Ventilation has been shown to be a key weapon in the fight against COVID-19, so now is the time for H&S consultants, FMs and building owners to work together to prepare buildings for people returning to work full time. Sara MacLean from MacLean Communications explains.
‘Ventilate, dilute the virus’. This should be the new mantra for building owners, H&S consultants and FMs as lockdown eases. To meet their duty of care, employers need to reduce workplace risk to the lowest reasonably practical level by taking preventative measures, and ventilation could be one of the most important factors when it comes to mitigating this risk. As a result, building services consultants, contractors and manufacturers working with FMs and H&S consultants, are becoming the new unsung heroes of the pandemic.
The Government has repeatedly put forward ventilation as a vital way to reduce the risk of COVID-19 transmission. ‘Keep Indoor Places Well Ventilated’ was one of the key principles cited in the UK Government’s COVID-19 Recovery strategy published on 11 May 2020. With the strategy also stating that ‘Evidence suggests that the virus is less likely to be passed on in well-ventilated buildings and outdoors’ and advises to ‘Use external extractor fans to maximise the fresh air flow rate.’
This guidance echoes the statement by Professor Jonathan Van-Tam, Deputy Chief Medical Officer at Government’s COVID-19 press briefing on 29 April 2020 where he said, “There is a definite truism across all of the science literature, that ventilation is a most critical part of reducing transmission from respiratory viruses.”
While the Government’s guidance on ventilation has been building, so have academic studies on the virus with a raft of research pointing to airbourne transmission of COVID-19. So, with ventilation key to reducing virus transmission what practical measures can be taken in buildings and how much airflow is enough?
Fortunately, the Chartered Institution of Building Services Engineers (CIBSE) has issued two useful documents to help building managers/owners and operators to prepare for an ease in lockdown. The first guide ‘CIBSE COVID-19 Emerging from Lockdown: Safely Re-occupying Buildings’ advises high levels of ventilation in all occupied areas of the building. “To minimise the risk of airborne transmission it is important to maintain higher ventilation rates and to consider increasing ventilation rates in toilets and circulation spaces such as stairwells.”
While CIBSE’s second document ‘CIBSE COVID-19 Ventilation Guidance’ gives detailed guidance for building managers/operators to minimise the risks of airborne transmission of COVID-19. Here the overarching advice is to increase the air supply and exhaust ventilation, supplying as much outside air as is reasonably possible to dilute and remove the virus as much as possible. More detailed advice includes: extending the operation times of supply and extract mechanical ventilation systems; start ventilation at nominal speed at least two hours before the building usage time and switch to lower speed two hours after the building usage time; in demand-controlled ventilation systems changing the CO2 setpoint to lower to maintain operation at nominal speed; and to keep ventilation on 24/7 with lower ventilation rates when people are absent. CIBSE also directs readers to refer to manufacturer’s guidance for help.
The CIBSE guidance is very useful, and welcome as we navigate the ‘new normal’ of working life. However, the devil is in the detail, when it comes to increasing airflow and following guidance on the amount of air changes per hour a premises needs, since this might not mean much to many building owners. This is where they need to recruit the expert advice from the building consultants, contractors and ventilation manufacturers as we all pull together to overcome the virus.