Circuit Diagram

As-built drawings -  are important for at least two main purposes. First of all, they are the record from which the future   system changes and / or additions can be designed. Future renovations will be more effective and less disruptive if built   documents can be depended on for critical information systems, such as pipe and duct routing and dimensioning of a   terminal unit locations, control sensor locations, etc. Second, because the built drawings can be a valuable O & M staff.   For example, we know that the exact description of the shut-off valve locations are critical to emergency   preparedness.At construction of all the red-lined changes to be transferred to the electronic CAD drawings, typically   using the designers of the original model drawing files starting point. These CAD drawings are then considered to be the   ultimate non-builts, and provide the owner as part of a project to close the process.