Paragraph 4
Every steam generating system which provided services essential
for the safety of the ship, or which could be rendered dangerous by
the failure of its feedwater supply shall 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.
If the design of the pump does not preclude the possibility of pressure
rising above the rated value, a relief valve or other relieving arrangement
shall be fitted on the pump casing or on the pipe before the first
stop valve.