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Likewise , many semi-conductors and electronic equipment requires closely controlled dry conditions . The presence of excessive humidity or moisture causes corrosion of ' circuit points ', condensation on a microchip ' s circuit surface and improper adhesion of photoresists causing operational failure of the semi-conductor .
Having the correct humidity levels are also not only about patient and personnel comfort . Air humidity that is too low , effectively dry air , has been known to increase and aggravate respiratory problems , and commonly affect a person ’ s eyes , skin , nose and mouth . These humidity scenarios have also shown to be detrimental to the human immune system . Dry air draws moisture from mucous membranes in the nose and throat , which is one of the body ’ s main defences against airborne contaminants . As well as increasing the survival rates of airborne viruses , dry air also impairs our natural ability to fight them off .
Air humidity that is too high , wet air , creates an uncomfortable environment and potentially further creates an ideal condition for bacteria and mould growth .
The optimum humidity level in some operating theatre may also depend on the preference of the surgeons involved . For procedures such as open heart or cranial surgery , dry air can promote electrostatic micro-shocks , which can pass from surgeon to patient and are potentially fatal . Typically , the environment during these operations is maintained at 50 % RH ± 5 %.
Other reasons for humidity control in operating theatres include preventing delicate membranes drying during stomach procedures , inhibiting the spread of airborne spores during operations involving highly infectious diseases , and preventing evaporation from swabs prior to weighing for more accurate blood loss assessment .
Other areas of medical facilities that are highly dependent on the correct humidity include MRI suites where electrostatic conditions would again be detrimental , as well as burn units and dressing rooms where the correct humidity assist in dressing changes and in the burn-healing process .
Research , based on the outbreak of the Covid pandemic , has now revealed that the right indoor climate and humidity levels particularly can help limit the transmission of a number of viruses , and plays an important role as an additional protection mechanism .
Studies on the novel coronavirus highlight the effects of air temperature and relative humidity on the virus , and how this impacts its ability to survive on surfaces . The rate of virus inactivation varied across different relative humidity levels , where the greatest level of virus inactivation took place at 50 % relative humidity . The virus had higher survival rates at both 20 % and 80 % relative humidity , so it ’ s not simply a case of increasing or decreasing the levels : it ’ s about controlling the climate to very specific parameters . Indications that maintaining an indoor RH % level between 40 to 50 % yields the maximum protective effect from aerosolised and settled virus particles . By maintaining these levels , it is possible to contribute to a healthier , safer environment .
New research has also suggested that because the coronavirus is so small and can effectively bypass HEPA filtration in aerosol form , that a controlled increased humidity will create sufficient particulate for the virus to attach to . This then , combined with two or three-stage air filtration and circulation , will enable capturing of the virus within the filter space that could then be further combined with UV-C sterilisation . Speculatively , this process could be used as a space purging programme , or a specific setting if or when required .
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RACA Journal I May 2021
MANAGING AIR QUALITY The ultimate goal of supplying and maintaining good air quality then is a combination of the aforementioned topics , and through either the packaged units or air handling unit option , this forms the heart of air into a space as well as the re-circulated air .
Per ISO category and application , there are specific air quality requirements as indicated earlier that determine a maximum particle count and there are further testing procedures that get undertaken in these facilities . www . hvacronline . co . za