Reg. 297, Reg. 298, Reg.
Opening in Shell
|No accessories other
than those integral with the Safety Valve shall obstruct
the openings in the boiler shell. Discharging steam shall
have direct access to the safety valve without flowing
through internal pipes.
|The safety valve discharge
pipes shall comply with the requirements of clauses (a)
and (b) of this regulation. The discharge pipe shall be
as short and straight as possible and be fitted with open
drain to prevent accumulation water in the pipe. Suitable
arrangement shall be provided in the discharge pipe system
so that the discharge can readily be heard by the Boiler
||Steam safety valves:
||Ordinary and high lift
valves. Where a waste steam-pipe is fitted
the pipe and the passage leading to it shall
have a cross-sectional area not less than
the minimum combined area of the safety valves
required by Regulation
||Full lift valves. For
full lift valves the area of waste steam-pipe
and passages leading to it shall have a cross-sectional
area not less than twice A, or such area above
this minimum as may be required for valves
having a higher approved constant, where A,E
and P are as defined in regulation
||Economiser safety valves.
The area of the discharge pipe from an economiser
safety valve shall be at least twice the area of
the valve seating. Where the discharge from several
economiser safety valves is connected to the main
discharge pipe, the diameter of the main discharge
pipe shall be designed to prevent accumulation of
pressure due to the formation of steam under the
particular conditions of temperature and pressure
which may be applicable.
|For each enclosed
safety valve chest a means of draining shall be provided.
The drain pipe shall be laid with a continuous downward
gradient clear of the boiler to a place where the discharge
is visible and cannot do injury to any person.