CoolSys Provides White Paper on Indoor Air Quality

Getting Back to Normal? For additional commentary on the indoor air quality methods described in the CoolSys white paper, Contracting Business spoke with Allan Samuels, an expert in supermarket engineering. Samuels is also the new president of CoolSys Energy Design, a Philadelphia-based consulting engineering firm providing innovative mechanical, electrical, plumbing and refrigeration building design strategies and services, as well as construction administration and commissioning services. Samuels said the pandemic has placed pressure on building owners — and indirectly, on HVACR contractors — to provide air purification solutions that occupants can trust. He added that he senses people want to get back to normal working conditions.

“There was a mass exodus from working environments to homes, but now, people are looking for solutions to get back into the office,” Samuels said. “I personally think certain businesses are much more efficient working in an office. I think we will see a hybrid work arrangement going forward, but definitely we are more efficient in an office, and certain businesses must work in offices.

“We hear talk about a vaccine becoming a closer reality, and I think people are starting to see the light at the end of the tunnel, and there is less interest in doing things at this point. I’m not saying that is definitely the case, but I think that’s the way group-think is at the moment. Of course, there are exceptions, such as gymnasiums, hospitals and jails.”

 Samuels acknowledged the influence the American Society of Heating, Refrigerating and Air-conditioning Engineers (ASHRAE) has on building heating, air conditioning and ventilation standards, but his guiding principle is that “all buildings are not alike.”

 “ASHRAE standards affect building codes, and ASHRAE and the Center for Disease Control are closely aligned. But in terms of maintenance and ventilation, I think you will see new codes and guidelines from ASHRAE that will be here for many years to come,” Samuels said.

 “However, you have to look at each building independently, and find the right solution for each building. I believe that applies to COVID-19 as well as general engineering problems. You have to customize the solution to what works best,” he said.

 Samuels also urged caution when presented with various IAQ “solutions” that may not deliver results.

“I get solicited by every Tom, Dick and Harry out there who has some sort of device that’s supposed to [purify the air]. I see them advertised all over, and some are comical. I would advise people to look for independent lab results that verify the device or method, and that it has validity to any claims about mitigating the virus,” Samuels warned.

We asked Mr. Samuels to provide some additional insight into the technologies referenced in the white paper:

UV-C and far-UV: “You can use UV-C in unoccupied buildings, or other places, as long as it does not shine on people. You’ve possibly seen UV-C robots cleaning aircraft and supermarket shelves or used in Amazon warehouses. But it has to be done when nobody is present. Regular UV-C can be used inside the ductwork. It has been used for many years, to keep bacteria off the coil. To destroy the virus inside ductwork, you need to slow down the air velocity a bit so the virus has more time to be exposed to the UV light.”

He continued: “But there are some difficulties with UV-C as well. You need to place it at a good location in the ductwork, usually straight off of the coil. If you have an area where the ductwork expands, you slow down the velocity. But you need to have a sight glass or other way to verify that the lights are on. Too many times you put things in ductwork and they don’t work for many years and nobody knows if they’re working or not.

“Also, remember that UV is damaging to some types of plastic,” he cautioned. “In addition to that, UV light typically lasts about a year and then begins to fade. A technician must be able to access the lights to provide maintenance. It’s important to have air handler access panels.”

“Far-UV is a good option to be used where people are present, such as in a retail environment or in a residential environment. You can have these lights on constantly, and it’s constantly working to clear the area,” Samuels said. 

Humidity: Samuels said increasing a building’s relative humidity could potentially pose a conflict of interest, comfort-wise.

“In many buildings, we work to remove humidity. Adding too much humidity can cause other problems inside a building other than those related to occupant comfort.

“You can increase humidity where possible and practical. CoolSys Energy Designs does a lot of work in supermarkets, and usually, the goal in supermarkets is to reduce humidity levels,” he said.

 “Again, each building must be independently evaluated. Determine what the effect would be to adding humidification to a building. It might be totally appropriate. In a gymnasium for example there’s a lot of moisture coming off of those bodies and you’re typically trying to remove that moisture.”

Ventilation: “The recommendation right now is to bring in as much fresh air as possible, which is actually counter to what we’ve doing for energy conservation. But you want to open dampers and bring in as much outside air as possible, within reason. That depends on where you are geographically, and on the time of year. Here in the Northeast we’re entering winter, and it may not be too successful to have dampers wide open at this point and bring in all the air you can.  But that is a good option where applicable, perhaps in Colorado rather than NJ.”

Filtration: Filter upgrades usually involve going from a MERV 9 to a MERV 13 or 16 level filter.

“But remember,” Samuels said, “due to static pressure and resistance to moving air through the system, you just can’t change filters without having an impact on velocity of air and the ability of the fan and pulley system to pull that air through the system. Which is why I say every building has to be independently evaluated.

“Improved filtration is absolutely a help. A MERV 13 filter is much more efficient than a MERV 9 filter in collecting these particles. But remember, that the COVID virus is .125 microns, whereas a grain of sand is 90 microns. So, you’re trying to catch a tiny, tiny particle. To be fully effective you need a HEPA filter, and as you and I know, you can’t just decide to put a HEPA filter into an existing building system.”

Bipolar ionization: “Bipolar ionization charges negative and positive particles. It puts out millions of these charged particles into the duct system,” Samuels explained. “This virus actually attaches itself naturally to those particles, either water droplets or dust particles. When you have these negative and positive charged particles, they attract each other and clump together. The .125 micron virus becomes much larger and is much more easily caught in a filter. “Therefore, if you have ionization combined with a MERV 13 filter, it’s 97% efficient in capturing the COVID virus. A MERV 16 filter is 99% efficient when used with ionization. So those two in combination could offer something that’s very good.                                                                                                                                                                                                                         

“In addition to clumping the particles and the virus together and capturing them in a filter, these charged particles also destroy the virus. This is proven by independent lab testing. The RNA covering of the virus is destroyed by these charged particles. Therefore, there are two ways that ionization is working for you to mitigate COVID-19 in the building.”  

 — Terry McIver