How do fire resistant doorsets work

How Do Fire Resistant Doorsets Work?  

Fire Dangers Persist

According to this Home Office report, fire and rescue services in England reacted to 182,625 fire incidents in 2018/19. Over 54,000 of those incidents were in homes, bungalows, apartments, high rises, etc. There were 237 fire-related fatalities, 191 of which were in dwelling fires. Nonfatal casualties amounted to 7,021, and 3,026 people required hospital treatment. But how do fire resistant doorsets work?

Fire Doors Are the First Line of Defence

The first line of defence in controlling the spread of fire in a compartmentalised building is a smoke- and fire-resistant doorset. Internal fire doors and accompanying compatible fire door frames (fire doorsets) have two important roles during a fire:

  1. When closed, it is a barrier that stops the spread of the fire and the passage of smoke.
  2. When opened, it provides a safe means of escape.

So, a well-designed, properly tested fire doorset delays the spread of fire and smoke while at the same time does not hinder the safe evacuation of people.

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Fire Door Standards

A fire doorset, then, is a passive, inert safety device. It acts as a normal door until a fire breaks out. Before heat hits the door, any smoke is withheld by the smoke seals. These work prior to any activation of the intumescent protection. When heat hits the door, its intumescent system expands and seals the door. Thus, the installed fire-resistant door seals the gap between itself and the fire door frame. It is a barrier and stops the fire from getting into or out of the affected room or compartment.

A glazed fire door may have vision panels and these are glazed with fire-resistant glass. These are called vision panels. Vision panels can be small for viewing or a large panels for maximum light transmission. The fire-resistant glass must withstand exposure to a fire for the same period of time as the fire door is certified. For example 30, 60 or 120 minutes.

To achieve fire doorset certification, fire door manufacturers must have their fire doorsets tested as specified within the rigorous guidelines of BS 475-22:1987 or BS EN 1634:2014.

Those tests are made on complete fire doorsets—the fire door and its door frame—along with its accompanying hardware (locks, latches, hinges, etc.). The testing exposes one side of the door to naked flame set to a temperature to achieve the anticipated heat conditions of a real fire. It is closely monitored over the period of assessment to record escape of flame, heat and it’s overall integrity.

The 30, 60, 90, 120 Fire Door Standards

Fire-doors are specified by their resistance and this is measured by minutes. You can get a 30-minute, 60-minute, 90-minute or 2-hour fire doorsets. The level of fire resistance for doorsets is determined by the fire strategy designed by a fire prevention expert, who will closely assess the building requirements. For example, main routes of escape will need a higher fire-rating (e.g. 60 minutes or 120 minutes) In contrast, a toilet or bathroom may only need a 30-minute door, if any fire rating at all.

The common categories of fire doorsets are the 30 minute (FD30) and 60 minute (FD60). To meet the minimum standards, each doorset must maintain its integrity—and stability—resistance to collapse–for the requisite number of minutes.

There are two higher rated fire doors: the 90 minute fire door and the 120 minute fire door. Both these high-performance, timber-based doors meet the fire door manufacturers standards of excellence in providing 90 and 120 minute fire resistance and independently tested to BS 475: Part 22 to meet fire door regulations.


Fire resistance takes precedence to acoustic or DDA requirements. However, it is important that all three are considered when specifying fire doorsets. Often in achieving the three requirements, the manufactured product will conflict. It is important that the client understands the limitations of the lesser requirements when specifying fire doorsets.

Additional assessment testing may be necessary when fire doorset solutions are required outside normal testing criteria. This is a specialist discipline and must be managed by a competent fire doorsets manufacturer who has the knowledge of the manufactured product and with a third party assessment centre

Whatever your bespoke security, safety or fire door requirements including further advice on bespoke assessments, RW Joinery has your solution. Looking for product solutions or costing advice? Contact us

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