Key outcomes:

  • Identify high risk locations
  • Optimise ventilation system
  • Optimise desk layout to minimise infection risk

Indoor health and safety in offices is now a serious and necessary consideration for all workplaces. Indoor environments have been shown to promote rapid spread of viruses. Sources of contact where viruses can spread on surfaces such as doorknobs, known as fomites, are easily identifiable. While contactless processes and surface sterlisation reduce physical transmission, airborne transmission is increasingly considered to be critical, and may be the dominant transmission mode in many situations. Droplet and airborne transmission vectors are harder to visualise and control. Large droplets are commonly released by coughing and sneezing, while smaller airborne droplets can potentially be released by breathing and talking. These droplets and particles then spread through the environment, where they may reach nearby people, spreading infection. Minimising these risks is a key part of having a safe, healthy, and happy workforce. Covid-19 drew attention to many simple ways to reduce the risk of infection, such as regular sanitising of high contact surfaces, maintaining at least 1.5 m of separation and the use of masks, however understanding the workplace layout and ventilation patterns can significantly improve the ability to quantify and minimise risks.

Particle tracks showing the paths of coughed particles for two different flow rates. The left hand image shows clean paths travelling a short distance, the right shows more chaotic paths

Figure 1: An example of transmission of droplets released by a cough for two different ventilation arrangements. Very high local ventilation rates, like the right hand image can significantly increase the risk of droplets reaching other occupants.

Computational fluid dynamics (CFD) modelling of indoor air quality has shown that minor changes can have a large effect on transport of virus laden droplets, for example Figure 1 shows the difference in spread between droplets generated by a cough in a space with two different ventilation arrangements. An inappropriate ventilation arrangement can significantly increase the travel distance of droplets.

Other options for mitigation include the optimal placement of barriers, or locating desk spaces to minimise impacts on other desks. Figure 2 shows a heat map of an office area floor play, showing concentrations of contaminants exhaled by a single occupant. Fine particles exhaled by an infected occupant are seen to reach many of the existing desks. To reduce this risk, improved ventilation rates and locations, utilising fresh or filtered air is a viable option.

Contours within a 16 desk office space, showing where high risks locations are.

Figure 2: Contours showing a heat map of particles exhaled by a sick worker within an office. The red region shows the infected employee’s desk. For this ventilation regime, high levels of contaminants are seen within the pod around the infected worker and the connecting walkway, with particles spreading from the walkway into the adjacent pods.

Any change to an office layout or ventilation involves upfront costs and should be modelled first to ensure it is done correctly and will deliver the desired results. This modelling allows designs to be optimised to generate the best results for minimal expenditure and will also quantify the benefits, demonstrating your improvmeents and advantages to stakeholders.

If you are interested in making your office safe contact Synergetics for more details.