What codes govern boiler requirements in Maryland?

The Maryland Boiler and Pressure Vessel Code is the correct answer because it specifically outlines the regulations and requirements for the design, construction, inspection, and maintenance of boilers and pressure vessels within the state of Maryland. This code is tailored to ensure safety and compliance in relation to these particular types of equipment, taking into account local conditions and practices.

The other options do have relevance in broader contexts: the Maryland Building Code provides general construction standards, the National Fire Protection Association Code focuses on fire safety, and the Occupational Safety and Health Administration Regulations cover workplace safety in general. However, none of these specifically address the unique requirements and provisions associated with boilers and pressure vessels as comprehensively as the Maryland Boiler and Pressure Vessel Code does. Thus, for matters directly concerning boiler requirements in Maryland, the state-specific boiler code is the definitive source.