Storm Protection Guide
Storm shutters: what the term actually means
We get asked from time to time for storm shutters, usually by people living somewhere exposed enough to have watched a window flex in a gale. It is a completely reasonable request. Working out how to answer it properly turned out to be much harder than we expected, and what we found is worth writing down.
The short answer
We can find no British Standard that defines the term "storm shutter", and no UK building requirement, in Scotland or elsewhere, that calls for one. There are British Standards covering shutters. BS EN 13659 sets wind-resistance classes for external shutters, and a UKCA or CE mark is where such a class gets declared. What we have not been able to find is any UK or European standard that tests a shutter against flying debris.
That distinction is the whole subject. European shutters are tested, and tested seriously, but for wind pressure. The thing most people picture when they say "storm shutter", a barrier that stops a flying roof slate going through the glass, is tested under a different regime that exists mainly in the United States and the Caribbean.
So when a UK company describes something as a storm shutter, that phrase carries no agreed meaning. It might sit behind serious testing. It might describe the weather the product is intended for. The words alone will not tell you which.
First, what counts as a storm?
The Beaufort scale still does this job well, but there is a trap in it that catches almost everybody.
| Beaufort force | Description | Sustained wind speed |
|---|---|---|
| 8 | Gale | 39 to 46 mph |
| 9 | Severe gale | 47 to 54 mph |
| 10 | Storm | 55 to 63 mph |
| 11 | Violent storm | 64 to 72 mph |
| 12 | Hurricane force | 73 mph and above |
The trap: Beaufort describes sustained wind, not gusts. A gust is a short peak sitting on top of the sustained wind behind it, and the peak is always the bigger number.
So a gust figure and a Beaufort force are not the same measurement, and one cannot simply be read off the other. Converting a peak gust into a sustained mean depends on terrain, height and exposure, is governed by the Eurocode, and is properly a job for a wind engineer rather than a shading company with a rule of thumb. What we can say without any arithmetic at all is that a gust above 73mph is at the speed that would be hurricane force if it were sustained, and that is well beyond what most external shading is built for.
The other thing worth understanding is that wind load does not rise in step with wind speed. It rises with the square of it. Double the wind speed and you roughly quadruple the force on whatever is standing in its way.
That is why a product that copes beautifully with a blustery day can be nowhere near what a genuine storm demands. The gap is far wider than the numbers make it sound.
How shutters are actually tested
There are two different worlds here, and confusing them is the single biggest cause of misunderstanding on this subject.
The European system
Wind pressure classes
External shutters are covered by BS EN 13659, external blinds and awnings by BS EN 13561, both tested using the method in EN 1932.
The product is subjected to a steady, even pressure across its whole face, pushing and pulling. It is rated on a scale from class 0 to class 6.
What it does not appear to test: impact from flying debris, and repeated pressure cycling over hours.
The US system
Impact and cyclic testing
Hurricane shutters in the United States are tested under the ASTM E1886 and E1996 standards. A missile is fired at the shutter, and only then is it put through a long programme of alternating positive and negative pressure cycles.
We have not bought those texts. What we have seen directly are the approvals that testing leads to, published by number: a Miami-Dade Notice of Acceptance, a Florida Building Code approval, a Texas Department of Insurance approval.
The point: it tests being hit, and then being worked on for hours. That is what a storm actually does.
The two things a European wind class cannot tell you
It says nothing about impact. A wind class is a pressure rating. Flying debris is not pressure, it is concentrated energy arriving at one point very quickly. As far as we can establish from the published scope of these standards, none of them involves throwing anything at the shutter. We do not hold the full texts, and we have asked the British Blind and Shutter Association to confirm.
It says nothing about endurance. The European test is a static one. A real storm is not a single push, it is hours of pressure building and reversing, which is what works fixings loose and fatigues joints. The US standards test that explicitly, with cycling after the impact.
There is a further subtlety worth knowing, because it cuts the other way and it is unfair to the products otherwise. A wind class is the pressure at which the shutter must still work, meaning it opens, closes and is not permanently deformed. It is not the point at which it fails. There is a separate, higher safety pressure it also has to survive without becoming dangerous. So a wind class is a floor, not a ceiling. A class 3 shutter does not fall apart at the class 3 pressure. What none of the published material tells you is how much headroom there actually is, so it is not a margin anyone should be relying on.
