Final answer:
Valves and fittings on feedwater piping, including check valves, must supply feedwater at b) 125% of the Maximum Allowable Working Pressure (MAWP), ensuring safe and reliable operation within pressure systems.
Step-by-step explanation:
The question refers to the necessary feedwater supply pressure in terms of Maximum Allowable Working Pressure (MAWP) for valves and fittings on feedwater piping, including check valves. In engineering, especially when dealing with boilers and pressure systems, ensuring that the feedwater supply pressure is adequate is critical for safety and efficiency.
Based on common practices and safety standards in the field of pressure system engineering, valves and fittings are generally required to meet or exceed a specific percentage of the MAWP to ensure they can handle the operating pressures without failure. For feedwater systems, this includes not just the continuous operating pressure but also the capability to handle surges or transients.
Therefore, the correct option is that valves and fittings on feedwater piping must supply feedwater at 125% of the Maximum Allowable Working Pressure to ensure safe and reliable operation.