HVAC Ducting Safety Information:
HVAC ducting and system cleaning must be performed when any of the following conditions are found in a cleanliness inspection or service repair procedure.
- Significant accumulations of contaminants, debris, or when evidence of mold and microbial growth is visually observed within the HVAC system.
- The HVAC system discharges visible airborne particles into an occupied area.
- Detection of airflow restrictions relating to the heat exchange and cooling coils, or airflow control and filtration devices which can cause significant HVAC system performance issues.
The National Air Duct Cleaners Association provides the following guidelines for HVAC ductwork to be cleaned, inspected, and have scheduled maintenance:
| Building Classification |
Air Handling Unit |
Supply Ductwork |
Return Ductwork and Exhaust |
Industrial |
1 year |
1 year |
1 year |
Commercial |
1 year |
2 years |
2 years |
Healthcare |
1 year |
1 year |
1 year |
Useful links:
Underwriters Laboratories Inc. |
www.ul.com |
The National Air Duct Cleaners Association |
www.nadca.com |
Sheet Metal and Air Conditioning National Contractors’ National Association |
www.smacna.com |
North American Insulation Manufactures Association |
www.naima.org |
American Society of Heating, Refrigerating and Air-Conditioning Engineers |
www.ashrae.org |
National Fire Protection Association |
www.nfpa.org |
