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

⑴ 切口表面應(yīng)平整、無裂紋、重皮、毛刺、凹凸、縮口、熔渣、氧化物、 鐵屑等；

(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 切口端面傾斜偏差不應(yīng)大于管子外徑的１％，且不得超過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規(guī)定進(jìn)行。

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

第二、管道預(yù)制時應(yīng)按單線圖規(guī)定的數(shù)量、規(guī)格、材質(zhì)等選配管道組成件，并按單線圖標(biāo)明管道的系統(tǒng)號和按預(yù)制順序標(biāo)明各組成件的順序號。

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、管道預(yù)制時，自由管段和封閉管段的選擇應(yīng)合理，封閉段必須按現(xiàn)場實測尺寸加工，預(yù)制完畢應(yīng)檢查內(nèi)部潔凈度，封閉管口，并按順序合理堆放。

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、聚氨酯保溫鋼管對接焊縫位置應(yīng)符合下列規(guī)定：

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

⑴管道位置距離彎管的彎曲起點(diǎn)不得小于管子外徑或不小于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管子兩個對接焊縫間的距離不大于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與管子對接焊縫重合，焊縫距離支吊架邊緣不得小于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管子接口應(yīng)避開疏放水、放空及儀表管的開孔位置，距開孔邊緣不應(yīng)小于50mm，且不應(yīng)小于孔徑。

(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.