COPPER
TUBES
Working
Pressure
The maximum
working pressures at temperatures up to 65OC, as specified in B.S.
2871: Part 1, are calculated in accordance with the following formula
and are stated in Tables X,Y and Z (q.v.)
P=20Ft /
D-t
Where
P= pressure
(1bar:0.1N/mm2),
F= stress (N/mm2),
T=thickness (mm),
D= outside diameter (mm)
| For Hard
condition |
F=72.5N/mm2 |
| For ½
Hard condition |
F= 60 N/mm2 |
| For 'O"
condition |
F= 46 N/mm2 |
If
tubes in the H or ½ H condition are annealed, e.g. for bending
or during brazing or hard soldering, the stress value quoted above
for condition "O" should be used for calculating working
pressures.
Copper tubes
are suitable in some circumstances for use up to a maximum temperature
of 200OC, but for pressure calculations a stress value appropriate
to the particular temperature should be used as follows:
| Temperature
(OC) |
<110O |
150O |
175O |
200O |
| Maximum
admissible stress for annealed “O” condition (N/mm2) |
40 |
34 |
26 |
18 |
Maximum working
pressures of copper tube to BS 2871:Part 1(Half-hard and Hard) are
given in the following tables.
Dimensions, weights & working pressure.
| Specification
: BS2871 Table X, Half Hard
Application
: Domestic Plumbing & Gas |
| SIZE
OF TUBE (mm) |
WALL
THICKNESS (mm) |
WEIGHT
(Kgs per mtr) |
MAX.
WORKING PRESSURE (bar) |
| 15 |
0.7 |
0.280 |
58 |
| 22 |
0.9 |
0.532 |
51 |
| 28 |
0.9 |
0.683 |
40 |
| 35 |
1.2 |
1.136 |
42 |
| 42 |
1.2 |
1.371 |
35 |
| 54 |
1.2 |
1.774 |
27 |
| 67 |
1.2 |
2.201 |
20 |
| 76 |
1.5 |
3.125 |
24 |
| Specification
: BS2871 Table Y, Annealed
Application: For underground with excellent ding qualities. |
| SIZE
OF TUBE (mm) |
WALL
THICKNESS (mm) |
WEIGHT
(Kgs per mtr) |
MAX.
WORKING PRESSURE (bar) |
| 15 |
1.0 |
0.392 |
50 |
| 22 |
1.2 |
0.695 |
41 |
| 28 |
1.2 |
0.900 |
32 |
| 35 |
1.5 |
1.407 |
30 |
| 42 |
1.5 |
1.701 |
28 |
| 54 |
2.0 |
2.912 |
25 |
| 67 |
2.0 |
3.640 |
20 |
| 76 |
2.0 |
4.150 |
19 |
| Specification
: BS2871 Table Z, Hard Drawn
Application
: Domestic Plumbing. |
| SIZE
OF TUBE (mm) |
WALL
THICKNESS (mm) |
WEIGHT
(Kgs per mar) |
MAX.
WORKING PRESSURE (bar) |
| 15 |
0.5 |
0.203 |
50 |
| 22 |
0.6 |
0.360 |
41 |
| 28 |
0.6 |
0.460 |
32 |
| 35 |
0.7 |
0.710 |
30 |
| 42 |
0.8 |
0.917 |
28 |
| 54 |
0.9 |
1.332 |
25 |
| 67 |
1.0 |
1.845 |
20 |
| 76 |
1.2 |
2.510 |
19 |
Thermal expansion
The following
table 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 OC)
| Tube
length (m) |
Thermal
expansion (mm) of copper tube as a function of
tube length and temperature difference |
| D
t =30O |
Dt=40O |
Dt=50O |
Dt=60O |
Dt=70O |
Dt=80O |
Dt=90O |
Dt=100O |
| 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 |
0,50 |
0,67 |
0,84 |
1,01 |
1,18 |
1,34 |
1,51 |
1,68 |
| 2 |
1,01 |
1,34 |
1,68 |
2,02 |
2,35 |
2,69 |
3,02 |
3,36 |
| 3 |
1,51 |
2,02 |
2,52 |
3,02 |
3,53 |
4,03 |
4,54 |
5,04 |
| 4 |
2,02 |
2,69 |
3,36 |
4,03 |
4,70 |
5,40 |
6,05 |
6,72 |
| 5 |
2,52 |
3,36 |
4,20 |
5,04 |
5,88 |
6,72 |
7,56 |
8,40 |
| 6 |
3,02 |
4,03 |
5,04 |
6,05 |
7,06 |
8,06 |
9,07 |
10,08 |
| 7 |
3,53 |
4,70 |
5,88 |
7,06 |
8,23 |
9,41 |
10,58 |
11,76 |
| 8 |
4,03 |
5,38 |
6,72 |
8,06 |
9,41 |
10,75 |
12,10 |
13,44 |
| 9 |
4,54 |
6,05 |
7,56 |
9,07 |
10,58 |
12,10 |
13,61 |
15,12 |
| 10 |
5,04 |
6,72 |
8,40 |
10,08 |
11,76 |
13,44 |
15,12 |
16,80 |
| 11 |
5,54 |
7,39 |
9,24 |
11,09 |
12,94 |
14,78 |
16,63 |
18,48 |
| 12 |
6,05 |
8,06 |
10,08 |
12,10 |
14,11 |
16,13 |
18,14 |
20,16 |
| 13 |
6,55 |
8,74 |
10,92 |
13,10 |
15,29 |
17,47 |
19,66 |
21,84 |
| 14 |
7,06 |
9,41 |
11,76 |
14,11 |
16,46 |
18,82 |
21,17 |
23,52 |
| 15 |
7,56 |
10,08 |
12,60 |
15,12 |
17,64 |
20,16 |
22,68 |
25,20 |
| 16 |
8,06 |
10,75 |
13,44 |
16,13 |
18,82 |
21,50 |
24,19 |
26,88 |
| 17 |
8,57 |
11,42 |
14,28 |
17,14 |
19,99 |
22,85 |
25,70 |
28,56 |
| 18 |
9,07 |
12,10 |
15,12 |
18,14 |
21,17 |
24,19 |
27,22 |
30,24 |
| 19 |
9,58 |
12,77 |
15,96 |
19,15 |
22,34 |
25,54 |
28,73 |
31,92 |
| 20 |
10,08 |
13,44 |
16,80 |
20,16 |
23,52 |
26,88 |
30,24 |
33,60 |
| 21 |
10,58 |
14,11 |
17,64 |
21,17 |
24,70 |
28,22 |
31,75 |
35,28 |
| 22 |
11,09 |
14,78 |
18,48 |
22,18 |
25,87 |
29,57 |
33,26 |
39,96 |
| 23 |
11,59 |
15,46 |
19,32 |
23,18 |
27,05 |
30,91 |
34,78 |
38,64 |
| 24 |
12,10 |
16,13 |
20,16 |
24,19 |
28,22 |
32,26 |
36,29 |
40,32 |
| 25 |
12,60 |
16,80 |
21 |
25,20 |
29,40 |
33,60 |
37,80 |
42 |
|
