# Duct Calculator

This duct calculator allows three different calculations to be carried out quickly and with ease. These calculations are divided in four areas:
1. Diameter converter, which allows converting circular to equivalent rectangular ducts.
2. Calculator of different ventilation parameters, with which will be able to obtain the diameter, the air speed, the airflow and the dynamic pressure of your installation.
3. Pressure drop calculation tool for installations with straight sections and duct system elements.
4. Units converter, with which you will be able to transform speed, airflow, power and pressure units for other equivalents in different scales.

## CIRCULAR DIAMETER TO RECTANGULAR CONVERSION

This tool allows converting circular to equivalent rectangular ducts.

### From circular to rectangular

• Set the diameter by moving ‘D’ marker on the bar or introducing the desired value into the corresponding cell.
• Set the duct height by moving ‘A’ marker on the bar or introducing the desired value into the corresponding cell.
• Automatically, the ‘B’ marker will move until showing the width of the rectangular duct.

### From rectangular to circular

• Activate the block of ‘A’ marker with the lock.
• Set the duct height by moving ‘A’ marker on the bar or introducing the desired value into the corresponding cell.
• Set the duct width by moving ‘B’ marker on the bar or introducing the desired value into the corresponding cell.
• Automatically, the ‘D’ marker will move until showing the corresponding circular diameter

Note: The relation a:b should not be higher than 1:4.

## VENTILATION PARAMETERS CALCULATOR

This tool allows obtaining different ventilation parameters. You will be able to obtain the:

• diameter
• air speed
• airflow and
• dynamic pressure of your installation.

Obtaining the airflow knowing the diameter and the air speed

• Move the ‘D’ marker on the diameter bar or introduce the desired value into the corresponding cell.
• Move the bar or introduce the value for ‘air speed’
• The corresponding airflow will show in the lower cell

Obtaining air Speed knowing the diameter and the airflow

• Set the diameter by moving ‘D’ marker on the bar or introducing the desired value into the corresponding cell.
• Set the airflow by moving the marker on the bar or introducing the acknowledged value.
• The corresponding air speed will show in the lower cell

Obtaining diameter knowing the airflow and the air Speed

• Move the ‘airflow’ marker on the bar or introduce the desired value into the corresponding cell
• Move the bar or introduce the value for ‘air speed’
• The corresponding diameter will show in the lower cell

Determining the dynamic pressure

• Move the ‘air speed’ marker on the bar or introduce the desired value into the corresponding cell
• The corresponding dynamic pressure will show in the lower cell

## PRESSURE DROP PCALCULATOR

This tool will allow obtaining the pressure drop in installations with straight sections and duct system elements.

### STRAIGHT SECTIONS

Pressure drop calculation in straight sections:

• Move the marker or introduce the desired value for the diameter ‘D’.
• Move the marker or introduce the corresponding value for air speed.
• In the lower cell ‘pressure drop’ the corresponding value for pressure drop by duct meter (mmcda/m) will show
• In the ‘meters’ cell you will need to add the length of the duct
• Then you can click on the ‘+’ icon to add this value to the cell of ‘Total Pressure Drop’

### DUCT SYSTEM ELEMENTS

Pressure drop in duct system elements

• Introduce the dynamic pressure of the duct when known. If unknown, it can be previously obtained by clicking ‘obtain’ button.
• Select the type of duct system element for which the calculation of the pressure drop is needed.
• If required, choose the specific kind of duct system element and the suitable dimensions.
• The solution will appear in the ‘result’ cell.
• If desired, you will be able to add the obtained pressure drop to the total.

## UNITS CONVERSION

With the units conversion tool you will be able to transform speed, airflow, power and pressure units for other equivalents in different scales.

What are the main calculations that can be performed using the duct calculator?
The duct calculator allows three main calculations to be performed: diameter conversion from circular to equivalent rectangular ducts, calculation of various ventilation parameters such as diameter, air speed, airflow, and dynamic pressure, and pressure drop calculation for installations with straight sections and duct system elements. Additionally, the calculator includes a units converter to transform speed, airflow, power, and pressure units to other equivalents in different scales.
How do I use the diameter converter to convert circular to rectangular ducts?

To convert circular to rectangular ducts using the diameter converter, simply set the diameter by moving the D marker on the bar or introducing the desired value into the corresponding cell. Then, set the duct height by moving the A marker on the bar or introducing the desired value into the corresponding cell. The B marker will automatically move to show the width of the rectangular duct. This allows for quick and easy conversion between circular and rectangular duct dimensions.

What ventilation parameters can be calculated using the duct calculator?

The duct calculator can be used to calculate various ventilation parameters, including diameter, air speed, airflow, and dynamic pressure. These parameters are essential for designing and optimizing ventilation systems, and the calculator provides a quick and easy way to obtain these values.

How does the pressure drop calculation tool account for duct system elements?

The pressure drop calculation tool takes into account the presence of duct system elements, such as bends, tees, and valves, which can significantly impact pressure drop in a ventilation system. By including these elements in the calculation, the tool provides a more accurate estimate of pressure drop and allows for more effective system design and optimization.

Can the duct calculator be used for both imperial and metric units?

Yes, the duct calculator includes a units converter that allows for easy transformation of speed, airflow, power, and pressure units between different scales, including imperial and metric units. This makes the calculator versatile and useful for designers and engineers working in different regions or with different unit systems.

What are some common applications of the duct calculator in HVAC system design?

The duct calculator has a wide range of applications in HVAC system design, including sizing ductwork, selecting fans and blowers, and optimizing system performance. It can also be used to troubleshoot existing systems, identify areas of high pressure drop, and optimize system components for improved efficiency and performance.