1. UV disinfection 1.1 Scope: for indoor air, surface of objects and water and other liquid disinfection.
1.2 UV disinfection lamps and UV sterilizers 1.2.1 UV rays used for disinfection are C-wave ultraviolet rays with a wavelength range of 200-275 nm, and the most bactericidal band is 250-270 nm. The ultraviolet light source for disinfection must be capable of generating irradiation values. A germicidal UV lamp that meets national standards.
1.2.2 For the preparation of UV disinfection lamps, graded quartz glass tubes should be used in order to obtain satisfactory UV irradiation intensity.
1.1 UV disinfection lamps can be equipped with reflectors made of materials with high UV reflectance (such as polished aluminum).
1.2.4 UV lamps required for disinfection at a voltage of 220V, ambient relative humidity of 60%, temperature of 20 ° C, the radiation of 253.7nm UV intensity shall not be less than 70uW / cm2 (ordinary 30W straight tube UV lamp in the distance lamp The tube is measured at 1 meter, the special ultraviolet lamp is measured at the distance of use, and the ultraviolet intensity meter used must be calibrated.)
1.2.5 During the use of ultraviolet light, its irradiation intensity is gradually reduced. Therefore, the intensity of ultraviolet disinfection should be measured frequently. Once it falls below the required strength, it should be replaced in time.
1.2.6 The service life of the UV disinfection lamp, that is, the lamp whose intensity is reduced to 70uW/cm2 (power ≥30w), or reduced to 70% of the original lamp intensity (power <30w= time, Not less than 1000h.
1.2.7 At present, the ultraviolet disinfection lamps used in China have the following types: (1) ordinary straight tube hot cathode low-pressure mercury ultraviolet disinfection lamp: the lamp tube is made of quartz glass or other glass with high ultraviolet transmittance, and the power is 40W. , 30W, 20W, 15w, etc. Requires the factory new lamp to radiate the intensity of 253.7nm ultraviolet light (measured at a distance of 1 meter, without a reflector): power > 30W lamp, ≥ 90uW / cm; power > 20W lamp, ≥ 60uW / cm2; power 150W lamp, ≥ 20uW/cm2. Since this lamp radiates a part of 184.9 nm ultraviolet rays while radiating ultraviolet rays of 253.7 nm. Therefore, ozone can be generated.
(2) High-intensity ultraviolet disinfection lamp: The intensity of ultraviolet radiation required to radiate 253.7 nm (measured at a distance of 1 m) is: power 30 W lamp, >180 uW/cm 2 ; 11 w lamp, >30 uW/cm 2 .
(3) Low-ozone ultraviolet disinfection lamp: It is also a hot cathode low-pressure mercury lamp, which can be straight tube type or H type; due to the special process and lamp material, ozone production is very low, and ozone production is required to be <1mg/h.
(4) High-ozone ultraviolet disinfection lamp: Due to the special process, this lamp produces a large proportion of ultraviolet light with a wavelength of 184.9 nm, so the ozone production is large.
1.2.8 UV sterilizer (1) UV air sterilizer: It is made of low ozone ultraviolet germicidal lamp and can be used for indoor air disinfection under human conditions.
(2) UV surface sterilizer: It is made of low ozone and high intensity ultraviolet germicidal lamp, so that it can achieve satisfactory disinfection effect in an instant.
(3) UV disinfection box: It is made of high-ozone and high-intensity ultraviolet germicidal lamp. On the one hand, it uses the synergistic bactericidal effect of ultraviolet light and ozone, on the other hand, it uses ozone to disinfect the parts that cannot be irradiated by ultraviolet light.
1.3 Scope and conditions 1.3.1 Ultraviolet rays can kill a variety of microorganisms, including bacterial propagules, spores, mycobacteria, viruses, fungi, rickettsia and mycoplasma, etc., where the surface contaminated by the above microorganisms, Both water and air can be sterilized by UV light.
