Reg. 282 b, Reg. 282 c
(b) Limits of cast Iron
| Cast Iron shall not be used
||Temperatures above 220°C;
||Pressure exceeding 13
||Valves exceeding 200
mm nominal bore which are connected directly to
||Wedge or double disc
gate valves which are connected directly to the
||Boiler blow down fittings.
Explanation: The expression connected directly to
the boiler covers any valve which cannot itself
be isolated from the boiler.
Spherodial iron may be used for temperature not exceeding
282 °C and pressure not exceeding 17.58 kg/cm2 provided
it complies with the following requirements in respect
of the physical properties.
(a) 0.2% proof stress 250 kg/mm2
(b) minimum elongation percent-12.
Reg. 282 c
Limits of copper alloy
| Copper alloy shall not be used
for temperatures above 225°C where the valves are
connected directly to the boiler. In the case of valves
not connected directly to the boiler this temperature
limitation may be increased to 260°C.