Duct appears in many mep engineering workflows, but it is easy to use the word without writing down the actual assumption. Fire Safety Drawing Checklist keeps the term connected to an action, a risk, and an export path.
Use this reference when a page visitor needs a compact definition before running the tool. The best version of a reference page is not a dictionary entry. It is a small operating note that helps someone make a better decision.
Review questions: What unit or standard is implied? Who owns the final check? What would make the result unsafe to reuse? Which output should be copied into the project record?
Next action: Open the tool, run a project-specific pass, then export the result for review.