–What Hong Kong hospitals should be doing now to prepare for the next pandemic
Globally, hospitals and healthcare spaces were caught off guard by COVID-19. A rethink of HVAC systems in Hong Kong hospitals, to improve flexibility during infection events, could put us in a stronger position next time.
Hong Kong is old.
Not only has our region been populated for at least 30,000 years, we also have the longest life expectancy of anywhere else in the world.
And our population is aging. In a little over 10 years, a third of our population is expected to be aged over 65.
It’s one of the reasons why earlier this year the government announced its second 10-Year Hospital Development Plan.
Worth HK$200 billion, the project is aimed at alleviating overcrowding in Hong Kong healthcare, with an estimated 5000 new hospital beds to be added to our capacity, as well as 90 additional operating theatres.
However, the project is not just a welcome boost to healthcare resources – it is also a prime opportunity to make sure how healthcare facilities have the flexibility to absorb the next global pandemic.
Infection control
When it comes to COVID-19, hospitals are crucial for the sickest patients, with ventilator machines and other intensive treatment saving tens of thousands of lives.
But for those who are in hospital for other reasons, those same hospitals can also be the very place where they catch COVID-19.
An analysis of UK hospitals in December 2020 reported that one in four hospitalised COVID cases (and one in three in some hospitals) was caught by hospital inpatients admitted for a different reason.
Similar figures were reported worldwide. In some cases in China, up to 44% of severe COVID-19 cases were acquired in hospitals.
Another study, published in The Lancet, found US and UK healthcare workers were more than 10 times more likely to catch COVID-19 than the general population.
There are some obvious reasons for this, such as the concentration of those with the virus in hospitals, as well as shortages of personal protective equipment in some countries.
But a third is that most hospitals are not designed for major infectious outbreaks.
HVAC’s role
While Hong Kong has so been spared the worst of the outbreaks faced by many other locations, images of overstretched, overloaded hospitals worldwide were hard to avoid.
The pandemic ruthlessly showed how hospitals and healthcare facilities, all built with specific uses for different rooms in mind, could struggle to be agile enough to fully protect other patients, healthcare workers and their families.
While the coronavirus can and does spread through surface and droplet transmission, airborne transmission – through aerosols – has proven one of the most problematic vectors of the virus’s spread.
This is where the design and operation of a healthcare facility’s HVAC system can make a huge difference in how much those aerosols – and the virus – can spread.
There are two key ways HVAC can help or hinder this spread. This first is through how it maintains air quality – this is a function of how well the air is ventilated, filtered and disinfected. The second way is through the airflow patterns in play.
Air quality
In general, hospitals and healthcare facilities generally have better air quality than almost any other building, with the exception of some advanced manufacturing facilities.
This is generally achieved by having particularly high rates of ventilation and filtration, particularly in high-risk environments such as operating theatres.
We know that increasing the amount of outside air that we bring into a building, or speeding up how quickly we replace the existing air in a building with fresh air from outside, can greatly cut the risk of airborne disease transmission.
We also know that in scenarios where it is not feasible to be supplying and exhausting vast amounts of fresh air, pushing that air through highly efficient filters before recirculating it can also reduce the disease risk.
Of course, the issue with both these approaches is the amount of energy each requires. Heating, cooling and cleaning air all take energy, and increasing the amount of air you are treating increases the energy it takes to do.
Already, HVAC accounts for between a third and two-thirds of hospital energy use.
Air flow
As important as the quality of the air being supplied to a hospital or healthcare facility is how that air travels around.
If the patterns of airflow push aerosols from infected people to others, disease will spread. Similarly, areas of low airflow or stagnation can allow pathogens to build up to levels where they pose risks to others.
For example, hospital corridors have often been utilised as return air paths. Air spills out of wards and into extract grills in those corridors. During the pandemic, this has led to greater infection rates at nursing stations, typically placed opposite wards.
The solution is ensuring patient rooms have extraction points located where they are most needed, but this type of solution can be extremely difficult to retrofit.
Flexible future
While patient and healthcare staff safety should and will always trump energy efficiency, the best designed facilities should allow both to be maximised.
More efficient HVAC equipment and smarter controls for that equipment can go some of the way to achieving this, but to truly maximise both flexibility is needed, particularly when confronted by the next novel, highly contagious respiratory disease.
This flexibility can come in many forms, but with a focus on building systems that can operate efficiently when infection risk is low, and increase air quality and safe airflow patterns as needed during infectious events and pandemics..
It could mean having standby chillers to allow a HVAC system to handle a larger volume of outside air during infectious events.
It could mean having HVAC systems that can increase how much filtering air undergoes as needed, allowing confidence that any air recirculated during infectious events poses minimal risk, while not using unnecessary energy at other times.
It could mean a supply and exhaust system that can be configured to create positive pressure spaces for nurses’ stations and other staff spaces, to ensure their risks of infection are minimised.
Hong Kong is in an enviable position, undergoing a significant hospital works program just as the world learnt what sort of major public health threat we are currently vulnerable to.
Learning the lessons from the past two years will enable Hong Kong to build a flexible hospital and healthcare system that will be resilient for what the future brings.
Want to learn more about how flexibility in healthcare HVAC can help us be better prepared for future challenges? Download Hitachi’s white paper Planning for uncertainty: Why hospitals need HVAC flexibility.
by Hitachi
