UV Disinfection Lamp Test Methods And Standards Interpretation

This article interprets the relevant test methods and standards for the UV disinfection lamp and aims to introduce the quality requirements for UV disinfection lamps and their evaluation methods

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1 Introduction

2 Test Standard Introduction

3 Technical requirements and test methods

1. Product classification
2. Safety requirements
3. UV radiation efficiency / radiation flux
4. UV radiation illumination
5. Ozone output rate
6. UV radiation flux maintenance rate/lifetime
7. UVC air disinfector
8. UV disinfection equipment in water
9. UV lamp disinfection efficacy identification test

4 UV disinfection lamp scope of application and conditions

5 Conclusion

1 Introduction

The germicidal effect of UVC has been known since the 19th century, but the production conditions at that time prevented the realization of UVC-related derivatives, but the attention and research on UVC played a major role in the later development of UVC. In the early 20th century, mercury lamps were used as artificial UV light sources, and the first quartz UV lamps were manufactured and widely used for water disinfection.

UV is an electromagnetic wave with wavelengths from 100 nm to 400 nm. Pathogenic microorganisms are most sensitive to UV at wavelengths from 200 nm to 280 nm, and after absorbing UV at that wavelength, their DNA or RNA is destroyed, causing the cells to stop dividing in order to inactivate pathogenic microorganisms. Based on the excellent germicidal disinfection effect of UVC, UVC disinfection lamps are widely used in the field of disinfection. UV disinfection lamp is a kind of low-pressure mercury vapor discharge lamp using quartz glass, or other violet glass, whose discharge produces ultraviolet radiation at a wavelength of 253.7 nm, which has a very good effect on pathogenic microorganisms to achieve the purpose of disinfection and sterilization. At home, it can be placed in the kitchen, bathroom, and other dark and humid places where bacteria are easy to breed; in public places, it can effectively alleviate the carrying and spreading of germs caused by dense personnel and prevent cross-infection among personnel; it can also be used in spaces with high requirements for environmental quality, such as wards, operating rooms and other medical places to prevent the spread of germs. UV disinfection lamps are widely used in environmental air disinfection, drinking water, and sewage disinfection, clothing and tableware surface disinfection, and other fields.

2 Test Standard Introduction

The current standards for evaluating the quality of UV disinfection lamps and their related products are GB/T 19258-2012 “Ultraviolet Germicidal Lamps”, GB/T 28795-2012 “Cold Cathode Ultraviolet Germicidal Lamps”; YY/T 0160-1994 “Straight Tube Shaped Quartz Ultraviolet Low-Pressure Mercury Disinfection Lamps”; GB/T 19837-2005 “Ultraviolet Disinfection Equipment for Urban Water Supply and Drainage”; GB 28235-2011 “Safety and Health Standards for Ultraviolet Air Disinfectors”; “Disinfection Technical Specification” (2002 version).

The standard mainly specifies the quality requirements of UV disinfection lamps and their effectiveness in different fields in terms of product classification, electrical safety, radiation efficiency, radiation illumination, ozone output rate, life span, disinfection effect, etc.

3 Technical requirements and test methods

1. Product classification

According to GB/T 19258 in the UV sterilization lamp classification, there are two, first, according to the product shape can be divided into the double-ended lamp, single-ended lamp, and self-ballasted lamp three categories; second, according to whether to produce ozone can be divided into ozone-containing and non-ozone two. In addition to the above two classifications, different UV disinfection lamps used in the diameter of the lamp and output power is also different.

2 Safety requirements

GB 19258, according to the different shapes of the UVC germicidal lamp, its safety requirements, size, start characteristics and initial electrical parameters’ performance, according to the standards and requirements are shown in Table 1 for testing and meet the relevant requirements.

UVC germicidal lamps should be in line with the above requirements, the glass tube, and the lamp should also be confirmed through visual inspection and gauge inspection to meet the relevant requirements to ensure that normal use will not be dangerous to users and the surrounding environment, safe and reliable.

3. UV radiation efficiency / radiation flux

(1) limit requirements

GB/T 19258, double-ended lamp, and single-ended lamp UV radiation efficiency should be in line with the provisions of Table 2. Self-ballasted lamps should be no less than 85% of the single-ended lamp requirements in Table 2.

Table 2 for the parameters of the double-tube class lamp requirements, four-tube, multi-tube, square, and ring-shaped lamp data as specified in the table for 90% of the value of the requirements. The measured value of the radiation flux should not be less than 90% of the nominal value.

