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Waterproof casing installation Note: When the surface is corrosive media, can be used to block the closure of the gap casing casing wall in case of non-concrete walls, the local use of concrete walls, the pouring range should be more than the diameter of the ring (D5) large 200, and must be poured once in the wall of the casing. Penetration of the concrete wall thickness should be not less than 300, otherwise the wall should be thicker or thicker on both sides. The diameter of the thickened part is at least D5 + 200. The weight of the casing is calculated at L = 300, and if the wall thickness is greater than 300, it should be calculated separately.