HPL cladding

Revision as of 13:07, 22 July 2019

The term 'cladding' refers to components that are attached to the primary structure of a building to form non-structural, external surfaces. This is as opposed to buildings in which the external surfaces are formed by structural elements, such as masonry walls, or applied surfaces such as render.

High Pressure Laminate (HPL) panels are a form of cladding typically manufactured by layering sheets of wood or paper fibre with a resin and bonding them under heat and pressure. They sometimes include additional chemicals to provide fire retardant properties and are available in a wide range of colours and finishes.

Panels which do incorporate fire retardant chemicals are sometimes referred to as “FR grade” and these will typically achieve Class B-s1, d0. Panels manufactured without fire retardant chemicals are typically Class C or D, depending on the thickness of the panel.

Following the Grenfell Tower Fire, and subsequent concerns regarding the fire performance of cladding panels (in particular Aluminium Composite Material (ACM) cladding), The Ministry of Housing, Communities and Local Government (MHCLG) conducted a BS8414 test of a cladding system comprising an HPL panel with fire retardant (Class B-s1, d0) together with stone wool insulation. This system achieved the performance criteria set out in BR135 Fire performance of external thermal insulation for walls of multistorey buildings. As a result, the MHCLG Expert Panel consider that this combination of materials can be safe on existing buildings, depending on the composition of the entire cladding systems and how it is fitted.

However, the Expert Panel consider that systems using HPL panels of a European classification of Class C or D are very unlikely to adequately resist the spread of fire. In addition, systems using any type of HPL panels (Class B, C or D) with combustible insulation are very unlikely to adequately resist the spread of fire. Building owners with these systems should immediately take action in line with Advice Note 14 (first published in December 2017 and updated in December 2018).

The Expert Panel consider that the level of risk from unsafe HPL systems is not as high a risk as unsafe systems using ACM Category 3 panels. Therefore, they advise that the immediate removal of unsafe systems using ACM Category 3 panels should be the priority of focus, followed by immediate action to remediate unsafe HPL systems. However, for the avoidance of doubt they reiterate that both the removal of unsafe ACM Category 3 panels and action to remediate unsafe HPL systems should be carried out as soon as possible.

The Expert Panel is not aware of any HPL panel meeting the requirements of the ban on the use of combustible materials in external walls which limits materials to products achieving a classification of Class A1 or A2-s1,d0, and so these should not be used in the external wall when carrying out building works on new residential buildings of 18m or more (i.e. new build, refurbishment of the external wall or a material change of use).

Ref https://www.gov.uk/government/publications/advice-for-owners-of-residential-buildings-with-hpl-systems

Related articles on Designing Buildings Wiki

• ACM cladding testing by BRE.
• ACM cladding.
• BS 8414 Fire performance of external cladding systems.
• Celotex RS5000 PIR insulation.
• Consultation on banning the use of combustible materials in the external walls of high-rise residential buildings.
• Fire performance of external thermal insulation for walls of multistorey buildings, third edition (BR 135)
• Grenfell Tower articles.
• Grenfell Tower fire.
• Grenfell Tower independent expert advisory panel.
• Grenfell Tower Inquiry.
• Independent review of the building regulations and fire safety.