Insight: Whose responsibility is it when it comes to ducting and insulation?

According to US Department of Energy, one has to verify that ducts have been sealed in accordance with approved design documents and code requirements.


The intent of energy efficiency codes, with respect to duct insulation, is to keep mechanically warmed or cooled air as close to a desired temperature as possible and prevent the conditioned air from escaping the duct system while it is being moved to spaces where it is needed. If reduced heat transfer through insulated ducts is accounted for in the heating, ventilating, and air conditioning (HVAC) load calculations, it may even be possible to reduce the size of HVAC equipment.
According to US Department of Energy, one has to verify that ducts have been sealed in accordance with approved design documents and code requirements. Verifying all seams and connections for the entire duct system in a commercial building can be tedious and time consuming. Typically, inspectors will perform spot checks to confirm the seams and connections are being sealed properly. Testing the duct system for air tightness provides the final confirmation of proper duct sealing.
However, one of the more difficult and confusing issues is determining who is responsible for the maintenance and repair of ductwork and insulation. 
In an early roundtable interview with MEP Middle East, Sunil Nair, project controls – technical lead, BK Gulf, said: “I would think the biggest problem is that none of the people who are involved in the construction phase are really responsible for the power [bills] later.  The consultant actually designs; he’s is given some figures of how his design is optimised.  When it comes to finally handing over, the bills are paid by the tenant.  So the owner is not really bothered because somebody else is paying [the bill]. No tenant is not going to complain about paying 10 dirhams more. There is no onus on any of the designers to come back and say ‘I said that this building is going to cost so much’. Nobody does that. It’s all on paper, all the figures, percentages, etc. Unless you put the onus on the people who are selling or designing, to actually show that savings is achieved, it is pointless.”
Talking about whether guidelines are enforced, Anil Mishra, manager technical specifications, MEA, KIMMCO, said: “In terms of leakages SMACNA, ASHRAE, etc., have worldwide standards that specify the type of sealing that you need to use for each duct to reduce the amount of leakages. What are the kind of connections that you have to do (herringbone or c-clip), whether transverse joints have to be connected and sealed, or longitudinal joints or any other connections where flanges should be connected to FCUs, AHUs or terminal points.  These are very big standards and those standards are based on static pressure. Leakage is basically a function of static pressure.  The more pressure you have in AHUs and the longer the duct is, the more are the chances of leakage. That has to be mitigated by implementing the standards. The onus first lies with the designers, the HVAC designers, to specify the kind of pressures that we have in the system.  Be it is insulation, or sealants, there are relevant standards.  It just needs to be enforced.  As Sunil very rightly believes, 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 what implemented is as per the standard, I don’t see any reason why there should be a problem.”
Although there are regulations and standards with regards to installation, there is no regulation or onus on the consultants or the owners to actually prove that the right practice is happening. Nair said: “There should be a drive for everybody to save energy, and then some incentivisation, and finally, making someone responsible.”
The Dubai green building regulation is converting to Al Sa’fat (a green building rating system). Al Sa’fat is trying to have a system of regular auditors of buildings. The purpose of the Al Sa’fat regulations is to improve the performance of buildings in Dubai by reducing the consumption of energy, water and materials, improving public health, safety and general welfare and by enhancing the planning, design, construction and operation of buildings to create an excellent city that provides the essence of success and sustainable living.
Arvind Bhatnagar, general manager, Technical & Trading LLC – a member of Easa Saleh Al Gurg Group, raises some pertinent questions. He asks: “In a country like the UAE, where the climate dictates that we spend 90% of our lives in air-conditioned air, why don’t we ask our landlord about the last time the AC ducts were cleaned? Better yet, demand proof of the same each year when we renew our tenancy contract.
“If we own our property, do we ask our facility management company to clean the ducts every six months? Many of us don’t and this ignorance has a significant impact. We never make the connection between nursing a heavy head or occasionally being listless at work as a symptom of sick building syndrome. We spend about 40% of our life time at our place of work and another 40% within our homes, yet very few people ever touch on this important aspect of regular building maintenance and the link to our health.” 

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