Slab gate valve construction includes spring energized floating seats, which provide positive Seating on both sides, regardless of upstream or downstream pressure conditions. The seat seals are spring energized to ensure sealing under low pressure conditions. When the line pressure increases, the seat-to-gate contact pressure increases accordingly to provide positive shutoff. Since both seats are individually energized by differential pressure across the seat itself, the valve cavity can be vented when the upstream and/or downstream side is pressurized. The valve exhibits identical performance, regardless of direction of flow, and/or orientation of differential pressure. Different solutions are available for seat-to-body gaskets, depending on Service fluid type, pressure, and temperature conditions.