top of page

Rectangular Ducting
Galvanised and stainless steel ducting

We manufacture and supply a wide range of bespoke rectangular ducting in both galvanised steel and stainless steel. Our team of ducting experts are available to help with your selection, contact them today on 0116 2448515 or email

Rectangular ducting sizing

Sizing rectangular ducting involves determining the appropriate dimensions (width, height, and sometimes depth). We will require a drawing including these factors, before we can provide a quotation. You can upload your file on our Contact page or email it to us.


We can help with the sizing of the ducting you require, so contact our team and we will ensure you have the correct products for your project.

Call us on 0116 2448151 or email

Here's a general overview of the steps involved in sizing rectangular ducts:

1. Calculate Airflow Requirements: Determine the airflow (in cubic feet per minute, CFM) needed for the specific HVAC system or application. This requirement is typically determined by factors such as the size of the space, occupancy, equipment heat load, and ventilation standards.

2. Select Design Criteria: Establish design criteria such as the maximum allowable air velocity, pressure drop, and noise level. These criteria may be dictated by HVAC design standards, building codes, or project specifications.

3. Choose Duct Material and Insulation: Select the appropriate material for the rectangular ducts based on factors such as durability, thermal conductivity, and cost. Consider insulation requirements if thermal performance is a concern.

4. Determine Friction Losses: Calculate the friction losses in the duct system based on the selected duct material, dimensions, airflow rate, and duct layout. Friction losses account for the resistance to airflow caused by duct surface roughness and bends.

5. Size the Ducts: Use duct sizing charts, tables, or duct sizing calculators to determine the dimensions (width, height, and sometimes depth) of the rectangular ducts required to meet the airflow and pressure drop criteria. These sizing tools consider factors such as duct shape, airflow velocity, and available static pressure.

6. Consider Duct Layout: Design the duct layout to minimize bends, transitions, and obstructions that can increase pressure drop and reduce airflow efficiency. Optimize the duct routing to achieve balanced airflow distribution to different zones or rooms within the building.

8. Review and Adjust: Review the duct sizing calculations and design layout to ensure compliance with applicable codes, standards, and project requirements. Make adjustments as necessary to optimize the system performance and meet the project goals.

Proper sizing of rectangular ducting is essential for ensuring efficient and effective HVAC system operation, maintaining indoor air quality, and minimizing energy consumption. 

Rec 1.png
Rec 4.png
Rec 3.png
Rec 2.png
Rec 6.png

To place an order, or if you need help selecting your required products, contact our specialist team.

Related products

Waiting Room
Rectangular ducting

Rectangular ducting

See options


Ducting supplies

Ducting supplies

See options

Get in Touch

Call or email to find out more about our prices and availability

0116 2448151

Thanks for your message

bottom of page