Common installation of PVC drain pipe

With the rapid development of our country's hard PVC pipe, pipe fittings production technology and construction technology and supporting fire prevention measures, especially "Code for Design of Building Drainage PVC Pipe" (CJ J29-1989) and "Building Drainage PVC Pipeline Construction and Acceptance Regulations "(CJ J30-1989) since the implementation of PVC pipe has been widely used in building drainage projects. However, mistakes often occur in the actual installation process, leading to seepage of the floor, water leakage at the joints of the pipe fittings, poor water launching and dirty indoor air, which have seriously affected the normal use of households.

1 common installation errors and countermeasures

1.1 three links or four links

Due to the negligence of construction workers, the three-way or four-way pipes will be installed at the connection between the riser pipe and the horizontal pipe branch, resulting in the formation of water tongues at the junction, poor water flow in the horizontal pipe branch, large pressure fluctuation in the drainage system and water seal of the sanitary appliance being easily destroyed , The toxic and harmful gases in the drainage pipe will invade the room. The correct approach should be installed in this oblique oblique links or oblique links.

1.2 trap

1.2.1 under the drain trap

Some engineers think buckle bowl drain with water seal can deodorant, it does not need to be installed under the drain drain, the result is often due to the leakage of water can not reach the required depth [1] and was destroyed; the other in Household improper use of clogged debris will buckle bowl open, will make the smell of sewer escape into the room, affecting the indoor air quality. According to many years of practical experience and relevant data, the correct approach is to install a P-type trap under the floor drain [2]. Recently, the new type of floor drain-static seal with horizontal drain leakage performance is also superior [3].

1.2.2 Washbasins and sink under the trap

In the case of unknown design drawings, construction and installation personnel often mistakenly think that the water trap under the washbasin and the sink is installed on the floor and under the floor, which is not the case. Washbasins and sinks under the trap due to hair, debris and other debris, very easy to plug, if necessary, need to open the trap on the check Qingtong. If the trap is installed below the floor, Qingtong must go downstairs to the residents at home, the average family kitchen, bathroom will be ceiling, it is very inconvenient. The correct approach is to install S-shaped trap above the floor (but not at the same time two water traps), so that households in their own homes at any time can be easily cleared.

1.3 elbow under the toilet

Under the toilet with 90 ° elbow and transverse pipe connection is not proper, the hydraulic conditions are not good 45 ° elbow, if installed with 90 ° elbow, it is best to use with a check port. The correct method of installation is to use a 45 ° elbow to connect with the cross pipe.

1.4 telescopic section

In the drainage riser installation, it is often found missing or less installed expansion joints, which is not in conformity with the requirements of the specification. Due to the larger linear expansion of hard PVC pipe, the larger the amount of expansion and contraction caused by temperature changes.

The correct installation method is as follows: When the storey is less than 4 m, the riser shall be provided with an expansion joint at each floor; when the storey is greater than 4 m, the expansion shall be determined based on the design expansion and contraction, which shall not exceed the maximum allowable expansion joint Flexibility [4].

1.5 outlet pipe and riser connection

In some architectural drainage, the use of a 90 ° elbow for the outlet cross-over pipe and riser pipe has a high rate of blockage and a reasonable installation method is to use two 45 ° bends.

1.6 vertical pipe and horizontal pipe installation

As the construction of PVC drainage pipes have greater flexibility, easy to bend, the installation of riser pipe often fails to meet the requirements of the verticality, affecting the appearance; and the lateral bending is too large, or even downhill, Resulting in poor water flow, joint seepage, affecting the normal use. The correct method of installation is the need to suspend the riser; horizontal pipe need to hang, support, slope correction, in strict accordance with the rules and regulations of the installation [4].

1.7 PVC pipe through the floor to seal the hole

Pipeline through the floor, some construction workers for convenience and convenience, not for civil support, only paper scraps, debris and other debris to simply block the hole filled with cement mortar, combined with rigid PVC pipe surface is relatively smooth, and Concrete bonding is not very solid, it is very easy to cause serious floor seepage phenomenon, affecting the normal use of households. The correct approach is: the use of civil support, placement of not less than the floor markings of fine stone concrete plugging holes, if necessary, add waterproofing agent.

2 project examples

A unit for raising funds for the three six-storey unit multi-storey residential, a total of 108 households. The total construction area of 10368m2, the total cost of 5.621 million yuan, of which part of the indoor water supply and drainage 99,000 yuan. Each household has a wash basin, wash basin two, a toilet, a bathtub, floor drain three. Started in March 1999, delivered in December. During the indoor PVC drainage pipe installation engineering rework several times, the direct economic loss of up to ten thousand yuan.

2.1 three links or four links

The original design was 90 ° inclined three-way or four-way (along the water three links). Due to the negligence of the construction and installation personnel, the drawings were not carefully disregarded, and all the three links or the four links were mistakenly installed on the riser, resulting in all rework. In order to minimize losses, the original 90 ° inclined three-way or four-way (straight three-way) to 45 ° oblique three-way or four-way, after the original pipe without a waste after the adjustment, the effect is better.

2.2 trap

2.2.1 drain leakage under the trap

In fact, the floor drain installed in the project is a floor drain with buckle bowl. The water seal is 30 mm. There is no trap installed under the floor drain. In fact, this is not in conformity with the requirements of the code. The specification requires that the water seal should be> 50 mm. Therefore, according to the requirements of the specification and the actual situation, a P-type trap has been added under the floor drain to ensure the indoor air quality.

2.2.2 Washbasins and sink under the trap

As the floor plan of the construction drawing is not well marked, the installer made his own proposal to install the water trap under the washbasin and sink below the floor, which did not meet the specifications [5] and did not meet the requirements and caused all Rework. In order to make full use of the original pipe section which has been pierced through the wall and fixed on the floor slab to reduce the loss, the pipe section after removing the water trap is connected with several 45 ° elbows to adjust the direction for proper connection, The impact is not too great.

2.3 kitchen, bathroom floor, the flooding test

According to the general requirements, kitchen, bathroom floor should do pan-water test, check the water seepage. However, according to Party A's requirements, the project kitchen, bathroom ground only 24 h immersion test. The inspection revealed that 40% of the pipe seepage through the floor of the pipe was caused by the failure to strictly follow the normative operation when sealing the hole. Treatment is the use of "King of plugging" fine brush seepage on the ground, the first pass after a fine brush through the water seepage is still 10%, and then by the second time after the basic fine brush no water seepage, the better.

3 Conclusion

Building drainage PVC pipe construction and installation of convenience, but the operation should be carefully bonded, it must be in strict accordance with the "Construction and drainage PVC pipe construction and acceptance rules" (CJ J30-1989), to avoid leakage joints, seepage on the ground, Cross pipe downhill, improper use of pipe fittings and installation errors occur. Otherwise, once the rework, remedial difficulties, not only affect the appearance, but also cause huge economic losses.