frequent mistakes and recommended best practices based on industry experience.

Common Mistakes in Ductwork Installation

❌ Mistake 1: Incorrect Duct Sizing

Many installers size the ductwork to match the compressor’s exhaust opening. This is the most common and critical mistake.

✅ Kapa’s Tip: The duct’s cross-sectional area should match the size of the compressor cooler, not just the exhaust port. In most cases, this means using ductwork with double the area of the exhaust outlet to prevent backpressure and ensure proper airflow.

❌ Mistake 2: Ignoring Duct Length and Resistance

Long duct runs and multiple bends can significantly reduce airflow and cause air stagnation.

✅ Kapa’s Tip: For long runs or systems experiencing high backpressure, install booster fans to maintain airflow. Design the system with smooth, sweeping bends rather than sharp angles to minimize resistance.

❌ Mistake 3: Combining Multiple Compressors into a Single Duct

Connecting multiple compressors to a shared exhaust header often causes uneven airflow, backflow, and overheating of idle units.

✅ Kapa’s Tip: Use separate exhaust ducts for each compressor. If combining is necessary, consult a qualified engineer and install backdraft dampers or louvres to prevent reverse airflow into idle equipment.

❌ Mistake 4: Allowing Warm Air Recirculation

Recirculated hot air entering the intake increases the compressor’s operating temperature, reduces efficiency, and shortens service life.

✅ Kapa’s Tip: Ensure there is adequate distance between air intakes and exhaust outlets. Proper room layout and airflow management are essential to prevent heat recirculation.

❌ Mistake 5: No Temperature-Controlled Ventilation

Fixed-speed fans and passive louvres may not adjust to seasonal temperature changes, leading to overheating in warmer months.

✅ Kapa’s Tip: Install thermostatically controlled fans and automated louvres. These systems respond dynamically to temperature fluctuations. In colder climates, they also help mix warm exhaust air with fresh intake air to prevent freezing issues and maintain optimal operating conditions.

❌ Mistake 6: Inadequate Ventilation for Small Compressors

Compact compressors are often installed in tight spaces like closets or sheds with insufficient airflow.

✅ Kapa’s Tip: At a minimum, install louvres for both intake and exhaust. In most cases, a fan is required to maintain adequate air exchange. Use thermostatic control for the best results. Regularly monitor room temperature, even with a simple thermometer, to prevent overheating and avoid unnecessary maintenance.