The periodic cleaning of HVAC systems is necessary to ensure delivery of acceptable air to the indoor environment. Cleaning may be required on older systems that have not been properly maintained, damaged systems, or in cases such as following indoor or outdoor construction activities.
Determining the Need for Cleaning
HVAC systems should be cleaned when a visual inspection indicates excessive particulate debris or microbiological growth on any interior surfaces. A fiber optic system or video inspection system is recommended to determine the condition of the system both before and after any cleaning. Obvious problems that require cleaning and restoration would include visible microbiological contamination, significant amounts of particulate debris coming out of supply ducts, or deteriorated fiberglass insulation that was contaminating the supply air. In all cases, the source or cause of particulate contamination or microbiological proliferation must be determined and corrected prior to system cleaning.
In general, most HVAC systems should be inspected annually or biannually for cleanliness.
HVAC System Cleaning
For cleaning purposes, the HVAC system includes any interior surface of the air distribution system. This includes all components from where the air enters the system to all points of discharge in the facility. Methods to clean HVAC systems involve both mechanical techniques and chemical sanitizers or biocides. The preferred method of cleaning depends on the system component, type of debris or contamination, and access to the area.
Mechanical Cleaning Techniques
Mechanical techniques are useful to clean certain HVAC components including duct work, fan components, diffusers, dampers, and internal surfaces of the air handling unit. When using mechanical cleaning methods, strict controls such as physical barriers, devices equipped with HEPA filtered exhaust, and system negative pressure must be used to contain and collect debris. Mechanical cleaning methods incorporate techniques to agitate and dislodge material as well as contain and remove it. Agitation devices may include power brushes, pressurized air and water systems, as well as hand tools such as brushes. Collection of dislodged particulate debris is achieved by vacuums. A vacuum collection device with an appropriate capture velocity should be connected to a service opening and operated continuously to collect material as it is dislodged. In certain areas of the HVAC system, direct contact vacuuming with a brush may be used to remove material from contaminated surfaces.
Chemical Sanitizers and Biocides
The use of chemical sanitizers or biocides may be necessary to clean certain HVAC system components such as heating or cooling coils. We use antimicrobial products which are EPA approved for use in HVAC systems.
Determining HVAC System Cleanliness
HVAC system cleanliness should be evaluated by visual inspection. An HVAC interior surface is considered visibly clean when it is free of non-adhered debris. We use powerful HEPA Negative Air Machines and powerful gas motor vacuums in order to generate enough vacuum power. Our on board air compressors are connected to powerful agitation tools in order to break loose the debris inside the vents.