10.1.1 Stainless
steels may be used for a wide range of services and are particularly
suitable for use at elevated temperatures. For guidance on the use
of stainless steels in outboard water systems see
Pt 5, Ch 10, 11.3 Steel pipes 11.3.4.
10.1.3 Where
stainless steel is used in lubricating and hydraulic oil systems,
the corrosion allowance may be reduced to 0 mm. For pipes passing
through tanks, an additional corrosion allowance is to be added to
take account of external corrosion; the addition will depend on the
external medium and the value is to be in accordance with Table 12.2.3 Values of c for steel pipes . Where the pipes are
efficiently protected, the corrosion allowance may be reduced by not
more than 50 per cent.
10.1.4 In no
case is the thickness of the stainless steel pipes is to be less than
that shown in Table 10.10.1 Minimum thickness for austenitic
stainless steel pipes.
Table 10.10.1 Minimum thickness for austenitic
stainless steel pipes
| Standard pipe sizes (outside diameter) in mm
|
Minimum thickness, in mm
|
| 10,2
|
to
|
17,2
|
1,0
|
| 21,3
|
to
|
48,3
|
1,6
|
| 60,3
|
to
|
88,9
|
2,0
|
| 114,3
|
to
|
168,3
|
2,3
|
| 219,1
|
|
|
2,6
|
| 273
|
|
|
2,9
|
| 323,9
|
to
|
406,4
|
3,6
|
| Over
|
406,4
|
|
4,0
|
Note The external diameters and thicknesses have been selected
from ISO Standard 1127:1980. Diameter and thicknesses according to
other National or International Standards may be accepted.
|
10.1.6 Where
pipe work is butt welded, this should preferably be accomplished without
the use of backing rings, in order to eliminate the possibility of
crevice corrosion between the backing ring and the pipe.