Published on 05/05/2026 by infobuild.it.
In a construction sector increasingly oriented towards energy efficiency, fire safety and material circularity, expanded polystyrene is once again at the centre of the technical debate. This is discussed by Eng. Marco Piana, Technical Director of AIPE, and Emanuela Gallo, Technical Affairs Manager & Fire Expert at EUMEPS. They are examining in depth fire behaviour, regulations, external thermal insulation composite systems (ETICS), roofs with photovoltaic systems and market prospects.
The issue of the fire safety of insulating materials is today one of the most delicate challenges in building envelope design.
The progressive spread of external thermal insulation composite systems (ETICS), the energy refurbishment of the existing building stock, the integration of photovoltaic systems on roofs and the evolution of the regulatory framework are, in fact, shifting attention from the individual product to the overall performance of the construction system.
In this context, expanded sintered polystyrene, identified by the acronym EPS, is often referred to in the technical and public debate through interpretations that are not always complete, risking oversimplification of a far more complex issue.
The correct assessment of EPS in construction instead requires a performance-based approach, capable of considering not only the characteristics of the material, but also the stratigraphy, installation, protective coatings, operating conditions, intended use of the building and compliance with fire prevention regulations.
The central point, as emerges from the interview with Eng. Marco Piana, Technical Director of AIPE, and Emanuela Gallo, Technical Affairs Manager & Fire Expert at EUMEPS, is that the insulation material must be assessed within its application context: in ETICS systems, stratified roofs and compartmentation closures, safety depends on the interaction between all components and on the consistency of the design with the Fire Prevention Code, RTV V.13 and the most up-to-date technical guidance.
The interview therefore provides an opportunity to clarify several aspects: from the behaviour of EPS in the event of fire to the role of large-scale testing, from the distinction between mandatory standards and guidelines to the new requirements arising from insulated roofs with photovoltaic systems. A useful in-depth analysis for designers, contractors, fire safety engineers and supply chain operators, at a time when the construction sector is required to combine energy efficiency, durability, safety, recyclability and the economic sustainability of interventions.
The Italian EPS market between stabilisation, construction and recycling
The market outlook confirms the consolidated role of EPS within the Italian construction supply chain. AIPE data indicate that the national market for expanded sintered polystyrene reached consumption levels of approximately 120,000 tonnes between 2024 and 2025, returning to levels closer to the pre-Superbonus and pre-COVID period following the extraordinary cycle linked to building incentives. This therefore represents a normalisation of volumes, in which EPS continues to maintain a significant presence in the main application sectors, starting with construction.
In the construction sector, its use covers applications ranging from external thermal insulation composite systems (ETICS) to radiant systems, through to lightweight construction solutions and interventions in which the relationship between performance, weight and workability represents a determining factor. Alongside this is the packaging sector, where EPS continues to be used in fields with high performance requirements, such as food, fishery and pharmaceutical applications, thanks to its characteristics in terms of protection, hygiene and insulation.
Another significant figure concerns recycling. In 2024, the PEPS Platforms, dedicated to the recovery of EPS packaging and connected to the Corepla system, handled 11,500 tonnes, with growth of 11.6% compared to 2023. Considering also other non-domestic waste streams, AIPE estimates that more than 22,000 tonnes were overall sent for recycling. This is an important factor at a time when European policies — from the EPBD IV “Green Homes” Directive to the new PPWR Regulation on packaging and packaging waste — are steering the market towards materials and systems capable of demonstrating measurable performance throughout the life cycle, recyclability and traceability.
In this context, EPS forms part of a development trajectory that concerns not only thermal insulation, but more generally the capacity of the construction sector to respond to increasingly integrated objectives: reduction of energy demand, fire safety, environmental sustainability, cost control and scalability of refurbishment interventions.
The interview with AIPE and EUMEPS starts precisely from this scenario, addressing the issue from a technical and systemic perspective, far removed from oversimplifications and oriented towards the correct design of the building envelope.
EPS in construction and fire safety: discussion with Eng. Marco Piana of AIPE and Emanuela Gallo of EUMEPS
In the public debate on the fire safety of insulating materials, EPS is sometimes described in an oversimplified way. From a technical perspective, which elements make it possible to define it as a safe material when correctly integrated into a façade or roof construction system?
Eng. Marco Piana: “The issue of the fire safety of insulation materials in construction is complex and specific; it requires knowledge of the technical and performance aspects not only of the material itself but also of the entire construction system, as well as of the relevant regulatory framework. Expanded sintered polystyrene (EPS), used for more than 40 years in public and private buildings — when incorporated into a construction system that complies with fire prevention regulations — is a safe material from a fire safety perspective and suitable for all applications in construction, both in roofing systems and in ETICS systems.
