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Stopping Corona from sticking to the surface

Mohanad Abobakr elaborates on the importance of façade design in healthcare sectors

| | Jun 23, 2020 | 4:53 pm
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Healthcare systems have been overwhelmed by a high rate of hospitalisation and quarantine measures necessitated by the persistent COVID-19 pandemic caused by the novel coronavirus (SARS-CoV-2). Thousands of lives have been lost, and millions have required medical care; the quality of care given has raised questions on the state of healthcare facilities.

The challenges that have emerged have highlighted the importance of refining healthcare frameworks and proposing innovative tools to accommodate the rapid increase in patients, worldwide. It has become obvious that countries the world over have to expand, upgrade and retrofit existing healthcare facilities with appropriate selection of façades and building design materials, such as cladding, flooring and ceiling.

Healthcare-acquired infections (HAIs), caused through the transmission of pathogens from infected patients to other patients, visitors and healthcare personnel have gained much attention. Such infections can also be acquired through the devices used in medical procedures, such as catheters and ventilators. HAIs can extend hospitalisation stays and exert tremendous economic burden on patients and healthcare systems. Within healthcare facilities, environmental contamination is often identified as a major contributor to the transfer of pathogenic HAI. Research has shown that HAIs are linked to the presence of patients, visitors and medical personnel in the hospital environment.

Several design parameters can contribute to infection control. These parameters include urban design, geographic location, HVAC systems, selection of façades and the associated indoor air quality. Façades play a critical role in protecting buildings in terms of hygiene. Therefore, façade design and its selection are becoming increasingly important in current and future hygienic buildings. Figure 2 illustrates the schematic of protection agencies that complement one another to improve the performance of healthcare facilities. The interrelation of the aforementioned parameters cannot be overemphasised and require a universal performance optimisation approach to be implemented. This would mean an innovative healthcare design with an integrated method to accommodating various parameters (Figure 1).

Figure 1: 3D rendering of future urban healthcare design

 

Figure 2: Schematic diagram of design parameters

 

Façade, the skin of a building

A building façade acts like a fence that controls the indoor environment in terms of radiation, particles and light, among other factors. While a façade may be regarded only as an external skin, it can also be used internally by means of modular cladding systems. This would involve the employment of surface finishes of operation theatres, patient rooms and intensive care units (ICUs), in which it is of critical importance to provide the highest level of hygiene.

There are two aspects as far as a healthy façade is concerned. The first aspect has to do with the design of external and internal systems, where the façade system has a high impact on the quality of a patient’s health inside the building. In fact, the form of the skin and the façade units’ design influence the air circulation and ventilation ratio due to the air movement mechanisms inside the façade. Furthermore, the design of the façade units determines the amount of radiation that can be reflected or absorbed in the rooms, besides that radiation, which penetrates into them; all these influence the wellbeing of patients and other indoor occupants. On the other hand, the number of transparent and opaque units in the skin itself affect patients psychologically in terms of daylight absorption quantity. However, while the façade protects from the outside, is it capable of doing so from inside-out? In other words, can it protect the community from nosocomial infection?

The implementation of different values of air pressure to prevent airborne infections in operation theatres and ICUs have been considered broadly in the design of hospital rooms. For example, the design approach used in operation theatres – of applying positive air pressure inside and negative air pressure outside the theatres – could be reformulated in the façade skin design of the hospitals to limit the prevalence of microbes in the outer atmosphere, as per Figure 3. The positive pressure values will restrict the airflow from the outside to the inside and will assist in preventing microbes from spreading to the inner atmosphere. Façade, in this case, will work as the first defensive line against the microbes coming from outside.

Figure 3: Sketch of airborne precaution mechanism for façade.

 

The Second aspect: Material surface selection

“Materials and finishes need to be robust and easy to maintain, as well as attractive. Well-selected, fit-for-purpose furnishings will complement a clear approach to design”.1 Therefore, the importance of appropriate material selection plays a pivotal role in infection control, due to the continuous exposure to the surrounding environment. Moreover, surfaces may vary in responding to microbes based on their material properties and on environmental factors. Further, the surfaces in healthcare facilities could incubate nosocomial infection through inappropriate use of antimicrobial agents in hospitals. Consequently, characterising the performance of hygienic materials becomes increasingly important in healthcare facilities. This can be conducted by investigating their properties to assess their efficiency in thwarting microbial growth. In addition, the ability of the cladding material surface in preventing the adherence of microbes and their growth is also an essential element in healthcare facilities design.

 

Acidic environments and detergent resistance

The materials used in hospitals as surface cladding should be suitable for acidic environments and detergent resistance. Hospitals undergo daily sterilisation process, and one of the features subjected to detergents is the surface of hospitals. The components that are used in the sterilisation process, such as detergents, increase the acidic concentration on the surfaces and, subsequently, lead to acidic corrosion in the surfaces, which in turn, increases the growth ratio of mould (Figure 4). For quite some years now, stainless steel material has been deployed in healthcare applications to improve hygiene. However, while the material’s characteristic should ensure high corrosion resistance, the fact of the matter is that the detergents applied on the stainless steel affect the performance of the material in the way of ion exchange between surface and solution, which leads to corrosion stain.

A recent study has shown that frequent sterilisation accelerates the ageing or deterioration of surface cladding materials and substructure[2]. However, some materials that are neither acidic nor detergent-resistant are susceptible to corrosion stain ratio to a great extent, which may eventually lead to materials failure. So, the question to ask is, ‘Did inappropriate sterilisation approach affect our health in the long term?’

Figure 4: Diagram shows the influence of detergent use and acidic environment in materials corrosion rate

 

 

Self-healing and smooth surface

Scratches on building surfaces could increase the ability of microbes to colonise in the material. Micro-organisms can settle in the grooves or scratch-depth, which may foster their reproduction over time. In that context, self-healing materials have gained great momentum through their application in various buildings. Self-healing, in this particular instance, is defined as the ability of materials to treat the light scratches through the reaction between the material itself and surrounding components. For instance, the components of stainless steel material react with oxygen and water to treat the light scratches.

 

Materials with self-healing performance characteristics will have a high influence on the health ratio inside the hospital. Besides, the smoother and denser the surface, the greater the hygienic performance (Figure 5). This is because higher surface smoothness of the building materials reduces the adhering forces of the microorganisms. Further, surface smoothness plays a role in decreasing the microbe’s colonisation on surfaces. Almost needless to say, wider applications of smooth surfaces in the facilities contribute to a greater level of hygiene.

 

Figure 5: Diagram shows that hygienic atmosphere ratio will increase respectively by increasing the smooth surface and self-healing feature

 

Conclusion

Global demand is focused on better facilities and a hygienic atmosphere for both healthcare and non-healthcare buildings. Therefore, quantifying the hygienic aspects requires further research and development, particularly to improve the wellbeing of human occupants. The need to improve has been intensified by the recent pandemic, which has placed more emphasis on reshaping all aspects of design that we have for so long taken for granted.

 

 

References:

[1] – Mike Kagioglou & Patricia Tzortzopoulos, Improving Healthcare through Built Environment Infrastructure, 2010.

[2] – M. Abobakr, Design study of different façades for various zones of hospitals and rehabilitation resorts, 2017.

 

 

The writer is a healthcare architect and specialist in healthcare façade design. He holds a master’s degree in International Façade Design and Construction from Ostwestfalen-Lippe University, Germany. He may be reached at abobakr.m@outlook.com.


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