EN 13823 defines the single burning item test: a corner specimen of the product, built as two wings, is exposed in a test room to a propane burner of about 30 kW. The test represents a single burning object in the corner of a room, and it is the decisive test for EN 13501-1 classes A2, B, C and D for construction products.
The indices that decide the class
FIGRA (fire growth rate index) combines peak heat release with the time it occurs, capturing how fast a fire grows; its threshold values separate the classes. THR600s caps total heat in the first 600 seconds. SMOGRA and TSP600s do the same work for smoke, giving the s1/s2/s3 smoke additions. Lateral flame spread and flaming droplets complete the picture, the droplets giving the d0/d1/d2 addition. A classification such as B-s1,d0 is simply these SBI results read against the EN 13501-1 tables.
What an SBI installation involves
This is a room, not a bench: a 3 m x 3 m test room, a specimen trolley, an exhaust system moving roughly half a cubic metre of gas per second, and an analysis section measuring oxygen, smoke attenuation and flows. The Motis SBI page documents the installation's dimensions and capacities, and the construction sector page shows how SBI combines with ISO 1182, ISO 1716 and ISO 11925-2 across the classes.