Our Learnings: COVID-19 - Health, Safety and Building Controls

March 24, 2021

In regions such as Europe and the United Kingdom where the COVID-19 pandemic has forced the continuation of ‘work from home’, there is growing optimism that a return to the office may be soon. Pending the easing of government restrictions, current indications suggest that it could be early in the second half of 2021.

Ash Chilakwad, a member of our EMEA Customer Success Team who you may of met on our last Meet the Team Blog, recently completed ‘Safe Operations of buildings and HVAC Systems during the COVID 19 Pandemic’, a course conducted by industry group, Federation of European Heating, Ventilation and Air Conditioning Associations (REHVA).

Specifically addressing resume activities, the safe operation of buildings and the use of densely occupied indoor spaces during and after the COVID-19 pandemic, the course was a continuation of REHVA’s COVID-19 Guidelines.

As we strive to improve building safety and performance, and of course remain mindful of Public Health, it is our ongoing commitment to recommend REHVA’s guidelines as best practice.

To help assist your return to the office, Ash has prepared his thoughts in line with REHVA’s guidelines below.

It is noted that the guidance here is precautionary and local government & healthcare guidelines should first be followed before further precautions are implemented.

Importance of Building Analytics

Building analytics plays a key role in occupant safety. Monitoring of CO2 sensors, equipment alerts, and smart dashboarding solutions are equally important to ensure issues within a building are highlighted and resolved quickly. While Building Analytics doesn’t set safety guidelines or standards, we can use data to monitor the systems to ensure buildings remain within guidelines.

A message from ECDC - European Centre For Disease Control

“HVAC systems may have a complementary role in decreasing transmission in indoor spaces by increasing the rate of air change, decreasing circulation of air and increasing use of outside air’

The Virus and Ventilation

We’re all aware through health guidance that ventilation plays a factor in reducing transmission. The virus particles are microscopic, at 0.1 microns. If we were to place 10,000 virus particles in front of each other it would be equal to 1mm. In terms of ventilation, the size of this virus is important as the forces of lift are greater than the force of gravity - resulting in the virus floating in the air for up to 41 hours depending on the airflow in the area.

COVID-19 and IAQ (Indoor Air Quality) concepts

Indoor exposure is affected by:

- Source strength (Number of Infected people)

- Ventilation (via natural and mechanical ventilation)

- Filtration (use of HVAC system filters, separate air-cleaning devices, masks)

- Events – meetings or gatherings in small spaces with mediocre fresh air supply (1-2l/s/person)

Recommended Building Checks According to REHVA

Below are the main guidelines REHVA recommends, and the key points I wanted to share. I believe they definitely create a starting point for developing processes around Building Safety as more of your workforce returns. Reassuring staff that the building is being managed with their safety as a priority is important as they return to the workplace.

Many companies are using Building Analytics reporting specifically on these guidelines to present to staff daily, and give them additional comfort entering the building.

Recommended Bathroom Ventilation checks

- Bathroom ventilation needs to be high with increased airflow.

- Ventilation should be on 24 /7 , toilets to be flushed with lids down and wastewater treatment needs to be checked.

Recommended Building Checks

- Gas appliance and legionella checks should be completed

- Occupants risk assessment carried out covering -

- How many occupants are in the building?

- Is there an area such as a gym where vigorous exercise would occur (air changes in these areas should be increased)?

- Is the building open to the public (Can you document each occupant)?

- Building operators need to address:

- Social distancing requirements within the building - Calculate how many occupants can occupy each zone and common areas.

- Space availability and working routines, including flexible or staggered working schedules.

- Cleaning regimes to minimize risks from common touchpoints and to give staff reassurance of enhanced cleaning.

- The source will move unexpectedly - Due to the nature of the virus you are not be able to tell the presence of the virus until after an occupant has been diagnosed with COVID-19.

- Building entrance and exit protocols, temperature checks, lift control programs, meeting area sizes, and restrictions in numbers may be required.

- Identification of poorly ventilated zones will improve safety. Reduction in capacity in these areas or closing these areas will improve the safety of the building.

Recommended Equipment Checks

- Air Handling Units (AHUs) time schedule should be increased to start earlier in the day and finish later in the day to improve airflow in rooms

- Reduce AHUs to low-speed operation during weekends and off-peak hours

- Toilet exhaust air should operate 24/7

- Zones with FCUs and split units

- Ensure sufficient outdoor air in these zones

- Install CO2 sensors in the zones and operate a traffic light system to ensure adequate levels are met for occupants. Ie. 800 ppm yellow 1000 ppm red

- Allow 15 minutes between change in occupants in each zone such as meeting rooms

- Recirculation is NOT recommended

- Room air cleaners are also recommended but need to have HEPA-filter-like efficiency and need to be placed closer to people to be most effective. To select the right sized air cleaners select one with appropriate noise level, at least 2 air changes per hour (ACH) with a positive effect until 5 ACH.

If you want to find out more about REHVA’s guidelines or are interested in CIM’s building analytics software, please contact us here.

In need of more information? We have you covered.

We have some further pieces of information that you may find helpful for your current situation with the COVID 19 Pandemic –

How to Remotely Monitor and Manage Your Building Operations


Adapting Your Buildings for Partial Occupancy


  1. Wu, Yongjian. “Prolonged presence of SARS-CoV-2 viral RNA in fecal samples.” Lancet, vol. 5, 2020, p. 1. TheLancet.com, https://www.thelancet.com/pdfs/journals/langas/PIIS2468-1253(20)30083-2.pdf.
  2. REHVA safe buildings operations during COVID-19 - https://www.rehva.eu/activities/covid-19-guidance
CIM Team
March 24, 2021