|
The maximum working pressure on such pipes shall be
deter-mined by the following formula:-
| WP = |
200 x S
x t |
Eqn.(93) |
| D - t
|
where,
WP = working pressure in kg/mm²
t = minimum thickness of tubes, that is nominal thickness
less the permissible negative tolerance in mm.
D = outside diameter of pipe in mm.
S = maximum permissible design stress at the appropriate
maximum design temperature in kg/mm²
(See the Table below)
Maximum Design Stress Value of S for Copper pipes (in
kg. per sq. mm)
| Maximum design stress
for temperature not exceeding |
| 66°C |
121°C |
149°C |
177°C |
207°C |
| 4.9 |
4.31 |
3.5 |
2.66 |
1.75 |
Note: Where the conditions of services are such
that corrosion, erosion or mechanical damage to the
surface of tubes may occur, an appropriate thickness
allowance shall be added to the minimum thickness of
the tube.
|
