Section
7 Copper and copper alloy piping and components
7.1 Copper and copper alloy pipes, valves and fittings
7.1.1 Materials
for Class I and Class II piping systems, also for ship-side valves
and fittings and valves on the collision bulkhead, are to be manufactured
and tested in accordance with the requirements of Ch 9 Copper Alloys of the Rules for Materials, see also
Vol 2, Pt 7, Ch 1, 4.1 Metallic materials.
7.1.2 Materials
for Class III piping systems are to be manufactured and tested in
accordance with the requirements of acceptable national specifications.
The manufacturer’s test certificate will be acceptable and is
to be provided for each consignment of material. See
Ch 1, 3.1 General 3.1.3.(c) of the Rules for Materials.
7.1.3 Pipes
are to be seamless, and branches are to be provided by cast or stamped
fittings, pipe pressings or other approved fabrications.
7.1.4 Brazing
and welding materials are to be suitable for the operating temperature
and for the medium being carried. All brazing and welding are to be
carried out to the satisfaction of the Surveyors.
7.1.5 In general,
the maximum permissible service temperature of copper and copper alloy
pipes, valves and fittings is not to exceed 200°C for copper and
aluminium brass, and 300°C for copper-nickel. Cast bronze valves
and fittings complying with the requirements of Ch 9 Copper Alloys of the Rules for Materials may be accepted up to 260°C.
7.1.6 The
minimum thickness, t, of straight copper and copper alloy
pipes is to be determined by the following formula:
where p, D and a are
as defined in Vol 2, Pt 7, Ch 1, 3.2 Design symbols 3.2.1
|
c
|
= |
corrosion
allowance |
| = |
0,8 mm for copper, aluminium brass, and copper-nickel
alloys where the nickel content is less than 10 per cent |
| = |
0,5 mm for copper-nickel alloys where the
nickel content is 10 per cent or greater |
| = |
0 where the media are non-corrosive relative
to the pipe material |
Table 1.7.1 Copper and copper alloy
pipes
| Pipe material
|
Condition of supply
|
Specified minimum tensile strength,
N/mm2
|
Permissible stress, N/mm2
|
| Maximum design temperature, °C
|
| 50
|
75
|
100
|
125
|
150
|
175
|
200
|
225
|
250
|
275
|
300
|
| Copper
|
Annealed
|
220
|
41,2
|
41,2
|
40,2
|
40,2
|
34,3
|
27,5
|
18,6
|
–
|
–
|
–
|
–
|
Aluminium
brass
|
Annealed
|
320
|
78,5
|
78,5
|
78,5
|
78,5
|
78,5
|
51,0
|
24,5
|
–
|
–
|
–
|
–
|
90/10
Copper-
nickel-iron
|
Annealed
|
270
|
68,6
|
68,6
|
67,7
|
65,7
|
63,7
|
61,8
|
58,8
|
55,9
|
52,0
|
48,1
|
44,1
|
70/30
Copper-
nickel
|
Annealed
|
360
|
81,4
|
79,4
|
77,5
|
75,5
|
73,5
|
71,6
|
69,6
|
67,7
|
65,7
|
63,7
|
61,8
|
7.1.7 The
minimum thickness, t
b of a straight seamless
copper or copper alloy pipe to be used for a pipe bend is to be determined
by the formula below, except where it can be demonstrated that the
use of a thickness less than t
b would not
reduce the thickness below t at any point after bending
where p, D, R and
a are as defined in Vol 2, Pt 7, Ch 1, 3.2 Design symbols 3.2.1
σ and c are as defined in Vol 2, Pt 7, Ch 1, 7.1 Copper and copper alloy pipes, valves and fittings 7.1.6. In general, R is
to be not less than 3D.
7.1.8 Where
the minimum thickness calculated by Vol 2, Pt 7, Ch 1, 7.1 Copper and copper alloy pipes, valves and fittings 7.1.6 or Vol 2, Pt 7, Ch 1, 7.1 Copper and copper alloy pipes, valves and fittings 7.1.7 is less than
shown in Table 1.7.2 Minimum thickness for copper and
copper alloy pipes, the
minimum nominal thickness for the approriate standard pipe size shown
in the Table is to be used. No allowance is required for negative
tolerance or reduction in thickness due to bending on this nominal
thickness. For threaded pipes, where permitted, the minimum thickness
is to be measured at the bottom of the thread.
Table 1.7.2 Minimum thickness for copper and
copper alloy pipes
Standard pipe
sizes
(outside diameters)
|
|
Minimum overriding
nominal
thickness
|
|
|
Copper
|
Copper
alloy
|
| mm
|
|
mm
|
|
mm
|
mm
|
| 8
|
to
|
10
|
|
1,0
|
0,8
|
| 12
|
to
|
20
|
|
1,2
|
1,0
|
| 25
|
to
|
44,5
|
|
1,5
|
1,2
|
| 50
|
to
|
76,1
|
|
2,0
|
1,5
|
| 88,9
|
to
|
108
|
|
2,5
|
2,0
|
| 133
|
to
|
159
|
|
3,0
|
2,5
|
| 193,7
|
to
|
267
|
|
3,5
|
3,0
|
| 273
|
to
|
457,2
|
|
4,0
|
3,5
|
|
|
|
508
|
|
4,5
|
4,0
|
7.2 Heat treatment
7.2.1 Pipes
which have been hardened by cold bending are to be suitably heat treated
on completion of fabrication and prior to being tested by hydraulic
pressure. Copper pipes are to be annealed and copper alloy pipes are
to be either annealed or stress relief heat treated
|