Otis Study: Masks, Duration Make Elevator Rides Safe Amid Virus

FARMINGTON, CT — Elevator rides, with the proper precautions, do not fester the transmission of the coronavirus, according to a study commissioned by a major manufacturer based in Connecticut.

Farmington-based Otis last week released the results of a three-month academic study that investigated how elevator airflow affects potential exposure to the virus and a science-based approach for how to mitigate that exposure in elevators.

According to a summary, the findings show the "significant" amount of air exchange present in most elevators, combined with "simple mitigation strategies," that include all riders "properly wearing a surgical-style mask" and the installation of a "common type of air purification system," put an elevator ride on the "lower end of the exposure spectrum."

The study concludes that a short elevator ride represents a "relatively low risk of exposure compared to several everyday activities."

That's less than outdoor dining and comparable to a trip to the supermarket – when simple mitigation is in place, according to the study.

Otis bills itself as the world’s leading company for elevator and escalator manufacturing, installation and service.

With science "continuing to point to respiratory droplets and aerosols as a principal means of transmission," the study focused on airflow and the impact of ventilation rates and types, purification technologies (specifically needlepoint bipolar ionization) and the proper use of masks.

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

Otis officials said the study used "sophisticated computational fluid dynamic modeling" in his research, which focused on indoor environments, tight cabins and building design and analysis.

Otis officials said Chen and his team looked at likely exposure to the virus, which can be quantified by the frequency, duration and intensity of exposure.

The duration of a typical elevator ride is short – usually less than a minute. Multiple scenarios of two-minute elevator rides were modeled to assess relative risk, Otis officials said.

According to the study, intensity of exposure is impacted by the level of air exchange or ventilation and elevators have significant air exchange by design, compared with many other indoor spaces, and are required by code to have openings for ventilation.

Many elevators also have fans to increase ventilation, the study said.

"Air exchange is important. Our findings concluded that the higher ventilation in an elevator, relative to the compared activities, results in lower exposure opportunity," Chen said. "If all passengers properly wear masks, the relative exposure risk drops 50 percent."

He continued, "Air purification, called NPBI, can reduce this by an additional 20-to-30 percent. We compared the relative exposure risk of elevators to other common activities in a typical workday, including an hour-long bus ride and eight hours in an office environment. Riding an elevator was a lower exposure risk activity, given the short duration of an elevator ride."

Qualitative comparisons place riding an elevator with all passengers wearing masks in a low exposure risk category, with a relative risk similar to that of shopping in a supermarket.

"Elevators are an essential part of everyday life for many, often the first leg in your journey and the last on your route home. We know many passengers have questions about exposure risks associated with riding an elevator, and we want to provide answers verified by science,” said Robin Fiala, the vice president of marketing and sales at Otis. "We're sharing the study results broadly in advance of publication to keep riders well-informed and limit misconceptions."

More details of the elevator airflow study, including a technical whitepaper, are available on otis.com.

The full technical report is expected to be published in an academic journal later this year.