Hospitals are very complex environments that require special HVAC system design, maintenance and repair considerations. HVAC systems in healthcare facilities provide a broad range of services in support of populations who are uniquely vulnerable to an elevated risk of health, fire, and safety hazard. These heavily regulated, high-stakes facilities undergo continuous maintenance, verification, inspection, and recertification; typically, operate 24 hours per day, 7 days per week; and are owner-occupied for long life cycles. HVAC systems are responsible for keeping indoor air quality (IAQ) high and providing a safe temperature for patients and staff alike..
HVAC in Healthcare Facility
Increasing interest has been expressed towards intelligent heating, ventilation and air conditioning (HVAC) systems in hospital environments. Hospitals require efficient heating, ventilation and air conditioning (HVAC) systems to maintain good indoor air quality (IAQ), aseptic conditions, and to secure healthy, safe and suitable indoor thermal conditions (i.e. temperature, humidity, air quality and airflow) for the hospital personnel and the patients.
Hospital ventilation must be effective for controlling airborne transmission and preventing outbreaks of infectious diseases. A correlation exists between ventilation, air movements in buildings and the transmission of infectious diseases. Poorly designed, maintained (i.e. contaminated) and used HVAC systems are common in hospitals and often lead to poor IAQ.
Effect of breakdown of Hospital HVAC System
Patient feel uncomfortable
Risk of hospital infection spread
Surgical procedures delay
Emergency situations rerouted to other hospitals
Fog in the hallways and operating rooms
Damages to supplies which require refrigeration or lower temp
HVAC & Infection Control
In a hospital environment, there tend to be high concentrations of harmful micro-organisms. From an infection control perspective, the primary objective of hospital design is to place the patient at no risk for infection while hospitalised. The special technical demands include hygiene, reliability, safety and energy-related issues.
Infections, which may result from activities and procedures taking place within the facility, are a cause for great concern. Three main routes responsible for infections are contact, droplet, and airborne transmission, which are quite affected by room design and construction factors.
An airborne infectious isolation room is constructed to minimise the migration of air from an isolation room to other areas of healthcare facilities. The risk of being infected through the airborne route is a function of particle concentration. The chance of a particle that is carrying an organism falling into an open wound increases with particle concentration. By reducing the concentration, one can reduce the chance of infection and, hence, the number of patients infected.
Recommendations for engineering controls to contain or prevent the spread of airborne contaminants center on general ventilation, air cleaning (primary and secondary filtration), and local exhaust ventilation (source control)
The most effective means of controlling contaminants, odour and indoor air pollution is through ventilation, which requires simultaneous control of number of conditions:
Air change rates
Pressure gradient appropriate with class of isolation
Appropriate air distribution in the compartments being air conditioned
High quality air filtration including absolute filtration
Precise temperature and humidity control ensuring maintenance of the intended microclimate