See the Light (Source)

This Product Spotlight details the HoldSafe handrail disinfection unit, which offers visible assurance to escalator riders.

by Lawrence Madanda

Escalator and moving-walk handrails are typically covered in germs, bacteria and viruses that can lead to the spread of infectious diseases. According to a report by the U.S. Department of Energy, under the right conditions, the number of bacteria on a surface can double every 4-20 min.[1] Other studies have shown that infectious viruses can survive on solid surfaces for hours, days or even weeks. Conventional disinfectants, if used properly, can quickly kill and reduce the number of bacteria on a handrail but, once the solution dries, the bacteria regrows and returns to unsafe levels. There has long existed a need for a practical, continual solution to this problem, and the COVID-19 pandemic has greatly highlighted it.

PürHealth Technologies Inc., a Canada-based technology wellness company, recently introduced the HoldSafe^TM Handrail UV Disinfection Unit to the North American market, offering several advantages:

• It uses UV-C light to eliminate up to 98% of the germs, bacteria and viruses found on a handrail.
• It is self-contained and powered. No wiring or complex installation is necessary.
• It easily attaches to any escalator or moving-walk balustrade to immediately and continuously disinfect the handrail.
• It is UL listed to meet or exceed safety standards for North America.
• A visible reminder to the public that the location has taken measures to improve public health and safety

UV-C as a Disinfection Solution

Ultraviolet (UV) light is present in sunlight and accounts for about 10% of total light output. It is divided into three ranges categorized by wavelength: UV-A, UV-B and UV-C. UV-A and -B penetrate the ozone and are the wavelengths that lead to tanning, sunburns and more-dangerous side effects, such as melanoma, depending on exposure. However, UV-C light, filtered out by the ozone layer, has a short wavelength of 100-280 nm and is germicidal. It deactivates the DNA of bacteria, viruses and other pathogens and destroys their ability to multiply and cause disease. Using UV-C is a physical process that kills bacteria and other microorganisms without the use of harsh or toxic chemicals. It has been shown to kill coronaviruses, including the one that causes COVID-19.

The market today has numerous UV-C products making claims about their effectiveness, but there is a basic principle that applies to the usefulness of UV-C as a germ-killer: time plus power plus distance. Unless the UV product has been tested in a controlled and certified laboratory environment, any claims should be questioned.

The HoldSafe Handrail UV Disinfection Unit uses two powerful UV-C LED modules to expose the handrail to UV-C light as it passes through the unit. The handrail is exposed for 0.2-0.4 s per rotation at a distance of 2 cm. This is powerful enough to kill and neutralize pathogens with each cycle. PürHealth has conducted laboratory testing of HoldSafe that confirms a 98% elimination rate after 16-30 cycles (30 min to 1 hr, depending on escalator operating speed). Validated field tests confirm a 93% reduction in overall bacteria on an ongoing basis on operating handrails in a real-world setting.

External Versus Internal

There has been some debate about the safety of embedded UV-C solutions (those installed under the escalator) versus external units, such as HoldSafe. Although both can make claims about UV-C effectiveness, they are not necessarily comparable when it comes to expectations for the post-COVID-19 “new normal.” The public wants to see visible measures in place to mitigate the risk of infection in all venues — such as retail, hospitality, transportation and entertainment — that draw large crowds. While signage and labels can communicate that measures have been taken, a smartly designed, visible product such as HoldSafe can be more effective in making the point. Of course, promoting an external device should be done only when it is shown to be safe.

PürHealth worked closely with UL to test the HoldSafe unit for safety, and the product is UL listed to meet or exceed safety standards. The factors tested and addressed include:

• Entrapment: no risk of fingers being caught or pinched in the unit
• UV-C eye safety: no UV-C ultraviolet light can escape the unit and harm the public; also, the unit will not operate if it is removed from the escalator or the handrail stops
• Electrical safety: No risk of electric shock, as the unit is self-powered and generates low voltage
• Impact resistance: Tested for impact

Additionally, there have been no accidents or damage reported in more than three years of use in international markets, where thousands of the units are in operation.

Reference
[1] U.S. Department of Energy, Pacific Northwest National Laboratory.
“Just How Fast Can Bacteria Grow? It Depends.” December 2010
(www.pnnl.gov/science/highlights/highlight.asp?id=879).