The leading standard for fire classification of construction products and building elements in Europe is the EN 13501. At the core of this classification is the SBI-test (Single Burning Item). What exactly happens during this test? And what does this mean for the fire safety of your building?
What is an SBI test (Single Burning Item test - EN 13823)?
An SBI test (Single Burning Item) simulates the start of a fire to assess the fire behaviour of building products. Out of this test, the tested material (kit) gets a classification (Euroclass) based on the different parameters that are being measured during the test. These parameters include the flame spread, ignitability, the amount of heat, smoke and toxic gas release and whether a product melts, drips or chars. The classification is based on a certain end-use situation and field of application.
Things to keep in mind with regard to SBI-testing
During an SBI test, a specific combination of building materials is tested: a certain type of insulation is used, a type of subframe is chosen etc. This is the so-called End Use Application. Test results are only valid for this specific build-up of the construction. Since it is undoable to test all possible variation, the standard foresees in the so-called Field of Application rules. This set of predefined rules (part of the Harmonized Technical Specification of a building product) makes it possible to extend the test results to other construction build ups where the reaction to fire classification is proven to be unchanged.
During the design and realisation of a building, a lot of changes to a kit can happen. Sometimes out of necessity, sometimes due to choices made within the supply chain. In such cases, fire safety is only assured when it is part of the Field of Application of a classification. If for instance a panel is tested with mineral wool and then is used with another type of insulation, the classification out of the SBI-test is only valid with non-combustible insulation. With combustible insulation, this classification is no longer valid as the kit can show a different fire behaviour.
Another issue is the unclarity that exists on test results. Test reports aren’t always made public, and in that case you don’t know what combination of materials have been tested. It’s therefore wrong to assume, for instance, that a kit can be of Euroclass B if the insulation is B and the panel is B as well. To prevent the uncertainty coming from all of these issues surrounding an SBI-test, it is strongly advised to use non-combustible materials for both insulation and facade cladding panels as all classification of facade panels in the Harmonized Technical Specifications is defined with mineral wool.