They provide access to internal components of duct systems (such as HVAC or commercial kitchen exhaust systems), including dampers and filters, for maintenance, cleaning, and inspection.
These access doors are typically made of galvanized steel or stainless steel, and come in various sizes and types to meet different pressure requirements (low-pressure or high-pressure).
Featuring raised edges and rotating cam latches, the doors ensure a tight, leak-proof seal.
Regulations often require installation at specific locations—such as at intervals along the duct or at points where the direction changes—particularly in commercial kitchens, to facilitate fire safety inspections.