Crucial guidelines issued for ventilation of workplaces as lockdown eased

The Chartered Institution of Building Services Engineers (CIBSE) has consulted Dr Abigail Hathway to draw up critical guidelines for the ventilation of buildings as people return to their places of work.

CIV ventilation

CIBSE is the professional body of building services engineers who advise the government on matters such as ventilation in the built environment. As a charity they work for the benefit of the public and their guidance is aimed at all building owners or operators.   

Dr Abigail Hathway’s research background includes the modelling of bioaerosol spread in hospitals, and how human behaviour and ventilation characteristics affect indoor air flows (and the potential for infection transfer).  She helped to develop the guidelines that clarify how employers and building managers can ensure workplaces are better managed in order to reduce the spread of COVID-19.

The main take-home from the guidance concerns ventilation and the need to ensure that as much fresh air is circulated around the building as possible.  This is such a crucial factor that using more energy in the short term to ensure thermal comfort should be accepted. Workplace dress codes should be relaxed to enable workers to stay comfortable. For smaller buildings this may just mean opening windows or even external doors. Care needs to be taken around internal doors to avoid recirculation – particularly for toilet blocks where the doors should always be kept closed.  Building owners and managers are tasked with having a thorough understanding of how their HVAC (heating, ventilation and air conditioning) systems operate, and they must be able to adapt the systems in order to avoid the recirculation of air between rooms.

There have been several outbreaks linked to crowded poorly ventilated internal spaces, and alongside regular cleaning, handwashing and social distancing it is essential to dilute inside air as much as possible to limit the spread of coronavirus among workers. The guidelines provide ways to adapt your systems easily without expending money or significant time on substantial building changes.

Dr Hathway comments, “Getting fresh air into buildings has always been crucial to dilute indoor pollutants and to keep people healthy. Unfortunately, too often, spaces are not ventilated adequately and many people do not understand how their spaces are ventilated. Our guide provides information to help you recognise what type of ventilation you have, and then offers guidance about how to run it appropriately to reduce the risk of infection spread. There is still much to learn about transmission routes of Covid-19 and the guidance will continue to be updated as this knowledge advances.”

The guidelines were written by Dr Chris Iddon (Chair of the CIBSE Natural Ventilation Group), Dr Abigail Hathway (University of Sheffield), Dr Shaun Fitzgerald (Royal Academy of Engineering Visiting Professor at the University of Cambridge), and coordinated by Hywel Davies (CIBSE). For the full guidelines please visit

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