What is the pressure of the identical superheated steam supply in each Main Machinery Room (MMR)?

• A. 100 psi
• B. 125 psi
• C. 150 psi
• D. 175 psi

Answer: (C)

Uniform steam pressure across every Main Machinery Room keeps all turbines and steam-driven equipment receiving the same inlet conditions. When the supply is identically pressure-regulated, the steam arriving in each room has the same temperature and energy content, which reduces risk of uneven expansion, vibration, or control problems in the propulsion system.

Choosing 150 psi as the supply pressure provides enough energy and superheat for efficient turbine operation while staying within the equipment’s design limits. Pressures lower than this could limit the available energy and risk under-supply to the turbines, while higher pressures would demand heavier piping and hardware and could push components toward their stress limits.