UV is effective against many pathogenic microorganisms and therefore has the potential for reducing the spread of airborne infections in hospital buildings
In a 12-month study carried out at leading UK hospital, ultraviolet (UV) disinfection systems from Hanovia achieved a 98.9% reduction of Staphylococcus aureus, Mycobacterium tuberculosis (MTB) and other airborne pathogens within the hospital's air conditioning system.
It is well known that infectious diseases such as tuberculosis are spread by airborne transmission.
Nosocomial infection (infection originating in hospitals) is now a major problem in many health-care facilities, with about one in ten patients acquiring an infection during a hospital stay.
A study in the USA has estimated that in 1985 the total annual cost of nosocomial infection was $4 billion, with 8 million lost bed days.
A smaller study in the UK carried out in 1986 estimated that in acute-care hospitals in England, 950,000 lost bed days, and financial costs of £111 million, were associated with nosocomial infection.
Given these statistics, it is not surprising that health care authorities around the world are continuously seeking new ways of controlling the problem.
UV is effective against many pathogenic microorganisms and therefore has the potential for reducing the spread of airborne infections in hospital buildings.
Relatively little research, however, has been carried out on into the practical effects of UV disinfection in hospital buildings.
Consequently, the 12-month study was commissioned by NHS Estates to investigate the practical application of this technology.
In the tests, a range of pathogens associated with nosocomial infection was treated with medium pressure UV lamps - both within the hospital air ducts and in controlled laboratory settings.
All the pathogens tested were found to be very susceptible to UV; in fact, when a four-lamp UV system was used, there was a 98.9% reduction in bacteria capable of growth on mannitol salt agar, including both S aureus and M tuberculosis.
Compact and easy to install within existing ductwork, Hanovia UV systems are silent in operation and can treat up to 4m3/second of air per lamp.
They are virtually maintenance-free, the only regular requirement being the replacement of the UV lamp twice a year, a simple operation that can be carried out by general maintenance staff.
UV technology is already widely used within the food, beverage and pharmaceutical industries to destroy spoilage organisms and pathogens.
