Anyone attempting to clean a building’s air ducts will need to have access to the hvac system, including the ductwork.

The existing system may already allow access in the form of vents, grilles, and ductwork end caps. Sometimes air handlers and furnaces include factory-installed doors or removable panels.

Occasionally they need more — possibly in the form of new openings that won’t damage the structural integrity of the system.

Both the Sheet Metal and Air Conditioning Contractors’ National Association (SMACNA) and North American Insulation Manufacturers Association (NAIMA) have set official construction standards for access ports. They must have:

•  Openings that can be sealed airtight;

•  Closures that do not significantly hinder, restrict, or alter the system’s airflow;

•  Properly insulated closures to prevent heat loss, gain, or condensation on inside surfaces;

•  Openings on fibrous glass that do not leave exposed fibrous glass edges within the system;

•  Openings that do not compromise the structural integrity of the hvac system; and

•  Construction standards conforming to SMACNA and NAIMA standards.

More advice

Cutting access openings into flex duct is not recommended. Instead, disconnect the duct at one end for cleaning and inspection.

Cleaners may install openings that are permanent and removable or, under certain circumstances, sealed openings.

Usually, removable doors are used in locations such as coil compartments, fire dampers, smoke detectors, and other frequently serviced components. Check local and state codes for specific requirements.

Check with SMACNA (703-803-2980) for procedures to use to build permanent enclosures.