Model KSBBFI /BSFI, which is used for the protector of fluid storage tank, is composed of one body with the functions of pressure relief, vacuum relief, and to block the external repellent fire. This is consist of the flame arrester which blocks the external repellent fire, the function of discharge the overpressure developed during intake air to the storage tank, and the function of intake the air under the constant pressure during unloading. And this is the safe valve to prevent the many kinds of storage tank from the deflation (vacuum), inflation ( pressure ) and fire. The standard flame cell is suitable for NEC group D or IEC IIA gases, Cells for other gas groups are available as additional extras.