All fire doors are required to have at least 3 hinges, which must be certified and tested for use on fire-rated doors.
Fire door hinges should be CE/UKCA marked along with a fire identification stamp which is easily visible. If they don’t have these markings, then it is not a fire door hinge and this should be rectified and replaced.
Normal doors vs fire door hinges
It’s important to install fire door hinges on fire doors rather than standard door hinges as they differ in a few ways:
The weight of a fire door
A fire door is usually heavier than a standard door. A standard hollow core door weighs approximately 15kg, whereas a 30-minute fire door typically weighs around 40kg. A standard hinge would wear out quickly when trying to support this kind of weight, whereas fire door hinges are tested to withstand this mass for years.
For use with a door closer
Most fire doors are installed with a fire door closer, and as a result, the wear and tear on the hinges is increased. A rule of thumb is to add 20% for standard closers, but 75% for back-check closers. Fire door hinges are designed to take this extra weight factored in.
Withstanding a fire
In the event of a fire, a fire door must hold a fire back for a specified period of time in line with the door's certification. During this time, the door itself will warp and char and there is considerable air pressure difference on either side of the door. An ordinary door hinge would not be able to withstand such conditions whereas a fire door hinge can.
This is due to fire door hinges being made up of the following characteristics:
- Thick steel construction gives fire door hinges added strength
- The large hinge area and large screws allow for a solid fix to the door
- The pinned and capped design prevents the pin from dropping out of the hinge
What grade should fire door hinges be?
As standard, fire door hinges are made from Grade 13 stainless steel. The higher the grade, the stronger the steel, and as outlined above it’s important that the steel is strong enough to withstand extreme pressure, weight and heat.
It is also possible to get Grade 11 and Grade 7 fire door hinges, but these are often only for 30-minute fire doors and they can carry less weight.
Always check with the door core manufacturer to see what grade of steel they tested their door with.
Where do you place hinges on a fire door?
If a fire door is installed correctly, there should be a gap of 2-4 mm between the door and the frame and a minimum of 3 fire door hinges used however sometimes 4 are needed depending on the specification.
The placement of the hinges on a fire door depends on the door core manufacturer's testing so it's important that this is checked.
Most fire doors have fire door hinges placed 200mm from the top and bottom of the door and the third hinge in the middle of the two.
Another alternative is to have one hinge at the bottom of the door as previously outlined, with two placed towards the top to help support the weight. If 4 hinges are used, these are normally equally spaced.
How We Can Help
If you need advice on the fire door hardware products you need for your project, get in touch with our expert team who will be happy to help you.
