2.8
but for pressure calculations a stress value appropriate to the particular temperature should be used, see Table 5.
Table 5 Stress values for working temperatures in excess of 65°C Temperature °C Max. admissable stress for annealed, R220, condition, N/mm2
110
150
175
200
40
34
26
18
Thermal expansion
Table 6 shows the increase in length due to thermal expansion as a function of change in temperature ∆t and the length of the tube at the lower temperature, irrespective of temper or wall thickness. (Coefficient of linear expansion 16.8 x 10-6 per °C).
Table 6 Thermal expansion (mm) of copper tube as a function of tube length and temperature difference. Tube length,
Temperature difference
∆t =40°
∆t=50°
∆t =60°
∆t °C
m
∆t = 30°
∆t =70°
∆t =80°
∆t =90°
∆t =100°
0.1
0.05
0.07
0.08
0.10
0.12
0.13
0.15
0.17
0.2
0.10
0.13
0.17
0.20
0.24
0.27
0.30
0.34
0.3
0.15
0.20
0.25
0.30
0.35
0.40
0.45
0.50
0.4
0.20
0.27
0.34
0.40
0.47
0.54
0.60
0.67
0.5
0.25
0.34
0.42
0.50
0.59
0.67
0.76
0.84
0.6
0.30
0.40
0.50
0.60
0.71
0.81
0.91
1.01
0.7
0.35
0.47
0.59
0.71
0.82
0.94
1.06
1.18
0.8
0.40
0.54
0.67
0.81
0.94
1.08
1.21
1.34
0.9
0.45
0.60
0.76
0.91
1.06
1.21
1.36
1.51
1.0
0.50
0.67
0.84
1.01
1.18
1.34
1.51
1.68
2.0
1.01
1.34
1.68
2.02
2.35
2.69
3.02
3.36
3.0
1.51
2.02
2.52
3.02
3.53
4.03
4.54
5.04
4.0
2.02
2.69
3.36
4.03
4.70
5.40
6.05
6.72
5.0
2.52
3.36
4.20
5.04
5.88
6.72
7.56
8.40
10.0
5.04
6.72
8.40
10.08
11.76
13.44
15.12
16.80
15.0
7.56
10.08
12.60
15.12
17.64
20.16
22.68
25.20
20.0
10.08
13.44
16.80
20.16
23.52
26.88
30.24
33.60
25.0
12.60
16.80
21.00
25.20
29.40
33.60
37.80
42.00
3 3.1
General requirements for the use of copper tube Copper tubes and fittings are also suitable and widely used
The various uses
Copper tubes are generally used in buildings for the
for the following services:
following services:
❍
Chilled water and refrigeration
●
❍
Fire sprinkler systems
❍
Air conditioning
pressure from a storage tank
❍
Steam
●
Sanitary waste water drainage
❍
Medical gases
●
Wet central heating systems (with radiators/
❍
Pneumatics
❍
Hydraulics
❍
Waste water
Domestic hot and cold water supplies under pressure, usually up to mains pressure (typically 60 psi or 4 bar or maybe up to 10 bar) or head
convectors) ●
Underfloor heating
●
Gas services for heating and cooking
●
Oil services for heating
These various applications impose as many stresses on the tubes as the different conditions of use. Such as: 6
