In recent years, many companies have humidified their offices as a means of cutting down on absenteeism. For hospitals, however, where infections can mean the difference between life and death for those in fragile health, it is even more critical to maintain humidity within the 30% to 50% range recommended by the CDC.
Great River Hospital (GRH) in Kitchener-Waterloo, Ontario is one facility that takes this matter to heart. With a staff of 2,350, it is the largest medical center in the Waterloo region, an urban area of 420,000 people, about an hour's drive southwest of Toronto. The hospital originally installed a sprayed coil humidification system in 1988 but replaced it with a steam system as part of an energy-saving program in 1990-91. In 1998, it switched to a high-pressure fog humidification system on nine of its air-handling units (AHUs). This improvement eliminated the health risk of additive chemicals in boiler feed water from the steam system entering the air stream, one of the drawbacks of the direct-steam method. However, rather than proving to be a costly improvement to offer patients cleaner air, high-pressure fogging turned out to be a cost-saving initiative.