When this guide is useful
A mechanical system serves spaces with different uses and ownership arrangements.
The distinction that matters
Document locations served and the system's actual purpose. A specialty use does not by itself make the entire mechanical system shorter-life property.
A worked situation to investigate
A mixed-use building has a common system plus dedicated cooling for an equipment room.
The example is illustrative. Begin with the underlying event and its source documents, then separate missing facts from disagreements about their treatment. Work through the checks below in the order that matches your file, rather than treating a completed checklist as a tax conclusion.
Build a traceable handoff
Identify the affected person, entity or property and the relevant period. Keep original evidence, corrections and the reviewer's written conclusion connected. If the facts change after review, preserve the earlier version and ask whether the change affects implementation.