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Table 6-2-1 Thicknesses of annealed copper pipes
(2) Joints
For copper pipes, flare joints or socket joints are used. Prior to use, be sure to remove all contaminants.
(a) Flare Joints
Flare joints used to connect the copper pipes cannot be used for piping whose outer diameter exceeds
20 mm. In such a case, socket joints can be used.
Sizes of flare pipe ends, flare joint ends and flare nuts are as shown in Table 6-2-3 to Table 6-2-5 below.
(b) Socket Joints
Socket joints are such that they are brazed for connections, and used mainly for thick piping whose diameter
is larger than 20 mm. Thicknesses of socket joints are as shown in Table 6-2-2.
Table 6-2-2 Minimum thicknesses of socket joints
6-2-2. Processing of Piping Materials
When performing the refrigerant piping installation, care should be taken to ensure that water or dust does not enter
the pipe interior, that no other oil other than lubricating oils used in the installed air conditioner is used, and that
refrigerant does not leak.
When using lubricating oils in the piping processing, use such lubricating oils whose water content has been
removed. When stored, be sure to seal the container with an airtight cap or any other cover.
(1) Flare Processing Procedures and Precautions
(a) Cutting the Pipe
By means of a pipe cutter, slowly cut the pipe so that it is not deformed.
(b) Removing Burrs and Chips
If the flared section has chips or burrs, refrigerant leakage may occur.
Carefully remove all burrs and clean the cut surface before installation.
Nominal diameter
Outer diameter (mm)
Thickness (mm)
R410A or R32
R22
1/4
6.4
0.80
0.80
3/8
9.5
0.80
0.80
1/2
12.7
0.80
0.80
5/8
15.9
1.00
1.00
Nominal diameter
Reference outer diameter of copper pipe
jointed (mm)
Minimum joint thickness (mm)
1/4
6.4
0.50
3/8
9.5
0.60
1/2
12.7
0.70
5/8
15.9
0.80