(2)Testing method

The radiation flux measurement system should be consistent with Figure 1, the requirements of the integral sphere used should be the inner wall of the UV non-absorbing, non-fluorescent diffuse reflective coating; tester center wavelength 253.7nm; the standard lamp selected and the shape of the lamp to be tested similarly.

Figure 1 Measurement system of radiation flux

The radiation flux is calculated according to the formula.

Where.

— the total radiant flux of the lamp to be tested.

—–

–the measured photocurrent values of the standard lamp and the lamp to be tested, respectively

—–

–The total radiation flux of the standard lamp

—–

α–Absorption correction factor.

The UV radiation efficiency is calculated by Eq.

Where.

ηe253.7 – the UV radiation efficiency of the lamp at a wavelength of 253.7 nm.

P – the input power of the lamp.

4. UV radiation illumination

(1) limit value requirements

Double-ended lamps and single-ended lamps should be no less than 93% of the initial UV radiation illumination required in Table 3 and Table 4.

(2) Test method

The measurement of UV radiation illuminance needs to be carried out on the photometric bench shown in Figure 2. In Figure 2: 1 – lamp; 2 – positioning table; 3 – UV probe; 4 – optical track; 5 – diaphragm.

In order to avoid stray light errors, the whole test system needs to be located in a dark room with black painted walls, and a UV radiation illuminance meter with a central wavelength of 253.7 nm should be used for the test.

The test lamp is fixed on the rail, ignite the lamp, adjust the position so that the horizontal normal of the middle of the lamp through the UV radiation illuminance meter probe, and the distance between the two for 1000 mm ± 1 mm. to be lit UV lamp warm-up 20 min after reading the illuminance meter readings, recorded as the UV radiation illuminance of the lamp to be tested.

5. Ozone output rate

(1) Limit value requirements

GB/T 19258, no ozone lamp should be less than 0.05g / (kW – h); with ozone, lamp should not be less than 80% of the nominal value.

(2) Test methods

The test is conducted under the environmental conditions specified in the standard, and the lamp to be tested should be connected to the test line using the reference ballast. The test system is shown in Figure 3. The ozone output rate is calculated by the formula.

N = 3600c × V / (t × P)

Where.
N – ozone output rate, g/(kW-h).
c – ozone concentration, mg/ m³.
V – ozone collector volume, m³.
t – time, s.
P – lamp power, W

6. UV radiation flux maintenance rate/lifetime

(1) Limit requirements

GB/T 19258 in the provisions of the average life of the germicidal UV lamp should not be less than 5000h. 2000h UV radiation flux maintenance rate of not less than 85%, the end of life when the UV radiation flux maintenance rate of not less than 65%.

(2) Test method

The test should be conducted in an environment of 15 ℃ ~ 50 ℃, no convective wind. The ballast used should be matched with the test lamp to ensure that the power consumed by the UV lamp overdue rated value of the difference does not exceed 4%, the measured voltage and rated value of the deviation should not exceed 2%, in the rated voltage of the preheat current and the corresponding parameters’ table deviation should be less than 10% of the specified value. Lamp to ignite 165 min, close 15 min as a cycle, calculate the single lamp UV radiation flux down to the specified value of the cumulative time or can not be properly lit time.

7. UVC air disinfector

Ultraviolet air disinfector is composed of ultraviolet germicidal lamps, filters and fans for the components of air disinfection products, inspection is based on GB 28235, the product is mainly used for the disinfection of indoor air. For its use of ultraviolet disinfection lamp should meet the requirements of GB/T 19258, in addition to the air disinfector machine also increased the disinfection effect and leakage evaluation requirements.

The evaluation method of disinfection effect is determined according to the method specified in the “Disinfection Technical Specification” (2002 edition), which requires the killing rate of white staphylococcus ≥ 99.90%. Leakage requirements are evaluated from two aspects, one is the UV leakage, which requires that the UV leakage should be ≤ 5μW/cm3 at 30 cm around the disinfection device; the other is the ozone leakage, which requires that the disinfector should not exceed 0.1 mg/m³ of the maximum allowable 1h average concentration of ozone in the indoor air during normal operation. In addition, the safety indicators of the disinfector should also comply with the provisions of GB9706.1; noise should be tested in accordance with the test method specified in GBZ/T 189.8, the noise limit does not exceed 55dB (A).

