On April 3, REHVA updated its COVID-19 guidance document with the following revisions and additions:
- Latest information on the airborne transmission and implications to HVAC systems was added;
- Ventilation continuous operation guidelines were updated to be explicit;
- SARS-CoV-2 stability data at different temperatures and relative humidity was added;
- Heat recovery equipment guidance was revised including the recommendation of inspection;
- Guidance for room level circulation units was complemented;
- HVAC maintenance personnel protection recommendation was added;
- A summary of 14 points of practical measures for building services operation was added.