Ultraviolet sterilization is a traditional and effective disinfection method. It has been widely used in hospitals, food factories, water treatment, etc., but it is affected by many factors during use, especially the low radiation intensity of the lamp and improper application. Disinfection and sterilization effect. In order to ensure a satisfactory disinfection effect, we mainly implemented the following monitoring and management measures during use.
1. The radiation intensity of the lamp:
Ultraviolet radiation intensity is the most basic factor that affects the disinfection effect. According to the requirements of the "Disinfection Technical Specification", the radiation intensity of the new ultraviolet lamp should be greater than 100VW/cm2 (at a distance of 1m) to be qualified. The radiation intensity of the lamp in use The minimum should reach 70VW/cm2 and can be used temporarily, but the irradiation time must be extended. According to the formula that the ultraviolet radiation dose is equal to the radiation intensity multiplied by the radiation time, the extended radiation time required for different intensities can be obtained. It can also be seen that high intensity short time or low-intensity long time can achieve the same sterilization effect. If the intensity of the ultraviolet light source is lower than 40VW/cm2, the bactericidal effect will not be satisfied even if the irradiation time is prolonged, and the use should be stopped. Don't think that as long as the UV lamp is on, it will have a sterilization effect.
2. The number of lamps installed
According to the “Disinfection Technical Specifications” issued by the Ministry of Health, the third edition of the second sub-volume (Hospital Disinfection Specifications), the number of indoor suspended ultraviolet disinfection lamps installed (30 W ultraviolet lamps, the radiation intensity is higher than 70μW/cm at a vertical position of 1m) 2) The average is not less than 1.5 W per cubic meter, and it is required to be evenly distributed, and the lifting height is 1.8 to 2.2 m from the ground so that the human breathing belt is in the effective irradiation range. Continuous irradiation is not less than 30 minutes, the intensity of ultraviolet radiation is inversely proportional to the radiation distance, and the suspension is too high, which will affect the sterilization effect. If the surface of the object is disinfected, the distance between the lamp tube and the irradiated surface should be 1m for the disinfection to be effective.
3. Ambient temperature
The ambient temperature has a certain influence on the intensity of ultraviolet radiation. Too high or too low temperature will reduce the radiation intensity. If the temperature drops to 4 ℃, the radiation intensity can be reduced by about 65% to 80%, which seriously affects the sterilization effect. Generally, room temperature 20 ～ 40 ℃ is the suitable temperature for ultraviolet disinfection. In this temperature range, the intensity of ultraviolet radiation is the largest and stable, which can achieve the ideal disinfection effect.
4. Relative humidity
With high relative humidity, the penetration of ultraviolet radiation into cells is reduced. According to relevant literature, when the relative humidity is 55% to 60%, ultraviolet rays have the strongest killing rate of microorganisms. When the relative humidity is above 60% to 70%, the sensitivity of microorganisms to ultraviolet rays is reduced, and the relative humidity is above 80% or even, On the contrary, it has an activating effect on microorganisms, which can reduce the bactericidal power by 30% to 40%. UV disinfection immediately after mopping the floor and wiping the tabletop will increase the indoor humidity and affect the disinfection effect. Therefore, the room should be kept clean and dry when using ultraviolet disinfection.
5. Prevent UV radiation damage
It is mainly to prevent ultraviolet radiation from radiating damage to the eyes and the exposed skin of the face. Do not look directly at the lamp to prevent conjunctivitis. Do not allow the ultraviolet light source to directly irradiate people to prevent erythema on the skin. Ultraviolet rays can emit ozone, and too much ozone can poison people. In a human working environment, the concentration of ozone should not exceed 0.3mg/m3. UV radiation should be carried out when the room is unoccupied. When conducting radiation intensity monitoring, use a special radiation intensity detection tool ruler to observe the light source with your back. Ordinary glass or sunglasses can be used as a protective mask, and protective glasses can protect the eyes and facial skin.
6. Regular cleaning of the lamp
Dust and grease on the surface of the ultraviolet lamp will hinder the penetration of ultraviolet rays. Pay attention to the wiping and cleaning of the lamp during use. Before using the new lamp, wipe it with a 75% alcohol cotton ball. Generally, wipe once every 2 weeks during use. When dust or oil stains are found on the surface of the lamp, wipe it at any time to keep the lamp clean and transparent, so as not to affect the penetration and radiation intensity of ultraviolet rays.
7. Strengthen the monitoring of UV lamp radiation intensity
The ultraviolet lamp in use should be tested for intensity with an ultraviolet radiation illuminance meter within 3 to 6 months. If the intensity is found to be unqualified, the lamp should be replaced in time. Use the ultraviolet radiation illuminance meter to make a measurement calibration once a year to maintain accuracy. During the monitoring, the measurement conditions in the "Disinfection Technical Specifications" must be followed, the voltage is 220V, the temperature is above 20 ℃, and the relative humidity is less than 60%. The stable intensity after turning on the lamp for 5 minutes is the radiation intensity of the ultraviolet germicidal lamp. It can also be measured with a chemical indicator card of ultraviolet radiation intensity. When the indicator card is irradiated 1m away from the lamp tube for 1 minute, the photosensitive paint changes from white to purple-red. Compared with the standard color block, the lamp radiation intensity can be known.
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