General Information about Clean Air Ducts

A building's heating, ventilation, and air conditioning (HVAC) system provides conditioned air to occupied spaces within the facility. Typically, air from within an occupied space, along with fresh air drawn from outdoors, in drawn in through air ducts to an HVAC unit, where it is conditioned. Before the air gets to the unit, it usually passes through a filter designed to protect the mechanical equipment from becoming contaminated by large particles of dust and debris. Many air duct filters commonly used today will not prevent the introduction of small particles of dust and debris from the air stream into the system. Over time, these deposits may form sizable accumulations.

In the course of normal building operations, the humidity level within the healthy ac system can vary greatly. High humidity can combine with dust and debris in the system, often resulting in the growth of microbial contamination. In an HVAC system, microbial contamination (such as mold, fungus and their spores) may cause adverse health reactions among building occupants. Condense drain pans and other ac ducts often become heavily contaminated with fungal and bacterial slime.

In order to maintain acceptable indoor air quality (IAQ) it is commonly recommended that mold, fungi, dust and other contaminants are cleaned out of the air ducts. Cleaning HVAC systems provides many benefits. Cleaning air ducts lessens the likelihood of indoor air pollution in the building, and may help to alleviate health and comfort complaints by occupants. Clean HVAC systems perform more efficiently, which may decrease energy costs. Well maintained mechanical components are likely to last longer, reducing the need for costly HVAC system replacement or repairs and provide clean air.

With growing awareness of the dangers of indoor air pollution, public concern for the cleanliness of ventilation systems has led to significant increase in demand for HVAC system cleaning services. Solving complex IAQ problems, however, often requires a team of multi-disciplined professionals, such as mechanical contractors, filtration experts, test and balance specialists, industrial hygienists, and, of course, professional HVAC system cleaning contractors.

In most cases, HVAC system cleaning alone will not solve IAQ problems. It can, however, greatly reduce the threat of indoor air pollution when performed in conjunction with a program of regular building maintenance and IAQ evaluation. The U.S. Environmental Protection Agency (EPA) has published a comprehensive guide for building owners and managers which is designed to help reduce the risk of indoor air pollution. The publication, "Building Air Quality," (provide link) provides guidelines which all owners and managers should use and implement in their facilities.

There are several ways to clean an air ducts. Recommended cleaning methods employ "Source Removal," the mechanical cleaning of system components to remove dirt and debris from within air ducts. Source removal methods employ vacuum units, compressed air, mechanical and hand brushes, and other tools to loosen dirt and debris and convey it to a containment device for proper disposal.

Source removal requires two key elements to be effective. The first element is a means of agitating the dust and debris within the air ducts. The second element is the extraction of contaminants from the HVAC system. Removal methods must be capable of removing the foreign material to the levels specified within industry standards and provide a healthy ac unit.