Why good indoor air quality in healthcare facilities is so critical...

Expert Commentary

Serkan Keleş, Senior Business Development Engineer, Systemair Turkey, writes on the impact poor indoor air quality in hospital facilities can have on patient health and how thoughtful design practices and standards mitigate the risk of potentially fatal infections.

Infections in hospitals are an ever-present reality, and cases in which these infections lead to death serve as the worst nightmare of any healthcare facility. At its core, hospitals have the primary aim of preserving and protecting life. However, it’s not easy for humankind to always be dominant in the surrounding universe of microbes and viruses, which are masters of mutation and variation. These infections have an especially high potential to occur in critical areas, such as operation rooms, intensive care units, and intensive care nurseries.

The critical nature of these spaces underlines the importance of the hospital’s mechanical systems, which must place an intense focus on hygiene. This would not be possible without well-designed air conditioning and ventilation solutions. However, healthcare facilities are fundamentally different from other comfort applications. Hospitals should be hygienic from the beginning, as soon as people walk through the main entrance, and these unique requirements must be considered from the architectural planning stages.

First, areas need to be sterile and must be divided into zones. Septic areas of the hospitals must also be isolated from the other sections of hospitals with the help of construction materials and equipment that ensures complete tightness.

Particulate control is another unique requirement of hospitals, especially for clean rooms like operating theatres, intensive care units, and intensive care nurseries. In these areas, the concentration level of infectious particulates and pathogens must be observed along with turbulence level and the velocity of the air, which means filtration and flow pattern must be considered during the design of the ventilation systems.

Operation procedures of hospitals are also more tailored. Certain rooms, such as isolation rooms or septic or aseptic operation rooms, must be consistently maintained under positive or negative pressure compared to the adjacent room or corridor with increased or decreased air volume.

Consequences of poorly designed facilities

Although the ventilation and air conditioning systems provide the required fresh air, temperature and humidity level, there are also cases in which ventilation systems themselves are the source of pathogens due to unhygienic design and wrong material choice.

Wrongly designed or installed ventilation systems could quickly spread microorganisms and infection to a broader area and cause fatal diseases. For example, poor control over differential pressure of isolation rooms or operation rooms for septic surgeries can lead to further infections.

Equipment that is installed should also be appropriately operated. For example, cooling coils, such as fan coil units or VRF indoor units, used to cool patient rooms with the air temperature below dew points can be harmful as the dust it collects is mixed with moisture, leading to an increase in the number of pathogens.

To avoid condensation and contamination, the water temperature running through the fan coil units should be selected as high as possible, so the units provide sensible cooling only.

For this reason, healthcare facilities are much stricter compared to comfort applications in terms of ventilation system requirements. Ventilation also helps control the concentration level of infectious particulates and shorten its hang time in the air, thereby reducing its effects and the exposure time of patients.

An overview of essential and relevant standards

We must keep in mind the primary purposes of mechanical systems in hospitals and healthcare facilities, which are:

  • Protection of public health

  • Infection control

  • Providing comfort requirements

  • Removal of thermal loads

  • Removal of odour and toxic gases

  • Optimisation of energy consumption

  • Sanitary needs

As such, we urge stakeholders to follow the standards and guidelines available in the market, which serve as an essential reference point to ensure optimum systems are installed.

There are several commonly used standards across the globe, such as “DIN 1946-4, Ventilation in Buildings and Rooms of Healthcare”, “VDI 6022-1, Hygiene and Hygiene Inspections of HVAC Systems” and “ASHRAE 170, Ventilation of Healthcare Facilities”.

These standards provide

  • complete ventilation system designs,

  • set rules for equipment to be used, and,

  • an overview of allowable and forbidden material choices.

These standards also help determine pressure balance and limit the concentrate level of particulates by referring to other standards. For example, “ISO 14644-1 Cleanrooms and Associated Controlled Environments – Classification of Air Cleanliness by Particle Concentration” is one of the referred standards by DIN 1946-4. These standards are also referred by certification institutes for certification of air handling units, VAV units, and HEPA filters.