On the heels of Signify announcing it is cranking up production of ultraviolet-C-band (UV-C) lamps proven to kill the coronavirus in a lab, Osram said that it, too is ramping up output of a similar product, which like Signify’s uses conventional mercury discharge, not LED technology.
Osram said Chinese hospitals in Wuhan and Beijing have installed 2000 of the company’s 254-nm (253.7-nm, to be precise) ultraviolet AirZing tube lamps, and that it has supplied about 10,000 to children’s nurseries.
While Osram did not rule out eventually using LED technology for UV-C, and told LEDs Magazine that it is working on such a product, its 30-year-old mercury product is now getting the call in the fight against COVID-19.
“We are working hard to increase the production volume of our UV-C disinfection systems because they can make an important contribution to the fight against coronavirus,” said Wilhelm Nehring, CEO of Osram’s digital business unit. Osram makes its AirZing line in Kunshan, China, where it currently has a capacity of 35,000 units per month. The lamp is the size of a T8 but uses a different glass — without a fluorescent coating — to deliver a higher transmission rate, Osram told LEDs Magazine.
It is the same general type of lamp that Osram rival Signify provided to a Boston University lab, where a research team showed that the UV radiation killed 99% of SARS-CoV-2, commonly known as the coronavirus, which causes COVID-19. Whether the lamp would be equally effective outside of a lab is another question, but the Boston team said that a larger dose than what it used could deactivate over 99.9% of the virus.
Unlike Signify, Osram did not cite a study showing the light’s effectiveness on SARS-CoV-2. It told LEDs that a team at China’s Guangdong Detection Center of Microbiology determined that an AirZing model 5040 lamp provided by Osram China Lighting Ltd. killed 99.8% and 99.9% of a similar virus, H3N2, in a series of six “air virus elimination tests” that started in March and concluded on May 6. Coronavirus samples were not available at the time of testing, Osram said.
It also noted that in February it donated more than 1000 AirZing 5040s to Wuhan hospitals, where “the positive effect was measurable.”
Osram pointed to a paper by the International Ultraviolet Association which states that light (or more properly, radiation in the UV-C band, which is not visible light) — defined by the IUVA as between 200 and 280 nm — “inactivates (aka, ‘kills’) at least two other coronaviruses that are near-relatives of the COVID-19 virus: 1) SARS-CoV-1and 2) MERS-CoV.”
The IUVA fact sheet added, “An important caveat is this inactivation has been demonstrated under controlled conditions in the laboratory. The effectiveness of UV light in practice depends on factors such the exposure time and the ability of the UV light to reach the viruses in water, air, and in the folds and crevices of materials and surfaces.”
Some observers have questioned whether lab results show whether the light can effectively penetrate a droplet that might carry the virus in aerosol form.
UV-C lighting has been used extensively for more than 40 years in disinfecting drinking water, waste water, air, pharmaceutical products, and surfaces against a whole suite of human pathogens, the IUVA noted.
All ultraviolet light is shorter than visible light. Two bands that have longer wavelengths than UV-C — UV-A (the longest, and the nearest to visible light) and UV-B — can be effective against bacteria, but they are not regarded as virus killers.
UV-C is dangerous to human skin and eyes, so Osram outfits the AirZing with sensors that turn off the light when a person enters a room.
“UV-C light should only be used by trained staff,” Osram cautioned.
The company told LEDs that it received European CE and US UL safety certification in May. It is offering the lamps in Europe having started in Italy in May, and plans to offer them in the US in July.
The availability of the mercury lamp in the Osram’s stable might be a surprise to some observers, as Osram is generally known to be exiting the lamp business (with a notable exception being horticultural lighting) in order to focus on optical chips and photonics.
“We’ve been still in [the] lamps business for certain industrial applications where a change to LED is still not feasible from technical or commercial standpoint, including the UV-C business,” it told LEDs.
It also said that LEDs could eventually be up to the task of fighting viruses economically, and that Osram’s chip division, called Osram Opto Semiconductors (OS), is working on it.
“The cost and performance ratio for LED is still not in the right balance for mass production and all applications,” a spokesperson told LEDs, echoing a point made by Signify CEO Eric Rondolat. “But Osram OS is working on it as well with high speed. The clear way to go for Osram beside our lamps and new fixtures is the UV-C LED technology where the price/performance ratio is currently not on the same level like for lamps but it is improving rapidly.”
The possibilities of LEDs as a source for UV-C are getting increasing attention, and germicidal UV-C was the subject of an informative talk by Bob Karlicek, director of the Center for Lighting Enabled Systems & Applications (LESA) at Rensselaer Polytechnic Institute, in a recent LEDs Magazine webinar.
One technology that Osram has ruled out, however, is “far UV-C”, which is even shorter-wavelength UV light. Some believe it can be a safer light than UV-C while still killing viruses, and are examining it in particular at 222 nm. Its technology includes discharge sources as well as lasers. LESA’s Karlicek maintained that it won’t be suitable for LEDs.
Osram said it stopped making far UV-C products over 10 years ago.
MARK HALPER is a contributing editor for LEDs Magazine, and an energy, technology, and business journalist ([email protected]m).
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