1/12/2025
Meeting sustainability, energy efficiency and safety targets in buildings depends on the presence of a properly designed insulation strategy. Thermal insulation materials not only reduce energy losses, but also directly affect many performance parameters such as fire safety, acoustic comfort, mechanical strength and overall system integrity. For this reason, the correct definition and verification of product performance is regulated within the harmonized standards system of the European Union through a well-established engineering infrastructure.
Thermal insulation materials cover a wide range of product families, including mineral wool products, cellular polymeric structures, elastomeric foams, and phenolic or polyurethane-based insulation materials for building services. The harmonized standards developed for these products (the EN 13162–13171 series and, for building equipment and industrial installations insulation, EN 14303, EN 14304, EN 14313, etc.) define the technical characteristics of the products, test methods and the way performance is declared. EN 13172, which stands above these product standards, serves as the reference document for conformity assessment and establishes common principles applicable to all product groups. In this way, comparability, traceability and verifiability of performance among different materials are ensured.
Thermal Conductivity Performance
The thermal conductivity coefficient (λ) is the most fundamental parameter defining the performance of thermal insulation and directly affects the accuracy of energy calculations.
All harmonized standards prepared for thermal insulation materials clearly state that the λ value must be determined under laboratory conditions.
Within this scope, measurements shall be carried out in authorized and notified laboratories in accordance with the test methods referenced in the relevant product standard. The obtained results are subjected to statistical evaluation to determine the declared thermal conductivity value (λᵈ) of the product, which forms the basis of the Declaration of Performance (DoP). Thus, the reliability of energy efficiency calculations is ensured both at the design stage and during application.
Reaction to Fire Performance and Safety Criteria
The fire behavior of thermal insulation products is one of the critical components of building safety. The reaction-to-fire classification includes a multidimensional performance assessment based on flame spread, smoke production and flaming droplets. While the chemical composition, pore structure and additives of the material directly affect fire performance, density influences it indirectly depending on the type of material.
Mineral wool products stand out with their high temperature stability and non-combustibility properties, whereas in polymeric and elastomeric cellular products, smoke density, thermal degradation behavior and flame-retardant technologies play a decisive role. Therefore, fire performance should be evaluated not only through the declared class, but also as a whole together with the test methods prescribed by the relevant harmonized standard, laboratory competence and the AVCP system.
| Class | Smoke Production (s) | Flaming Droplets (d) |
| A1 | – | – |
| A2 | s1 – s2 – s3 | d0 – d1 – d2 |
| B | s1 – s2 – s3 | d0 – d1 – d2 |
| C | s1 – s2 – s3 | d0 – d1 – d2 |
| D | s1 – s2 – s3 | d0 – d1 – d2 |
| E | – | – |
| F | – | – |
| s1: Very limited smoke production s2: Medium smoke production s3: High smoke production d0: No flaming droplets/particles occur d1: Limited occurrence of flaming droplets d2: Significant occurrence of flaming droplets | ||
Table 1: Reaction to Fire Classification
The AVCP System: A Framework Ensuring Consistency of Performance
The AVCP (Assessment and Verification of Constancy of Performance) system defined in harmonized standards provides a quality assurance mechanism that is not limited only to the placing of the product on the market. The selection of the AVCP system is determined according to the intended use of the product, its level of risk and its fire behavior. Most thermal insulation products are assessed under System 1 or System 3.
| AVCP System | Manufacturer Responsibilities | Notified Body (NB) Responsibilities |
| System 1 | – Establishes and maintains Factory Production Control (FPC) – Performs regular FPC tests – Prepares the Declaration of Performance (DoP) and affixes the CE marking | – Approves type testing – Audits production and FPC – Performs continuous surveillance (twice per year) |
| System 3 | – Establishes and maintains FPC – Performs regular FPC tests – Prepares the DoP and affixes the CE marking | – Carries out and reports type testing – Does not audit the production process |
| System 4 | – Performs type testing on its own – Establishes and maintains FPC – Performs regular FPC tests – Prepares the DoP and affixes the CE marking | – Not involved |
Table 2: AVCP Systems and Responsibilities
CE Marking and Its Impact on the Market
CE marking of thermal insulation products is the legal indication that the product has been manufactured in compliance with the relevant European harmonized standards and the requirements of the Construction Products Regulation (305/2011/EU). The Declaration of Performance (DoP) prepared within the scope of CE marking ensures that the essential performance characteristics of the products are placed on the market in a transparent, traceable and comparable manner. In this way, a technical confidence environment is established in the market in terms of building safety, energy efficiency and fire safety. At the same time, CE marking constitutes a prerequisite for manufacturers to place their products freely on the European Union market.