Engineers and facility planners rely on a duct selection chart to match airflow requirements with the right duct size and material. This practical tool helps balance pressure loss, velocity, and noise while keeping installations on schedule and budget.
Use the structured summary below as a quick reference for common duct types, typical applications, and key performance factors before diving into detailed design choices.
| Duct Type | Typical Use | Velocity Range (m/s) | Key Advantage |
|---|---|---|---|
| Galvanized Steel | Commercial HVAC, industrial | 6–10 | Durable, fire-resistant |
| Aluminum | Clean rooms, labs | 8–12 | Lightweight, corrosion-proof |
| Flexible Hose | 风机连接与局部调整10–15 | Ease of installation around obstacles | |
| Fiberglass Board | Noise-sensitive spaces | 4–8 | Built-in acoustic damping |
Material Options and Performance
Steel vs Aluminum vs Composite
Material choice directly affects longevity, weight, and maintenance needs in a duct selection chart. Steel offers robust pressure handling, while aluminum reduces installation weight and resumes oxidation in moist environments. Composite panels can lower noise and thermal conductivity but may require protective coatings in harsh conditions.
Sizing and Pressure Loss
How to Use Velocity and Diameter Data
Proper sizing starts with calculating the required airflow, then selecting a velocity that keeps pressure loss within fan capacity. A duct selection chart usually provides diameter tracks for common velocities, helping you avoid oversized ducts that increase cost or undersized runs that raise noise and pressure drop.
Installation Environment Considerations
Space, Accessibility, and Climate Factors
In tight mechanical rooms or suspended ceilings, slim profiles and flexible connections become priorities. Corrosive atmospheres, temperature swings, and condensation risk may steer the choice toward coated or nonferrous materials listed in the duct selection chart, ensuring long-term performance without frequent replacements.
Energy Efficiency and Noise Control
Optimizing Fan Power and Sound Levels
Smooth internal surfaces and insulated sections reduce both fan energy and transmitted noise. Refer to the duct selection chart to compare surface roughness and insulation grades, aiming for velocities near the lower end of recommended ranges to enhance efficiency and occupant comfort.
Practical Duct Planning Recommendations
- Confirm required airflow and system layout before reading the duct selection chart.
- Choose materials that tolerate the local climate and indoor contaminants.
- Target moderate velocities to limit noise and pressure drop without oversizing ducts.
- Plan insulation thickness and joint seals to maintain efficiency and meet acoustic specs.
- Verify fan capacity against total pressure loss for the selected duct paths.
FAQ
Reader questions
Which velocity range should I pick for standard office spaces?
For typical office environments, keep air velocity between 6 and 8 m/s to balance noise, pressure loss, and energy use while maintaining comfortable airflow patterns.
Is galvanized steel always the best choice for outdoor runs?
Galvanized steel works well outdoors due to its corrosion resistance, but in coastal areas with high salinity, aluminum or coated composites may offer longer life with less maintenance.
How does duct insulation affect the selection chart values?
Adding insulation changes effective diameter and acoustic performance; the chart usually separates bare and insulated options so you can match thickness to thermal and noise requirements.
Can flexible hose be used as the main supply trunk in a duct selection chart?
Flexible hose suits branch runs and vibration isolation but is less efficient as primary trunking; use it only where space constraints or movement justify the higher pressure loss.