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Coronavirus : What is the risk of propagation in your buildings?

INDALO, our indoor air quality simulation software, was designed to predict the concentrations of pollutants in a building in relation to regulatory thresholds and find improvement strategies. In this, when SARS-COV-2 (COVID-19) arrived in Europe, at Octopus Lab, we felt that we could not make our contribution to the fight to combat this new health problem while our business it is precisely to ensure health in buildings.

As a result of requests from our partners and internal reflections, we began to learn about current research on COVID-19 and what had been done during the SARS-CoV epidemic in 2002. A study dating back to of 2017 particularly caught our attention. Carried out by the Boeing Research Department and the University of Hong Kong, it focused on the contamination of airplane passengers during commercial flights during which a few sick passengers had contaminated a large part of the occupants of the airplane (passengers and flight attendants).

We reproduced the methodology of this work and collected all the accessible data specific to SARS-COV-2 to adapt INDALO to this problem. Our software now includes a probability that one or more occupants are sick, based on a random draw with the assumption that an occupant has a 1% risk of being sick.

From this, we estimate all possible transfers of the virus:

  • by close contact
  • by transmission in the air of the virus on fine particles exhaled during a coughing fit
  • by touching surfaces contaminated by contact with patients

We integrated data from studies that estimated the survival times of the covid in aerosols, on the surfaces of objects, etc. Finally, based on our knowledge of SARS-COV from 2002, we have an estimate of the amount of SARS-COV-2 to be inhaled to have a 50% risk of being contaminated as well.

The purpose of the exercise? Provide an estimate of the risk of the virus spreading within a building.


  • What is the impact of having 30 students per class rather than 15?
  • Within my company, for a patient present on Monday, how many will be contaminated at the end of the week?

    From all this, we make simulations to compare scenarios and assess the risk of transmission between occupants and find out how to limit the spread with the best ventilation strategy.

Among these strategies, we will have, for example, the impacts: cleaning, ventilation, opening windows, supply of fresh air vs recirculation of air, filtration, limiting the number people per space, general wearing of masks, etc.

At Octopus Lab, we will not find a vaccine for SARS-COV-2 but we can now help you limit its spread within your buildings and make the right decisions.