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.

Table of Contents

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.