Duct and insulation maintenance negligence may cause UAE building pitfalls
Notable experts from the Middle East’s HVAC industry gather in the UAE to discuss the importance of ducting and insulation, and the perils of overlooking their installation and maintenance
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.”
The panel also debated which of the two scenarios was more dangerous: water leakages in pipes, or in ducts. Nair said that the temperature of the medium must be considered before deciding.
“You are comparing 4-5°C of water being carried in pipes compared to 23-24°C of air,” he said, adding that comparisons would be unfair.
Mishra argued that generally, duct leakages could lead to energy losses, while pipe leakages could be disastrous, particularly to false ceilings and other structural elements.
Nair countered, however, stating that duct leakages were the bigger risk, because they “are never seen”. BK Gulf’s expert said leakages were among his team’s biggest challenge at the commissioning stage of a project, adding: “On every job, we spend manpower and money to find ways to reduce leakages through commissioning, and during construction this is not visible.
“At BK Gulf, we are putting a regime in place where we actually leak-test all the ducts going into the concealed areas and shafts. A building can never be leak-proof, but we try to limit the cases,” he added.
Khansaheb’s Groves stated: “We are carrying out a project now with a big multinational company, where the insulation work for one of its buildings was not done properly. So we are carrying out a complete analysis with a consultant to make proper recommendations. I think proper ductwork and insulation can lead to meaningful savings.”
Regulations and responsibilities
Groves said he believed that many consultants overlooked issues related to ducting and insulation, while Nair said that stakeholder roles and involvement also played a role in the process.
Nair continued: “I think the biggest problem is that none of the people who are involved in the construction phase are really responsible for the building’s power performance after construction.
“The consultant designs, and he or she is typically given some figures on how to optimise the design. After handover, the bill is borne by the tenant, so owners are not really involved either. There is no onus on any of the designers to come back and say how their design action might affect costs. It is all on paper, as figures and percentages.
“Unless you put the onus on the people who are selling or designing to actually show that savings are achieved, little can be changed,” BK Gulf’s Nair explained.
Enforcement and compliance
Commenting on whether guidelines and regulations related to HVAC were being enforced across the market, KIMMCO’s Mishra said: “In terms of leakages and related items, Sheet Metal and Air Conditioning Contractors’ National Association (SMACNA) and American Society of Heating, Refrigerating, and Air-Conditioning Engineers (ASHRAE) have worldwide standards.
“These standards specify the type of sealing that you must use for each type of duct to reduce the amount of leakages, and the type of connections, such as herringbone or C-clips, as well as whether transverse joints must be connected and sealed, and so on.
“These standards are based on static pressure, and leakage is a function of static pressure. The more pressure you have in AHUs, and the longer the duct is, the greater the chances of leakage. That has to be mitigated by implementing SMACNA’s and ASHRAE’s standards.
“The onus lies on HVAC designers to specify the kind of pressures that we have in the system. Be it insulation, or sealants, there are relevant standards for each – they just need to be enforced. From a contractor’s point of view, there has to be a balance between design and cost. If the contractor is implementing what is specified, and if the consultant is checking that everything is implemented as per the standard, I do not see any reason why there should be a problem.”
Groves said that “there is a big difference between knowing how to, and actually doing it”. Nair agreed, adding that although regulations and standards existed to monitor installation, there was no regulation that required consultants or the owners to actually prove that the specifications were being followed.
“There should be a drive for everybody to save energy, some incentive to make it happen, and finally, clearly defined responsibility to ensure it,” Nair added.
Groves pointed to Dubai’s new green building rating system, Al Sa’fat, and its mandate to implement regular building audits. Mishra commended the system, adding that the promotion of energy audits would lead to increased awareness about consumption and savings.
He added, however, that designers, fabricators, installers, and contractors must be involved in the process to ensure that the desired results were achieved. Meanwhile, Faisal Jassim’s Hameed said that all parties – including consultants, contractors, and operators – should be accountable. Nair disagreed, however: “If the consultant is being paid for the design, then they must take the project all the way forward, and be responsible for it all along,” he stated.
“A consultant is responsible for design, construction, testing and commissioning, and handover. Other parties may carry out the jobs, but the consultant is responsible for inspections. For instance, everything we submit to Dubai Municipality is through the consultant – it is not a contractor’s submission. The consultant is responsible for ensuring compliance.”
Khansaheb’s Groves said an excellent duct cleaning practice was the use of wire hanging systems where appropriate, in addition to cleaning that required limited access doors, the use of modular units that provided better installation quality and speed, and the implementation of proper testing and acoustic design.
Meanwhile, negative ductwork industry trends that should be changed included the use of long, flexible ductwork; lack of testing; poor acoustic design; lack of appropriate vapour barriers; part-insulation of ductwork; and delayed repair of – or failure to repair – damages to galvanised iron ductwork systems.
Commenting on design improvements that could be implemented in the Gulf, Hameed said: “The design practices typically carried out in the GCC are the standardised model. Design teams are not catering to a project by selecting the design that the customer is looking for. They work based on experience, but that should not always be the case. Obviously the duct design has to be a prime factor; design and installation teams should use lengthy ducts, ducts that have sharp corners, and so on.
“The second priority is installation. Ductwork professionals must select materials of the proper thickness to avoid the unwanted use of energy. Insulation must be done to avoid heat gains from the ambient environment, to avoid condensation,” Hameed said.
Groves added that the overuse of flexible ductwork was one of the malpractices he had often observed in the region: “Flexible ductwork has quite an impact on air flow efficiency, and I have seen some systems designed that are too long, and that change direction several times.
“Flexible ductwork changing directions, is wrong, I think,” he said.
Mishra commented on another common ducting theme that should be amended in the region: “Fabrication is one issue that actually has a big impact on the functioning of ducting systems.
“Poor workmanship can lead to losses of up to 30%. For example, sometimes you will notice that the flanges are not insulated properly – this is not ideal. Some ductwork contractors are good, but not all of them provide the same high quality. Not all teams monitor every element of the process, and this includes consultants as well,” Mishra added.
With Expo 2020 Dubai on the horizon, all participants agreed that there was a growing demand for improved ducting and insulation systems in the region’s built environment. In addition to accountability, proper installation and testing must also be prioritised. HVAC system must be used to not only move air around, but also to condition it. To ensure both, the industry must prioritise ducting and insulation.