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Why are most UV lamps on the market ineffective?

Time: 2020-07-01

With the spread of viruses and bacteria, many products are becoming more and more popular, such as UV lamps. Nowadays, the market is flooded with a large number of UV lamps, some of which can indeed provide sterilization effect, while others may even cause harm to the human body.


Under the situation, it's necessary for us, especially international buyers, to master the basic knowledge of UV lamps. The key issues that need to be solved include whether the UV light can sterilize, and how to choose the appropriate UV lamp.


different uv lamps


Is UV light for disinfection effective?


Of course, it works. UV light sterilization is not a new thchnology, it was discovered in 1879 and then widely used in the 20th century,  cause UV light has a shorter wavelength than visible light and can penetrate and destroy the viruses and bacteria.


A large number of studies have shown that UV light can kill more than 99% of viruses, bacterial, and fungi in a short time. Because of the effectiveness, various types of UV lamps for sterilization have been developed, which makes it difficult to determine which UV lamps will provide the best results for the facility.


Please note that one of the most efficient and effective UV applications is air sterilization. Because UV light has no refraction ability and are easily blocked by other substances, only in a confined space can UV light achieve the best sterilization result.


In a confined space, UV light can sterilize the viruses & bacteria even when they are in a high-speed flow air, and then improve the air quality without chemical residues.


Due to the wide range of applications for UV light, you need to determine the best UV lamp depends on the project you are working on.


Related KnowledgeCan UVC light kill the viruses and bacteria?


Different UV lamps and their features


Nowadays, there are four main UV lamps on the market, they are UV Mercury Lamp, UVC Sterilizing Wand, UVC Sterilizing Box and UVLED+Photocatalyst.


Type one: UV Mercury Lamp 


UV Mercury Lamp, popular for the low cost and high power but not suitable for family use. Why? There are three reasons:

 

1. "Mercury" is a toxic substance in UV Lamps

 

If mercury accidentally leaks, it is very harmful to the human body, also risky for food&water. And According to the Minamata Convention on Mercury, China will not produce and sell such UV lamps starting since the year 2021.


2. Such UV lamps will produces ozone.

 

There are two main wavelengths of UV mercury lamp: 254nm and 185nm. Besides 254 nm indeed can kill viruses. Ozone will be produced when 185nm wavelength combined with oxygen.


Although ozone has a disinfecting effect, it is harmful to humans, which may cause pharyngitis and even neurotoxicity. This is why the window must be opened for 30-60 minutes after using such a UV lamp.

 

3. Such UV lamps are not portable.

 

UV mercury lamps are big (at least 40cm height or above) and long strip shapes, which leads to narrow applications. We cannot combined it with other applicances.


Therefore, UV mercury lamps are more suitable for industrial scenes.


However, in the household scene, because ultraviolet rays are harmful to the human body, there will be higher requirements for operation.


Once your child collided with the UV lamp and broke the tube, mercury will flowe out. Or once there is no venrilation for 30 minutes after the operation of UV lamps...These injuries are very dangerous and irreversible.


Type Two: UVC Sterilizing Wand


This type of UV lamp solves the cost problem and also publicizes that if the item is scanned 5-10 times by lamp, the bacteria and viruses will disappear immediately.

 

However, in the eyes of professionals, this kind of UV lamp has only a psychological effect.

 

Although UVC does have a Sterilization effect, its effect is a combination of ultraviolet energy and irradiation time.

 

Related Knowledge: Which UV light is the best?

 

In the case of sufficient UV dose, bacteria can be completely killed. However, if it is insufficient, the bacteria will only temporarily lose activity, and then slowly repair their own structure.

 

According to the industry standard, the UV dose required for a 99.99% inactivation rate is 40mJ / cm2.


 uv dose

 

If converted into the radiant power of UVC LED,  a 40 milliwatts UV lamp needs to radiate per square centimeter for 1 second. 40mW.S/cm2).

 

Does it mean 10 seconds of irradiation can achieve sterilization effect since most UVC LEDs on the market are  4 milliwatts?

 

Unfortunately, according to the test, when it is 1cm above the object, the UV radiation area is 20.71 square centimeters.

 

uvc dose

 

Further considering the decay of UVC in the air, under the requirement of 40 millijoules, such a UV lamp needs to be irradiated for 13.3 minutes to achieve the sterilization effect, and keep 1 cm away from the object.

 

In summary, this UVC Sterilizing Wand makes no sense for consumers, because no one will use the wand for 13 minutes.


Type Three: UVC Sterilization Box


As for the UVC Sterilization Box, is a more suitable application. Why? Because it's the most cost-effective sterilization solution.

 

Based on the high cost of UVC LED and the fast decay rate, it is currently impossible to achieve efficient sterilization.

 

But if the UVC LED is placed in a confined space, all problems will be solved. Due to the reflection of light, the decay of UVC will be relatively reduced. And the confined space will allow more time for the sterilization process.

 

For example, we can put mobile phones, glasses and even clothes in the UVC Sterilization box.

 

Of course, its disadvantage is obvious. That is, we can only sterilize small objects.


Type Four: UVLED+Photocatalyst 


To better play the sterilization role of UVC, more and more manufactuers are paying attention to the combition of UV lamps and HVAC Units.


Why? Because air sterilization is the best application of UVC for now. Only it can meet the following conditions:

 

1. Small & confined space


2. Long enough operating time

 

3. Working on presence of human

 

air sterilization

 

Through repeated trials and experiments,  we have developed an efficient and harmless sterilizing process, which is UVLED+Photocatalyst.

 

UVLED+Photocatalyst is the air disinfection system applied for air heating and cooling system, with UV LED Strip & photocatalyst. It has a double effect on killing virus/ bacterial/ VOCs/ animals smelling immediately at a 99.93% killing rate.

 

photicatalyst action

 

The UV system belongs to Feton owned technology, composed of UV LED Strip and TiO2 filter. Then, how does the sterilization process work? There are five steps:

 

1. Tio2 filter was irradiated by UV LED Strip (UVA+UVC), which will cause the Photocatalyst effect.

 

2. Under the Photocatalyst effect, strong oxidizing agent OH+ is produced.

 

3. OH+ starts to surround and destroy harmful substances.

 

4. All carbon-based organisms, including bacteria, viruses, smoke, formaldehyde, pollen, mites, etc, will be disintegrated into H2O & CO2.

 

5. For harmful substances not killed by TiO2, UV-C will offer supplementary function.

 

Therefore, the killing efficiency is higher than 99.93%.


All in all, UV light for sterilizatioon has been around for about 100 years because it is a very efficient physical disinfectant without chemicals.


However, there are many UV lamps on the market during the period and many of them are ineffective or unproven.


We should pay attention to the safety and effectiveness of those UV lamps and make an informed purchasing decision.

 

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