As they whisk visitors up 520 ft to the observation deck, the elevators in the Seattle Space Needle administer a wash of light intended to reduce viruses and pathogens in these enclosed spaces.

It’s part of the attraction’s Swiss Army Knife of tools to mitigate the spread of COVID-19, one that allowed it to quickly reopen in 2020 amidst the early phase of the pandemic.  

The lighting technology in those elevators uses a specific wavelength of ultraviolet light to perform these treatments – namely 222nm. It’s a technology that has been increasingly adopted since the beginning of the pandemic and, in addition to the Space Needle, is being used in settings like hospitals and senior centers. As many parts of the world return to travel, the technology team within our Interiors business unit is adapting the application of this lighting inside the aircraft cabin to increase passenger confidence.

Getting the right wavelength  

Using ultraviolet light for germicidal application isn’t a new frontier; in fact, it was discovered well over 100 years ago that UV light showed promise in reducing pathogens on surfaces and in the air. Early adoption in schools and hospitals proved its ability to inactivate bacteria, viruses and microorganisms.     

The pandemic has renewed interest in using Far Ultraviolet (“Far UV”) light - specifically the 222nm wavelength – to reduce virus transmission through the air. Studies have shown that when installed and used properly, 222nm Far-UV has demonstrated efficacy against viruses and other pathogens.*  In clinical studies and published reports, 222nm lamps have been found to inactivate various bacteria and viruses on targeted surfaces at prescribed dosages. Recently, 222nm lamps have been found in limited clinical testing to be capable of inactivating SARS-CoV-2 (the virus which causes COVID-19) at certain doses.  Results vary depending on installation distance and application.    

Using light to elevate aircraft cabin hygiene  

The technology team within Collins’ Interiors business unit took interest in the 222nm Far UV technology when investigating potential solutions for elevating cabin hygiene in the early months of the COVID-19 global pandemic.  

 As global commercial air traffic ground to a halt, Collins began conversations with airlines to understand their current cleaning methods and to determine how to assist in creating more robust methods of elevating hygiene standards on board.   

Borne out of this was Lilac 222nm, a lighting system for the aircraft cabin that, when properly applied, reduces certain viruses and bacteria on targeted surfaces during flight using Far-UV light. Lilac gets its name from the faint violet hue that’s emitted when its lamps are activated during a cleaning cycle.   

The first application of Lilac 222nm is intended for the interior of the aircraft lavatory by administering light onto frequently-touched surfaces including the sink, toilet and door. The system is set up to operate only between passenger visits; occupancy sensors inside the lavatory detect when the space is empty before automatically initiating each cleaning cycle.

Developing for use in aircraft cabin spaces  

Given that 222nm lamp technology is not new, the real work in bringing Lilac 222nm into the aircraft cabin involved several considerations, including integration of an aircraft compatible power source, occupancy detection and cabin materials compatibility.   

 The team had to determine if long-term exposure from Far-UV lamps had any effect on the materials and surfaces commonly used in lavatory spaces, from degradation to discoloration. Collins’ internal testing confirmed that materials remained robust, and an indiscernible amount of surface discoloration was observed over a very long period of exposure – results that aligned with a similar evaluation of materials conducted by Boeing.   

Development of the sensing technology was a critical step in tailoring the system for automated performance in the lavatory. The system architecture was created to automatically detect occupancy inside the space, determining when a passenger has left the lavatory and activating a cleaning cycle before the next passenger enters.  

 Beyond the lavatory environment, the technology team is exploring its use throughout the aircraft cabin. Potential areas for implementation include galley and cockpit spaces, and eventually main seating areas of the cabin.

Flight testing aboard Boeing’s ecoDemonstrator aircraft  

While lab testing has gotten the team far in proving out the Lilac 222nm lighting system, on-aircraft testing provides a distinct advantage in ensuring the system is suitable for the rigors of regular passenger travel. That’s why the team has partnered with Boeing to install two systems on the 2022 Boeing ecoDemonstrator, a 777-200ER aircraft that will be used to test out various technologies in an operational environment.   

 As they look at Lilac 222nm’s potential use in cabin spaces beyond the lavatory, the technology team has installed two systems in the ecoDemonstrator’s cabin, with one in a galley space and the other in the ceiling of a passenger area at the rear of the aircraft. Installation of the systems in these cabin spaces will allow the team to verify the coverage and occupancy-sensing technologies. 

New technology for a new normal 

Realizing a solution like Lilac 222nm in lavatory spaces is a step in providing an additional layer of confidence in the cleanliness of the aircraft as the public resumes more normal travel activities. It also opens the door for greater adoption of 222nm Far UV lighting in occupied aircraft cabin spaces, as the public becomes more knowledgeable and comfortable with the technology.  

Collins has partnered with Boeing to accelerate the deployment of additional safe and effective methods to make commercial aircraft more hygienic during flight. This partnership combines Boeing’s years of research in 222nm with Collins’ technology and integration expertise to implement a comprehensive solution. 

With the world more attuned to mitigating the spread of germs and viruses in light of the COVID-19 pandemic, incorporating technology tools like Lilac 222nm to raise hygiene levels is integral in elevating the overall onboard experience for passengers and crew alike.  

*As published in a 2020 study conducted by Hiroshima University under lab conditions at a distance of 24cm, a dose of 1 and 3 mJ/cm2 of 222nm resulted in an 88.5% and 99.7% reduction of SARS-CoV-2, respectively.  This testing occurred over a 30-second period.  Collins’ Lilac 22nm system uses these results as a baseline for performance, as it is assumed that a typical lavatory installation will operate at a similar duration and dose for each cycle.  Results in specific aircraft or other environments have not been tested. 

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