Which code has not been adopted by all provinces regarding boilers and pressure vessels?

The correct choice regarding the code that has not been adopted by all provinces concerning boilers and pressure vessels is NFPA (National Fire Protection Association). The primary focus of the NFPA is on fire safety and protection standards, which may overlap with some boiler and pressure vessel safety aspects, but it is not specifically dedicated to them. Each province and territory in Canada tends to adopt specific boiler and pressure vessel codes that align more directly with ASME (American Society of Mechanical Engineers) standards, ANSI (American National Standards Institute) standards, and relevant provincial regulations.

Whereas ASME codes are widely recognized and adopted for their comprehensive guidelines on design, materials, and safety for pressure vessels and boilers, and ANSI provides essential national standards that often complement ASME guidelines, not every jurisdiction has mandated NFPA guidelines. Thus, while NFPA generates valuable resources for fire protection, its standards are not universally adopted for boiler and pressure vessel regulations across all provinces.