1. What is the Square Duct Size Calculation?

The square duct size calculation determines the side length of a square duct based on airflow (CFM) and velocity (ft/min). This is essential for proper HVAC system design and efficient air distribution.

2. How Does the Calculator Work?

The calculator uses the square duct equation:

Where:

• \( Side \) — Side length of square duct (ft)
• \( CFM \) — Airflow in cubic feet per minute
• \( V \) — Air velocity in feet per minute

Explanation: The equation calculates the required side length of a square duct to achieve the desired airflow at a specific velocity.

3. Importance of Duct Sizing

Details: Proper duct sizing is crucial for efficient HVAC system operation, ensuring adequate airflow while minimizing pressure drops and energy consumption.

4. Using the Calculator

Tips: Enter CFM (cubic feet per minute) and velocity (feet per minute). All values must be valid (CFM > 0, V > 0).

5. Frequently Asked Questions (FAQ)

Q1: What is the typical velocity range for HVAC ducts?
A: For main ducts, velocities typically range from 1000-2000 ft/min, while branch ducts range from 600-900 ft/min.

Q2: How does duct shape affect airflow?
A: Round ducts are more efficient for airflow, but square/rectangular ducts are often used where space is limited.

Q3: What factors should be considered in duct design?
A: Air velocity, pressure drop, noise levels, space constraints, and energy efficiency should all be considered.

Q4: How does duct size affect system performance?
A: Undersized ducts increase velocity and pressure drop, reducing efficiency. Oversized ducts increase material costs and may not maintain proper air velocity.

Q5: Are there standard duct sizes?
A: While there are common sizes, duct dimensions are often customized based on specific project requirements and space constraints.