What type of equipment does the recommended practice primarily focus on?

The recommended practice primarily focuses on pressure-containing and structural equipment, which includes vessels, heat exchangers, piping, and valves because these components are crucial in industries that involve handling, transporting, and processing fluids under pressure. Understanding the integrity, safety, and operational standards of this equipment is essential as they are integral to ensuring the safe and efficient operation of industrial facilities. These systems must adhere to specific industry standards and practices to prevent failures that could result in safety hazards or environmental impacts.

The other choices, while relevant to industrial operations, do not align with the central theme of the recommended practice. Electrical and electronic equipment are important but involve different standards and practices distinct from those concerning pressure-containing systems. Similarly, software tools and applications for project management and heavy machinery relate to broader industrial functions but do not directly pertain to the specialized focus on fixed equipment like vessels and piping systems.