Based on the principles of this test method, reaction to fire of materials in B, C, and D classes is determined. This test is performed in addition to SFI test. SBI test is a test method carried out by directing a flame source of 30 KW size from a corner of the room to the material. Although internal corner detail is actually used less in exterior wall applications, test results can be obtained by simulating as if an internal corner detail existed. Oxygen consumption, carbon dioxide release, and temperature values are determined in SBI test. By calculating these values obtained, the Total Heat Release (THR) and Fire Growth Rate (FIGRA) data for the first 10 minutes of the sample subject to fire are obtained. This test provides crucial insights about the fire growth for the first 10 minutes and how the material would react to fire in the buildings. The fire classes of the materials (B, C, and D) are determined based on the data obtained. In addition, it is also observed whether the flame spreads laterally (Lateral Flame Spread (LFS)) in the material subject to fire for 20 minutes. If lateral flame spread occurs, such material is classified as D. On the other hand, classification called as d0, d1, and d2 is determined based on whether burning droplets are formed within the first 10 minutes and whether such burning droplets burn for more than 10 seconds. Based on the smoke produced during the first 10 minutes, Total Smoke Production (TSP) and Smoke Growth Rate (SMOGRA) values are determined and then classification as s1, s2, and s3 is assigned based on these values.