Good indoor air quality needs to be assured in all hospitals and healthcare facilities. Inappropriate temperature and humidity level in a hospital building with access from wards to waiting rooms can trigger bacterial, fungal and viral infections and allergies to patient, staffs and visitors. It is important to note that bacteria travels on water vapour in the air. To prevent biological contaminants from spreading and proliferating, the relative humidity should ideally be kept in control. In many critical healthcare facilities, humidity can cause problems and expose the institutions to unnecessary risk.

Effects of Uncontrolled Humidity in a healthcare facility

• Hazardous Microbiological growth
• Fungus growth due to condensation on the walls
• Inaccurate readings in sensitive devices
• Corrosion and Micro corrosion of mission-critical equipment
• Uncomfortable environment for surgeon and patients

Corrosion of Sensitive Equipment

Expensive and sensitive equipment used in hospitals requires protection against external agents, temperature, humidity, contaminants, etc. But while temperature control is achieved through airconditioning, the importance of humidity control is often overlooked. This causes the atmospheric water vapour to condense on the surface of the equipment, during power cuts, causing corrosion or micro-corrosion related damages.

Causes of Uncontrolled Humidity

A large quantity of outside air must be brought into the building through the ventilation system of hospitals and healthcare facilities. This outside air account for 90% of the moisture load typically seen in many healthcare buildings.

Similarly, most OT rooms are designed for 100% fresh air system and fresh air has exceptionally high moisture content.

General Recommendations of Humidity Levels in Healthcare Facilities

High humidity affects both man and machine equally. Inadequate ventilation air and fresh air can promote the build-up of chemical and biological contaminants which can further deteriorate the patient’s health. Here are some recommended humidity levels for different types of room in a healthcare facility:

Room	Temperature (ºC)	Relative Humidity (%)
Operation Theatre	18-20	50-55
Imaging Department: X-ray room, MRI, CT Scanner, Mammography, Ultrasound, Fluoroscopy, Angiology, Tomography	22-24	50
Pathology Department: Dark Room, Biology lab, Chemical lab, Immunology, Hematology	22-24	50