SAFETY
General Safety Note
Germicidal UV rays are invisible to the eye, thus present a variety of potential health hazards, including eye damage, skin burns and even the potential to cause skin cancer
Safety aspects to minimize the hazards from UV exposure
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Good engineering design
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Proper procedures
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Automatic controls
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Common sense
UVB and UVC spectrum 180~320nm is the concern for biological safety and health
Small amounts of UVB can be beneficial to health (i.e. from sunlight)
Very small levels of UVC may have no long-term effects since human cells can recover from low-level damage
Health effects on human and animals are the same as for germicidal effects of UV on microbes
Different frequencies of UV have a greater or lesser effect on skin and eyes, relative to some peak of spectral effectiveness (same to germicidal effectiveness), and the peak reaches at about 270 nm.
UV Effects on Eyes
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Actinic (photochemical) UV light is not detectable by the visual receptors in mammals
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Accidental or chronic excessive exposure to UV can cause:
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Photokeratitis
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Conjunctivitis (or Keratoconjuctivitis)
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Other corneal injuries, potentially including cataracts in the eye lens
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Lens fluorescence, pterygium, climatic droplet keratopathy (CDK)
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UV Effects on Skin
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Accidental or chronic UV radiation exposure can produce various effects on skin:
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Erythema (reddening of skin, i.e. sunburn)
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Photosensitivity
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Skin aging
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Immune system damage
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Skin cancer
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Erythema is a photochemical process in which the skin reddens due to overexposure in the UVB and UVC regions (30 J/m² at 270 nm) and UVA (sunshine) region (greater than 100,000 J/m²)
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The maximum sensitivity for the most severe type of erythema occurs between 290~300 nm (dependent on the skin pigmentation).
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UVB considered to be the major cause of skin cancer, even though it does not penetrate as deeply as UVA or react with the outer skin layer as vigorously as UVC. UVB causes base modifications in human DNA.
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UVC has the strongest genotoxic effects on DNA and directly damages DNA through base modifications, i.e. mutations of the p53 tumor suppressor gene
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For UV protection apply number 15~25 rated sunblock (benzophenone-containing lotion or other sunscreen
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A number SPF=15 sunblock is the minimum recommended for UVGI hazards, filter 92% of UVB
Personal Protective Equipment
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Eye protection equipment should meet NIOSH recommendation HSM-73-11009 for protection against UV (NIOSH 1972).
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Glass or plastic of at least 1/8 inch (3.175mm) thickness provides adequate attenuation of UV rays, or Class 2C or Class 3 Welding helmet
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Eyewear for UV protection should meet minimum standards such as:
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CSA Standard Z94.3-07
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ANSI Z87.1-2003
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Avoid wearing UV transmitting fabrics
UV Exposure on Materials
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UV exposure can cause a number of secondary effects on materials as a result of photochemical reactions and heat, including:
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Solarization
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Photodiscoloration
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Photodegradation
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Damage of plants
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Generation of ozone, which can itself degrade materials
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Damage to materials can cause equipment problems, fire hazards and unexpected costs
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Materials used in conjunction with UVGI or maybe exposed to UV irradiation should preferably be resistant to UV damage, i.e. UV-proof.
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UV-proof materials are those that will suffer no damage under extended UV exposure. Virtually, all metals are UV-proof
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UV-resistant materials are those that will suffer minimal damage under extended UV exposure.
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UV-susceptible materials are those likely to degrade significantly under extended UV exposure.
Warning
UV lamps emissions may pose a safety and health hazard, particularly to the eyes and skin. The system is NOT to be used in the presence of individuals without appropriate precautions, including the use of personal protective equipment for skin and eyes. Operator should use PPE including UVC Rated safety glasses, gloves, and should cover all exposed skin. Operator should never direct the UVC light toward him/herself or any other person. Use warning signs to prohibit individuals from entering the treatment area while the UVC light is activated.
The product must be installed in accordance with the manufacturer’s site planning recommendations, including location, dosage, and duration. Lamps contain mercury. If a lamp breaks, ventilate the room for 30 minutes and remove the parts, preferably with gloves. Put them in a sealed plastic bag and take it to your local waste facilities for recycling. Do not use a vacuum cleaner.
PROP65 Warning: This product can expose you to chemicals including Di-isodecyl Phthalate, which is known to the State of California to cause cancer and birth defects or other reproductive harm. For more information, go to www.P65Warnings.ca.gov.
Occupational Safety and Health Administration (OSHA)
The Occupational Safety and Health Administration (OSHA) does not have any mandated exposure limits to ultraviolet light. OSHA only provides technical guidance regarding protecting employees from ultraviolet laser exposure. While general information about ultraviolet contained in that guidance is described below, it is important to note that Violet Defense Technology does not currently deploy ultraviolet lasers. For more information on OSHA’s guidelines, visit https://www.osha.gov/pls/oshaweb/owadisp.show_document?p_table=INTERPRETATIONS&p_id=24755.
Ultraviolet radiation is divided into three regions: UV-A: 315-400 nanometers (nm), UV-B: 280-315 nm, and UV-C: 100-280 nm. UV can be associated with adverse health effects due to prolonged exposure and the wavelength of light.
According to OSHA’s guidelines, “exposure in the shorter UV-C and longer UV-A ranges seems less harmful to human skin. The shorter wavelengths are absorbed in the outer dead layers of the epidermis and the longer wavelengths have an initial pigment-darkening effect followed by erythema if there is exposure to excessive levels.”
“The hazards associated with skin exposure are of less importance than eye hazards.” Exposure to light may cause photokeratitis or cataracts.
National Institute for Occupational Safety and Health (NIOSH)
The National Institute for Occupational Safety and Health (NIOSH) recommends limits to exposure determined by the wavelength of UV light and intensity. NIOSH recommends that the time of exposure to an intensity of 100 microwatts per square centimeter at wavelength 254 nm not exceed 1 minute. Per the programming, UV exposure from S.A.G.E. unit for a 30-minute cycle is less than two seconds. For more information, view the recommended standards from NIOSH (https://www.cdc.gov/niosh/docs/73-11009/pdf/73-11009A.pdf).
Environmental Protection Agency (EPA)
The Environmental Protection Agency (EPA) is the governmental agency responsible for regulating ultraviolet light products. It regulates chemical disinfectants along with devices, such as equipment that generates UV light, used to control pests like bacteria and making antimicrobial claims. For more information about EPA guidelines, visit https://www.epa.gov/safepestcontrol/pesticide-devices-guide-consumers.