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Fire doors are, without doubt, essential passive fire protection. Buildings use two main complementary types of fire protection system, passive and active. Passive fire protection refers to elements of the building structure such as doors, floors and walls. So, why are fire doors so crucial to the system as a whole?

What is the purpose of passive fire protection?  

Let’s first look at what passive fire protection does in the event of a fire. It remains dormant or inert during normal conditions and only becomes ‘active’ when a fire occurs. Its main purpose is to contain fire or slow its spread to allow the safe evacuation of a building. It also gives the fire brigade sufficient time to fight fires safely and reduces the chance of you losing property.

Compartmentation is essential to passive fire protection. Building regulations state that all buildings must be split into compartments. Walls and floors between compartments are constructed according to fire safety standards known as ‘fire rated’. Every joint or opening that allows services (e.g. pipes, ducts, sockets) to pass through must be well protected by fire stopping products like intumescent seals to be effective. And in the case of doors, all openings must have a fire rated door, frame and hardware installed.

This guidance defines a fire stop as: ‘A seal provided to close an imperfection of fit or design tolerance between elements or components, to restrict the passage of fire and smoke.’

Essential fire protection: the fire door

We see many cases of overlooked fire stopping systems, such as unsealed penetration openings. You can find openings above ceilings, in riser cupboards or below raised access floors. If there’s no fire stopping around walls and floors, they will lose their fire rating. This would allow the rapid spread of fire and smoke throughout the building endangering the lives of the occupants of the building.

Fire doors contribute greatly to fire stopping. Fire walls and floors are only compliant and capable of retaining their fire rating if all doors are up to standard. You also need to correctly fire-stop all service penetrations passing through them.

Saving lives with compartmentation

Sub-dividing buildings into a number of compartments can effectively restrict the spread of fire. Walls and floors made of fire-resisting compartment materials separate the compartments. Many years of R&D go into the construction of these materials to ensure they’re capable of containing and holding back fire.

The Department for Communities and Local Government’s own building regulations describe a fire compartment as ‘… a building or part of a building comprising one or more rooms, spaces or storeys constructed to prevent the spread of fire to or from another part of the same building or an adjoining building. (A roof-space above the top storey of a fire compartment is included in that fire compartment.) A separated part of a building is a form of compartmentation in which part of a building is separated from another part of the same building by a compartment wall. Such walls run the full height of the part and are in one vertical plane.’

Fire compartmentation offers many benefits:

  • Preventing the rapid spread of fire
  • It limits the chance of the fire building and growing. Limiting immediate danger for people in and around the building as well as the emergency services
  • It limits the damage to the building itself and its contents

Compartmentation design depends on a number of elements:

  • What is the building used for?
  • The size of the building (in particular, its height)
  • The fire load in the building (the potential severity of any fire that might break out)
  • Does the building have a sprinkler system?

The finer details of fire compartmentation

There’s an abundance of information out there on compartmentation. We’ve done some of the hard work for you and selected a number of useful links.

The 2010 building regulations provide guidance on the dimensions of fire compartments – see Table B12 – (for buildings other than dwellings, the definition of which can be found here).

Compartment walls and compartment floors form a complete barrier between fire compartments and must provide a minimum degree of fire resistance. Guidance for this can be found here. Doors and other openings within compartment walls should have a similar fire resistance to the compartment walls or floors they penetrate.

We express fire resistance using the number of minutes of resistance that each building element provides against fire. Methods for testing building materials and structures for fire resistance are set out in the British Standard 476 Fire Tests.

Joints between compartment walls or floors should be fire-stopped to maintain compliance and openings for timber beams, joists, purlins and rafters, and pipes, ducts, conduits or cables that pass through any part of a fire-separating element should be as few as possible, as small as practicable; and fire-stopped.

Intumescent fire dampers should be used in the ducts of ventilation systems, including heating and air conditioning systems which penetrate any part of a building’s fire resistant material. The dampers operate via a thermal element. This melts on the detection of heat and closes the springs on the damper.

What about the parts of a building around compartments?

For essential fire protection, you must protect the spaces connecting fire compartments, such as stairways and service shafts (described as ‘protected shafts’). This restricts the spread of fire between compartments. Depending on the type of building, there are a number of additional requirements:

  • Use compartment walls to separate parts of a building that are occupied for different purposes
  • Construct walls common to two or more buildings as compartment walls
  • Continue compartment walls in the top storey beneath a roof through the roof space
  • Ensure that the walls separating semi-detached houses or terraced houses are compartment walls.
  • Install compartment walls and floors between garages attached to houses
  • There are additional requirements for flats, institutional buildings, other residential buildings and non-residential buildings.

The importance of third party accredited contractors

Fire stopping is easy to get wrong. The smallest breaches in compartments can lead to loss of life from the ingress of smoke and fire. For essential fire protection, we recommend you always use a specialist fire protection contractor who has third party accreditation such as Loss Prevent Standard LPS 1531 governed by BRE Global Limited. Accreditation provides the customer and enforcement authorities with total confidence that qualified technicians carry out installations to the correct standard.

We have over 15 years’ fire door and passive fire protection experience. What’s more, we’re third party accredited and are LPS1197 & LPS1531 certified.

With ever more intricate building service requirements, passive fire protection is becoming an increasingly complicated area.  We can help you make sense of it, so why not call us today on 08000 234114?

Drew Stewart

Passive Protection Manager

As an industry professional with over 30 years in passive fire protection, Drew manages fire door, fire stopping, integrity testing, steel fire escapes and related works for Fire Safety Services nationally.

Read more blogs from Drew.

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