The 5th of #SCAIMondays conducted on May 25 by the Shopping Centres Association of India 2020, focused on making both the Government as well as the Shopping Centre Industry understand the myths surrounding high-tech air-conditioning systems in malls and other closed environments. The agenda was to analyse the factors associated with the topic so that the myth and fallacies surrounded around air-conditioning, as a medium of the spread of COVID-19 can be busted.
“The subject of air-conditioning in the context of allowing shopping centres to open has been a point of concern for policymakers. Presentations to all concerned authorities have been made by SCAI, as air-conditioning is a key component not only for the entire retail and shopping centre industry but also for consumers at large that find malls as safe places to visit. Implementation of stringent Standard Operating Procedures (SOPs) prepared by SCAI assures all possible measures to provide a safe and hygienic environment, social distancing and safe air-conditioning. If offices are allowed to function and in some stated with full strength, if AC buses and trains are allowed to ply and if from May 25, domestic aviation is being allowed to operate, why are shopping centres still not being allowed to open?” asked Amitabh Taneja, Chairman, SCAI.
The session was moderated by Mukesh Kumar, CEO, Infiniti Malls and the experts present in the panel were:
– Aneesh Kadyan, Executive Director – Property Management – India, CBRE South Asia
– Ashish Verma, Head of Engineering, Inorbit Malls
– Richie Mittal, National President, Indian Society of Heating, Refrigerating and Air Conditioning Engineers (ISHRAE)
– Vishal Kapur, Technical Committee Chair & Presidential Member, ISHRAE
Mukesh Kumar introduced the panel which was high on experience and technicality an also discussed the rumours, debates, and theories associated with air-conditioning playing a negative role in a closed and open environment, leading to the spread of the COVID-19 virus.
“ISHRAE has confirmed that the virus doesn’t spread through air. Mall air conditioning is very safe to operate. As a matter of fact, not operating air conditioning can have adverse effect on the health of visitors and employees. ISHRAE has advised malls to increase the intake of fresh air and operate the exhaust few hours longer than the mall operating hours. Ideal temperature to maintain would be 24-30 degree centigrade. All these advises have been incorporated in the mall SOP,” said Kumar.
He also mentioned key criteria, as part of SCAI SOPs in preparedness of opening of malls:
– Dedicated technical team to monitor and implement air-conditioning measures
– Replace or clean/disinfect HVAC Air-filters prior to re-opening
– Disinfection and cleaning of Filters, grilles, diffusers & internal surfaces
– Disinfection / treatment of condensate drain pan
– Coil cleaning and sanitisation as per protocol
– AHU’s / CSU’s filter cleaning will be increased & dilution of some disinfection chemical can be used in water to wash filters.
The Indian Society of Heating, Refrigerating and Air Conditioning Engineers (ISHRAE), was founded in 1981 at New Delhi by a group of eminent HVAC&R professionals. ISHRAE today has more than 30,000 HVAC&R professionals and Student-members. ISHRAE operates from 43 Chapters and sub Chapters spread all over India, with HQ in Delhi. It is led by a team of elected officers, who are members of the Society, working on a voluntary basis, and collectively called the Board of Governors.
Aims & Objectives
– Advancement of the Arts and Sciences of Heating, Ventilation, Air Conditioning and Refrigeration Engineering and Related Services.
– Continuing education of members and other interested persons in the said sciences through Lectures, Workshops, Product Presentations, Publications and Expositions.
– Rendition of career guidance and financial assistance to students of the said sciences.
– Encouragement of scientific research.
Operating Guidelines Prepared by ISHRAE
– Air Filters must be kept clean as given in the Section – Operation & Maintenance.
– Provide adequate Ventilation (Fresh Air and Exhaust)
– Inspect and clean the indoor unit Coils, as given in the Section – Operation & Maintenance.
– Set Room Temperature between 24°C and 30°C. Maintain relative humidity between 40 percent and 70 percent.
– (In humid Climates set temperature closer to 24°C for dehumidification and in Dry Climates closer to or at 30°C Use Fans to increase air movement)
– Heat Recovery Wheel (HRW): It is advisable to keep this wheel in off mode to reduce cross contamination. Upon restarting, the wheel must first be sanitized
– Toilet and Kitchen Exhaust Fans must be kept in operating mode
Richie Mittal, National President, ISHRAE also shared a document consisting of recommendations and other measures for the shopping malls, government offices, private firms and other organizations to ensure a safer environment in their premises related to air-conditioning.
