Fire Egress Windows: how to ensure an escape route

Configuring a fire egress compliant window

There are 5 rules to follow when configuring a fire egress compliant new build window. However, we also recommend getting as close as possible to these if you’re renovating. Everything we discuss is relevant for timber , composite , plastic and aluminium windows.

• Both the width and the height must have 450mm or more clear opening space. Please bear in mind that this isn’t the same as the frame size displayed on a quote. For example, a flush casement sidehung window with a total frame width of around 630mm, only just allows a 450mm clear width. You will also need just over 10mm tolerance around all sides of the window. Therefore, your structural opening width will need to be around 650mm to give you enough clear width.
• Overall, the clear opening area must be more than 0.33m². This means that a window with exactly 450mm clear in both width and height will not be large enough.
• The lower edge of the clear opening must be no more than 1100mm from the internal floor level.
• The window must keep itself in the open position without you needing to hold it whilst moving through.
• The route through the window must lead you somewhere that is safer from the danger of the fire.

All habitable rooms in a new build home must have a fire egress route. A window is the most common way of providing this.

For renovations, your new windows should not make the fire escape route worse than it currently is. However, as we’ve mentioned above, we recommend that you aim for a fully-egress compliant window in any habitable room.

Combining Ease of Escape with Child Safety

Guidelines allow for fire escape windows to have both key-locking handles and child-proof stays. Simply, the stay must be releasable, so you can still be safe and secure.

However, it is worth considering the complexity of combining a key-locking handle and a releasable restrictor on the same window. As well as, the fact some windows will require both hands and perhaps some practise to release quickly. Not ideal in a stressful situation.

Subtle Options

You may see new homes with windows that split into small sections that are clearly not possible to fit through. These homes are most likely utilising a false mullion. This is a central post that doesn’t attach at the head or base. Essentially, this allows the window to open as though it were a small double door.

The vertical post is attached to one of the opening sashes, leaving you with a much larger opening. This is available on almost all of our products. It is our go-to option to maintain the style of a window whilst providing you with fire egress compliancy.

More images from this project can be found in our Minimalist Cotswold Cottage Renovation gallery.

Similarly, you can use fake sashes to balance a fire escape window where two openings are right next to each other. Choosing a fake sash in the third position avoids a non-symmetrical window and helps to create an overall uniform appearance. It’s surprising how much a different frame width can spoil an otherwise sleek design. The best way to achieve this is by using invisible guided hinges. However, these do naturally reduce the clear opening area, so they are sadly not possible in all situations. Side hung windows (with visible hinges) are normally the best for providing larger opening areas. However, side guided windows have invisible hinges and allow you to clean the outside from the inside

More images from this project can be found in our Sleek, Modern and Uniformly-Designed Leicestershire New Build gallery.