From a technical point of view, EPS does not propagate fire, does not generate autonomous combustion and, without a continuous external source, extinguishes itself (it is self-extinguishing). Furthermore, due to its expanded nature, when exposed to high temperatures it contracts, while at the same time forming a carbonaceous surface layer that slows the propagation of any potential fire.
As regards the self-extinguishing aspect, this can be clearly understood by referring to the concept of the ‘fire triangle’, which tells us that — in order to maintain a flame — an adequate temperature (or ignition source), fuel (that which burns) and an oxidising agent (that which sustains combustion and which is normally the oxygen present in the air) must coexist. When one of these three elements is removed, combustion stops. EPS contains a specific substance which, in the presence of heat, is released and removes oxygen from the combustion process, thereby promoting the extinguishing of the flame.
Furthermore, when exposed to heat — already at 70 °C — EPS tends to contract; and if temperatures become very high, exceeding 300–400 °C, it forms a carbonaceous surface layer with a protective shield effect against the development and propagation of flames.
It should also be recalled that, as a thermoplastic polymer, Italian and European fire safety regulations require EPS — like all insulation materials — always to be installed with a protective covering, such as plaster, plasterboard, metal sheets or resins, preventing its direct exposure to fire. As such, and in accordance with CE marking, it is suitable and safe for all construction applications, complying with the requirements of the regulations and standards in force.”
In Italy, what are currently the main regulatory references to consider when discussing EPS and fire safety in construction, particularly with regard to the Fire Prevention Code and RTV V.13 relating to the compartmentation closures of civil buildings?
Ing. Marco Piana: “When discussing fire safety in the construction sector, it is first necessary to distinguish between mandatory regulatory references and guidance documents, which, however, are not binding.
Mandatory provisions are the laws and decrees issued by the National Fire Brigade Corps, which must be considered the principal regulatory sources. The Fire Brigade also issues references in the form of Guidelines, which may be useful to the designer, but which are not binding in nature.
In the past, the regulatory framework was based mainly on decrees, or rather on ‘prescriptive’ indications for specific applications and buildings according to their intended use — whether hotels, hospitals, schools, etc. — with rules indicated in a specific and detailed manner.
In recent years, the framework has changed in the direction of reorganisation: the Fire Brigade has, in fact, introduced the Fire Prevention Code, now considered the principal reference for fire safety design. Through the Horizontal Technical Rule (RTO), the Code represents a sort of guided pathway for the designer, helping to define the characteristics of the building so that it is safe and suitable for its intended use. In this new approach, the role of the designer carries greater responsibility and centrality, as they are required to make decisions regarding materials and structure.
The Code also includes all the Vertical Technical Rules (RTV), dedicated to different contexts and/or components and constantly updated. To date, there are more than 15 RTVs (for example for offices, car parks, hotels, schools, hospitals, etc.). Among these is RTV13, relating to compartmentation closures, namely the set of surfaces delimiting the building towards the outside: walls, roofs and, more generally, the building envelope.
The use of EPS, widely employed in compartmentation closures, is regulated in a detailed and precise manner by the Code and RTV13: with a design approach correctly following the requirements of both texts, components made with EPS fully satisfy all fire safety requirements.
In general, since the application of RTV13 falls solely within the scope of the Code, the design process must first address everything required by the latter and subsequently everything required by the relevant RTVs.
Furthermore — like all RTVs — it only concerns activities subject to Fire Brigade inspections, therefore not all building types. For example, a building with a height of 30 metres is a regulated activity and must therefore adopt RTV13, whereas a single-family house does not fall within its scope; for the latter, the 2013 Fire Safety Guide for Façades may be used as a reference.
For this reason, when discussing the prescriptions of RTV13, it is always necessary to contextualise the scope: the elements to be considered in order to navigate the regulatory framework are the building type, its intended use, the profile of occupants/users, life safety risk analysis, property risk analysis, environmental risk analysis, and much more.”
A central aspect is that EPS, like all insulation materials, is not intended to be left exposed but must be incorporated within a protected stratigraphy. How important is this principle in the correct assessment of the fire safety of the material?
Eng. Marco Piana: “It is a central principle, because the fire safety assessment of an insulation material must not be carried out by considering only the material itself, outside its application context. Fire prevention activity is specifically aimed at anticipating what could cause a situation that is difficult to manage and, consequently, at adopting every necessary precaution to prevent it already at the design stage.
EPS is always installed with a protective layer, which prevents direct contact with fire. The same applies to other materials: for example, steel is coated with intumescent paints, while wood is treated with coatings that protect it against flame ignition and propagation.
To better explain how safe EPS is, and even safer than other materials when correctly protected, I can refer to a laboratory test in which the behaviour of wall coverings in wood versus protected EPS was compared, considering the ignition temperature, namely the temperature at which flames develop: between the two cases there are differences in flame ignition in the order of 100–200 °C, where the lower temperature refers to coverings in pine or fir wood, while protected EPS has a higher ignition temperature.”
