Fire risk appraisal of external wall construction and cladding of existing blocks of flats. Code of practice

Fire risk appraisal of external wall construction and cladding of existing blocks of flats. Code of practice

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1   Scope

This PAS gives recommendations and guidance on undertaking a fire risk appraisal of external wall construction and cladding of an existing multistorey, multi-occupied residential building.

NOTE 1 For ease of reading, a fire risk appraisal of external wall construction and cladding is described in this PAS as a fire risk appraisal of external walls (FRAEW).

The purpose of a fire risk appraisal of external walls (FRAEW) is to assess the risk to occupants from a fire spreading over or within the external walls of the building, and to make a decision as to whether, in the specific circumstances of the building, remediation or other mitigating measures to address the risk are considered necessary. It is applicable where the risk is known, or suspected, to arise from the form of construction used for the external wall build-up, such as the presence of combustible materials. The outcome of an FRAEW is intended to inform fire risk assessments (FRAs) of multistorey, multi-occupied residential buildings.

NOTE 2 FRAEWs are particularly applicable to FRAs carried out in accordance with PAS 79-2, but they can be carried out independently of the PAS 79-2 FRA process.

NOTE 3 External walls of existing buildings that comprise only masonry or concrete construction, or in which combustible materials are limited to insulation within the cavity of double skin masonry walls, are usually considered to present an acceptable risk in terms of life safety, and an FRAEW is not considered necessary for these buildings.

NOTE 4 The reference to combustible materials does not include small quantities of combustible material that are likely to be present in most external wall build-ups, e.g. membranes, seals and gaskets, and that represent a negligible or inconsequential fire load.

This PAS also gives recommendations and guidance in relation to the competence of those completing FRAEWs.
This PAS relates to blocks of flats throughout the United Kingdom. It was developed primarily for those in England and, therefore, contains references to the legislation pertinent to buildings in England. However, it can also be applied in the devolved nations of the United Kingdom, subject to care being taken to apply its recommendations within the context of the appropriate regulatory regime and supporting guidance.

NOTE 5 The risk to occupants of new buildings from a fire spreading externally is controlled by building regulations. However, it cannot be assumed that external walls of newly constructed buildings present no risk, unless the external walls contain no, or negligible, combustible material. In England, buildings pre-dating the 2018 amendment to the Building Regulations 2010 [7] are deemed to be existing buildings within the scope of this PAS; in Wales, the equivalent change to the Building Regulations [22] in relation to the combustibility of external walls on relevant buildings was introduced in January 2020.

This PAS applies predominantly to multistorey blocks of flats, but also includes the following types of buildings if, from the perspective of general fire strategy and means of escape design, and specifically evacuation strategy, they are similar in nature to a purpose-built block of flats:
  1. a) student accommodation;
  2. b) sheltered and other specialized housing; and
  3. c) buildings converted into flats.

NOTE 6 Within this PAS, the term “flat” is used to describe a self-contained domestic dwelling within a building. Other terms, such as “apartment”, are commonly used to describe such accommodation. The term “flats” is intended to include those arranged on more than one storey, such as maisonettes or duplex apartments.

NOTE 7 This is also intended to include blocks of flats which are part of a mixed-use building with, for example, shops or offices below.

The approach set out in this PAS is intended to determine the need for any risk-proportionate actions in relation to external wall construction required to protect occupants of blocks of flats, including residents and their visitors, anyone working in the building and people in the immediate vicinity of the building.
This PAS addresses the risk from fire spread over the external walls of multistorey blocks of flats of any height.
It addresses situations in which there is a single wall type or a mixture of different wall types. It also addresses buildings that are partially clad, as well as those that are fully clad, in combustible materials.
Wall build-ups within the scope of this PAS include, but are not limited to:
  1. 1) external walls incorporating a rainscreen cladding system, with or without insulation within any associated cavity;
  2. 2) external thermal insulation composite systems (ETICS), particularly those comprising rendered insulation;
  3. 3) composite panels, including insulated core (“sandwich”) panels;
  4. 4) glazed façades with infill/spandrel panels;
  5. 5) substrates or backing walls, including concrete blockwork, brick, steel framing systems (SFSs), timber framing and structural insulated panels (SIPs); and
  6. 6) curtain walling.
It also covers attachments to the external walls of buildings.
This PAS does not address spread of fire from one building to another, the performance of external walls in terms of fire resistance, or the ability of the walls to maintain structural stability. It is not applicable to new buildings.