Specialty and Architectural Lighting — Ultraviolet Light

Owners and facility managers looking for a way to disinfect the indoor air in offices, medical centers, retail stores, schools and residential care facilities will find that their HVAC system may provide the safest and most cost-effective approach. Buildings equipped with a ducted heating, ventilating and air-conditioning (HVAC) system are prime candidates for in-duct ultraviolet (UV-C) units that can provide whole-building air sanitizing. UV-C germicidal lamps emit 253.7 nanometer wavelength irradiation that, in sufficient doses,...

In addition to the deadly and debilitating impacts of COVID-19, its spread within communities has also illuminated the inadequacies of basic prevention and control strategies in place at public facilities and institutions. One of the most glaring examples is residential care facilities. There are currently (2021) over 16,000 nursing homes and long term care facilities in the U.S. Of the total confirmed COVID-19 cases in the U.S. as of April 2021, residential care facilities accounted...

Upper air ultraviolet germicidal equipment is designed to provide air disinfection within an occupied space. The louvered upper air units are wall or ceiling mounted above the "human zone" in the space, generally at 7 feet or higher. The usual UV-C 253.7 nanometer (nm) wavelength emitted by the germicidal light bulbs is directed out of the unit by the louvers and into the layer of air at or above the mounting height of the unit....

Dating back to the late 1960's and early 1970's, ultraviolet light was used to cure wood fillers and coatings on furniture. Since then, with the development of a wide range of UV curable materials and specialized equipment, UV curing has grown exponentially - widely adopted in manufacturing, graphic arts, and printing. Technically, UV curing is the polymerization of a coating, adhesive, or ink when it interacts with ultraviolet radiation. This process makes possible rapid drying...

You may have noticed that the specifications for fluorescent tubes, compact fluorescent bulbs, and ultraviolet lamps provide watts, but almost never volts. Why not? Ballasts, invisible inside the fixture, are required for all fluorescent bulbs to operate. Ballasts modify the line voltage they are connected to (120V, 277V, etc.) so the proper current is supplied to the bulb. Because ballasts are hidden, it is easy to assume the bulbs are simply operated directly off line voltage from the...

Blacklights are not merely for special effects and lighting up cool posters. They also have an important clinical use by veterinarians. These bulbs are very common for diagnosing ringworm in cats, dogs, and other animals. The most common tool veterinarians use to diagnose ringworm on pets is a Wood's Lamp, which is another name for the common blacklight bulb with a blue filter. According to Wikipedia, Wood's lamps have been used since 1925 to detect...

The performance of fluorescent tubes, compact fluorescent light bulbs, and low pressure mercury ultraviolet bulbs deteriorates in ambient temperatures that rise above certain design parameters. At high fixture and room temperatures, light output and color characteristics deteriorate. CFLs are particularly affected by this, as anyone who has had a CFL bulb in a porch light or the garage fail on a hot summer day has learned. But this effect on ultraviolet germicidal bulbs can be...

Reasonable care should be taken in both the handling of broken light bulbs and the disposal of burned out bulbs that contain mercury. For decades, fluorescent and CFL bulbs have been used widely in commercial and residential general lighting settings, but there has been a vast increase in homeowners, businesses, and institutions utilizing ultraviolet bulbs to purify air and sanitize surfaces due to the COVID-19 situation. Fluorescent tubes, compact fluorescent, UVC germicidal, UVA blacklight, metal...

While no pathogen has been discovered that is immune to ultraviolet germicidal irradiation, biofilms present a unique challenge due to their structure. They allow harmful microbes a way to protect themselves against ultraviolet penetration and are ubiquitous on Earth. Biofilms are microbial communities in a wet complex matrix attached to a solid surface. The microbes produce polysaccharides that allow them to attach to a surface, and they can be found all over the planet, including...

More people than ever are utilizing ultraviolet UVC irradiation in their homes and businesses. This increase in popularity is a direct result of the response to COVID-19 over the last eight months. One of the most common questions we receive is how to measure UVC dose or intensity at a certain distance. This is an important question, and mathematically modeling UVC intensity at certain distances can be complicated or expensive with a UVC light meter....

Most of the impact of ultraviolet disinfection is in the UV-C range. UV-B has a much lower lethality rate for microbes than UV-C. However, a phenomenon called "photoreactivation" can impact disinfection. And UV-B can help prevent photoreactivation of pathogens. What Is Photoreactivation? Photoreactivation is the process whereby microorganisms are exposed to light in the visible spectrum after exposure to ultraviolet germicidal irradiation and begin to repair themselves. Photoreactivation can lead to a portion of the...

One unpleasant discovery that many homeowners and aquarium hobbyists make is that their ponds or aquariums can quickly become a haven to aggressive algae and harmful pathogens that kill fish and plants. Cloudy water, sick marine life, and an overall unhealthy look and feel to the water are the result. But growth of algae is a common, natural occurrence, resulting from feeding, filtration of biological materials, and fish/plant activities in the water. Also, light exposure...