The new guidance reinforces CIBSE's message that good ventilation is essential to reduce occupants' exposure to airborne pathogens, including COVID-19, influenza and the four endemic human coronaviruses that cause common colds.

It follows CIBSE's contribution to the Royal Academy of Engineering's report, published in July, on how to augment the infection resilience of buildings through improved management, maintenance and ventilation as well as through improved design standards in the future.

Commissioned by Government Chief Scientific Adviser, Sir Patrick Vallance, the report calls for clear, consistent communication and advice on ventilation from government and professional bodies to help building owners and operators manage Covid-19 infection risks.

The CIBSE guidance on ventilation and air cleaning technologies aims to provide advice to building owners and operators on how they can act to reduce the risk of airborne infection.

In well managed new buildings designed to current regulations ventilation rates are likely to be effective in preventing the spread of COVID-19. In older buildings it may be difficult to assess the effectiveness of ventilation so CIBSE's COVID-19 Ventilation guidance now includes advice on the use of CO2 monitoring. High levels of CO2 are an indication of poor ventilation and show where further measures are needed to improve air quality.

For spaces where all efforts to increases ventilation fail to provide sufficient ventilation to dilute and remove airborne pathogens then air cleaning devises may be an option for removing or inactivating contaminants in the air.

CIBSE's guide Covid-19: Air Cleaning Technologies has been written to provide both lay-readers and ventilation specialists with the knowledge to assess the variety of air cleaning devices currently marketed for the removal of SARS-CoV-2, and to discover whether any air cleaner will effectively reduce transmission risk in a space.

The guide is divided into two parts. The first summarises what is currently known about air cleaners and makes general recommendations about selecting such devices.  It provides advice on whether a device is likely to be effective in a particular situation.

The second part offers more detail for building services engineers, facilities managers and others involved in the provision of ventilation. It gives guidance on measuring airflow, pollutant levels and the rate of decay in contaminant levels. It also provides a tool for assessing the potential performance of air cleaners in particular applications.

All the guidance is available to download for free from the Coronavirus Advice section on the CIBSE website.