Someone asleep in bed in a room with a fire outside


While not exactly referring to a fire door, an early childhood joke goes: “When is a door not a door? When it’s ajar.”

Research indicates that in the worldwide built environment, there are around 42 billion doors. Each day, doors including fire doors, play an important role in the accessibility, safety and security of buildings.

But what is a fire door? Let’s rephrase the old joke and ask, when is a door a fire door?


What is a fire door?

Fire doors are specially designed and certified doors that help to limit fire spreading between different areas of a building. They ensure that both smoke and fire are kept from spreading for at least thirty minutes. This enhances the safety of the building occupants by allowing time to safely exit the building and makes it easy for fire fighters to enter. Stopping the spread of the fire also reduces fire damage.


Where should fire doors be fitted?

Guidance is similar worldwide. It requires that the building be divided into areas or compartments so that escape routes such as stairs and corridors are protected. There should be a fire door leading to the stairwell on every level of flats.

In public and commercial premises, internal doors leading to corridors and stairways should be fire doors. They then provide a clear way and prevent the fire blocking emergency exits.


A fire door opening onto a stairwell


Construction of fire doors

Fire doors are often heavier than standard doors. They are manufactured in a variety of materials such as metal, gypsum, timber, steel, and aluminium and combinations thereof. They can also have windows incorporated made of borosilicate or ceramic glass.


Different classes of fire doors

Fire doors can be recognised by a fire-resistant rating marked on the door which distinguishes it from regular doors.

Class A fire doors are 1-hour doors with a fire-resistant core panel one hour stability and thirty minutes of insulation.

Class B fire doors are 2-hour doors with a fire-resistant core panel. they offer two hours of stability and insulate for an hour. They are used for preventing fire from spreading through large chambers of a building. This makes them ideal for use in elevator shafts and stairwells.

Class C fire doors are 2-hour fire doors with two hours stability and holds integrity for two hours. Mostly used as room doors or in openings into corridors.


an exit sign in a multi unit corridor


Class D fire door are 2-hour fire doors with fire-resistant cores able to withstand an impact test with a mass of 27kg. This impact test should not create an opening wider than 25mm between the door and the frame. They are tested for two hours of stability, integrity and insulation. They also withstand flying debris and are typically used as external doors.

Class E fire doors are solid with either a chipboard or solid laminated timber core. They give thirty minutes of stability, integrity and insulation. The doors are often installed as front doors in multi-unit dwellings less than three storeys high and between garages and houses.

Class F fire doors are solid doors with either a chipboard or solid laminated timber core with stability and integrity of thirty minutes.

It is critical that fire doors are correctly installed as even the highest rated door will offer little protection if installed incorrectly.

The regulations referring to fire doors are found in SANS 1253:2016.


What does the law on fire doors say?

Buildings must comply with SANS 10400 Part T which covers design, construction and fire equipment and the local authority regulations.

Stated simply, the legislation requires all buildings to be designed, constructed and equipped so that in the event of fire occupants or people using the building will be protected – including persons with disabilities.

The spread and intensity of any fire within a building and possible spread to other buildings must be minimised. The building should remain stable enough so it does not endanger adjacent buildings. So, for multi-storey buildings, no major structural failure should occur. Smoke generation and spread also must be minimised which is where fire doors come into their own.


A fire escape featuring fire doors


For a fire door to be effective, it must comprise of more than just the door itself. It includes the frame, smoke seals, glazing, door closers, locks, latches and signage.

All these components are specifically designed to be used for fire doors. It is no good having a standard door handle which could cause serious injury.

Depending on the door, when the frame is exposed to high heat, seals will close the gap between the frame and the door. This prevents smoke from spreading.

Open fire doors are useless. To be able to be effective and form a barrier, the door must close completely. To do this, locks, latches, and door-closing devices must work correctly. The door closers, whatever kind, whether concealed or surface-mounted, use spring-loaded hydraulics to work effectively, close and engage the door into its latch, where it must be held firmly in place by the frame.


An internal fire door


For buildings and areas with high footfall, an electromagnetic hold-open device can be used. These systems are designed to keep certain fire doors open until a fire alarm is activated. This makes movement easier until an incident occurs. When triggered by a fire alarm, the system automatically releases and closes the doors.

Doors positioned in emergency escape routes can incorporate panic and emergency exit devices. These are meant to be operated easily to help users successfully escape through the doorway, meaning reliability is key every step of the way.



As a key element in a building’s passive fire protection system, fire doors and their hardware components are often the first line of defence against fire. Because of this they require first class engineering, testing installation and very importantly, they should form part of your regular inspection schedule.

Our team of professionals at Firebrand Group take great pride in what we do as it is not only passion that drives us, but the knowledge that we are saving lives and assets by educating, training and protecting our clients and their businesses.

We are a unique and fully comprehensive fire and security company, offering a wide range of products and services catering for the Commercial and Industrial Property sectors in Southern Africa.

Contact us to discuss your fire prevention projects and requirements.


A sign on a fire door