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Smart Buildings Report 1: 2020 The New Normal of Hyper-Cleanliness - Disinfection Robots and Cleaning Robots To The Fore

Under the looming shadows of Covid-19, focus on the hygiene and cleanliness of a building has emerged to the forefront.
Research studies has demonstrated that the Covid-19 virus can survive on environmental surfaces for 48 to 72 hours. Today, more than ever, there is an urgent need to contain the pandemic and prevent further uncontrolled viral spread by establishing cleaning practices that are more frequent, more thorough and more effective.
Facility managers need to manage the enhanced cleaning regimes with sustainable, cost-efficient solutions that must not rely on adequate manpower availability during pandemic lockdowns, opening up new opportunities for both robotics and IoT service providers. For this report, we will look at these various aspects of cleaning a building:
  1. Surface/air disinfection
  2. Restroom cleaning
  3. Waste clearing
  4. Floor cleaning
  5. Facade cleaning
  6. Solar panel cleaning


Disinfection robots, as a service robot category, has seen the most explosive surge in adoption since the onset of the Covid-19 pandemic. There are generally three types of disinfection approaches – by ultraviolet-C radiation (UV-C), by chemical spray and a dual approach incorporating both.
Among the three types of ultraviolet light (A, B, C), UV-C has the most lethal effect on genetic materials – of humans and viral particles alike. Studies have shown that direct UVC light at a short wavelength of 254nm can break down the DNA in microbes, deactivating them from further replication. In real-life, where the virus may often be shaded from direct UV-C light, researchers advocate UV-C dosages of 1,000 – 3,000 mJ/cm2 to achieve 99.9% deactivation of both airborne and surface-bound virus. Because of its lethal effects, the UVC disinfection process must not be conducted in spaces with human presence.
uv-c disinfection robots
UV-C Disinfection Robot - How it works (CC BY 4.0 International license )
Distance matters too. The distance between the UVC light source and the target surface is also a critical point of consideration. As a general rule of thumb, the exposure time needed to deactivate a virus is about 5 to 20 seconds at a 10-cm distance, with the exposure time increasing quadratically with distance (exposure time at a 1m distance could take several minutes).
Thus, for room-sized disinfection, the UVC light source will often need to be re-located either manually with safety measures or autonomously to different positions of the room for maximal surface disinfection. Such a process can take up to 15 to 30 minutes per room.
  • Human Safety. Due to the harmful effects of UV-C, a disinfection robot with a human safety system often has built-in motion detection sensors and can immediately turn off its UV lights if one or more persons enters its proximity area.
  • Autonomous Mobility. UV-C disinfection AMRs (autonomous mobile robots) use LIDAR, in-built cameras and SLAM (simultaneous localization and mapping) technologies to move autonomously and navigate safely without accident on a predefined route. AMRs can automate the disinfecting process, greatly relieving the strain on manpower resources. Advanced AMRs are capable of interfacing with elevators for extended autonomous mobility across different floors.
  • Charging vs Operating Time. Disinfection robots can effectively work only in spaces with no human presence. Operationally, this means that either rooms have to be vacated prior to disinfection (usually for hospitals, airports and other 24-hour premises) or the robots can only work during non-operational hours (for example, commercial offices). In addition, the disinfection team will also need to consider the charging duration and the operating duration of the robots upon full charge, which varies for different manufacturers and models. In general, disinfection robots may require 2 to 6 hours of charging time and 2 to 5 hours of operating time on full charge.
  • Automatic Re-charging. While some disinfection robots may require manual staff intervention for re-charging, AMR-type robots will generally be capable of self-navigating back to the charging station for automatic re-charging.
Started in 2014, Denmark-based UVD Robots is one of the few early innovators for UV-C disinfection AMRs. UVD Robots is one of the key suppliers of autonomous disinfection robots to Wuhan, ground zero of Covid-19, at the onset of the outbreak. Recognized with the prestigious IERA (Invention and Entrepreneurship in Robotics and Automation) award in 2019, UVD's UV-C disinfection robot is a high-performance worker, capable of consistently and reliably disinfecting a hospital room in 10-15 minutes.
Each disinfection robot costs between US$80,000 and $90,000, and requires a charging time of 6 hours while providing an operating time of 2 to 2.5 hours per UV module (equivalent to disinfecting 9 - 10 rooms on one full charge).
Tru-D SmartUVC at Rush Memorial Hospital, Indiana
Tru-D (acronym for Total Room Ultraviolet Disinfection) SmartUVC's approach is based on using measured dosage of UV-C to disinfect the whole room from a single position. By precisely measuring the dose of UVC energy that reaches the walls and is reflected back to the center of the room, Tru-D SmartUVC is able to perform consistent disinfection on surfaces, including shadowed areas, from a single cycle and a single, fixed position.
This method of room disinfection differs from the more common approach that performs unmeasured but fixed-intensity and fixed-distance disinfection from multiple positions in a room.
While most disinfection robots are floor-bound, drone company Digital Aerolus has innovated the Aertos 120-UVC, the world’s first indoor drone that enables aerial UV-C disinfection. One of the early deployments of the Aertos 120-UVC was at the BUGS Early Learning Center, disinfecting surfaces of the general play areas at the daycare facility. One advantage of aerial disinfection is the disinfection coverage for high surfaces, such as bar tops and table tops, that are typically out of reach for floor-bound robots.
Each flight time is about 10 minutes on average, remotely controlled by a trained drone pilot from a safe location. The pilot will need to consider the distance between the drone and the target surface, and the consequent exposure time (and hovering time) from the drone's 36 onboard UV-C emitters. The disinfection process for a large room could require several flight missions.

