Hospitals require efficient 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.
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.
- 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
- Equipment failure
- Financial loss
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