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Retrofit Firestopping

The regulatory reform (fire safety) order 2005 for existing buildings.

“A seal provided to close an imperfection of fit or design tolerance between elements, components or construction to restrict the passage of fire and smoke through that imperfection. Therefore, Fire-stopping and fire-stopped should be construed accordingly.’

Sub-divided buildings can block the spread of fire in specific fire-stopping compartments. These compartments are separated by walls and floors made of fire-resisting structures that prevent fire from spreading between compartments. 

But what does fire-resistant mean?

Fire resistance refers to the following: 

  • The resistance to collapse
  • The resistance to fire penetration
  • The resistance to transfer extreme heat

The junctions between fire-resisting components and gaps between them mustn’t create a weakness in the structure. 

All compartment walls and floors should be fire-stopped to ensure resistance at all times.  

Fire-separating elements & openings that need to be monitored and fire-stopped regularly are:

  • Timber beams
  • Joists
  • Purlins
  • Rafters
  • Pipes
  • Ducts
  • Conduits
  • Cables

Fire-stopping materials include:

  • Gypsum-based plaster
  • Cement mortar
  • Proprietary fire-stopping and sealing systems
  • Intumescent mastics
  • Glass fibre, crushed rock, blast furnace slag, or ceramic-based products
  • Cement-based or gypsum-based vermiculite/perlite mixes

When it comes to pipes or ducts, fire-stopping should allow thermal movement.

Where an unsupported span is more significant than 100 mm or where non-rigid materials are used (unless they have been shown to be satisfactory by test), materials used for fire-stopping should be reinforced with, or supported by, materials of limited combustibility.

Effective fire-stopping requires a good awareness of technical literature and standards and practical inspection of works on site. This is particularly important where fire-stopping may be left to the end of the construction process, installed by a subcontractor, or where it is concealed. The integrity of fire stopping must then be maintained through repairs and refurbishment works. 

In the case of Lakanal House in Camberwell, London, renovation works that compromised fire stopping resulted in the deaths of six people in 2009.

Source: The Guardian

Fire stops should not be confused with cavity barriers intended to block routes for smoke and flame spread through concealed spaces or cavities such as those found in walls, floors, ceilings, and roofs where concealed spread can present a significant danger.

In April 2018, the Independent Inquiry into the Construction of the DG One Complex in Dumfries was published by Dumfries and Galloway Council. The report presents the findings of an Inquiry commissioned by the Chief Executive of Dumfries and Galloway Council into the DG One leisure complex procurement, design, and construction following its enforced closure due to defects in October 2014.

Amongst several problems, the report pointed to a failure to incorporate fire-stopping properly or to incorporate fire-stopping at all and suggested that; “…these failures are indicative of systemic problems in the quality of work provided by the construction industry. The report recommends that public authorities should undertake appropriately informed inspections of existing buildings and new buildings nearing completion to ensure the adequacy of the fire-stopping installed.”

Fire dampers are installed in the ducts of heating, ventilation, and air conditioning systems which penetrate fire-resistant constructions and will automatically close on the detection of heat.

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20-22 Wenlock Road

Call Us

+44 019  7733 0206

Get in touch

20-22 Wenlock Road

Call Us

+44 019  7733 0206