While standard roller shutters are usually made of toughened metal and very durable, they aren’t designed to withstand fires. Instead, fire shutters are purposefully manufactured and tested to ensure resistance against flames, heat, and smoke.
Fire shutters are usually designed to self-close when signalled by a connected fire alarm, or when sensors on the door itself detect smoke. To make sure that a fire shutter can be advertised and sold with a fire integrity rating, they need to meet certain standards during testing.
These standards include a minimum duration of time that the fire shutter must be able to operate fully and withstand the heat of a fire. So, how long does a fire shutter need to last in a fire, and how does it work? Keep reading to find out.
How do fire shutters work?
Unlike roller shutter doors that are in use multiple times every day, fire shutters normally only operate during actual fire conditions. They usually remain withdrawn and mostly hidden until they’re triggered by a volt-free signal from the fire alarm system that they’re connected to.
As mentioned above, some fire shutters rely on independent detectors to trigger the shutter to lower if they sense smoke or excessive heat. This may be to allow people to use the area as a fire exit until it’s no longer safe to do so, when the shutter has to drop fully closed to prevent smoke and flames from spreading any further through the building.
Industrial fire shutters tend to be constructed from galvanised steel in solid laths, with the thickness dependent on the required fire rating. They can be fitted to structural steel or masonry openings no more than 12 metres wide, which must have at least the same fire rating as the shutter itself.
Fire shutters usually function using single or three-phase inline motors, which may also have a fuse that causes the shutter to automatically close when it melts at a certain temperature.
How long should fire shutters last?
Fire shutters are usually designed to fit larger openings like windows and bay doors in high-risk areas of a building, which can temporarily close off the fire from spreading to the rest of the property, giving people more time to evacuate until firefighters can get there and start putting the flames out.
In order to do this, a fire shutter should be able to maintain its integrity during a fire for at least 1 hour. Most fire shutters are tested for up to 2-4 hours of fire resistance, but they’ll only be as strong as the surrounding structure – if it can’t endure flames for the same amount of time, it will collapse anyway, taking the shutter with it. This is why the general requirements are usually for 1-2 hours.
In any case, the fire rating that the shutter achieves during the testing stage will be measured in minutes. Different types of resistance may have different durations, or they may be rated to the same level – for example, an EI60-rated shutter would be able to maintain both fire integrity and heat insulation for up to 60 minutes/1 hour. Here’s a quick guide to some of the fire rating codes:
- E (Integrity) – ability to prevent fire from spreading to the other side of the shutter
- I (Insulation) – ability to limit heat transfer to no more than 140°C to 180°C
- W (Radiation) – ability to reduce thermal radiation spreading from one side to the other
The fire rating given to a door or shutter explains how long it fulfilled the performance criteria for during standardised tests. The minimum requirements that fire shutters legally need to meet or exceed can be found in local building regulations and British Standards/European Standards like:
How to find long-lasting fire shutters
If you want to make sure that your business premises have thorough fire prevention and safety measures in place, you should order fire shutters that are manufactured and installed by a reliable local company. It’s likely that they’ll also offer fire shutter maintenance services, which will also help you comply with the regulations for twice-a-year check-ups on your fire safety equipment.
So, if you happen to have ordered durable roller shutters in Liverpool, your supplier may also provide high-quality fire shutters with the longevity your business needs for peace of mind. Be sure to find out whether you can set up an ongoing contract for fire shutter maintenance to save time and money, too – the last thing you need is for your fire shutters to fail at a crucial moment.