What UK shutter paperwork tends to lead with
Here is the thing that surprised us most, and it explains a great deal.
We looked closely at one UK listing, for a rolling shutter sold under the same product name on both sides of the Atlantic, by a US manufacturer and by a UK supplier. We should be careful here: all we have established is a shared name. The UK listing never names the US manufacturer, and we have not been able to match the two on specification, so these may or may not be the same shutter. What is worth looking at is not the product. It is the two completely different vocabularies used to sell it.
The US manufacturer's page leads with hurricane performance, and gives the approval numbers: Miami-Dade Notices of Acceptance 23-1010.06 and 23-1010.07, Florida Building Code approval FL39156-R4, and Texas Department of Insurance approval SHU-243. No European wind class appears anywhere on it.
We expected the UK listing to be thin on certification. It was not. It leads with burglary resistance tested to BR2 STS 202 by an independent test house, at specified sizes, which is the same size caveat we ask you to demand of everyone including us. It shows Secured by Design, the UK police initiative, and an LPCB badge. The wind class appears as a single line in a long specification list.
Neither page is hiding anything. They are answering different questions. In Florida, the question a shutter has to answer is "will it survive the hurricane". In the UK, the question our certification schemes are built to answer is "will it stop a burglar". Both are rigorous. Only one of them is about weather.
The weather information is on that page. It is just quiet. A wind class, stated as class 5, sits in the specification list, and a line at the foot confirms CE marking, which is normally where a shutter's wind class gets declared. Two lines, against a headline of security. And note that class 5 is above anything in our external shutter range, which is rather the point of showing you this: we are not claiming our products win, we are showing you where the information hides.
The practical consequence for you as a buyer: a wind class tells you nothing about impact resistance, and a security rating tells you nothing about either. BR2 means the product resisted somebody working at it with common hand tools and levers. That is a slow, leveraged, local force. A roof slate carried by a storm is not. If impact resistance is what you want, you have to ask for it by name, because very little in the standard UK paperwork will volunteer it.
How our own products stack up
We would rather tell you plainly than let you assume. We supply two external products that get asked about in this context, and neither one is a certified storm shutter. Here is exactly where each stands.
Portchester external aluminium shutters
Architectural aluminium louvred shutters, hinged into a four-sided frame. Individual panels are limited in width: 900mm on a hinged installation, less on a bi-fold, or up to 1050mm on a sliding by-pass track. A wide opening is therefore covered by several panels rather than one large one.
They are locking shutters, and the lock matters here for a practical reason. In windy or stormy conditions the panel should be closed inside the frame with the lock engaged. That is how the panel is held into the frame, rather than left to work against its hinges, and it keeps the window fully covered. What the lock does not do is give the shutter a wind rating. Wind is a spread load carried by the panel, the hinges and ultimately the wall, and no piece of hardware on the panel converts that into a tested rating.
We do not hold a wind rating for this product. It is not in any of the three product documents we have, so we have asked our supplier directly for a declaration of performance or a test report. Until we have one we will not quote a figure, and you should be wary of anyone who quotes you one without showing you the document behind it.
It is also louvred, which matters here. A louvred panel is not a sealed barrier: air and water pass through it, so the glass behind still meets the weather. It is a shading, privacy and weather-durability product built robustly for outdoor use, not a screen designed to keep pressure or debris off the glass, and it has never been tested as one.
Luxaflex external roller shutters
A solid curtain of interlocking aluminium slats running in side guides. Luxaflex rate these at up to wind class 3, depending on size, so which class applies to your opening depends on how big it is.
It is worth knowing what that number means, because "3 out of 6" sounds middling and it is not what most people would guess. Class 3 is a nominal test pressure of at least 110 N/m², which corresponds to roughly Beaufort 6, a strong breeze. That does not even appear on the storm table above, which starts at force 8.
Our own specification rule for coastal and elevated sites is to go a class higher than the plain reading. Applied to this product that gives an uncomfortable answer, and we would rather give it than dodge it: our coastal rule points at class 4, and class 3 is the top of this range. So we do not present these as a storm rating.
