UV lamps, are you using them all right?
Recently, many customers have asked about the UV lamps of our biosafety cabinets, wavelength, intensity, life, and the use of precautions and other issues. Today we will talk about, UV lamp sterilization of those things, please see below:
Introduction to the basics of UV lamps
1. What is the wavelength of an ultraviolet lamp?
According to the impact of ultraviolet radiation on the human body and the different radiation wavelengths, can be divided into long-wave ultraviolet (UVA, wavelengths of 315 ~ 400 nm), medium-wave ultraviolet (UVB, wavelengths of 280 ~ 315 nm) and short-wave ultraviolet (UVC, wavelengths of 200 ~ 280 nm) three major categories. The shorter the wavelength, the higher the energy, and on the contrary, the longer the wavelength, the better the penetration.
Disinfection using UVC band of ultraviolet light, its wavelength range is 200 ~ 275nm, the strongest bactericidal effect of the wavelength of 253.7nm. UV disinfection belongs to the radiation disinfection method of a way, mainly to destroy the microbial cells of the DNA and RNA, so that the structural bonds of the break or photochemical polymerization reaction, so that the loss of reproduction and viability, to achieve the purpose of sterilization and disinfection. Ultraviolet radiation has low energy and weak penetrating power, which is mainly applicable to the disinfection of air, object surface and liquid. UV disinfection can kill a variety of microorganisms, including bacilli, viruses, fungi, bacterial propagules, spores and so on.
2. How often should the UV lamp be replaced?
UV lamp in the voltage of 220V, environmental relative humidity of 60%, temperature of 20 ℃, the radiation of 253.7nm ultraviolet intensity (intensity in use) should not be less than 70 μW/cm2, we should regularly monitor the radiation intensity of disinfection of ultraviolet radiation, when the intensity of radiation is reduced to less than the required value, it should be replaced in a timely manner.
When sterilizing indoor air with ultraviolet lamps, the room should be kept clean and dry to reduce dust and water mist, and unoccupied conditions should be carried out, and the irradiation time should be prolonged appropriately when the temperature is lower than 20 ℃ or higher than 40 ℃ and the relative humidity is greater than 60%. When used for liquid disinfection, the thickness of the water layer should not exceed 2 cm, and the speed of water flow should be determined according to the intensity of ultraviolet radiation.
The service life of the UV lamp, i.e., the time to reduce the intensity of the new lamp to 70μW/cm2 (power ≥30W), or the time to reduce the intensity of the original new lamp to 70% (power <30W), should not be less than 1000h. The UV lamp production unit should provide the actual service life. We can use the UV intensity detector in the UV lamp under the vertical distance of 1m to be verified after the test.
3. Why is it important not to have people around when sterilizing with UV lamps?
If the human body is exposed to excessive UV radiation, it can cause photochemical reactions that lead to a series of changes in the body. It is harmful to the human eyes, skin and immune system. Long-term exposure to ultraviolet light can cause electro-optical ophthalmia, and repeated episodes of electro-optical ophthalmia can lead to conjunctivitis, chronic eye and face inflammation, and even eye and face skin cancer and other lesions.
Ultraviolet light has an inhibitory effect on the body's immune system, which can cause a number of inflammatory reactions, such as skin erythema, swelling and pain, epithelial hyperplasia and the body's ability to resist external aggression decreased. UV disinfection lamp damage to the human body is and ultraviolet radiation intensity and radiation time is directly proportional to, that is, the larger the dose of irradiation, the more serious the damage to people. Therefore, when using UV disinfection lamps to disinfect, do not have people indoors.
The ozone produced during ultraviolet disinfection not only stimulates and damages the deep respiratory tract, has a mild irritating effect on the eyes and can damage the central nervous system, but also destroys the body's immune function and induces chromosomal lesions in lymphocytes, so the use of ultraviolet lamps must be in a closed space, where the person is not present under the conditions.
UV lamps on our products
1. Do our UV lamps produce ozone?
As we all know, it is mentioned in YY 0569-2011 Class II Biosafety Cabinets that it is not recommended to install UV lamps, but all the biosafety cabinets on the market are equipped with UV lamps, why is that? Because a single bacterium can reproduce hundreds, thousands or even millions of bacteria in 24 hours, which also means that even the most effective air filters can't completely remove microorganisms, so using UV sterilization is the cure.
It is impo