（1） Instructions for four-way casing:

1. All dimensions in this drawing are measured in millimeters.

2. Flexible waterproof conduit is generally suitable for structures where pipelines pass through walls and are subject to vibration or have tight waterproof requirements.

3. After the waterproof casing is processed, apply a layer of primer (including camphor or cold primer oil) on its outer wall. The anti-corrosion of the outer layer is determined by the design.

4. When encountering non concrete walls, the wall where the casing passes through should be replaced with a concrete wall. The range of concrete pouring should be 200mm larger than the diameter of the wing ring (D6), and the casing must be firmly poured into the wall.

5. The thickness of the concrete wall at the pipe penetration point should not be less than 300mm, otherwise the wall should be thickened on one side or both sides. The diameter of the thickened part should be 200mm larger than the diameter of the wing ring (D6).

6. The material weight of the casing is calculated based on the wall thickness L value of 300mm. If the wall thickness is greater than 300mm, it should be calculated separately.

7. The welding material for the casing components is made of A3 material and welded with T42.

（2） The casing four-way is manufactured according to the S312 and 02S404 standard drawings developed and designed by the Institute of Building Science. Flexible waterproof conduit is generally suitable for structures where pipelines pass through walls and are subject to vibration or have tight waterproof requirements; Rigid waterproof conduit is generally suitable for structures where pipes pass through walls and require general waterproofing; The walls where flexible and rigid waterproof sleeves penetrate should be replaced with concrete walls if they are not made of concrete, and the sleeves must be solidified inside the wall at once; Waterproof conduit is used in construction, chemical, steel, tap water, sewage treatment and other units.