Construction Plan for Air Conditioner Copper Pipe空调铜管施工方案一、Generals 工程概况This project comprises roof air conditioning unit, indoor built-up type air conditioning box, and connection of copper pipeline in two equipment rooms. The site construction of copper pipe is the main quality point of construction.本工程包括屋顶空调机组，室内组合式空调箱及两设备间的铜管管线的连接。
其中现场铜管施工为本程的施工质量重点。
二、Copper pipe selection 铜管的选择Category of tubing is distinguished by maximum operating pressure (design pressure), according to drawing designed and construction specification, refrigerating fluid shall use R407Cor equivalent other refrigerant. R407C design pressure is generally about 3.45MPa, R410A design pressure is generally about 4.15MPa.配管的类别根据最高使用压力(设计压力)来区分的，根据图纸设计及施工说明，制冷剂采用R407C或相近的其它环保冷媒。
使用R407C设计压力一般为3.45MPa左右，R410A的设计压力一般为4.15MPa左右。
5 Computation formula of wall thickness 壁厚的计算公式The computation formula of the compulsory copper pipe (TP2M) thickness is as follows.铜管(TP2M)必须厚度的计算公式、如下。
ｔ= [(Ｐ×OD)／(2σa + 0.8P)] +α(㎜)ｔ：compulsory wall thickness 必须的壁厚(㎜)P：max. operating pressure (design pressure) 最高使用的压力(设计压力) (MPa)OD：standard outer diameter 标准外径(㎜)σa：min. allowable stress at temperature 125℃在125℃的基本许可应力(N／㎜2)＊σa = 33 (N／㎜2)α：Corrosion thickness (mm) ＊but, for copper pipe, it shall be 0(mm).腐蚀厚度(㎜) ＊但是，对铜管的话为0(㎜)。
Example of design selection （TP2M）:the following takes O-type (TP2M) copper pipe design as example设计选择示例（TP2M）:以下以O型（TP2M）铜管设计为例①Wall thickness selection of R407C refrigerating system exhaust pipe set, it is assumedthat the outer diameter of exhaust pipe set is φ19.05, the wall thickness selection methodshall be as follows:R407C制冷系统排气管组壁厚选择，假设排气管组外径φ19.05，其壁厚选择方法如下：Maximum pressure of R407C refrigerating system at exhaust air side takes 3.45MPa, calculation is as follows:R407C制冷系统排气侧最高压力取3.45MPa，计算如下：Wall thickness 壁厚ｔ= [(P×OD)／(2σa + 0.8P)] +α(㎜)=（3.45×19.05）/（2×33+0.8×3.45）+0=0.9558mmTaking round number 取整，t=1.0mm。
Note: φ19.05 copper pipe wall thickness deviation class V specified in GB/T1804 may be ±0.08mm, in this way, if supplier uses copper pipe with wall thickness deviation of -0.08mm to produce pipe set in order to economize cost, its wall thickness shall select 0.29mm. we can get to know from the calculation result, when design pressure of the pipe set is 3.45MPa, pipe cracking may happen. At this time, we must add copper pipe wall thickness to ensure the pipe set not cracked, or to explicitly stipulate in the technical requirement the pipe set wall thickness within suitable deviation, i.e. deviation range at （-0.4，+0.08）mm, to avoid the pipe set from cracking.注：国标GB/T1804规定φ19.05的铜管壁厚V级偏差可以是±0.08mm，这样如果供货厂家为节省成本，采用壁厚偏差-0.08mm来生产管组，则其壁厚就会选取为0.92mm了，这样由计算结果可知，该管组在设计压力为3.45MPa时，就会有裂管的隐患了。
这时必须通过适当增加铜管壁厚来保证该管组不会爆裂，或者在技术要求中明确规定管组壁厚在适当的偏差内，即偏差范围在（-0.4，+0.08）mm内，以免除管组爆裂隐患。
②R410AWall thickness selection of refrigerating system exhaust pipe set, it is assumed that the outerdiameter of exhaust pipe is φ19.05, the wall thickness selection method is as follows: 制冷系统排气管组壁厚选择，假设排气管组外径φ19.05，其壁厚选择方法如下：R410A refrigerating system max. pressure at high pressure side is designed as 4.15MPa, its wall thickness calculation is as follows:R410A制冷系统高压侧最高压力设计为4.15MPa，则其壁厚计算为：Wall thickness 壁厚ｔ= [(Ｐ×OD)／(2σa + 0.8P)] +α(㎜)=（4.15×19.05）/（2×33+0.8×4.15）+0=1.14mmTake round number t=1.2mm, such wall thickness can also meet design requirement according to GB/T1804. If the pipe set does not need folding, select O-type pipe with wall thickness of 1.2mm, the cost is increased by 20% to be compare with H/2 pipe with wall thickness of 1.0mm. Such design is uneconomical. Whereas, according to table 2, we may get to know that when we use H/2 (TP2Y) copper pipe, the wall thickness is 1.0mm, its resistance to pressure can reach 6.684MPa, fully conforming to the design pressure required. Therefore, under such a circumstance, we should select H/2 (TP2Y) copper pipe with wall thickness of 1.0mm.进行取整t=1.2mm,此壁厚按照国标GB/T1804规定V级偏差也能满足设计要求。
如果该管组不需要折弯，选择壁厚为1.2mm的O形管，相比选择壁厚为1.0mm的H/2型管，成本增加了20%，这样设计是不合算的。
而根据附表2可以知道采用H/2（TP2Y）铜管，壁厚为1.0mm时，其耐压可达到6.684MPa，完成符合设计压力的要求，因此这种情况下应该选择壁厚为1.0mm 的H/2（TP2Y）铜管。
It also can be calculated as per formula, when H/2 (TP2Y) copper pipe bears 4.15Mpa pressure, the wall thickness required is t=0.584mm. Therefore, selecting H/2 (TP2Y) copper pipe with wall thickness of 1.0mm can fully meet the 4.15Mpa design pressure required, just it is a pity that the H/2 (TP2Y) copper pipe cannot be folded, however, we can use matched bend to solve it.也可以根据公式计算，H/2（TP2Y）铜管承受4.15Mpa的压力时，需要的壁厚是t=0.584mm。