Fire Classification of Sandwich Panels
The reaction-to-fire classification of a sandwich panel depends on its complete tested construction, including the core, facings and joints. EN 13501-1 uses Euroclasses A1 to F. A core material's classification must not be treated as the classification of the finished panel. The examples below are indicative; always consult the classification report for the specified product and installation.
• EPS (Expanded Polystyrene): insulation commonly classified as Class E
• PUR (Polyurethane): panel classifications depend on the tested construction
• PIR (Polyisocyanurate): panel classifications depend on the tested construction
• Mineral Wool: non-combustible core options; check the complete panel classification
The core's chemical composition and combustion behaviour influence panel performance, but the classification applies to the product or system assessed in the relevant test.
EPS (Expanded Polystyrene)
EPS is a lightweight polystyrene foam used for thermal insulation. It is combustible, and fire fumes can be harmful. EPS insulation is commonly classified as Class E under EN 13501-1. The finished sandwich panel must be assessed using its own test and classification documentation.
PUR (Polyurethane)
PUR foams are produced by combining polyisocyanate and polyol components. PUR-core sandwich panels provide thermal insulation and structural performance. Some tested panel constructions achieve Class B or C; the classification must be confirmed for the particular product rather than inferred from the core alone.
PIR (Polyisocyanurate)
PIR has a chemical structure related to PUR and offers improved performance at elevated temperatures. PIR-core sandwich panels provide thermal insulation and structural performance. Class B is an example cited for some panel constructions; the applicable reaction-to-fire and smoke classifications must be checked in the product's classification report.
Mineral Wool
Mineral wool is an inorganic insulation material made from mineral fibres. It offers thermal and acoustic performance, with non-combustible core options. Mineral wool-core sandwich panels are widely used where fire performance is a key project requirement.
A1 and A2 classifications may apply to relevant mineral wool materials or panel constructions, according to their test results. A1 indicates no contribution to fire, while A2 indicates limited contribution. Neither a core label nor a general description establishes the smoke performance or fire resistance of every finished panel; consult the specific classification and test reports.
Fire safety design requires the appropriate sandwich panel to be selected using verified performance data for the complete product and its installation. Compare reaction-to-fire, smoke and fire-resistance requirements with the relevant certificates, alongside the project's structural and thermal requirements.
