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Article | Managing Risk

Managing composite panel risks: What risk managers need to know

By Mark Field and Frederick Gentile | January 3, 2024

Expert insight on identifying and managing the risks of combustible composite panels and presenting your composite panel-related risks more persuasively to insurers.
Risk Management Consulting
Insurer Solutions

Composite panels have been widely used in building construction for more than 30 years, their popularity driven by their thermal insulation properties and the faster construction methods they allow. However, as some of these panels can be highly combustible, they can leave your organisation facing prohibitive premiums on property damage cover.

Insurers’ biggest concern with composite panels is the combustibility of some insulation materials, resulting in significant property damage when composite panels have been involved in a fire (and, tragically as the Sun Valley factory fire demonstrated, loss of life due to structural collapse during firefighting attempts). As a result, insurers generally take a negative view of composite panels. If your organisation uses composite panels in the construction of its manufacturing or other sites, you will need to demonstrate you have fully identified any risks to property from the panels and evidence the controls around how you’re using and maintaining any composite panels to give underwriters the assurances they seek when assessing the acceptability of your risk.

In this Q&A, we take a closer look at composite panels – including some key definitions and technical details on the types of panels most and least acceptable to insurers – and suggest practical tactics for better managing the risks and associated risk finance costs.

Q. What are composite panels?

A. Composite panels consist of two metal faces positioned either side of a core of thermally insulated material that is bonded to both faces. These types of panels are not to be confused with ‘built-up systems’ that form separate component parts assembled on site, or single skin cladding that act as rain screens or decorative facings.

Q. How can you confirm whether a building uses composite panels?

A. Identifying whether composite panels have been used in the construction of a building based on a simple visual evaluation is not an easy task, with some types very similar in appearance to each other.

Your first port of call to understand whether a site includes composite panels is architectural or site drawings. Ideally, these will also include the specifications of the panels.

If you don’t have the drawings or specification details, you will need to carry out independent testing to determine the nature of any composite panels. Without any evidence to the contrary, insurers will assume any composite panels will be those lower rated in terms of flammability and insurability (see below).

Q. How can you use information on composite panels to better manage risk?

A. It’s important to enter any data you obtain on composite panels onto building or site plans. You should highlight both where you have built-up types of panel and any other type of composite panels detailing their insulation composition. This allows you to easily provide the emergency services with valuable insight to support their risk assessment should they need to respond to a fire and/or help ready them ahead of any incident.

Q. What are the key composite panel fire risks you need to assess?

A. Insurers consider all composite panels as combustible to a lesser or greater degree. Underwriters expect your organisation to have a management system in place to control the exposure of any of the insulation material to potential ignition sources. This could be from direct flames or from heat sources such as ovens, extraction flues or electric cables, for example.

Q. What should you include in composite panel risk management controls?

A. To manage composite panel risk most effectively – and to present your risk more persuasively to insurers – you should cover the following in your risk management system:

  • Identifying any damaged panels and detailing measures to quickly fix defects
  • Fire stopping of any openings in panels to seal exposed insulation and to protect from other fire inception risks, such as hot ducts
  • Control of work on panels to prevent hot works and where hot work is carried out, how this is authorised, monitored, and documented
  • Control of fitting of electrical equipment on or in close proximity to panels and protecting any cabling you need to route through the panel
  • Details of any additional protection provided to panels in areas susceptible to mechanical damage or in proximity to other hazards, such as ovens or heat-generating machinery
  • Assurances you will replace any panel damaged beyond repair with a non-combustible or an insurer-approved panel (and use non-combustible or an insurer-approved panel in any new constructions).

These measures are in addition to the normal fire risk management controls and human element management procedures you should have in place. You can also consider expanding each element of your risk management considerations to incorporate site-specific controls.

Q. What are the emerging composite panel risks that risk managers should be aware of?

A. There are emerging composite panel risks relating to photovoltaic panels on composite panel roofs. If your organisation uses these in its building construction you will need to show insurers how you are controlling risks relating to cabling and inverters. This might include incorporating additional non-combustible cladding over the roof, for example, on polystyrene or polyurethane insulated roofs.

For future new builds and refurbishments, we would always recommend your organisation considers non-combustible materials, such as brick or concrete block, with non-insulated or built-up type of panels incorporating stone wool or glass fibre insulation, which also offer better fire performance.

Using the higher-rated materials (see below) will ultimately give you better fire protection while improving business resilience and therefore supports insurers in deeming your risk more acceptable.

Q. What are the most and least acceptable composite panel types for insurers?

A. Below, we rank insulation types ranked in ascending order of insurer acceptability, offering technical specification details and some guidance on how you might visually identify each type:

  1. 04


    Expanded or extruded polystyrene (EPS/XPS) – These are white and often bead-like in appearance. Not often found in external building envelopes as a panel but can be found cement rendered. Often used in internal enclosures, temperature-controlled or clean rooms and within older cold-storage warehouses, these panels are moisture-resistant, cheap, and lightweight. They are also highly combustible, spreading fire easily while giving off noxious smoke. These panels are also easily damaged, exposing the core to a potential fire.

  2. 03

    Polyurethane (PUR) and non-approved polyisocyanurate (PIR)

    PUR is dark yellow to orange in colour PIR, off-yellow. Both types of panels are made of foamed plastic; both are combustible, but with better fire performance than polystyrene. These panels are widely found in external wall and roof cladding, in pre-1995 buildings. Some PUR panels are still being manufactured and are on sale in the U.K. In a fire, they will initially char before igniting, rapidly spreading fire with thick smoke.

  3. 02


    Pink in colour, these panels are not commonly used in external building fabrics, but are used more commonly as pipe and duct insulation. These panels consist of thermoset foam, in either a closed or open cell. These panels will ignite and spread a fire, producing toxic smoke. Some modified phenolic foams, blended with other products are now available as approved cores.

  4. 01

    Insurer-approved polyisocyanurate (PIR)

    This material is lighter yellow in colour and has been available since the late 1990s. It’s found increasingly on new constructions from around 1999. A foamed plastic product with an additional fire-retardant solution added during the polyisocyanurate process, insurer-approved PIR does not make a significant contribution to fire growth. A wide range of panels are now available that have been independently tested by an insurer-approved body the Loss Prevention Certification Board (LPCB), using the British Research Establishment (BRE) as its approved testing house.

The tested, approved panels available offer a variety of grades of performance regarding fire resistance, integrity, and insulation. The key standards required for insurer approval are:

LPS 1181

Part 1 – Built-up cladding and composite panel systems for use as the external envelope of buildings

Part 2 – Composite panels and built-up systems for use as internal construction in buildings.

LPS 1208

Fire resistance requirements for elements of construction used to provide fire compartmentation. This level of accreditation considers the integrity and insulation properties of the panel.

The Euroclass System is the main standard used in Europe to classify the fire reaction of construction and partition products. There are seven levels of categorisation within the Euroclass System, from A1 to F (A1 being the best and recognised as non-combustible), with further sub-categorisation in most levels. Other standards are also accepted, such as the American Factory Mutual (FM) approvals.

Next steps to manage composite panel risks

For future new builds and any refurbishments, we recommend using non-combustible materials as your first consideration. Using insurer-approved, higher-rated materials provides for better fire protection and improves your business resilience.

Having a panel management plan can also support better outcomes from your discussions with potential insurers around the acceptability of risk.

For smarter ways to manage and present the property damage risks associated with composite panels, get in touch with WTW’s experts.


Associate Director – Property Risk Engineering
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Director of Risk Engagement


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