Cover Story: Air Duct & Vent Cleaning

In the event that moisture infiltrates the HVAC system, there is an increased chance of mould, which releases spores into the air. These types of contamination would potentially result in the building occupants suffering from allergies or illness synonymous with sick buildings and compromised indoor air quality.

The United States Environmental Protection Agency reports that indoor concentrations of some pollutants have increased in recent decades due to factors such as energy-efficient building construction (when it lacks sufficient mechanical ventilation to ensure adequate air exchange) and increased use of synthetic building materials, furnishings, personal care products, pesticides, and household cleaners. Living in a region such as the Middle East, where it is inherently dusty owing to sand particles and dust storms, it becomes a necessity to maintain HVAC systems more frequently than in other regions.

The installation process

Maintenance and cleaning of the HVACR system and ducts/vents also improves the airflow which significantly reduces the energy consumption and associated costs. Air duct cleaning refers to the cleaning of various heating and cooling system components of forced air systems, including the supply and return air ducts and registers, grilles and diffusers, heat exchangers, heating and cooling coils, condensate drain pans (drip pans), fan motor and fan housing, and the air handling unit (housing). If not properly installed, maintained and operated, these components may become contaminated with particles of dust, pollen or other debris. These ducts are available in different types of materials such as galvanized, mild steel, aluminum, stainless steel, preinsulated in various coatings. Hence, the cleaning treatment completely depends on the kind of material. “The material selection completely depends on the consultant handling the project, but opting for zinc coated properties reduces the chances of corrosion,” says Hassan El-Doukhi, Head of Procurement, Firmac Industries, provider of a wide range of products in the MEP/Cooling market. “Once there is rusting then there are chances of bacteria, fungus, viruses growing inside the ducts and this calls for necessary cleaning,” he adds.

Importance of maintaining the ducts

The ducts and air vents should be maintained on a regular basis particularly in cases where there is clogging due to dust and debris or if there is visible growth of mould on the ducts or other par ts of the system. Sometimes small rodents and insects can also enter the duct. “The appointment of suitably qualified HVACR inspection and maintenance personnel is one of the most critical factor in the maintenance of the HVAC system. A facility management personnel should be inspecting ducts for these types of contaminants so that maintenance and cleaning take place as required,” asserts Nerissa Deoraj, Director Technical and Regulatory Affairs, Eurovent Middle East. Based in the UAE, Eurovent Middle East Association represents the region’s leading manufacturers of indoor climate (HVAC), process cooling, food cold chain, industrial ventilation, and building automation technologies, as well as sector associations and industry initiatives active in these fields.

According to El-Doukhi, the life span of an AC duct for a commercial facility is 15 years and above. As these ducts are installed and sealed under the ceiling there is very low probability of it getting damaged. Therefore, the only concern is maintaining the ducts to avoid bacteria and similar fungus.

How to identify mould in the air ducts?

The AC duct system is a natural breeding ground and a favourable habitat to numerous types of bacteria and fungus. This is especially true in climates that ar e humid and hot for the better par t of the year and where air condition systems are put into use 365 days a year. A comprehensive cleaning management of the ducts is a necessity and not a luxury. The presence of moderate to severe mould infestation is usually accompanied by a musty or mildew odour, with irritation of the nose, throat or eyes or allergies (hayfever like symptoms such as runny nose, headaches and rashes) experienced by the occupants. Visual inspection can help to identify the presence of mould, noticeable through the growth of black or white spor es around the vents and inside the ducts. “In a scenario where it is not possible to identify the mould visually, a suitably qualified professional should be contracted to test the duct,” informs Deoraj.

Ensuring that the entire HVAC system including the ducts, drip pans, grilles, vents and filters, are cleaned and maintained effectively significantly reduces the possibility of contamination and the spread of airborne substances. This leads to improved indoor quality and prevention of indoor air quality related health problems for the building occupants.

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