Fire doors are essential components of any fire protection strategy and can be made using a variety of materials, including timber, steel, gypsum, and aluminum. They can also feature viewing panels or windows, which are typically made from borosilicate or ceramic glass, both of which offer superior fire resistance compared to standard glass. In some cases, these viewing panels may include an anti-shattering wire mesh for added safety and protection.

To enhance their ability to prevent the spread of fire and smoke, fire doors are designed to fit flush with the frame, with any gaps between the door and frame filled with silicone-based fire-resistant sealant. In addition to this, many fire doors feature an intumescent strip attached at the base of the door.

This strip is designed to expand when exposed to heat, creating an additional barrier against the spread of smoke and flames. Fire doors are often equipped with a closing mechanism, which can be either spring-loaded or hydraulic. This mechanism is typically installed at the top of the door and is designed to ensure that the door closes automatically in the event of a fire. By keeping the door closed, the mechanism helps to prevent the spread of fire and smoke from one area of the building to another, giving occupants more time to evacuate safely.

The short answer is no. In order to be considered a "fire door", a door must meet specific certification requirements. To achieve certification, fire doors must be designed and manufactured to strict standards, and must meet certain criteria for fire resistance, smoke control, and durability.

This may include features such as intumescent seals, smoke seals, and specialised hardware such as hinges, locks, and latches. Fire door certification is awarded once a door has passed various tests at an approved centre, including a fire and stress simulation. You can tell which doors have been certified by a label or barcode attached to their top edge, which states the manufacturer, date of manufacture, and designated fire rating.

There are different grades of fire door, and each one provides a different level of protection. The grades are separated by how long they can withstand fire. The main grades are FD30 (30 minutes), FD60 (60 minutes), FD90 (90 minutes) and FD120 (120 minutes). The higher the rating, the longer the door can withstand fire and heat. It's important to choose the right fire door rating for the building's use and occupancy to ensure that occupants have enough time to escape in the event of a fire. The main aspect that differentiates the grades is the ‘certified core thickness’ of the doors. This is the core material of the door over which there can often be an aesthetic layer of different material. The cores span from a typical 45mm (FD30) 54mm (FD60) 60mm (FD90) 60mm< (FD120).

FD30 and FD60 are generally used internally for offices and residential buildings. Any grades over FD60 are more common for the protection of highly-valued properties or core infrastructures (for example, archives or server centres, power plants, manufacturing with hot works).

All regulations pertaining to the use of fire doors are contained in Fire Safety: Approved Document B and following incorporations. According to the legislation, fire doors are required in domestic buildings over 2 storeys high; each door leading to a stairwell (at every level) from a habitable room (not a bathroom, for instance) must be a fire door. For commercial or non-domestic buildings, fire door requirements vary according to whether escape routes are vertical or horizontal (down stairs or through corridors).