# Based on Friction Loss:

• Enter Friction Loss (inches of water), Duct Airflow (CFM), Duct Length  and the number of bends.
• Read Duct Diameter (inches) and Duct Velocity (FPM).

# Based on Duct Diameter:

• Enter Round Duct Diameter (inches), Duct Airflow (CFM), Duct Length and the number of bends.
• Read Friction Loss (inches of water) and Duct Velocity (FPM).

# Equivalent Rectangular Duct:

• Enter Round Duct Diameter.
• Enter the Desired Length of the Rectangular Duct.

# Equivalent Round Duct Diameter:

• Enter the Length of the Rectangular Duct.
• Enter the Width of the Rectangular Duct.

# Maximum Recommended Supply Velocity:

What is the significance of friction loss in flexible duct calculations?
Friction loss is a critical parameter in flexible duct calculations as it directly affects the pressure drop in the duct, which in turn impacts the airflow and overall system performance. Accurate estimation of friction loss helps designers and engineers to select the right duct size, determine the required fan power, and ensure that the system operates within the desired pressure range. The Flexible Duct Calculator provides a method to calculate friction loss based on duct diameter, airflow, length, and number of bends, enabling users to optimize their duct design for minimal pressure drop and maximum efficiency.
How does duct diameter impact airflow and velocity in flexible ducts?

Duct diameter has a significant impact on airflow and velocity in flexible ducts. A larger duct diameter results in lower velocities and reduced pressure drop, while a smaller duct diameter leads to higher velocities and increased pressure drop. The Flexible Duct Calculator allows users to input duct diameter and airflow to determine the resulting velocity and friction loss, enabling them to optimize their duct design for the desired airflow and pressure drop characteristics.

What is the equivalent rectangular duct method, and when is it used?

The equivalent rectangular duct method is a technique used to convert a round duct diameter to an equivalent rectangular duct size, taking into account the desired length and width of the rectangular duct. This method is useful when designing duct systems that require rectangular ducts, such as in tight spaces or for aesthetic reasons. The Flexible Duct Calculator provides an equivalent rectangular duct calculator that simplifies this process, allowing users to easily convert between round and rectangular duct sizes.

What is the significance of maximum recommended supply velocity in flexible duct design?

Maximum recommended supply velocity is a critical parameter in flexible duct design as it ensures that the duct system operates within a safe and efficient range. Excessive velocities can lead to noise, vibration, and increased pressure drop, while velocities that are too low may result in inadequate airflow and system performance. The Flexible Duct Calculator provides a table of maximum recommended supply velocities for main and branch ducts, helping designers and engineers to ensure that their duct systems are designed for optimal performance and efficiency.

How do bends affect friction loss and airflow in flexible ducts?

Bends in flexible ducts can significantly impact friction loss and airflow by introducing additional pressure drop and turbulence. The number and type of bends, as well as the duct material and diameter, all influence the degree of friction loss and airflow reduction. The Flexible Duct Calculator takes into account the number of bends when calculating friction loss and airflow, enabling users to accurately design and optimize their duct systems for minimal pressure drop and maximum efficiency.

What are the advantages of using a flexible duct calculator in HVAC system design?

A flexible duct calculator, such as the one provided, offers several advantages in HVAC system design, including accurate calculation of friction loss, airflow, and velocity, simplified duct sizing and selection, and optimized system performance. By using a flexible duct calculator, designers and engineers can reduce errors, save time, and ensure that their duct systems are designed for maximum efficiency and performance. Additionally, the calculator can help to identify potential issues and opportunities for improvement, enabling designers to optimize their systems for energy efficiency, cost-effectiveness, and reliability.

How can I use the Flexible Duct Calculator to optimize my HVAC system design?

To optimize your HVAC system design using the Flexible Duct Calculator, start by inputting the required parameters, such as duct diameter, airflow, length, and number of bends. The calculator will provide the resulting friction loss, velocity, and equivalent rectangular duct size. Use these results to iterate on your design, adjusting parameters to achieve the desired airflow, pressure drop, and system performance. By repeatedly using the calculator and refining your design, you can optimize your HVAC system for maximum efficiency, reliability, and cost-effectiveness.