Are Centralized ACs in Malls Safe for Visitors?
When asked to elaborate on the situation, Mittal said, “The most common mode of virus spread is when an infected person coughs or sneezes. As a result, most of the particles settle down on to a surface and few of them remain suspended in the air. Then there is temperature and relative humidity which comes into play. Yes, it can be spread by the air medium, but how much damage it can do to a person is yet to be established. Malls need to plan their air distribution system and pump in more fresh air by adding more fans, ventilators and exhausts which should be cleaned regularly. Shopping centres should flush out the indoor air 2-4 hours before they are thrown open to the public using outdoor air distribution systems. As far as the Air Conditioning systems of malls are concerned, it is at par with the airports.”
Vishal Kapur, Technical Committee Chair & Presidential Member, ISHRAE talked about the technical aspect of the topic saying, “A concern has been raised about the spread of the virus through operating of the air condition system. We all know that infectious disease can be spread by different routes and short-distance transmission being the most common route. Still, the question is being asked that the spread can be increased by the air conditioning medium needs more research and inputs.”
“After doing a lot of research, we realised that in the temperature range between 24-30 degrees indoor, the survival chance of the virus is decreased. Humidity is the other factor, as research shows that humidity above 40 percent has an impact on the survival of the virus. Therefore, we provided a range 40-70 percent humidity which the lowest chance of the virus infectivity. This is the first outcome of our study,” he added.
As per Kapur, the areas that need attention at this moment are:
Ventilation: Bringing a huge amount of fresh air into the workspace. Whatever pollutants are been generated is also been pushed out and diluted in this process
Filtration: Install the best filter into the units, as this virus very rarely travels on its own. It doesn’t travel a large distance by air and even if they do, it gets trapped at the filter level. ISHRAE recommends using UltraViolet Germicidal Irradiation (UVGI) in a further stage to keep the coils free from infection
Pressurization: The fact is that when we pressurize a space, it ensures that the outdoor air pollutants are not entering the air conditioning space or vice versa
Aneesh Kadyan, Executive Director – Property Management – India, CBRE South Asia, explained, “From a commercial point, even in the lockdown, things were operating in many places and ACs were also running in most of the environment. I am not sure how this issue actually came out that the usage of AC is not safe in a building. We have been following the directives given by the Government, we have our own SOPs, and best practices that should have been in place both in India and our structures globally. We have brought in certain changes. We have worked on implementing modern hygiene measures. Internationally, more or less the guidelines are same, at some places, they are bit different depending on the usage. One point is that air quality and the parameters that the international market have in terms of the malls and commercial building is higher and they are not looking at the air conditioner as the source of virus spread in a closed environment.”
“I would divide a mall into three to four parts to understand it better. The four parts are vanilla, anchor, F&B and the entertainment section. The unique thing in most mall designs is that there are multiple air-handling units throughout the mall. The anchor stores have their own units and the same is the case with the large entertainment zones as well. It has always been seen that the best-designed malls have a good quality of outdoor air already included. Secondly, one needs to create maximum exhaust points again to ensure maximum path and routes for the air exit and enter. This helps the air to not get static and move all around,” added Kapur.
Malls air conditioning chill water systems inherently safer than ductable split systems used by IT offices or stand-alone retailers since they have fresh air intake and do not recycle air but recycle chilled water. All malls have chilled water systems which provide cooling by circulating chilled water across the mall and not air. Mall air conditioning systems have additional advantage of fresh air inlet which can be increased as required
Mall systems have separate AHUs for each retail unit which further reduces recirculation of air
The existing central air conditioning systems in the malls are already capable of implementing the guidelines of CPWD and ISHRAE
Malls have qualified engineering teams to support systems
Malls have large common areas to provide shelter to waiting customers during monsoons thereby preventing over-crowding.