In the case of ETICS systems with EPS, what indications emerge from large-scale experimental testing? Which are the most important parameters for correctly assessing the fire behaviour of a façade?
Emanuela Gallo: “Large-scale experimental testing currently represents the most reliable tool for assessing the fire behaviour of ETICS systems with EPS, because it makes it possible to analyse the actual behaviour of the entire system and not of the individual materials. Small-scale laboratory tests are in fact not sufficient to realistically describe the development of a façade fire, particularly in terms of vertical propagation and involvement of the upper floors.
The assessment must therefore be based on overall performance parameters: the energy contribution of the system, smoke production and flaming droplets, the speed and extent of flame propagation (both vertical and horizontal), the temperatures reached, the propagation height, the time taken to reach critical thresholds and the possibility of fire transmission inside the building.
Large-scale tests on ETICS systems with different materials indicate that self-extinguishing EPS limits fire propagation under certain conditions, especially when correctly integrated into a complete and well-designed system.”
For roofs insulated with EPS and equipped with photovoltaic systems, what are currently the main criteria requiring attention from a fire safety perspective? How are the Fire Brigade Technical Guide and the rules of the Fire Prevention Code coordinated?
Emanuela Gallo: “The installation of Building Applied Photovoltaics (BAPV) systems inevitably modifies the risk profile and the dynamics of fire development on roofs. It should also be emphasised that, to date, no standardised large-scale test methods are available that can fully assess the fire behaviour of roofs in combination with photovoltaic systems. Current assessments are based on partial methods, adapted tests or engineering approaches aimed at filling the current regulatory gaps.
In the case of roofs insulated with EPS and equipped with photovoltaic systems, attention therefore focuses on preventing ignition and limiting fire propagation. The main criteria primarily concern the correct design and installation of the system, with particular attention to electrical components — cables, connectors and inverters — which represent the main potential ignition sources.
EPS in construction: Stratigraphic detail of the roof, including the insulation layer (EPS)
Stratigraphic detail of the roof, including the insulation layer (EPS) and the upper non-combustible layer.
A fundamental role is also played by compartmentation and propagation management, through the subdivision of the photovoltaic system into distinct and independent sections, achieved by introducing discontinuity elements or barriers, such as separation spaces and technical corridors, designed to limit fire propagation and facilitate safe access both during operation and maintenance and in the event of emergency intervention.
From a stratigraphy perspective, EUMEPS, the European association representing the expanded polystyrene supply chain, has recently conducted large-scale tests, not standardised but nevertheless followed and monitored by accredited research institutes, which showed that the presence of a non-combustible surface layer, even of limited thickness, positioned above the insulation, is able to effectively limit fire propagation, both horizontally and towards the inside of the building.
In general, EPS is confirmed as a reliable technical solution, capable of meeting the performance requirements for roof insulation in the presence of photovoltaics.
The presence of photovoltaic systems does, however, require greater design attention, especially in terms of safety. Current regulations also allow its use, provided that the system is correctly designed and installed.”
Eng. Marco Piana: “Today, the regulatory references for insulated roofs equipped with photovoltaic systems are RTV13 and the 2025 Technical Guide. These are two different approaches, since the former falls within the scope of the Code through a decree, whereas the latter is only a guide to which the designer may refer. The prescriptions of the former and the indications of the latter differ, and, consequently, it is the designer who must choose and adapt the design accordingly.
Certainly, the Technical Guide, being the most recent reference, takes into consideration certain aspects not covered by RTV13, such as the fire behaviour of photovoltaic panels.
In both situations, EPS is a safe material and may be used, as highlighted, with the appropriate protective coverings.”
From a technical and scientific perspective, what evidence is currently available regarding the behaviour of EPS in the event of fire and the related emissions? How important is it to distinguish between the behaviour of the individual material and that of the building system as a whole?
Emanuela Gallo: “It is essential to distinguish between the fire behaviour of the individual material and that of the building system as a whole: performance depends in fact on the interaction between all components, construction details and exposure conditions.
As regards emissions, EPS produces smoke to a lesser extent than many commonly used materials. In particular, it generates low quantities of carbon monoxide (CO) — the principal cause of fire-related intoxication — and does not produce hydrogen cyanide (HCN) or dioxins. Experimental studies* indicate in fact a lower smoke toxicity compared with materials such as wood, wool or cotton.
In systems such as thermal insulation systems (ETICS) or stratified roofs, EPS is furthermore protected by finishing layers that delay its involvement in the fire and significantly modify its behaviour.
Large-scale testing confirms that only a systemic approach makes it possible to realistically assess fire propagation, smoke production and the overall contribution to risk.”
At European level, CEN activities are underway with the aim of achieving a new standard on the fire safety of façades. At what stage is this process and what critical issues currently arise from the existence of different test methods among the various European countries?
