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Improving Ventilation Systems in Buildings after Lockdown
As people return to workplaces, pubs, restaurants and shops, there is a renewed focus on how we keep buildings safely ventilated during Covid and beyond. All eyes are on the Facilities Management and HVAC sectors for guidance on making this happen. This blog explores ventilation solutions in the context of Covid-19, how ventilation in buildings after Covid can finally get the attention it deserves and how Joblogic HVAC software can help you navigate this new landscape.
Why ventilation is important
The impact of indoor air quality on health is well documented. Even prior to Covid-19, the importance of ventilation for the health, wellbeing and comfort of building occupants has been widely reported on. Indoor pollution has been linked to a wide range of illnesses, including increased risk of respiratory problems, heart disease and stroke.
Covid-19 has ramped up ‘the importance of ventilation’ debate. Knowledge about the spread of coronavirus is evolving, but we know that it mainly spreads when people come into close contact with an infected person and that its airborne transmission is particularly effective in crowded, confined and poorly ventilated indoor spaces.
Effective ventilation has the potential to reduce how much virus is in the air and lowers the risk of aerosol transmission. As we try to get life back to some kind of normality, ventilation in the built environment will be a critical factor in preventing the spread of this highly infectious disease. Improving ventilation has the potential to become one of the more positive legacies of the pandemic.
The complexity of ventilation and risks of transmission
Speaking at a webinar run by the BESA (the Building Engineering Services Association), a leading expert Professor Catherine Noakes said, “controlling the airborne risks through ventilation is not as simple as just saying ‘we are going to ventilate’: there is an awful lot more to it than that. We need to consider factors such as the air distribution, pressure, relative humidity and temperature.”
Building managers will want to take steps to optimise ventilation and airflow indoors in order to limit viral spread. But, as Noakes points out, ventilation is complex. There will need to be stringent assessments and building managers will be looking to Facilities Managers and HVAC engineers for advice to mitigate risks.
In a paper prepared by the Environmental and Modelling Group (EMG) on the role of ventilation in controlling SARS-CoV-2 transmission, it is advised that the assessment of ventilation should be added to the checklists for Covid-19 risk assessments – organisations must explicitly show they have considered mitigation of aerosol transmission risks.
Mechanical ventilation systems, fresh air supply and Covid-19
As to the practicalities, the government’s Health and Safety Executive (HSE) says mechanical ventilation systems (including air conditioning) will provide adequate ventilation if they are set to maximise fresh air and minimise recirculation, and that it is preferable not to recirculate air from one space to another. The Executive’s recommendations say that recirculation units for heating and cooling that do not draw in a supply of fresh air can only remain in operation provided there is a supply of outdoor air, such as windows and doors being left open. This means that you will need to educate clients on these requirements.
In addition, a report by management consultancy firm McKinsey on the role HVAC systems can play, says technicians should consider “configuring ducted HVAC systems to increase the rate of exchange with fresh air from outside the building to reduce recirculation” and that “adjusting the settings may also help.” It recommends that HVAC systems run without interruption (i.e. are not shutdown overnight or at weekends) to increase the replacement of air and minimise airflow speeds – a view that is also echoed by the European Centre for Disease Prevention and Control (ECDP).
The ECDP also recommends that energy-saving settings, such as demand-controlled ventilation controlled by a timer or CO2 detectors, should be avoided. In buildings with old or inflexible systems, technicians should consider upgrading HVAC hardware.
Hepa filters
Filtration is the most common and effective method of air purification, included in all modern ventilation systems. High-Efficiency Particulate Air (HEPA) filters are most effective at removing small particles, but even these can’t trap all viruses. Hepa filters for air vents can also restrict airflow if particles build up on them.
It is important that heating, ventilation and AC systems are maintained according to the manufacturer’s current instructions. These should also be cleaned and changed according to the ECDP.
Coronavirus and air conditioning
Clearly there is a lot of research and examination of the link between air conditioning and Covid going on.
Current stand-alone air conditioning systems usually recirculate the air without mixing it with outdoor air. On the plus side, recirculated air does pass through filters before being returned to conditioned spaces. Common in shops and some office spaces, these are known as split-air conditioners. As already mentioned, this form of ventilation needs to be integrated with other types of air intake to reduce recirculation and ensure a fresh air circulation system.
Humidity is, according to recent research, another factor in the spread of coronavirus. In humid places, the viral droplet grows and it falls faster, “providing less chances for other people to breathe in infectious viral droplets.”
All of this research means that we are likely to see the rapid development of air conditioning systems to ensure safety against Covid and future airborne diseases, a good example of this effort is the work on a new anti-viral air conditioning filter that traps and kills the Covid-19 virus.
A roadmap for ventilation during COVID and beyond
So where do we go from here?
The government’s EMG paper states that ventilation should be integral to the Covid-19 risk mitigation strategy for all multi-occupant public buildings and workplaces. Multi-occupant spaces that are used regularly and are poorly ventilated (below 5l/s/person or above 1500ppm CO2) should be identified and prioritised for improvement.
A roadmap to improve and ensure good indoor ventilation in the context of coronavirus has been set out by the World Health Organisation (WHO). It lays out the major steps needed to reach ventilation levels that will help to reduce the risk of Covid-19 transmission in healthcare, non-residential settings and residential homes. The WHO says that well-maintained ventilation and air-conditioning (HVAC) systems can reduce the spread of Covid-19 in indoor spaces by increasing the rate of air change, reducing air recirculation and increasing the amount of outdoor air coming in. They recommend against using settings that recirculate the air and advise that all HVAC systems are regularly inspected, maintained, and cleaned. 
Refcom, the UK’s leading F Gas certification schemes agrees, in a statement it points out that “Any airborne contaminants can be minimised, if not eliminated, by proper and effective filtration and regular cleaning and maintenance of ventilation systems.”
As we move into a post-COVID world, HVAC engineers will see a rise in the maintenance of HVAC systems, including more regular inspection and changing of filters. To manage this increase in workflow accurately they will need the right systems in place. Joblogic’s air conditioning service management software ensures all work is planned effectively, enables efficiencies and boosts industry compliance.