By Cindy Kwok Asset Enhancement • Building Law • Building Technology • Design 0 Comments

Exposure on Elevator Ride is full of air-borne transmission

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Otis Worldwide Corporation (NYSE: OTIS) released the results of a three-month academic study that investigates how elevator airflow affects potential exposure to the COVID-19 virus and a science-based approach for how to mitigate that exposure in elevators.

Findings show the significant amount of air exchange present in most elevators combined with simple mitigation strategies, including all riders properly wearing a surgical-style mask and the installation of a common type of air purification system, puts an elevator ride on the lower end of the exposure spectrum.

The study indicates strongly the provision of air purification system inside the lift car reduce the airborne transmission

MITIGATION STRATEGIES – VENTILATION CAN REDUCE RELATIVE EXPOSURE EVEN FURTHER

The study was led by Dr. Qingyan (Yan) Chen, the James G. Dwyer Professor of Mechanical Engineering at Purdue, who is widely recognized for his research into the spread of infectious disease through indoor air systems – and how to prevent it.

“Air exchange is important. the study findings concluded that the higher ventilation in an elevator, relative to the compared activities, results in lower exposure opportunity. If all passengers properly wear masks, the relative exposure risk drops 50%. Air purification, called NPBI, can reduce this by an additional 20-30%,”

Source: https://www.otis.com/zh/hk/news?cn=otis-releases-elevator-airflow-study-findings-covid-19-exposure-on-elevator-ride-is-low-risk-with-simple-mitigation

RISK OF CONTAMINATION IN LIFT CAR – PISTON MOVEMENT CREATES THE AIR DRAG

The study further investigate the position of the air inlets and outlets relationship. Alike to our another presentation 2021 and the study-2008 by University of Hong Kong, the position of inlet/outlet does significantly influences the flow circulation and droplet dispersion.
An air purifier does not eliminate airborne transmission. The droplet dispersion is reduced when a pair of an inlet and an outlet is implemented. The overall practical conclusion is that the placement and design of the air purifier and ventilation systems significantly affect the droplet dispersion and AVT. Thus, engineering designs of such systems must take into account the flow dynamics in the confined space the systems will be installed.

 

Source：https://aip.scitation.org/doi/10.1063/5.0038180

VENTILATION & AIR PURIFICATION SYSTEM SELECTION

(NCCO installation by Kingclorence)

The ventilation inside the Elevator is governed by legislation and code of practice from EMSD. It will be great if the position of inlet / outlet may be given due consideration in term of droplet dispersion and aerosol. Thus , in the absence of retrofit for outlet / inlet , the quick fix is to install the air-purification machine which can encourage the positive air flow.

There are different types of air purifiers in the market which can kill virus and improve air quality of the indoor environment. The size of your room is an important factor for choosing a suitable Air purifier. Bigger spaces will need larger air purifiers so make sure you choose an air purifier that can operate in a space that is 20-40% larger than the room for the best performance. GBE offers site inspection services for air quality control and recommends the air purifier for your best suit. Please contact us for more details.

Thank you

 

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