1.3.2 Ultraviolet radiation has low energy and weak penetration. It can only kill microorganisms that are directly irradiated. Therefore, the disinfection site must be fully exposed to ultraviolet light during disinfection.
1.3.3 When using ultraviolet light to disinfect rough surfaces such as paper and fabric, it is necessary to extend the irradiation time appropriately, and both sides should be irradiated.
1.3.4 The most suitable temperature range for UV disinfection is 20-40 ° C. If the temperature is too high or too low, the disinfection effect will be affected. The disinfection time can be extended appropriately. When used for air disinfection, the relative humidity of the disinfection environment is less than 80%. As well, otherwise the irradiation time should be extended appropriately.
1.3.5 When using ultraviolet light to kill microorganisms protected by organic matter, the dose should be increased. Suspended particles in air and water can also affect disinfection.
1.4 How to use 1.4.1 Disinfection of the surface of the product (1) Irradiation method: It is best to use a portable UV sterilizer to move the light at a close distance or to illuminate with a UV light. For small items, it can be exposed to UV disinfection.
(2) Irradiation dose and time: Different types of microorganisms have different sensitivities to ultraviolet rays. When disinfecting with ultraviolet rays, it is necessary to use an irradiation dose to achieve the irradiation dose required to kill the target microorganism. When killing the general bacterial propagule, the irradiation dose should reach 10000uW.s/cm2; when killing the bacterial spore, it should reach 100000uW.s/cm2; the resistance of the virus to ultraviolet light is between the bacterial propagule and the spore; The resistance of the child is stronger than that of the bacterial spore, sometimes it needs to be irradiated to 600000 uW.s/cm2; when the target microorganism for disinfection is unknown, the irradiation dose should not be lower than 100000 uW.s/cm2. The irradiation dose is the product of the intensity of the irradiation of the ultraviolet lamp used at the surface of the irradiated article and the irradiation time. Therefore, according to the irradiation intensity of the ultraviolet light source, the time required for the irradiation can be calculated. For example, a surface sterilizer with an irradiation intensity of 70 uW/cm2 is used to illuminate the surface of the article at a close distance; the selected irradiation dose is 100000 uW.s/cm2; the time to be irradiated is: 100000 uW.s/cm2 ÷ 70 uW/cm 2 = 24 minutes.
1.4.2 Disinfection of indoor air (1) Indirect irradiation method: The high-intensity ultraviolet air sterilizer is preferred, which not only has a reliable disinfection effect, but also can be used when there is some activity in the room. Generally, it can be disinfected after being activated for 30 minutes (2) Irradiation method: Under no-one conditions in the room, ultraviolet light suspension or mobile direct irradiation can be adopted. When using indoor suspension UV disinfection, the number of indoor UV disinfection lamps (30W UV lamps, intensity >1.0 uW/cm2 at 1.0 meters) is not less than 1.5W per cubic meter. .
1.4.3 For the disinfection of water and other liquids, water or external water irradiation may be used. When using the water internal irradiation method, the ultraviolet light source shall be equipped with a quartz glass protective cover. Regardless of the method, the thickness of the water layer shall be less than 2 cm, the water flow rate is determined according to the intensity of the ultraviolet light source. After disinfection, the water must meet the national standards.
1.5 Precautions (1) During the use, the surface of the UV lamp should be kept clean. Generally, wipe it with an alcohol cotton ball every two weeks. If there is dust or oil on the surface of the lamp, wipe it at any time.
(2) When disinfecting indoor air with an ultraviolet lamp. The room should be kept clean and dry, reducing dust and water mist. The temperature should be lower than 20 °C or higher than 40 °C. When the relative humidity is greater than 60%, the irradiation time should be extended appropriately.
(3) When disinfecting the surface of the object with ultraviolet light, the irradiated surface should be directly irradiated with ultraviolet rays, and sufficient irradiation dose should be achieved. (4) The ultraviolet light source should not be irradiated to the person to avoid damage.