What does a boilermaker primarily construct and repair?

Boilermakers primarily construct and repair boilers, pressure vessels, and related piping systems because their primary role involves working with these specific components in various industrial settings. Boilers are essential for generating steam or hot water for heating and processing in different industries, while pressure vessels contain gases or liquids at pressures significantly different from ambient pressure, making their safe construction and maintenance critical.

Additionally, the related piping systems are crucial as they connect and transfer media between the boilers and pressure vessels to different processes, ensuring proper functionality and safety. Understanding the intricate design, construction standards, and regulations surrounding these systems is essential for a boilermaker, as failures in these areas can lead to significant hazards.

While the other options may include tasks that could fall under the broader umbrella of construction and repair in other trades, they do not specifically capture the core responsibilities and expertise required of a boilermaker. This makes the selected answer accurate and representative of the primary focus of boilermaker work.