The decision to use UV-C or chemical spray/fogging as the primary disinfection method depends heavily on the context of use and target environment. UV-C disinfection works by line-of-sight and performs well in environments with low light occlusion. Conversely, it is not effective for places with a lot of obstruction that can develop deep shadows which shelter the microbes.
Chemical spray or fogging provides volume coverage and thus, can be highly effective in nooks and crannies that UV-C irradiation cannot otherwise reach. However, it requires additional time and effort to seal the fogged environment before and after use for the disinfection to take place and may leave residual chemicals that cause harm to humans.
Developed by VTrac Robotics of Canada, the Spray Disinfecting Robot is an 136-cm tall autonomous mobile robot (AMR) that can perform automatic disinfection indoors with an optional elevator-travel function that enables multi-floor disinfection routines.
How the VHP robot disinfects Hong Kong MTR trains
One of the high-profile deployments of chemical spray disinfection robots is in the MTR trains of Hong Kong, which carries up to 75,000 passengers per hour per direction during the peak hours. To keep its trains safe for mass transit, the MTR Corporation, together with Avalon Biomedical Limited, co-invented the “Vapourised Hydrogen Peroxide Robot” or VHP Robot.
The VHP Robot is an autonomous mobile robot that trundles down the aisles of the MTR train, spraying atomized hydrogen peroxide solution that penetrate deep, narrow gaps within the train that are otherwise difficult to clean manually. Each train is consist of 8 cars and it takes about 4 hours to complete an automatic cleaning routine, a timing which fits neatly during the train’s maintenance period from 1:00am to 5:30am.
Intelligent Sterilization Robot at the Hong Kong International Airport
The Hong Kong International Airport (HKIA) is one of the world's largest airports, with two terminals totalling a combined floor area of 7.6 million square feet. Prior to Covid-19, the HKIA is also among the top ten busiest airports in the world, handling more than 70 million passengers annually.
To prepare towards an extensive cleaning regime for the large airport premises, the Hong Kong Airport Authority has employed the Intelligent Sterilization Robots from Time Medical Systems to perform disinfection of public areas and passenger facilities. The Intelligent Sterilization Robot supports both UV-C as well as chemical spray disinfection modes and has a high disinfection efficacy of covering 15,000 square feet within 3 hours.
You can discover other disinfection robots that we have not covered within this report in this list.

Continue to Page 2: Restroom Cleaning & Waste Clearing