Which of the following describes the requirements for a Grade C chief engineer?

A Grade C chief engineer is specifically responsible for low-pressure boilers. This designation recognizes the need for operators to have a certain level of expertise and knowledge in managing systems that operate under specific pressure thresholds, which in this case pertains to low-pressure applications.

Understanding this distinction is crucial because low-pressure boilers usually involve different operational and safety standards compared to high-pressure systems. Required knowledge might include familiarity with the boiler's design, maintenance practices, and safety procedures that are pertinent to low-pressure operations.

While the other options suggest various standards and responsibilities, they either oversimplify or misrepresent the qualifications expected from a Grade C chief engineer. Such a role inherently requires practical experience and knowledge focused on low-pressure systems rather than high-pressure applications or national board certifications, which are not mandated specifically for this grade.