Should the drainage pipe pass through the floor slab or not? Today, we will discuss it based on the specification.
3.3.13 of the Code for Acceptance of Construction Quality of Building Water Supply and Drainage and Heating Engineering stipulates that "metal or plastic casing shall be provided for pipes passing through walls and floors". Since it is not clear whether all pipes must be enforced, this provision is controversial in the actual construction process, especially PVC drainage pipes.
What is the function of the drainage pipe through the floor slab and casing?
Under normal circumstances, there are three main functions of the floor casing:
1. When the riser pipe is damaged, it is convenient to repair and replace the pipe.
2. When the waterproof construction is defective, there is a casing to remedy.
3. Solve the problems of expansion, expansion, stretching, deformation and displacement of pipelines.
Is there a casing for the drainage pipe to pass through the floor slab?
4.1.13 of the Technical Regulations for Building Drainage Hard PVC Pipeline Engineering stipulates that the construction of the pipeline crossing the floor shall comply with:
1. When the pipeline passes through the floor slab as a fixed support point, the installation of the pipeline should be completed with civil engineering for formwork, and C20 fine stone concrete should be used for secondary pouring and compacting. After the pouring is completed, combined with the construction of the leveling layer or the surface layer, a water-blocking ring with a thickness of not less than 20mm and a width of not less than 30mm should be built around the pipeline.
2. When the pipeline passes through the floor slab for non-fixed support, a metal or plastic casing should be installed, and the inner diameter of the casing can be 10~20mm larger than the outer diameter of the crossing pipe, and the casing shall not be less than 50mm above the ground.
Therefore, there are two ways to set up and not to set up the casing when the PVC drainage pipe passes through the floor slab. The standard atlas "Sanitary Equipment Installation Engineering" (05S1) (PVC-U pipe through the floor slab, roof panel) is also divided into two methods: setting up and not setting casing:
Atlas practices
Let's take a look at the role of the casing, mainly the function of anti-leakage and anti-telescopic deformation, and now the construction code stipulates that an expansion joint is installed every 4m (usually one per layer), so that the problem of telescopic deformation does not exist, and the remaining only need to be able to solve the leakage problem, and decide whether to set up the casing or not.
Two anti-leakage methods for drains to pass through floor slabs
For the setting or not setting up the casing, according to the technical regulations and atlas practices and combined with the actual summary, there are two anti-leakage methods respectively (the pipeline can only be carried out after the installation is completed and the ball and water tests are passed).
The ultimate goal is to prevent the common leakage of the illustrated leakage
➤ The first method (no casing through the floor)
In the construction stage of the structure, the holes are reserved by means of wooden shells, etc., and the pipelines are plugged after they are installed in place. Clean the hole before plugging, and properly treat the pipe itself: (1) the outer wall of the pipe is haired or glued and rolled on the sand, and (2) the finished plastic water-stop ring (this ring is matched with the pipe diameter and just clamps the outer wall of the pipe) is directly installed on the outer wall of the pipe.
Use 1:2.5 waterproof cement mortar to fill in layers, and use the second pouring of fine stone concrete in the reserved hole through the floor slab or in the hole drilled in the floor slab [if the PVC pipe is provided with a water-stopping ring, it should be slid onto the fine stone concrete surface after the first pouring of 2/3H (floor thickness) fine stone concrete, and then the second pouring of 1/3 fine stone concrete, and the ring is buried in the floor slab]. When plugging the hole, it is required to use a steel bar to vibrate and compact the concrete. Then make a cement mortar water-blocking ring around the pipe, and apply waterproof ointment at the gap is more reliable, as shown in the figure below.
➤ The second method (through the floor to set a rigid waterproof casing)
After the installation of steel casing pipe on the floor pipe, it should be 20mm higher than the finished surface, and the plugging method is basically the same as the plugging method without casing above, but finally it is necessary to plug to the nozzle level and make a waterstop ring ring); Finally, a water-repellent ointment is more reliable. As shown in the figure below.
After the above two methods are filled, the water maintenance test must be done, and the second water maintenance test (after the waterproofing is done) must be done in the bathroom to meet the functional requirements.
[Attached] finished water-stop section casing and reserved hole plugging template
At present, as a new construction technology, the finished water-stop section casing and plugging template have been widely used, and you can try to adopt them.
➤ Finished water-stop section casing
(1) The function of the plastic waterproof casing wing ring (water stop) increases the contact compactness with the floor slab, and reduces the probability of water leakage and water seepage.
(2) The pre-embedded positioning size of the plastic waterproof casing should be accurate, otherwise it will affect the installation of the drainage pipe.
(3) When embedding, it must be fixed firmly and the four corners of the casing must be nailed firmly with nails to prevent the displacement of the casing from affecting the accuracy of the size when pouring concrete.
(4) After the casing is buried, the part that exposes the concrete floor needs to be protected by fine concrete or cement mortar to avoid damage.
➤ Reserve the hole plugging template
The reserved hole plugging template is made of ethylene particles and recycled plastic as raw materials, which is specially used to quickly plug the gap after the installation of water and sewage pipes in the reserved hole of the pipeline of the new building, and solve the difficult problem of the construction of the reserved hole.
Directions of use:
(1) Stick the formwork flat upward, close to the floor slab, and fasten both ends with screws.
(2) Pour mortar concrete into the reserved hole from the upper floor, and compact and smooth it. After the concrete is solidified, remove the wire circlip, remove the hanging form, and reuse it.
Features:
(1) The construction speed is fast and saves labor.
(2) Good sealing performance, cement slurry will not leak, so that the surface of the pipeline is clean and tidy. The product is close to the slab surface, so that the surface of the reserved hole after plugging is as smooth as the surface of the floor slab.
(3) The plastic template is not deformed, not easy to age, and can be reused.
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