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Scottish Advice Note: Determining the fire risk posed by external wall systems in existing multi-storey residential buildings

This Scottish Advice Note (SAN) provides advice for those responsible for fire safety in residential buildings including building owners/managers/residents groups responsible for determining the fire risk posed by external wall systems on existing multi-storey residential buildings. It will also be of interest to fire risk assessors and specialist external wall appraisal experts.


Annex 1: Other External Wall System Features

The following features should also be considered:

Spandrel panels

Spandrel panels (including window panels, infill panels, etc.) can be part of the external wall of the building and are provided for both aesthetic and functional purposes. They are not normally loadbearing but are often designed to account for wind loading.

The design and materials of spandrel panels varies; some are made of singular components such as cement particle board, other panels are composite products comprising outer facing materials bonded to an inner core which may include combustible insulation. Vertically aligned spandrel panels or window infill panels create a greater risk of rapid fire spread vertically up the building fa├žade than a horizontal band.

The benchmark from building regulations guidance is that where the building has a storey at a height of more than 11 m above the ground, spandrel panels should be constructed of products achieving European Classification A1 or A2.

Balconies

The design and construction of balconies should not facilitate fire spread over the external wall to an extent that would pose a risk to life. There are indications that fires on balconies are becoming more common (see link below). The most common causes of such fires are deliberate ignition, careless disposal of smoking material and misuse of barbeques. The severity of a balcony fire can be increased by combustible materials, such as furnishings or discarded materials stored, or used, on the balcony.

Balcony fires have occurred which have led to rapid external fire spread. BRE Global published examples in a 2016 report 'Fire safety issues with balconies'. The report identifies additional risks from insulation materials used to prevent heat loss that may increase fire spread and concludes that there is potential for a fire in a balcony to pose a significant life safety issue.

The materials used in the construction of balconies should be identified to better understand the risk of external fire spread. Particular attention should be given to wooden balconies. Where balconies have been infilled and incorporated into flats, fire separation and fire stopping between flats should be checked.

Building owners may have policies on balcony use and storage and should review these to take account of the findings of the fire safety risk assessment. They should also engage with residents to develop their understanding of these risks and to share the significant findings of the fire safety risk assessment.

The benchmark from building regulations guidance is that where the building has a storey at a height of more than 11 m above the ground, balconies should be constructed of products achieving European Classification A1 or A2.

Other attachments

There is a risk of vertical fire spread from other attachments to an external wall including solar panels and solar shading. Solar shading are devices attached to an external wall to reduce heat gain within a building by deflecting sunlight. Fire-fighters may not be able to apply a water jet from a fire-fighting hose directly onto a fire that has spread onto specified attachments high above the ground.

The benchmark from building regulations guidance is that where the building has a storey at a height of more than 11 m above the ground, specified attachments should be constructed of products achieving European Classification A1 or A2.

Green Walls

Green walls (also called living walls) have become popular in recent years. Best practice guidance can be found in 'Fire Performance of Green Roofs and Walls' published by the Department of Communities and Local Government. While this document contains references to English building standards, it contains useful general guidance.

Contact

Email: Buildingstandards@gov.scot

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