Ultraviolet (UV) radiation is widely used in industrial, medical, and dental processes and practices for a variety of purposes, including killing bacteria, creating fluorescent effects, curing inks and resins, phototherapy, and sun-tanning. Some exposure to UV radiation is beneficial, but excessive UV exposure has extremely harmful effects to skin, eyes, and the immune system. Due to these damaging effects of UV radiation, ANSI/IES RP 27.1-22- Recommended Practice: Risk Group Classification And Minimization Of Photobiological Hazards From Ultraviolet Lamps And Lamp Systems covers safety recommendations and risk group classifications and assessments for lamps designed to emit UV radiant energy.
The Risk of Ultraviolet (UV) Lamp Systems
Ultraviolet (UV) radiation can cause severe burns (of the skin) and eye injuries (photokeratitis), as well as other hazards like erythema (sunburn), skin cancer, increased skin pigmentation (tanning), and cataracts. There are no immediate warning symptoms to indicate overexposure to UV radiation, since symptoms typically appear hours after exposure has occurred. UV lamp systems therefore may pose optical radiation hazards during use, so it is crucial to require risk assessment for direct and indirect exposure of the eyes and skin. These necessary risk assessments are detailed in ANSI/IES RP 27.1-22.
What is ANSI/IES RP 27.1-22?
This recommended practice summarizes the photobiological hazards of exposure to ultraviolet (UV) radiation and provides recommendations to minimize the risks of such effects from ultraviolet lamps and lamp systems. The American National Standard provides risk group classification for all ultraviolet lamp systems, and the measurement conditions for different applications.
Recommended Practices in ANSI/IES RP 27.1-22
The recommendations in ANSI/IES RP 27.1-22 apply to the following:
- Lamps and lamp systems designed primarily to emit ultraviolet (UV) radiant energy for consumer, industrial, scientific, and medical applications.
- Lamps and lamp systems where more than half of the optical radiation emitted between 180 nm and 3,000 nm is in the spectral region 180 nm to 400 nm.
- If more than half of the optical radiation emitted between 180 nm to 3,000 nm is outside of the spectral region 180 nm to 400 nm, then the base standard, ANSI/IES RP-27-20 Recommended Practice: Photobiological Safety For Lighting Systems, applies. ANSI/IES RP-27-20 applies to optical radiation hazards from all types of lamps or other broadband light sources, addressing LEDs, incandescent, low- and high-pressure gas-discharge, arc, and other lamps.
It is important to note that ANSI/IES RP 27.1-22 does not apply to general lighting sources (GLS) or laser systems.
What Are the Types of Ultraviolet (UV) Rays?
There are three types of UV rays based on their wavelengths between 100-400 nm:
- Ultraviolet A rays (UV-A): Long-wave UV that covers the range 100-400 nm. The atmosphere does not significantly filter UV-A rays. These rays cause skin aging, eye damage, and contribute to the risk of skin cancer. Although UV-A is less intense than UV-B, it is more prevalent and can penetrate deeper into the skin layers, impacting the connective tissue and blood vessels, resulting in premature aging.
- Ultraviolet B rays (UV-B): Medium- wave UV that covers 280-315 nm. The atmosphere shields humans from most UV-B rays. These rays cause sunburn, skin burns, tanning, wrinkling, aging of the skin and skin cancer. The eyes are most sensitive to UV radiation from 210 nm to 320 nm (UV-B and UV-C).
- Ultraviolet C rays (UV-C): Short-wave UV that covers the range 100-280 nm. These rays do not reach Earth’s surface because they are completely absorbed by the ozone layer. They are in artificial sources like germicidal lamps to kill bacteria and viruses, and this light can burn the skin and cause skin cancer. Even though UV-C does not affect people, it poses the maximum risk as it is highest energy portion on the UV spectrum.
When Is Ultraviolet (UV) Radiation Used?
Moderate UV exposure is essential for good health as it stimulates vitamin D production in the body and hence leads to improvement in mood and increased energy. Vitamin D aids in the regulation of calcium metabolism, insulin secretion, blood pressure, immunity, and cell propagation; higher levels of vitamin D have been correlated to lower rates of heart disease, stroke, and diabetes, along with a tendency towards lower blood pressure. Exposing patients with high blood pressure and a vitamin D deficiency with UV-B can lower their blood pressure.
Besides exposure to vitamin D, UV radiation is used for therapy, air purification, and sterilization. UV-B lamps can be a skin treatment aid for conditions such as psoriasis (scaly and itchy red patches on skin) and vitiligo (skin patches that lost pigment). UV-C radiation can be beneficial for air purification, breaking down indoor environmental contaminants. Lastly, UV-C LED can be applied to a variety of sterilization and disinfection applications to sterilize tools, workspaces, and drinking water, and it can kill microorganisms. This is useful in medical and biology labs, wastewater treatment facilities, and the food processing industry.