Tuesday September 1, 2015

Ultraviolets UV Rays Air Treatment

UV, regulation of tanning salons, etc. More often than not, when we hear of ultraviolets (UV), it is to let us know of the damage that they cause to our health. Often called the "black light" because they are invisible to the eye, ultraviolets don't only have a dark side, they also improve the quality of the air we breathe.

Ultraviolets were discovered over 200 years ago. In low doses, they are responsible for tanning the skin and they are necessary for the synthesis of vitamin D. However, in high doses, they can cause cancer, burns and are partialy responsible for cataracts.

Today, they are used among other things, to treat diseases such as rickets, psoriasis and eczema. They are used in fluorescent lamps, where the coating transforms them into visible light. In industrial environments, they are used for drying ink and varnish, as well as for hardening certain adhesives and composites.

They are also able to "break" many organic molecules and cause photochemical reactions. Since the early 20th century, UV ultraviolet lamps have been known for their ability to destroy microorganisms by attacking their cell core and disrupting their DNA. Thus, since the mid 20th century, they are used for sterilizing medical equipment and workplaces. They are also known for their ability to sterilize drinking water and treat wastewater.

Recently, the use of UV's in air handling systems has seen its popularity grow significantly. The poor maintenance of ventilation systems, inadequate cleaning of ducts and the change of use of buildings are just a few factors that have led to several health and hygiene issues in the workplace. Another factor that may be even more important is the reduction of fresh air intake performed for energy savings reasons. Indeed, a popular practice in energy savings is to control the fresh air based on the air quality which depends on CO2 and relative humidity.

A UV air purification system works as follows: when the impure particles in the air are struck by ultraviolets, they suffer damages to their molecular structure. Following a certain exposure, the damage caused is sufficient to completely destroy the particle in question or prevent it from reproducing, whether it is a bacteria, virus, or other. Some lamps even allow oxidation of the particles that cause certain cooking and smoke odors.

Purification de l'air par rayon UV

By placing the luminaire parallel to the air passage, over 90% of harmful microorganisms can be removed with one passing, thus reducing the risk of being exposed to air quality related problems, such as the spread of disease, respiratory infections and allergies.

The use of UV's is relatively new and has proven its efficiency in a large number of buildings. This practice is recognized by several associations, such as the Centers of Disease Control, the Air Institute of Respiratory Education, the Air and Waste Management Association, and many others. Nevertheless, it remains a discipline where  experience is needed. It is not enough to put a UV lamp in a conduct : the flow rate, the volume of air, the optimum positioning of the lamp are only a few elements that must be considered. It is very likely that UV's will be more and more used in our buildings.

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