8. UV disinfection equipment in water

GB/T 19837 specifies the life of the UV lamp, the effective dose, disinfection indicators and other requirements. Specified low-pressure lamp and low-pressure high-intensity lamp operating life should not be less than 12000h, medium-pressure lamp life should not be less than 3000h. When it is used for sewage disinfection, the effective dose should be ≥ 15mJ/cm², for drinking water or drinking water disinfection effective dose should be ≥ 40mJ/cm², for the disinfection of reclaimed water effective dose should be ≥ 80mJ/cm².

Disinfection index requirements, UV disinfection equipment applied to drinking water should meet GB 5749, urban sewage should meet GB 18918, urban Miscellaneous water should reach GB/T 18920, landscape environment water should reach GB50335 and other relevant standards in the relevant test methods and requirements.

9. UV lamp disinfection efficacy identification test

According to the requirements of the “Disinfection Technical Specification”, UV lamp disinfection efficacy and sterilization effect test should be conducted, 30W UV lamp, irradiance should be ≥ 90μW/cm² at the center of the lamp below 1000 mm. In addition to testing irradiance In addition, bacteria and fungi should also be carried out to kill the effect of the test, the test requirements of the UV disinfection lamp to kill the pair of values are ≥ 3, can be judged to be disinfection qualified.

4 UV disinfection lamp scope of application and conditions

Due to the weak penetrating power of UV irradiation, its disinfection effective area is only 1.5 m ~ 2 m around the device, in order to ensure a good disinfection effect, the distance between the UV disinfection lamp and the disinfected part should not exceed 1 m, and can not penetrate the surface of the object, so to ensure that the UV fully irradiated disinfection surface. When using UV disinfection, the appropriate temperature range is (30±10)℃, the temperature above or below this temperature will weaken the UV and affect the disinfection effect, when the UV is used for air disinfection, the relative humidity should not exceed 80%, can not meet the requirements of the above conditions, the irradiation time should be extended to ensure the disinfection effect. When disinfecting the surface of goods, the required irradiation time is about 24 min according to the dose required to kill most microorganisms, when disinfecting indoor air, the irradiation time should be no less than 30 min, and because of the weak penetration ability of UV light, a UV disinfection lamp may be difficult to ensure the indoor disinfection effect, according to the “Disinfection Technical Specification” (2002 version), generally according to each cubic meter of space should set not less than 1.5W UV disinfection lamp, according to the actual size of the room to choose the appropriate power of UV disinfection lamp.

Due to the destructive effect of ultraviolet light on biological cells, when using UV disinfection lamps should be careful not to directly irradiate the human skin, which can lead to redness, swelling, pain, and itching of the skin surface, and even cause cancer in severe cases; and do not directly use your eyes to look directly at the lamp, which can cause inflammation of the cornea and other symptoms, and can cause irreversible damage in serious cases. UV disinfection lamp in use, first, should ensure that personnel away from the disinfection area to prevent UV damage to the human body; and should keep the surface of the UV lamp clean, it is recommended that every two weeks with alcohol cotton balls on the surface to It is recommended that the surface be wiped once every two weeks with alcohol cotton balls to ensure that the lamp surface is free of dust and oil. At the same time, according to UV disinfector use conditions, the temperature and humidity in the room should also be noted, the temperature is too high or too low, it will affect the intensity of ultraviolet radiation, and when the water and dust content in the air is high, it will affect the intensity of UV radiation. When the water and dust content in the air is high, it will also have a certain weakening effect on ultraviolet light. So to ensure that the indoor environment is clean and dry, more conducive to UV disinfection The sterilization efficacy of the lamp.

5 Conclusion

After more than 100 years of development, UV disinfection equipment and related technologies have become very mature, and in addition to industrial applications, they are now also becoming widely used in the home, becoming an important means of disinfection at home. Compared with the common use of chemical disinfection in the home, UV disinfection is safer, less pollution, and sterilization effect is significantly better than chemical disinfection, and the life of UV lamps is relatively long, the average life of 8000 hours, some high-performance products can reach more than 10,000 hours, coupled with low prices, the cost of use is very low, it is increasingly favored by Consumers are increasingly popular.

With the widespread use of UV disinfection lamps, the development of related standards has become particularly significant. UVC disinfection lamps and related equipment for home use should be established as soon as a possible standard system and quality supervision system to ensure quality and safety. At the same time, the market for related products should be regulated to ensure that consumers can purchase The UVC disinfection lamps with guaranteed safety and performance quality should be established as soon as possible.

References

[1] Bottle washing wastewater reuse treatment project in brewing industry [J]. Guo H, Chen GW, Ding ZW. Industrial water and wastewater. 2012(02)