Common quality problems and prevention of the hott

Common quality problems and prevention of indoor gas pipeline engineering

1 hidden safety hazards of roof gas pipes

Shenzhen generally adopts the upper ring and lower supply mode to transport liquefied petroleum gas to users, so a large number of gas pipelines on the roof are installed along the parapet wall. The design generally sets the elevation of the gas pipe to be no less than 30cm from the roof. In addition, a downcomer valve box is installed on the parapet wall, and the upper part of the valve box is sometimes only 50cm from the roof, The height of the parapet is not less than 110cm according to the national specification, which creates a problem. Because there are gas pipes and valve boxes as steps, the height of the parapet here is relatively reduced, which can not meet the requirements of the specification, resulting in potential safety hazards

how to solve this problem? Generally, the height of parapet is increased, but this will not only affect the viewing of people increasing their independent innovation on the roof, but also affect the effect of building facade, so it is not feasible, and the effect is not good. Plastic packaging has been widely used. The author believes that to solve this problem, the following scheme should be adopted in the design or at least before the construction: that is to raise the elevation of the gas pipe. The field measurement shows that the distance between the gas pipe and the roof can be set as no less than 80cm, the tee is downward connected to the downcomer valve, and the upper part of the valve box is 5cm away from the gas main pipe. In this way, the gas facilities will not become steps, but the hardness is not enough, which not only meets the requirements of the building code, but also avoids the damage of the gas pipe caused by pedal

2 waterproof problem between gas pipeline and wall

in order to enter the user, it is very common for gas pipeline to open a wall hole in the outer wall, and in some cases, several holes must be opened. Therefore, the waterproof problem of wall hole appears, especially the plugging problem between casing and wall. Who should do it? How to do it? At present, it is not clear. Disputes often arise between the construction and gas construction units, and the plugging quality is not good

in order to avoid reopening when the external wall has been constructed, especially when the waterproof construction has been completed, the best way is to improve the quality of design drawings and civil construction. The reserved position of the wall hole is reasonable and accurate, the casing embedding meets the specification requirements, and the gas construction unit directly uses the reserved wall hole after entering the site. In this case, the plugging quality between the casing and the wall is good, The gas construction unit only needs to plug the gap between the gas pipe and the casing. The research and production of the company's new material formula are completed in the German production base, and each unit is clear

but at present, due to various reasons, the effect of reserved wall holes is not very good. It is often necessary to plug the reserved wall holes again, so how to solve this problem? The author believes that the construction unit must complete the construction of all wall holes before the waterproof construction of the outer wall. After the wall holes are opened, the casing should be buried and the gap between the casing and the wall should be blocked. At this time, because the external construction bent has not been removed, it is convenient for construction and relevant units to check its sealing quality. Similarly, after the household branch pipe is welded, the gap between the branch pipe and the casing should also be blocked immediately. At this time, the professional company should do the waterproof of the outer wall, The effect is better

so what kind of material is used to block it? Although article 5.2.10 of the code for indoor construction and acceptance of urban gas requires that "flexible waterproof materials should be used to fill between the casing and the pipeline, and cement mortar should be used to fill between the casing and the wall (or floor)", the author believes that in order to strengthen waterproof, it is better to use flexible waterproof materials to fill between the casing and the wall of the outer wall

in addition, it should be noted that according to the requirements of the specification, the wall hole should have a slope of no less than 0.02 outward and downward. If the wall hole is reserved, it can be done, but at present, due to the simplicity of construction machines and tools, it is difficult to open the wall hole in practice, but at least the wall hole can not be reversed. In addition, it is best to block the outer wall first and then the inner wall. During the inspection of a construction site, the author found that water flowed out of the casing when opening the sealing glue of the inner wall, but the sealing of the outer wall was good. After investigation and analysis, it is believed that the construction unit blocked the inner wall first, then the rainwater entered the casing, and the construction unit blocked the outer wall, causing water in the casing