ACs and Social Distancing
When asked how important is to maintain the social distancing in a closed and centralized air-conditioning environment, Kadyan explained, “Going by a dynamic figure, earlier it was 150 sq. ft. per person, now it has come down to 75 sq. ft. to 50 sq.ft. depending on the offices. However, the most important thing here is the ventilation rate. With the limited number of person entering the premises currently, the ventilation is rate is higher than the normal situation, which is very safe as per the guidelines. Through the apps, we have a track of how many people are coming to the offices, and as far we are keeping a check on the crowd control, the per person sq. ft area is not a concern. Lesser number of people in the mall and offices are beneficial for everyone in this situation. Different countries are experimenting on measures to check crowd control. In commercial buildings, this is a bit easier as they have a fixed number of employees coming in on a daily basis.”
Key Protocols for Restarting the Operations
The first protocol is to check the ‘plant management’, but as some sections of the mall have been operational, which means the AC has been working for few hours on a daily basis, so this won’t be of much of a problem.
“From the indoor management point of view, the critical thing is the filter and the coil. We have to ensure that the filters were always kept clean and sanitized. Fortunately, every shopping mall has a very skilled engineering team so taking care of the cleaning and hygiene protocol will not be a problem. Other thing is that when you are reopening a mall to keep your AC operational on a full-day basis, we recommend opening the doors and windows fully for a few hours. Run the ACs on the fan mode for few hours, without the cooling,” concluded Kapur.
Key Protocols:
1. Sanitize the entire area
2. Study the fresh air and exhaust system adequacy as per the guidelines and inform the user to modify the system if found inadequate
3. Carry the preventive maintenance on all the units as per the manufacturer’s guidelines. This should include disinfecting and cleaning of:
– Filters, grilles, diffusers & internal surfaces: It is recommended to use 5 percent Cresol solution (containing 50 percent Cresol and 50 percent Liquid soap solution). Mix 1 liter of this solution in 9 liters of water. The surface shall be sprayed with this solution, left for 10 minutes and then washed / wiped clean with water/ cloth. (for washable filters only)
– Condensate Drain Pan: Disinfecting / treatment of condensate drain pan is suggested using UV treatment or 1% sodium hypochlorite dosing. This will apply only if the HVAC equipment is working on a re-circulatory mode.
– Coils: Follow standard recommendations of coil cleaning and then sanitize using the same protocol as that of the filters specified above
4. In case the area has ducted air distribution, it is advisable to clean the ducts by an appropriate method
5. The following process is recommended at start-up:
– Open all the doors and windows of the space.
– Ensure that all cleaning protocols as advised above are complete
– Run the fresh air system at the maximum intake of air setting.
– Start and run the exhaust systems if available.
– Start the air conditioning system in fan mode only, without filters and run it for a minimum of two to four hours with doors open and exhaust system operational.
– Install the clean & sanitized filters
– Start the AC in normal mode and run for two hours with doors open and then close the doors and windows.
6. The fresh air and ventilation system should be kept on throughout the off-cycle and on the weekend and holidays in the air circulation mode.
Case Study: Handling a Shopping Mall AC
When asked how shopping malls can achieve the action plan and other measures, Ashish Verma, Head of Engineering, Inorbit Malls, explained, “Currently there are many essential stores which are already operational in the malls and we are running the mall AC system to cater the requirements of employees and visitors. There is not much load as we are managing the things in a much-organised way. We do have a ‘Building Automation System’ which works on the demand basis. This is about catering to the need of the special stores in the mall. As far as the maintenance part is concerned, we have a skilled team who does all the work to maintaining and monitoring the situation in a much-organised manner. We control and check the temperature and humidity on regular intervals through our system.”
“As mentioned, malls in India are designed for 100 percent occupancy and therefore we have to design the operations to fulfil those occupancies needs. Yes, there is a margin by which we can leverage and retune our air in-take, either in the form of a mechanical in-take or operational windows, we are capable to increase and decrease the amount of air in-take in our malls,” he further stated.
Scheduling and Re-Tuning: Inorbit Malls have their own SOPs, structural process in place to take off the scheduling of these operations. “Going by the situation, there is a need for retuning of the process, screening of filters, coil cleaning frequencies, flushing, maintaining AHUs, chillers, individuals packaged units, on a regular basis and we are doing it every week,” said Verma.
