Internal Fire Rated Windows
Internal fire rated windows hold back flames, smoke and heat between rooms, corridors and stairwells for a set period: 30, 60, 90 or 120 minutes. Aluminium Fire Systems manufactures EI fire rated windows specifically for your project to specifically meet your building’s fire strategy outlines. The fire windows are made using aluminium framing and fire resistant glass units tested and certified as a single assembly.
What Are Internal Fire Rated Windows?
An internal fire rated window sits on an internal partition inside a building rather than on the outside of it: between an office and a corridor, either side of a protected stairwell or dividing a school classroom from a shared hallway. The glass and frame are tested and rated together as one system, because a fire rated window is only as good as its weakest component.
Fire rated internal windows and internal fire doors aren’t exposed to the weather so they are single glazed. We reserve double glazed units for external applications, where the second pane improves thermal performance rather than fire resistance.
EI Ratings Explained
What EI30, EI60, EI90 and EI120 Actually Mean
Fire rated glazing is tested against two criteria under EN 13501-2:
| RATING | |
|---|---|
| Integrity (E) | Stops flames and hot gases passing through the window. |
| Insulation (I) | Stops the unexposed side of the glass getting hot enough to ignite anything nearby. |
An EI60 window has passed both tests for 60 minutes, an EI90 window for 90 minutes, and so on. We manufacture internal fire rated windows across the full range, from EI30 through to EI120.
It’s important that you know what fire rating your building needs, this figure will be set out in your buildings fire strategy which is often set by your fire engineer or based on occupancy, escape distances and building height. This recommendation must be cross-checked against Approved Document B of the Building Regulations to ensure your building strategy is compliant with the law. Our job starts once that number is fixed. We manufacture your fire window to match that number, often requesting the fire strategy document so that we can quote you for the glazing that you need for your project.
Why We Quote EI, Not FD
A lot of enquiries still ask for “FD30” or “FD60” windows. FD is an older classification system; EI is the current one used in EN 13501-2 testing. When a client asks for an FD rating, we quote the equivalent EI product and explain the difference, because EI is what current UK test certificates are actually written against.
Where Internal Fire Rated Windows Are Used
Internal fire rated glazing is popular in buildings that need to divide space without losing natural light or sightlines.
Commercial and public buildings: compartment walls in offices, meeting room partitions and glazing along protected corridors. If you’re pricing a full project rather than a single opening, our page on commercial fire rated glazing covers wider specifications.
Schools: classroom-to-corridor glazing and internal screens that keep sightlines open for supervision while meeting the higher occupancy ratings schools require. We cover this in more detail on our school fire safety glazing page.
Healthcare buildings: wards, treatment rooms and staff areas where compartmentation has to work around round-the-clock occupancy and equipment. See our page on fire rated glazing for hospitals for sector-specific detail.
Residential and mixed-use buildings: internal windows between flats and shared corridors, or above internal fire doors to keep protected stairwells lit without breaking compartmentation.
Internal Fire Rated Windows or Fire Rated Glass Partitions?
Whether you need a fire rated window or a glass partition largely depends on your project. If you’re:
- Replacing an internal window = Fire rated window
- Implementing a new internal division that is mostly or fully glazed = Fire rated partition
Our single glazed fire rated glass partition can be manufactured to be from floor to ceiling. They come as glass units that start from 15mm thick for EI30, 25mm for EI60 and 35mm for EI90.
How We Check Compliance
Every internal fire rated window order goes through the same checks before it goes into production:
- We review the technical drawings against the rating set out in your building fire strategy
- We ask for the build up of the wall which the window would be installed in, to check it is compliant – It would need to be installed into something that has at least the equivalent fire rating that the fire rated window/door is.
- For high risk buildings, we ask for the building’s fire strategy so the specification lines up with what the building actually needs.
- We can send over our Fire Rated Product Compliance Pack alongside your quote, so your project paperwork is in order from the start.
Building regulations and safety standards are continuously being changed and updated. It’s important to have certified paperwork about what fire rating your glazing needs. Having this information at the order stage prevents any delays further down the line as we will make your order to that exact spec.
Lead Times
Our standard lead time for fixed internal fire rated windows is 6 weeks from order to delivery. Larger orders or high-volume projects may need longer, depending on our production schedule at the time of order.
Why Choose Aluminium Fire Systems
Fire rated glazing is the only thing we make, from quoting through to manufacturing. Every person involved in your order already understands the compliance questions that come with fire rated products. If you’d like to talk through a specific project, our team is easy to reach through our contact page.
About The Author
Chris Wall, Commercial Development Manager
Chris Wall is the Commercial Development Manager at Aluminium Fire Systems, he leads the company’s sales and commercial team. He liaises with architects and end users daily, acting as a source of information and helping to educate people so the correct products are specified and quoted for the job. Chris talks with customers daily about their projects and is upfront about whether their requirements are something Aluminium Fire Systems can help with. He works as the middleman between architects, sub-contractors and end users, keeping communication clear between everyone involved in a project.
FAQs
Internal Fire Rated Windows FAQs
What fire rating do I need for my internal windows?
The fire rating that you need for your internal windows completely depends on your building’s fire strategy. Occupancy, escape distances and building height all determine the fire rating a fire engineer or building control will specify. We manufacture your fire rated windows to the EI rating your building requires from EI30 to EI120.
What's the difference between FD30/FD60 and EI ratings?
FD is an older UK classification. EI is the current system used in EN 13501-2 testing and it’s what current fire test certificates are written against. If you ask for an FD rating, we’ll quote the EI equivalent and explain how the two relate.
Are internal fire rated windows single or double glazed?
Our internal fire rated windows Single glazed. We use double glazed units for external applications, where they help with thermal performance. Internal windows aren’t exposed to the weather, so a single glazed fire rated unit does the job.
How long does it take to get internal fire rated windows made and delivered?
Our standard lead time for fixed fire rated windows is 6 weeks from order to delivery. Larger or high-volume orders may take longer depending on our production schedule.
How much do internal fire rated windows cost?
Fire rated glazing runs from around £1,100 up to £2,500 or more depending on size and finish, based on current UK market pricing. A typical “normal sized” fixed window can cost from under £1,000 and then go up massively depending on colours, glass types, fire rating, sizes etc.
NEED INTERNAL FIRE RATED WINDOWS?
Get in touch
We provide internal fire rated windows and doors across the UK. For help or to place your order please contact us today by phone on (+44) 121 277 4870, or send us a message via the form on our contact page to discuss your requirements.