Last edited 31 Jan 2021

Fire insulation in buildings



[edit] Introduction

Fire occurs as a result of a series of very rapid chemical reactions between a fuel and oxygen that releases heat and light. For combustion to occur, oxygen, heat and a fuel source must all be present; this is the ‘fire triangle’. Flames are the visible manifestation of combustion.

Fire insulation (or more usually fire-rated or fire-resistant insulation) is a term that covers insulation materials which have insulative properties but are also non-combustible or have limited combustibility. As passive fire protection elements, they do not need to be activated to provide fire resistance and hence can help prevent the spread of flame between spaces and components within and between buildings.

By slowing the spread of flame, such materials can protect structure and property and allow people valuable time to escape.

A typical example is stone wool insulation which can be non-combustible. Other types of insulation that may provide fire resistance include mineral wool, fibreglass and cellulose-based wool insulation. Sheep’s wool is regarded as a sustainable insulation solution but must first be treated to make it more fire resistant. Some of these products are available in blankets (supplied in rolls) and/or rigid slabs.

For further information, see Insulation

Fire-rated insulation in a building can be used in a number of places, including in:

In addition to its fire-resisting properties, the insulation used in the above applications may also provide acoustic and thermal insulation.

[edit] Regulations and standards

Part B of the Building Regulations sets out the fire performance requirements of buildings. For a fire-rated insulation to be used in a building it must pass certain British Standard (BS) tests: products are classified according to how they perform in the tests, enabling specifiers and contractors to choose the best fire-rated insulation for a given application. The tests are:

BS EN 13501-1:2018 has three fire performance ratings which cover:

[edit] Grenfell Tower

The 2017 Grenfell Tower Fire is thought to have been exacerbated by ACM cladding which incorporated a Celotex RS5000 PIR insulation. As a result, In December 2018 changes to approved document 7 came into force banning combustible materials in the cladding for buildings over 18m in height.

For more infomation see: Grenfell Tower fire.

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