First, the quality of pipe cut shall meet the following requirements:

⑴ 切口表面应平整、无裂纹、重皮、毛刺、凹凸、缩口、熔渣、氧化物、 铁屑等；

(1) the surface of the incision shall be smooth and free from cracks, double skin, burr, concave convex, shrinkage, slag, oxide, iron filings, etc;

⑵ 切口端面倾斜偏差不应大于管子外径的１％，且不得超过３mm；

(2) the inclination deviation of the end face of the incision shall not be greater than 1% of the outer diameter of the pipe and shall not exceed 3 mm;

⑶ 有坡口加工要求的，坡口加工形式按焊接方案规定进行。

(3) for groove processing requirements, the groove processing form shall be carried out according to the provisions of the welding scheme.

第二、管道预制时应按单线图规定的数量、规格、材质等选配管道组成件，并按单线图标明管道的系统号和按预制顺序标明各组成件的顺序号。

Second, the pipeline components should be selected according to the quantity, specification and material specified in the single line diagram, and the system number of the pipeline should be indicated according to the single line diagram and the sequence number of each component according to the prefabrication sequence.

第三、管道预制时，自由管段和封闭管段的选择应合理，封闭段必须按现场实测尺寸加工，预制完毕应检查内部洁净度，封闭管口，并按顺序合理堆放。

Third, the selection of free pipe section and closed pipe section should be reasonable. The closed section must be processed according to the measured size on site. After prefabrication, the internal cleanliness should be checked, the pipe orifice should be closed and stacked reasonably in order.

第四、聚氨酯保温钢管对接焊缝位置应符合下列规定：

Fourth, the butt weld position of polyurethane insulation steel pipe should meet the following requirements:

⑴管道位置距离弯管的弯曲起点不得小于管子外径或不小于100mm；

(1) the distance between the pipe position and the bending starting point of the elbow shall not be less than the outer diameter of the pipe or not less than 100 mm;

⑵管子两个对接焊缝间的距离不大于5mm.

(2) the distance between two butt welds of the pipe shall not be greater than 5mm

⑶支吊架管部位置不得与管子对接焊缝重合，焊缝距离支吊架边缘不得小于50mm；

(3) the position of the pipe part of the support and hanger shall not coincide with the butt weld of the pipe, and the distance between the weld and the edge of the support and hanger shall not be less than 50 mm;

⑷管子接口应避开疏放水、放空及仪表管的开孔位置，距开孔边缘不应小于50mm，且不应小于孔径。

(4) the pipe interface shall avoid the opening position of water drainage, vent and instrument pipe, and the distance from the opening edge shall not be less than 50 mm, and shall not be less than the hole diameter.