SECURING THE CURE

The earlier purpose of most hospitals was to house – not cure – the sick in tightly packed rows of beds in dark open wards. Then, in the early 1900s, hospitals started focusing on curing patients and using X-rays and cardiographs, which revolutionised patient care and saved the lives of millions. However, keeping the machines needed for treatment near patients represented a significant challenge for the staff and fundamentally changed how designers approached hospital layouts. Today, staying overnight in a hospital could mean experiencing a shared room poorly lit by flickering fluorescent lamps and with no windows. Furthermore, the persistent odour might keep the patient up all night, if the cacophony of beeping from various old machines does not. Likewise, research has established that Hospital Acquired Infections (HAIs), cross-contamination and Sick Building Syndrome, owing to fluctuating temperatures and poor Indoor Air Quality, can worsen the health condition of patients[1-3]. So today, raising the bar of air quality through multi-stage filtration and energy-efficient HVAC systems that are responsive and adaptive, constitute an innovative way towards a modern and sustainable hospital environment. Additional studies have suggested that balancing natural and artificial lighting through windows and lamps, respectively, can impact the healing process of patients[4,5]. However, avoiding temperature fluctuations from external sources, through exterior windows, is critical to the indoor environment. Therefore, the appropriateness of HVAC system selection and performance is paramount to controlling the climate, in terms of temperature and moisture. Climate control does not necessarily mean the thermal comfort relevant to human occupants; in a hospital context, it addresses the appropriate temperature and humidity for wounds, so that chemicals and enzymatic processes are optimally engaged in the healing process with the metabolism of cells and tissue[6]. Furthermore, despite efforts to attain the best air quality, the contaminants carried indoors from outdoors represent a risk for infection outbreak, even after the treated patient has left the hospital [7-9]

Hospitals require more than just a design facelift; therefore, the narrative alters how hospitals are perceived and conceived. Hospitals do not have to be daunting, especially since patients are usually not in the best emotional state, and feel vulnerable due to their health conditions. While a modern and sustainable hospital environment should provide the best medical expertise and a pleasant place for occupants, it is equally important to have such a healing space free of contamination. HVAC and filtration systems can play a greater role in improving air quality while meeting thermal comfort targets. Ultimately, patient satisfaction is attainable if better air quality, filtration systems and operational efficiency are integrated towards sustainable performance.

The evolving nature of hospital design

Healthcare facilities are continually evolving to help revolutionise and redefine how care be delivered in the future. Architects incorporate the planting of trees to bring a calming ambience to hospital facilities, as shown in Figure 1. Architects also consider other parameters to optimise their designs, such as the building’s geographical location, the site’s topography, annual weather and aerosol data. Furthermore, humanity can realise its dream of a utopian hospital that embraces sustainability by generating its power with a minimal environmental footprint and using its waste as a resource.

In a hospital environment, the methods of reducing contaminant concentrations range from source control to dilution with ventilation and extraction with filtration. The dispersion of various pollutants humans can carry indoors is a significant challenge to the IAQ rendered by filtration-intensive systems. When patients talk, sneeze and cough, they produce many particles light enough to remain suspended in the air and spread infection[10]. In addition, poor visitors’ health conditions can impact the air quality in the hospital environment and the wellbeing of the staff to work and patients to heal and recover[11]. Our respiratory systems are often exposed to multiple pollutants simultaneously. Consequently, it may be difficult to correlate specific symptoms to a given pollutant when they co-exist in solid or in gaseous state, or as bioaerosols. Innovative hospital design must leverage various advanced technologies, not only those relevant to air filtration and HVAC systems. That would enable the hospital environment to engage its facilities to make real-time adjustments to facilitate a sterile therapeutic environment. Ultimately, realising that no engineering measure can single-handedly enhance air quality sustainably is critical to the need for such performance integration. Overlooking the role of ventilation, entertaining modest maintenance plans, and weak approaches to air quality improvements will hinder any plans to exit the status quo and may result in additional pandemics[13-15]. The solution cannot simply lie in frequent filter replacement to resolve air quality issues. That can easily fall under the sustainability knife, which endorses the circularity concept of extending the lifetime of air filters in operation balanced by sustainable performance. Therefore, further research on sustainable air filters and HVAC systems performance is required to reduce the transmission of airborne contaminants.

The challenge of managing the hospital built environment lies in engineering and interfacing several parameters in complex building settings. Indoors, healthcare facility design is more complex than other building types, influencing HVAC, air quality and filtration requirements. For example, HVAC requirements for the design of operating rooms range from regulating temperature and moisture to appropriate space pressurisation between adjacent zones. In addition, operating theatres require clean room applications, mandating advanced air filtration systems to yield acceptable air quality. And laminar air diffusion represents the final critical step towards achieving thermal comfort by utilising equal clean air distribution in individual zones.

The final stage of filter performance is their disposal after usage. Leaving behind loaded filters, such as HEPA types, at the storage of regular waste