The Slide Gate is an isolation device and can be supplied in low leak and zero leak designs. The low leak design is primarily used when a small amount of flue gas leakage past the closed gate can be tolerated. Typical leakage can vary from a few percent to less than one percent of flow depending on the type of seal system provided. The zero leak design is used when zero flue gas leakage past the closed slide gate is required. Zero leakage is achieved by pressurizing the seal chamber located around periphery of the closed blade with seal air.