In addition to the HVAC system, what other system is shown in mechanical drawings?

The correct answer is plumbing, and it is included in mechanical drawings for a few key reasons. Mechanical drawings are comprehensive representations that not only focus on HVAC systems but also integrate other essential systems that interact with or depend on these systems. Plumbing, in particular, is one of the fundamental systems that must be coordinated with HVAC design because both systems often share space and infrastructure within a building.

In practice, plumbing contributions in mechanical drawings include water supply lines, waste systems, drainage, and possibly fixtures that are connected to both plumbing and HVAC systems. Understanding the plumbing layout in relation to HVAC is crucial for issues such as drainage from HVAC condensate, coordination of piping, and ensuring compliance with building codes.

This coordination helps prevent conflicts during the installation process and ensures that all systems operate effectively together. While other systems like electrical, civil, and structural may be represented in separate drawings or disciplines, plumbing is directly integrated with mechanical systems in these contexts, making it the relevant choice here.