High-risk starter answer - stop before covering, blocking, fastening, modifying, insulating, or closing anything around a fire/smoke damper, ceiling radiation damper, access door, or rated assembly. Verify the damper type, approved submittal/detail, manufacturer instructions, access requirement, and foreman/AHJ direction before continuing.
Ask when access is missing/blocked, damper type is unclear, rated construction is involved, or manufacturer/AHJ detail is not known.
Watch out
Do not treat damper or rated-assembly work like normal duct.
Check
Confirm the damper type and exact location.
Find the access side, label, actuator, fusible link, sleeve, blade area, or inspection point.
Check that permanent access remains reachable after walls, ceiling, insulation, hangers, and other trades are installed.
Steps
Identify damper type and label.
Find access side, actuator/handle, and blade path.
Check whether duct, insulation, ceiling, or another trade blocks access.
Focus on the actual issue: duct insulation covers required access.
Photograph or mark the condition if someone else needs to approve it.
Say this to your foreman
In Fire/Smoke Dampers, Access Doors & Rated Assemblies, I'm looking at: Duct insulation covers required access. What should I verify before I cut, drill, seal, cover, move, or install?