If you have been looking at specifications for a commercial roller shutter, you may have seen terms such as 20SWG and 22SWG listed alongside the steel curtain.
Unless you work with steel products regularly, those numbers do not immediately tell you much.
In simple terms, SWG refers to the gauge or thickness of the steel used for the shutter curtain. Understanding the difference can help explain why one shutter specification may be recommended for a particular opening while another is better suited elsewhere.
At QSec, we consider the overall opening and how the shutter will be used, rather than choosing a steel gauge in isolation.
What does SWG mean on a roller shutter?
SWG stands for Standard Wire Gauge.
One detail that can initially seem confusing is that a lower SWG number represents thicker steel. For example, industry specifications commonly list 22SWG steel at approximately 0.7mm thick and 20SWG steel at approximately 0.9mm thick.
That means a 20SWG steel curtain uses thicker steel than a 22SWG curtain.
The steel curtain itself is made from individual interlocking slats. These travel within guide channels at either side of the opening and roll around the barrel above the entrance when the shutter is raised.
What is the difference between 20SWG and 22SWG?
The main difference is the thickness of the steel.
A thicker curtain can provide additional rigidity but also increase the overall weight of the shutter.
This means choosing between 20SWG and 22SWG is not simply a case of saying that thicker steel is always better.
The specification needs to account for the complete shutter system.
Factors we consider include:
- The width and height of the opening.
- The level of physical security required.
- How frequently the shutter will open and close.
- Whether manual or electric operation is suitable.
- The fixing conditions around the opening.
- Whether a solid or perforated curtain is needed.
- The type of commercial or industrial premises being protected.
This is why two businesses can need different specifications even if both are installing a steel shutter.
When might 22SWG steel be suitable?
22SWG can provide a practical option for many commercial shutter applications where the opening and required security level suit the specification.
Because it uses a lighter steel curtain than 20SWG, it may be appropriate where the additional thickness of the heavier option is not required.
The final choice still needs to consider the size of the opening, the shutter design, and the method of operation.
We would not recommend selecting a gauge solely because it is the cheapest or lightest option. It needs to be appropriate for the application.
When might 20SWG steel be recommended?
20SWG uses thicker steel and may be considered where the opening or security requirements call for a heavier curtain.
Larger commercial and industrial openings can place different demands on the shutter, so dimensions, guide arrangement, operation and the complete specification all need to be considered together.
Our QS-75T steel roller shutter is available with either 20SWG or 22SWG galvanised steel, allowing the specification to be selected around the individual application.
For full technical details, see the QS-75T steel roller shutter.
Does thicker steel automatically mean a more secure shutter?
Not necessarily.
Steel thickness is only one part of roller shutter security.
The curtain needs to work as part of a complete system that includes the guides, bottom rail, locking arrangements, fixing method and other components.
The building itself matters too. A strong shutter needs to be correctly specified and fitted to a suitable structure.
This is why we prefer to understand the property and the required level of security before recommending a product.
If you have a specific insurance requirement or need a formally rated security product, let us know when you enquire. We can then look at the wider security roller shutter range rather than assuming a thicker standard curtain is automatically the correct solution.
Does the steel gauge affect manual or electric operation?
The size and weight of a shutter can influence how it should be operated.
For suitable smaller applications, manual operation can provide a straightforward solution.
As shutters become larger or heavier, electric operation may be more practical for regular day-to-day use.
The steel gauge is part of that overall calculation because increasing the curtain’s thickness increases its weight.
The correct motor or manual operating system, therefore, needs to be considered alongside the curtain rather than as a completely separate decision.
What about solid and perforated steel curtains?
Steel gauge and curtain style are two different parts of the specification.
A solid steel curtain closes off the opening from view, creating a continuous physical barrier.
A perforated curtain includes small openings through the steel and may be used where some visibility or airflow is desirable.
Both options can still use galvanised steel. The right combination will depend on what you need the shutter to achieve when it is closed.
How do you choose the right steel roller shutter specification?
There is no single steel gauge that is right for every commercial or industrial building.
A warehouse loading opening can have very different requirements from those of an agricultural building, storage facility, or smaller commercial entrance.
Before choosing a shutter, it is worth considering the opening dimensions, how often the shutter will operate, the security level you need and whether visibility through the closed curtain matters.
The steel gauge can then be selected as part of the complete shutter specification.
If you are currently comparing options for a larger commercial or industrial opening, our guide to traditional galvanised steel roller shutters explains the available curtain, operation and finish options in more detail.
Need help choosing the right shutter?
You do not need to decide between 20SWG and 22SWG before speaking to us.
Tell us about the opening you need to secure and how the building is used. Our team can then discuss the available options and help you understand which specification is suitable.
QSec offers free quotations and surveys, so we can assess the specific requirements of your premises before recommending a shutter.
Call 0113 345 0599 or contact QSec to arrange your free survey.