Structurally it is the more interesting of the two, because a solid interlocking slat curtain is one of the forms genuine hurricane shutters take, alongside accordion shutters and bolt-on storm panels. The shape is in the right family. What is missing is the impact and cyclic testing, not the concept.
Closed over the glass, a roller shutter is a substantial physical layer, and it does a great deal besides: insulation, room darkening, noise reduction, and a solid aluminium layer between the weather and the glass. What we cannot tell you is the wind speed at which it stops doing that job, because the tested class describes the pressure at which it must still operate, not the pressure at which it fails, and we do not hold the failure figure. On exposed sites these can be paired with a wind sensor so the shutter closes automatically rather than being left to argue with the weather.
Where we actually sit
There are roughly four rungs on this ladder:
- Nothing at all
- A robust louvred external shutter with no wind rating we have been able to obtain, such as Portchester
- A solid roller shutter with a manufacturer-stated European wind class, such as the Luxaflex range
- A shutter with genuine impact and cyclic certification
We occupy the middle two rungs, and we are telling you so. If what you need is the fourth, we would rather point you towards it than sell you the second and let you believe it is the fourth.
The part almost nobody talks about: the fixings
You can buy the best shutter in the world and it will do nothing for you if the wall will not hold it.
This is not a detail. In the American system an approval does not certify a shutter on its own. It certifies an assembly: the shutter, the specified fixings, at the specified spacing, into a specified substrate, up to a specified size. Change any one of those and the test result no longer describes what you have installed.
Which raises an obvious problem when a product tested for American construction is fitted to a Scottish one. Fixing into rubble-filled stone, into a rendered cavity wall, or into a modern timber frame are three completely different engineering problems, and none of them is the one the shutter was tested against.
So on an exposed site the questions that actually decide the outcome are these. What is the wall made of? How deep is the reveal? Is there sound material behind the render to fix into? Can the anchors carry the load, and the pull-out force when the wind reverses?
A shutter that comes off the wall in a violent storm has not just failed to protect the glass. It has become a large piece of flying metal. That is why we will not put a price on an exposed job from a photograph alone. Photographs are fine for a first indication on an ordinary window. On an exposed coastal opening the wall decides the outcome, and we survey before we commit to anything.
What to ask any supplier, including us
If you are being sold something described as a storm shutter, these five questions will tell you very quickly what you are dealing with. A supplier who can answer them has done the work. A supplier who answers with a headline wind speed and no standard has not.
- Which standard was it tested to? A named standard, not an adjective. And check what that standard is for, because a security rating is not a weather rating.
- What result did it achieve, and at what size? Ratings usually drop as the product gets bigger, so a rating quoted without a size is close to meaningless.
- Was it tested for impact, or only for pressure? These are different tests. Most European products have only had the second.
- What is the fixing specification, and what substrate does it assume? Then ask whether your wall actually matches it.
- Can I see the test report or the approval document? If it exists, you can be shown it, and it will have a number on it.
Where this leaves you
If you live somewhere genuinely exposed and you want tested protection against flying debris, you are looking for a product certified under the American system. Such products exist, and there are UK routes to them, though we have not yet verified one well enough to point you at it. We could not find a published price from any UK route we looked at, and they are bespoke enquiry items here rather than something you order off a shelf.
It is also worth remembering that a shutter is not the only answer. With no shutter fitted, the glass takes the weather first, and how the window unit is specified and fixed into the structure matters at least as much as anything hung in front of it. On a genuinely extreme exposure that is a conversation for a structural glazing engineer, not a shading company.
And if your exposure is serious but not extreme, which covers most of coastal Scotland, a well specified and properly fixed external shutter or roller shutter is a genuinely worthwhile piece of protection. It just is not a hurricane shutter, and we would rather you heard that from us first.
A note on this page, last reviewed 27 July 2026. We could not find a UK or European impact certification scheme for shutters while researching this, and we would rather be corrected than assume. We have put the question to the British Blind and Shutter Association, and asked our own supplier for the test data behind their external shutters. If either answer changes what is written above, we will say so here and re-date this note.
Related reading: external aluminium shutters and external roller shutters.
Exposed site? Talk to us before you buy anything
We survey exposed and coastal properties properly, and we will tell you plainly what a shutter will and will not do for you. If what you need is something we do not supply, we will say so.