Si30-408
REFNET Piping
Introduction
19
5.2
For
Refrigerant Piping
Guideline for Tightening Flare Nut
(When No Torque Wrench is Available.)
Notes:
1. When pipe jointing with flare nut, use both open-ended spanner and a torque wrench.
2. If no torque wrench is available, refer to the following item 3 as a guide.
3. In the work of tightening flare nut, there should be a spot where the tightening torque
suddenly increases. Thereafter, tighten further with tightening angle shown in above list.
Bending Radius in Pipe and Flare Tightening Torque
Processing Dimension for Flare Section
Calculation List on Equivalent Length of Joint
(For Reference)
Unit: m
Piping size
Tightening angle (guideline)
Recommended arm length of tool
φ
6.4
60º ~ 90º
Approximately 150mm
φ
9.5
60º ~ 90º
Approximately 200mm
φ
12.7
30º ~ 60º
Approximately 250mm
φ
15.9
30º ~ 60º
Approximately 300mm
φ
19.1
20º ~ 35º
Approximately 450mm
Piping size
Bending radius
Tightening torque (N·cm)
φ
6.4
30 to 40 mm
1420 ~ 1720
φ
9.5
30 to 40 mm
3270 ~ 3990
φ
12.7
40 to 60 mm
4950 ~ 6030
φ
15.9
40 to 60 mm
6180 ~ 7540
φ
19.1
—
9720 ~ 11860
Piping size
Dimension-A
Flared shape
R22, R407C
For R410A
φ
6.4
8.6 ~ 9.0
8.7 ~ 9.1
φ
9.5
12.6 ~ 13.0
12.8 ~ 13.2
φ
12.7
15.8 ~ 16.2
16.2 ~ 16.6
φ
15.9
19.0 ~ 19.4
19.3 ~ 19.7
φ
19.1
23.3 ~ 23.7
(24)
Pipe diameter
Type
φ
6.4
φ
9.5
φ
12.7
φ
15.9
φ
19.1
φ
25.4
φ
31.8
L joint
0.16
0.18
0.20
0.25
0.35
0.45
0.55
Trap bend
1.4
1.3
1.5
2.0
2.4
3.4
4.0
REFNET joint
0.5
REFNET header
1.0