The saying ‘out of sight, out of mind’ often holds true for a building’s ducting and insulation systems. However, as heating, ventilating, and air-conditioning (HVAC) experts will agree, this is an unwise approach for building owners and users alike.
Poor duct connections and lack of insulation can result in high energy consumption, eventually leading to high electricity bills. Additionally, faulty duct lining can also hinder the flow of air moving through the building. Over a prolonged period of time, the wear and tear to duct lining may cause blockages.
Construction Week’s sister title, MEP Middle East, recently organised a roundtable in Dubai to examine these issues. The session’s participants included Sunil Nair, technical lead for project controls at BK Gulf; Abdul Hameed, sales manager at Faisal Jassim Group; Anil Mishra, manager – technical specifications for Kuwait Insulating Material Manufacturing Company (KIMMCO) in the Middle East and Africa (MEA); and Paul Groves, business development manager at Khansaheb Industries.
KIMMCO’s Mishra began the discussion by outlining the basics, explaining the significance of ducts and insulation: “Ducts basically provide the means to transport air from the point of origin – which is typically a fan coil unit (FCU) or an air-handling unit (AHU) – to the point of discharge, which is usually indoors. Insulation, of course, plays an extremely important role in energy savings. Metals are good conductors of heat and electricity, so they increase the air stream’s temperature. This means the air-conditioners have to work harder, which increases energy consumption.”
Khansaheb’s Groves, citing a study by consultancy Aecom, revealed that up to 50% of a building’s total life cycle cost is consumed by mechanical, electrical, and plumbing (MEP) systems, of which around 60% was taken up by HVAC elements.
Commenting on how the choice of ductwork could reduce energy costs, he added that his company had seen reductions of around 58% through the installation of its systems on selected regional projects. Two recent projects in the Gulf had reported savings of 28% and 38%, he added.
According to Mishra, awareness about energy consumption was high in Kuwait, where KIMMCO had recently completed energy audits for the government. He said that insulation systems contributed to the improvement of not only a building’s HVAC systems, but its entire envelope: “Through some of our audits, we found that around 30% of energy loss occurs through ventilation systems that are not insulated.”
Mishra explained that heat losses also occurred through windows (24%), basement floors (3%), and roofs (6-7%), so insulating the entire envelope could prove beneficial for a building: “When we insulate the entire envelope with proper materials and R-values [thermal resistance], heat losses can be reduced by about 70%.
“It relates to 46% of annual cooling loss. And normally, the payback time after insulating a building is around two years, in terms of running costs.” He added: “A well-insulated building means a saving of approximately 1,000 megawatts (MW) per year, which translates to [the generation capacity of] one power plant.”
Proper insulation for savings
BK Gulf’s Nair said material was a key consideration when selecting insulation systems: “Every material has insulation properties. The thickness of the insulation does not matter – as contractors, what we look at is the cost of the product, so as to get the same output on the same type of insulation thickness.
“It comes down to cost, the longevity of the insulation, the certifications involved, smoke values, and so on.”
Faisal Jassim Group’s Hameed added: “Apart from the design and the type of product, the main thing is the installation. Most of the time, issues arise because of bad workmanship. As a principle, we should have some kind of training for the people who are at the site, so that they know how proper installation can be done. That will solve at least 70% of the common issues.
“Also, suppliers should conduct regular site visits. In fact, it should be one of the clauses that consultants include in their contracts, but unfortunately that does not happen yet. Suppliers also do not take the initiative to visit the site and [carry out inspections].”
BK Gulf’s Nair added: “Some consultants look at all of the elements involved in the project, but some others do not.”