How is UVC measured, How much UVC to kill germs?

How is uvc measured ？

As we all know, the dose of UVC is related to whether it can kill the virus. If the intensity of the germicidal lamp is not enough, it is difficult to achieve the sterilization effect，But how to measured uvc dose?

The answer is UV Sensor, it is used for detecting the intensity of incident ultraviolet(UV) radiation. This form of electromagnetic radiation has shorter wavelengths than visible radiation. UV Sensor is based on the sensor GUVA-S12D which has a wide spectral range of 200nm-400nm.

Principle of operation:

The principle of ultraviolet light meter detection is to select specific photosensitive elements to make receiving elements according to the specific wavelength of ultraviolet light. When the light receiver is irradiated by ultraviolet light, the light signal is converted into electrical signal, and the light signal is amplified and transmitted. Signal or digital signal display 

How can UVC kill a virus?

 You may be confused，How can a UVC light kill a virus? One theory is that the UVC light damages the virus’s RNA so that it is no longer able to reproduce and infect. It can also damage the protein that coats the virus, disabling its ability to attach to a host cell.

But How much uvc to kill germs?

Typical germicidal UVC light kills viruses at a wavelength of 254 nanometers. But all viruses are different and some respond to shorter or longer wavelengths. They also require a different UV dose, which is measured by light intensity and exposure time.

The UV dose can be expressed as the product of the UV intensity and the exposure timeIn uv dosage sufficient conditions, inactivation of virus bacteria not resurrection, but insufficient dosage, many virus inactivation of bacteria by ultraviolet radiation can through the help of a light effect to repair damaged structure in the uv dose phase at the same time, can use high strength short-term or the illuminate of low intensity for a long time, in order to achieve sterilization to kill 1 104 / mL helix bacili, uv dosage required around 30 mJ/cm2, and kill the same number of spores, requires about 70 mJ/cm2 of uv dose.

Commonly used uv sterilization irradiation dose table:

Here is the germicidal effect of Suntech LED strips:

 A. 18 leds UVC strip 12v，UVC dose about 90mW，The sterilization effect is as below：

             B. 18 leds stripe 24v，UVC dose about 150mW ，The sterilization effect is as below：