Patch Plate Sizing for Duct Modifications
When duct modified in field, patch plates cover cutouts. Wrong size or attachment creates leaks.
What You Might Be Looking At
piece of sheet metal covering hole or cutout in duct section
Apprentice words: cover plate, patch piece, metal patch, duct cover
Trade terms: patch plate, cover plate, closure plate, field modification plate
Check First
What Not To Do
Don't use patch smaller than opening. Don't rely on tape or mastic alone. Don't skip screws at corners and edges.
What can go wrong: Air leakage, pressure test failure, patch plate blowout, inspector rejection
Better Foreman Question
Minimum overlap required for this patch plate? What screw spacing?
Verify With
Reference type: SMACNA, project specs
Source to verify: SMACNA HVAC Duct Construction Standards
Safe wording: Patch plate requirements vary by pressure class and opening size. Verify SMACNA and project specs.