Elevators, HVAC and Cleaning are the three most essential elements in retaining commercial tenants in high rise buildings. While we can argue about the levels of acceptable performance and client expectations, we cannot argue that having a reliable elevator service, good heating and cooling system as well as clean environment are essential. Covid-19 and this plague of 2020 impacted all three elements the hardest. Three most essential components and all three were impacted by the virus.
What surprised us was how all three components played out in elevator cabins creating a free for all to capitalize on the fear or concerns of the public to sell components that may or may not add any significant value. If the goal is to promote public health, then cleaning the elevator cab interior or components is welcomed. Installing components that may or may not generate any benefits is not necessarily in the public interest. In fact, it may lull the public to think that they are safe, hence dropping their guard when there is a need for doing the right thing.
In this blog, we are going to focus on the air circulation in the cab.
The way the elevators are designed, air flows from the bottom to the top. The fan/blower pull the air out of the cab from the bottom vents. There is a benefit to having a good amount of air exchange because the air inside the elevator does not stay stagnant. We know that in some cases, the cabs may not have been designed properly either because the drop ceiling may have not been designed to allow ample air to escape through the top or for the vents at the bottom are blocked or plugged or not fully open. We may also have an issue with the fan which may not be working.
What is important to realize is that when in motion, the elevator cab is not a small static space like a bathroom or a closet. When the elevator moves in the elevator shaft the air is pushed out of the cab through the fan. Most fans in elevator have the ability to move 250 cubic feet per minute (CFM). A simple 2500lb (1150kg) elevator cab that’s 8 feet high, is 222.2 cubic feet. So, with a 250 CFM fan, the air can be completely exchanged every minute. This means that the air in an elevator with the door closed, can completely be replaced with new air every minute. If we open the elevator door, the air exchange can happen ever faster because the elevator door on a 2500lbs car is typically 42” wide by 84” high or 24.5 square feet. When the door is open, the elevator creates a 24.5 square feet of open space for the air to escape and hence any variance in temperature will cause the air to escape even faster. This is no different than opening the doors or windows in a home to allow the air to be exchanged
The air that flows in your building is what you will end up with inside the elevator. If someone sneezes or coughs in the elevator, the droplets from the person in the elevator will rise and be evacuated to the top of the elevator shaft or the droplets will fall on the ground if they are heavier than what the air can lift due to moisture. There is too much air movement in the elevator space to allow the droplets to remain suspended in the air.
With that said, we did not find any shortage of products promising to ionize the air in the elevators. We did a review of a product that works well in bathrooms and small 800 Square foot space, but not necessarily in elevators. While we do no have an issue in principle with these products on their own, their application in elevators was something that we did not feel that works well. Therefore, if you plan to buy a fan with a UV-C light or an air ionizer for your elevator cab, you can. But if you are looking to capitalize on the benefit of spending hard earned money, we recommend spending your money on something else.
