Elevators & Airflow: The Impact of COVID-19 on Skyscrapers

[berkeman]

Actually, I've already developed a solution. Proper air flow circulation, removal of contaminated air, filtration and sterilization of air removed and, return of air purified and sterilized. All in a continually circulating system moving air from floor to ceiling. Many installs already and both in house and third party tested for efficiency (over 95% in PM10, PM2.5, PM1 and just under 90% PM>0.3 removal than a typical elevator fan based system, as well as 33% more efficient at VOC reduction). This is with twin MERV13 filters and I now have a developed certified HEPA M17 that I will be testing. Sterilization is UV-C based and no risk of exposure. Also, sealed from shaftway so not subject to stack / piston effect nor subject to smoke infiltration risk.

Welcome to PhysicsForums.

Interesting system. I'm curious why you chose bottom-to-top airflow, instead of the reverse. The floor is one of the dirtiest places in terms of pathogens.

 

[NickG012]

Welcome to PhysicsForums.

Interesting system. I'm curious why you chose bottom-to-top airflow, instead of the reverse. The floor is one of the dirtiest places in terms of pathogens.

The floor is subject to inflow air pressure with door open cycles making it the breading ground for waiting contaminants to recirculate to passengers. I looked into some ideas on the best way to clean the air inside the elevator and landed on hospital operating / clean room type negative ceiling pressure designs. The system is made with CFM capacity to exchange a typical 3500lbs car's air volume twice per minute so the upward flow of air effectively draws air and contaminants up and away from passengers (especially imperative in the case of a cough or sneeze in a crowded car) and into the filtration / sterilization unit. With elevators, downward flow will ultimately fail as the influx of passengers into a car, as well as the inflow at door open with keep contaminants within the enclosure.

 

[berkeman]

hospital operating / clean room type negative ceiling pressure designs

Yeah, but in clean rooms we walk across sticky mats and then put on booties over our shoes. Clean room floors and operating room floors are very clean and mostly sterile. The carpet on the floor of an elevator is a mess...

 

[NickG012]

Agreed. Most elevators though use resilient tile such as VCT, stone, porcelain, etc. For carpet...I generally steer most away when we are asked for that reason. If there is a carpet, it is typically two sets, bound and continually vacuumed and replaced with second when sent out for professional cleaning. All in all, based on testing, the problem is there is no ventilation at all in elevators. This is what allows all to settle on the floor and surfaces. Adding this system is a combative tool in working toward cleaner cabs. Unfortunately, nothing will 100% work to rid of all contaminants but, doing nothing is far less successful. From other systems I am seeing out there, the conditions created by them would be ineffective, counter-effective or downright dangerous. We tested in house and a 3rd party UL test on interior conditions showed absolutely huge differences when test comparatives were taken over a month period of two side by side elevators in an occupied and active building.