Kebakaran stasiun pompa bahan bakar umum akibat nyala uap bahan bakar tahun 2020 terekam 38 kali di wilayah Indonesia. Konsentrasi uap bahan bakar yang flamabel pada area diantara batas bawah flamabilitas (Low Flammability Level, LFL) dan batas atas flamabilitas (Upper Flammability Level, UFL) merupakan faktor penyebab kebakaran. Tujuan penelitian: perancangan peralatan pengujian LFL bensin dengan metoda tabung menggunakan evaporasi internal untuk menghasilkan uap bensin. Alat ukur berupa tabung kaca vertikal d= 80 mm t= 300 mm, permukaan atas terbuka dan pemantik api listrik tegangan tinggi 10 J. Dua metoda pengukuran: arah propagasi ke atas (upward propagation) dan propagasi ke bawah (downward propagation) dilakukan terhadap enam sampel pada temperatur 28oC. Hasil pengujian: konsentrasi LFL propagasi ke atas untuk sampel RON_88 adalah 1,63%, RON_90-1; 1,77%, RON_90-2; 1,61%, RON_92; 1,65%, RON_95; 1,61% dan IO_100; 1,05%. Sedangkan arah propagasi ke bawah RON_88 adalah 2,49%, RON_90-1; 2,42%, RON_90-2; 2,4%, RON_92; 2,31%, RON_95; 2,12% dan IO_100; 1,58%.Pengujian LFL Iso-octane metoda propagasi ke atas 1,15% (tabung d= 5,3 cm) dan 0,98% (tabung d= 2,5 cm) (Coward, 1952)Angka oktan tidak banyak berpengaruh pada hasil pengujian LFL dengan metoda propagasi ke atas. Akan tetapi pada metoda propagasi ke bawah hasil LFL akan menurun dengan naiknya angka oktan.

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Public fuel pump station fires due to fuel vapor flames in 2020 were recorded 38 times in Indonesian. The flammability of the fuel vapor concentration in the area between the lower flammability level (LFL) and the upper flammability level (UFL) is a cause of fire. The purpose of the study: the design of gasoline LFL testing equipment with the tube method using internal vaporization to produce gasoline vapor. The measuring instrument is a vertical glass tube d= 80 mm t= 300 mm, the top surface is open and a high voltage electric lighter 10 J. Two measurement methods: the direction of upward propagation and downward propagation were carried out on six sample at a temperature of 28oC. Test results: the concentration of LFL propagation upwards for samples RON_88 is 1.63%, RON_90-1; 1.77%, RON_90-2; 1.61%, RON_92; 1.65%, RON_95; 1.61% and IO_100; 1.05%. While the downward propagation direction of RON_88 is 2.49%, RON_90-1; 2.42%, RON_90-2; 2.4%, RON_92; 2.31%, RON_95; 2.12% and IO_100; 1.58%.

LFL Iso-octane testing with upward propagation method is 1.15% (tube d= 5.3 cm) and 0.98% (tube d= 2.5 cm) (Coward, 1952)

The octane number does not have much effect on the LFL test results with the upward propagation method. However, in the downward propagation method, the LFL results will decrease with increasing octane number.