Description of the band of the UV UV aging test chamber
Ultraviolet (UV) light is categorized into four main bands based on its biological effects and wavelength ranges. Understanding these classifications helps in assessing their impact on human health, materials, and various applications.
The first category is the UVA band, which spans wavelengths from 320 to 400 nm. Also known as long-wave ultraviolet light, it has strong penetrating power and can pass through most transparent glass and plastic. More than 98% of UVA radiation from sunlight reaches Earth’s surface after passing through the ozone and cloud layers. UVA rays penetrate deep into the skin, reaching the dermis, where they damage elastic and collagen fibers, contributing to premature aging. At a wavelength of 360 nm, UVA aligns with the phototactic response of insects, making it useful for light traps. Additionally, UV-A light at 300–420 nm can be filtered through special colored glass tubes that block visible light, emitting only near-UV light centered at 365 nm. This is widely used in applications such as mineral identification, stage lighting, and counterfeit detection. In 2009, German and Italian scientists discovered that astaxanthin could effectively counteract UVA-induced damage to skin cells.
The second band is UVB, ranging from 275 to 320 nm. Known as medium-wave ultraviolet light, it has limited penetration and is mostly absorbed by glass. Most UVB radiation from the sun is blocked by the ozone layer, with less than 2% reaching Earth's surface. UVB is particularly intense during summer afternoons. It causes erythema (redness) and plays a role in vitamin D synthesis, but excessive exposure can lead to tanning, sunburn, and skin peeling. Special lamps, such as UVB therapy and plant growth lights, use translucent glass that blocks wavelengths below 254 nm and phosphors that emit around 300 nm.
The third band is UVC, with wavelengths between 200 and 275 nm. This is referred to as short-wave sterilizing UV due to its high energy and ability to kill microorganisms. However, it has very weak penetration and cannot pass through most transparent materials. All UVC radiation from the sun is completely absorbed by the ozone layer, protecting life on Earth. Prolonged or intense exposure to UVC can cause severe skin burns and increase the risk of skin cancer. UVC lamps are commonly used for sterilization in medical and industrial settings.
The final band is UVD, which covers wavelengths from 100 to 200 nm, also known as vacuum ultraviolet. This type of UV is highly energetic and is typically absorbed by air and most materials, limiting its practical applications. It is mainly used in specialized scientific research and certain industrial processes.
UV aging test chambers are custom-built to meet specific customer requirements, simulating environmental conditions to evaluate material durability under prolonged UV exposure. These devices are essential in industries like automotive, aerospace, and packaging, where product longevity and performance under UV stress are critical factors.
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