4.4.1 Every steam boiler and every unfired steam
generator should be provided with not less than two safety valves
of adequate capacity. However, the Administration may, having regard
to the output or any other features of any boiler or unfired steam
generator, permit only one safety valve to be fitted if it is satisfied
that adequate protection against overpressure is provided.
4.4.2 Every oil-fired boiler which is intended
to operate without manual supervision should have safety arrangements
which shut off the fuel supply and give an alarm at an attended location
in the case of low water level, air supply failure or flame failure.
4.4.3 Every steam generating system which could
be rendered dangerous by the failure of its feedwater supply should
be provided with not less than two separate feedwater systems from
and including the feed pumps, noting that a single penetration of
the steam drum is acceptable. For those services not essential for
the safety of the unit, only one feedwater system is required if automatic
shutdown of the steam generating system upon loss of the feedwater
supply is provided. Means should be provided which will prevent overpressure
in any part of the feedwater system.
4.4.4 Boilers should be provided with means to
supervise and control the quality of the feedwater. As far as practicable,
means should be provided to preclude the entry of oil or other contaminants
which may adversely affect the boiler.
4.4.5 Every boiler essential for the safety of
the unit and which is designed to have a water level should be provided
with at least two means for indicating its water level, at least one
of which should be a direct-reading gauge glass.