AsepticSure = Sterilization. No other systems reac
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AsepticSure = Sterilization. No other systems reaches that...
The effectiveness of germicidal UV in such an environment depends on a number of factors: the length of time a micro-organism is exposed to UV, power fluctuations of the UV source that impact the EM wavelength, the presence of particles that can protect the micro-organisms from UV, and a micro-organism’s ability to withstand UV during its exposure.
In many systems redundancy in exposing micro-organisms to UV is achieved by circulating the air or water repeatedly. This ensures multiple passes so that the UV is effective against the highest number of micro-organisms and will irradiate resistant micro-organisms more than once to break them down.
The effectiveness of this form of sterilization is also dependent on line-of-sight exposure of the micro-organisms to the UV light. Environments where design creates obstacles that block the UV light are not as effective. In such an environment the effectiveness is then reliant on the placement of the UVGI system so that line-of-sight is optimum for sterilization.
Sterilization is often misquoted as being achievable. While it is theoretically possible in a controlled environment, it is very difficult to prove and the term 'disinfection' is used by companies offering this service as to avoid legal reprimand. Specialist companies will often advertise a certain log reduction i.e. 99.9999% effective, instead of sterilization. This takes into consideration a phenomenon known as light and dark repair (photoreactivation and excision (BER) respectively) in which the DNA in the bacterium will fix itself after being damaged by UV light. [5]
A separate problem that will affect UVGI is dust or other film coating the bulb, which can lower UV output. Therefore bulbs require annual replacement and scheduled cleaning to ensure effectiveness. The lifetime of germicidal UV bulbs varies depending on design. Also the material that the bulb is made of can absorb some of the germicidal rays.
Lamp cooling under airflow can also lower UV output, thus care should be taken to shield lamps from direct airflow via parabolic reflector. Or add additional lamps to compensate for the cooling effect.
Increases in effectiveness and UV intensity can be achieved by using reflection. Aluminium has the highest reflectivity rate versus other metals and is recommended when using UV.