Emanuela Gallo: “EUMEPS actively follows European activities relating to technical standardisation and policies for the building envelope, with particular attention to the fire safety of façades.
In this context, the European project coordinated by RISE Research Institutes of Sweden has recently been completed, representing today the most advanced attempt to define a harmonised method for the assessment of façade fire performance. The project included a comparison between the principal national methods, comparative experimental campaigns and validation activities, with the objective of developing a shared testing and classification approach.
The need for harmonisation derives from the current regulatory fragmentation: different European countries, including Italy, adopt different methods — including BS 8414 in the United Kingdom, Lepir2 in France and DIN 4102-20 in Germany — with test configurations and acceptance criteria that are not directly comparable. This makes technical assessment complex and hinders the free movement of construction systems, with the risk that the same solution may be compliant in one country but not in another.
On the basis of the project results, Working Group 10 was established within CEN in December 2025, tasked with developing the standardisation request and laying the foundations for a future harmonised European standard.”
Looking at the market and the sector’s future prospects, what role could EPS play in the coming years in a construction industry required to combine energy efficiency, fire safety, durability, recyclability and integration with new building services systems?
Eng. Marco Piana: “The role of EPS in the coming years will not only be significant, but structurally central within the transformation of the construction sector.
We are in a phase in which European and national regulations — from the EPBD IV ‘Green Homes’ Directive to the strengthening of CAM requirements and LCA approaches — are changing the paradigm: materials alone are no longer simply required, but rather measurable, integrated and verifiable performance throughout the entire life cycle of the building.
In this scenario, EPS starts from a very clear competitive advantage.
On the one hand, it is one of the few materials capable of effectively combining energy efficiency, lightness, durability and safety, fully meeting the performance requirements currently demanded by the regulatory framework. On the other hand, it possesses intrinsic characteristics that are difficult to replicate: it consists of 98% air, has a reduced environmental impact during the production phase and a high level of recyclability, elements that make it perfectly consistent with circular economy criteria.
But the key point is another: the most recent regulations are progressively moving beyond prescriptive approaches towards performance-based approaches. This means that it is not the material ‘by definition’ that is rewarded, but the one that guarantees the best balance between technical performance, environmental sustainability and efficiency.
And from this perspective, EPS currently represents, in a great many applications, the most efficient technical solution available.
We see this clearly in construction, where it continues to be the reference material in ETICS systems, radiant systems and lightweight solutions, with extremely high market shares. The same also applies to less visible but strategic applications, such as structural lightweight fills, geotechnical fills or integration with advanced building services systems, where the relationship between performance and weight becomes decisive.
At the same time, environmental data also confirm a positive trend: EPS has lower production energy consumption than many alternative materials and, in insulation applications, enables energy savings throughout the service life of the building that are significantly greater than the energy used to produce it.
Added to this is an element often underestimated but decisive: economic sustainability. At a time when the energy transition must be scalable and accessible, the cost/performance ratio becomes a critical factor. EPS, thanks to its efficiency and ease of processing and installation, makes it possible to achieve high performance at contained costs, making large-scale interventions concretely achievable.
For this reason, we believe that EPS is not simply one of the available options, but a solution that in many areas makes it possible to optimise technical performance, environmental impact and costs simultaneously throughout the life cycle.
The outlook is therefore clearly positive and is also reflected in the principal market indicators.
In Italy, between 2024 and 2025, EPS consumption stabilised at around 120,000 tonnes, returning to stable levels after the extraordinary phase linked to incentives.
The most significant figure, however, is its end use: more than 70% of EPS in Europe and around two thirds in Italy is used in the construction sector, confirming the now structural role that this material has assumed within the building industry.
At European level, forecasts and trends indicate growth rates of around 5% per year, supported in particular by demand for thermal insulation and by the evolution of the regulatory framework towards highly energy-efficient buildings.
In this scenario, the principal driver is represented by the refurbishment of the existing building stock, where the integration of insulation solutions is now a recurring and increasingly central element in intervention processes.
In the European ETICS market, EPS recorded a market share of 77% in 2024, remaining the most widely used material for this application**.
At the same time, increasing attention is also being paid to safety issues, with growing demand for solutions capable of combining energy performance and fire behaviour within certified construction systems.
In this context, EPS is confirmed as a consolidated technical solution fully consistent with the evolution of the sector, capable of responding effectively and in an integrated manner to the requirements for energy efficiency, safety, durability and sustainability demanded today — and increasingly in the future — by the construction industry.”
* Gurman, J.L., Baier, L. and Levin, B.C. (1987), Polystyrenes: A review of the literature on the products of thermal decomposition and toxicity. Fire Mater., 11: 109–130. https://doi.org/10.1002/fam.810110302
** Source: EAE (European Association for ETICS) – European ETICS Market Survey 2025