1. Pipeline bending shall conform to the following rules:
1. Cold bending should be adopted for elbows, and the minimum bending radius of elbows should not be less than 3 times of the outside diameter of pipelines; when stamping elbows are used, the bending radius should not be less than 1 times of the outside diameter of pipelines.
2. The difference between the maximum diameter and the minimum diameter after bending should not exceed 8% of the pipe diameter.
3. The bending part of the pipeline should not have wrinkles, peeling and other defects.
4. Pipeline thread processing should conform to the rules of design technical documents. After thread processing, there should be no cracks, depressions, burrs and other defects on the surface. For threads with micro-mechanical damage or imperfect cross-section, the total length should not be greater than 1/3 turns, and the reduction of thread height should not be greater than 1/5 of its height.
2. The laying of compressed air carbon steel pipes shall conform to the following rules:
1. Pipeline alignment should meet the requirements of design technical documents. The degree of pipeline flatness is allowed to deviate to 2/1000 and not more than 30mm. The vertical degree of riser is allowed to deviate to 3/1000 and not more than 20 mm. According to the coordinate position and elevation dimension of the design technical document, the coordinate position is allowed to deviate to 15 mm and the elevation allowed to deviate to (+15 mm).
2. The distance between the outer wall of the pipeline and the edges of adjacent pipelines and fittings should not be less than 10 mm. The flanges or loose joints on the same row of pipelines should be staggered not less than 10 mm. The pipe through the wall should be bushed. The distance between the joint position and the front should be more than 800 mm.
3. The slope of compacted air carbon steel pipe should conform to the rules of technical documents. If the timing is neglected, the slope will be 12.5/1000~25/1000.
4. The connecting pipe and pipeline of flange should be concentric, the connecting bolt should penetrate freely, the interface of two flanges should be parallel, and the allowable deviation of parallelism should not be greater than 1.5/1000 of flange diameter.
5. Pipe brackets and pipe clamp devices shall conform to the following rules:
(1) The bracket device is positioned correctly, fixed firmly, the pipe is in close contact with the pipe clamp, and there should be no pipe weld at the pipe bracket and pipe clamp.
(2) The spacing of pipe brackets should be in accordance with the rules at the straight pipe part, and brackets should be added at the bending part near the left of the starting point.
(3) There should be no direct contact between stents.
6. Hose fittings shall conform to the following rules:
The minimum bending radius is not less than 7 times of the outer diameter of a tube with an outer diameter greater than 30 mm.
Hose shall not be distorted.
7. Pipeline paint thickness and number of times shall meet the design technical requirements. The coating should be uniform, with different coloring and no defects such as leakage, flow and bubbles. It is necessary to stop beating and purging in accordance with the process for purging compact air carbon steel pipes. After cleaning, the inner wall of the pipeline shall conform to the rules of the design technical documents, and there shall be no rust, iron oxide scale and other foreign bodies in case of irregularities.