COVID-19 | HOARE LEA HQ OFFICE Before Hoare Lea started offering advice to clients about making their offices Covid-secure it looked at how its own air handling units could be modified to make its Kings Cross headquarters safe and comfortable. Hoare Leas Steve Wisby explains DISTANCE AND DILUTION A Figure 1: Staggered workstations fter the recent rise in Covid-19 cases in the UK, the government has recommended office workers who can work effectively from home should do so over the winter and only those that are unable to work from home should go to the office. The work undertaken to our office means that we can welcome back staff into a COVID secure environment if they need to come in. Foremost in our minds when making our office Covid-secure was creating a calm, reassuring space that was productive. We wanted the office experience to be as close to that of the pre-Covid workplace, while being as safe as possible. The first step was a survey to discover how people felt about returning and how they were working at home. This information was invaluable, leading us to conclude that any return to work should be on a phased basis, with only those struggling to work from home because of IT issues, home conditions, and so on invited back in our first phase. The distance dilemma Figure 2: Individual bubble with 1m safe distances side to side and back to back Most modern offices, including our London one, use straight workstations, where employees sit about 1.8m apart, opposite each other, face to face. The government guidance emphasises 2m social distancing or 1m with risk mitigation where 2m is not viable. Not wanting to install a vast array of Perspex screens, we have used a staggered, diagonal, active workstation arrangement to comply with the 2m social distancing guidance (see Figure 1). This, obviously, places capacity limitations on the reoccupation permitted. The governments mantra is follow the science, so I was curious to read the supporting documentation behind the 2m guidance. The evidence is in a paper prepared by the Environmental and Modelling Group and published by SAGE in June 2020. This paper does indeed detail face to face safe distances of 2m where prolonged periods are necessary. However, it also details that the risk of 1m side to side or back to back carries the same risk as 2m face to face. This is not mentioned within the governments guidance. If adopted within the guidance, the resulting planning bubble around an office employee would, I believe, be along the lines of Figure 2. It is no surprise that following government guidance leads to office occupancies of around 30-45% without further intervention measures. If the governments guidance was to fully adopt the scientific evidence, occupancies could increase perhaps, up to 50%. Also, if the government was bold enough to lower the face-to-face distance to 1.8m, office planning occupancy levels may well rise above 75%. A dilemma, indeed, if we are to see numbers return to their office workplace. Dilution There is clear scientific evidence that dilution of indoor air with the introduction of outside air plays a crucial role in minimising the risk of airborne viral transmission. 34 October 2020 www.cibsejournal.com CIBSE Oct20 pp34-36 Hoare Lea Covid-secure.indd 34 25/09/2020 16:37