Re-learning the importance and possibility of natural air ventilation during Covid

‘The Penang Hospital began life as a double-storey, colonnaded brick-and-timbre building. As was the norm for most bungalows in Penang at the time, the building would have been raised on a brick plinth, allowing for air to flow underneath. The floors were probably hardy and washable, and tiled with terra cotta. The veranda on the first-floor was 5ft wide and protected by a roof jack, a feature developed by builder designers of the day in observance of tropical architecture.

“A roof jack,” explains conservation architect Laurence Loh, “is a secondary roof located at the ridge that is literally jacked up for the hot air within the space to rise up and escape through the open gaps between the two roofs, based on the principle that air, once warmed, becomes more buoyant, with a tendency to rise.” This process employs what is known as stack effect or ventilation. The surrounding cool air is pulled into the building from openings like doors and windows at the lower level, with the heated air being pushed up and out.’

But how has it evolved?

Read here (Penang Monthly, October, 2021)

The role of built environments in preventing contamination and reducing the spread of Covid-19 for future pandemics

‘The built environment contributes to the spread and contamination of the virus, as people spend more than 90% of their time indoors and even more during lockdown and community quarantine. During the current pandemic, healthy and asymptotic individuals are staying in their houses, and many people that are affected by the virus are now in hospitals and in healthcare facilities. These situations might affect the spread and contamination of the virus, as well as individuals’ interactions with each other.

‘To reduce the contamination and spread of the virus in the built environment that might affect healthy individuals – such as health care professionals, office workers – it is important to understand the steps that need to be taken and the policies to be implemented along with the theories underlying them. One of the approaches to be considered in designing effective fresh air supply and air extraction ventilation systems to minimize the concentration of suspended viruses. This is in addition to other essential procedures to understand the movement of viruses in the indoor air and its suspension/resuspension to and from surfaces.’

• Is it safe to reopen theaters during the Covid-19 pandemic?
• What’s in the pipeline? Evidence on the transmission of SARS-CoV-2 via building wastewater plumbing systems
• Ventilation for residential buildings: Critical assessment of standard requirements in the Covid-19 pandemic context
• Ventilation system design and the coronavirus (Covid-19)
• Outdoor airborne transmission of coronavirus among apartments in high-density cities

Read here (Frontiers in Built Environment, as at September 12, 2021)

The plan to stop every respiratory virus at once

‘The benefits of ventilation reach far beyond the coronavirus. What if we stop taking colds and flus for granted, too?

‘The challenge ahead is cost. Piping more outdoor air into a building or adding air filters both require more energy and money to run the HVAC system. (Outdoor air needs to be cooled, heated, humidified, or dehumidified based on the system; adding filters is less energy intensive but it could still require more powerful fans to push the air through.) For decades, engineers have focused on making buildings more energy efficient, and it’s “hard to find a lot of professionals who are really pushing indoor air quality,” Bahnfleth said. He has been helping set COVID-19 ventilation guidelines as chair of the ASHRAE Epidemic Task Force. The pushback based on energy usage, he said, was immediate. In addition to energy costs, retrofitting existing buildings might require significant modifications. For example, if you add air filters but your fans aren’t powerful enough, you’re on the hook for replacing the fans too.

‘The question boils down to: How much disease are we willing to tolerate before we act? When London built its sewage system, its cholera outbreaks were killing thousands of people. What finally spurred Parliament to act was the stench coming off the River Thames during the Great Stink of 1858. At the time, Victorians believed that foul air caused disease, and this was an emergency. (They were wrong about exactly how cholera was spreading from the river—it was through contaminated water—but they had ironically stumbled upon the right solution.)’

Read here (The Atlantic, Sept 8, 2021) 

Ventilation for residential buildings: Critical assessment of standard requirements in the Covid-19 pandemic context

‘After the arrival of a new airborne virus to the world, science is aiming to develop solutions to withstand the spread and contagion of SARS-CoV-2. The most severe among the adopted measures is to remain in home isolation for a significant number of hours per day, to avoid the spreading of the infection in an uncontrolled way through public spaces. Recent literature showed that the primary route of transmission is via aerosols, especially produced in poorly ventilated inner spaces. Spain has reached very high levels concerning contagion rates, accumulated incidence, or number of hospitalizations due to COVID-19. Therefore, this article aims to develop a quantitative and qualitative analysis of the requirements established in Spain, with respect to the European framework in reference to ventilation parameters indoors. The different parameters that serve as calculation for the ventilation flow in homes are analyzed to this aim. Results show that the criteria established in the applicable regulations are insufficient to ensure health and avoid contagion by aerosols indoors.’

Read here (Frontiers in Built Environment, August 24, 2021)

Ventilation system design and the coronavirus (Covid-19)

‘Most new office buildings in Nordic countries are equipped with balanced mechanical ventilation systems. The purpose of ventilation in office buildings is to provide thermal control by supplying cold or warm air for adequate indoor air quality. However, the role of ventilation in preventing virus transmission and maintaining a sufficient fresh air supply to obtain a low virus level through dilution is not currently well defined. Ventilation in office buildings is expected to contribute to preventing the spread of contaminants and provide comfort for occupants. The study reveals differences between risk areas for spreading airborne contaminants in office buildings in northern Europe, including Denmark, Norway and Sweden. The differences in the spread depends on different ventilation designs used in different countries.’

Read here (Frontiers in Built Environment, April 27, 2021)

We’re just rediscovering a 19th-century pandemic strategy

‘The first way to fight a new virus would once have been opening the windows...

‘Miasma theory—discredited, of course, by the rise of germ theory—held that disease came from “bad air” emanating from decomposing matter and filth. This idea peaked in the 19th century, when doctors, architects, and one particularly influential nurse, Florence Nightingale, became fixated on ventilation’s importance for health. It manifested in the physical layout of buildings: windows, many of them, but also towers erected for the sole purpose of ventilation and elaborate ductwork to move contaminated air outdoors. Historic buildings still bear the vestigial mark of these public-health strategies, long after the scientific thinking has moved on.

‘That era saw the rise of well-ventilated “Nightingale pavilions,” named after Florence Nightingale, who popularized the design in her 1859 book, Notes on Hospitals. As a nurse in the Crimean War, she saw 10 times more soldiers die of disease than of battle wounds. Nightingale began a massive hygiene campaign in the overcrowded hospitals, and she collected statistics, which she presented in pioneering infographics. Chief among her concerns was air. Notes even laid out exact proportions for 20-patient pavilions that could allow 1,600 cubic feet of air per bed.’

Read here (The Atlantic, Feb 22, 2021)

Germans embrace fresh air to ward off coronavirus

‘Ventilating rooms has been added to the German government’s formula for tackling coronavirus, in refreshing news for the country’s air hygiene experts who have been calling for it to become official for months. The custom is something of a national obsession, with many Germans habitually opening windows twice a day, even in winter. Often the requirement is included as a legally binding clause in rental agreements, mainly to protect against mould and bad smells. But while some people may dismiss the method as primitive, “it may be one of the cheapest and most effective ways” of containing the spread of the virus, Angela Merkel insisted on Tuesday.’

Read here (The Guardian, Sept 30, 2020)