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Ventilation in buildings

The National Institute for Public Health and the Environment (RIVM) tightened up its recommendations for ventilation on 28 July. We have examined whether these recommendations will have additional consequences for the UvA buildings in terms of ensuring a safe environment.

Key topics here are particularly the recirculation of indoor air without bringing in fresh air from the outside and the potential risk of very small particles (aerosols). RIVM distinguishes recirculation that can pass from room to room (where the air travels a relatively long distance) from recirculation within the same room (where the air travels a short distance and flows in a relatively straight manner from person to person). Mobile air-conditioning units and table fans are not recommended if they cause a direct flow of air from one person to another.

At an earlier stage, the decision was already made for the UvA buildings to switch off the central recirculation of the air-treatment system at the building level. During the coronavirus measures, ventilation is prioritised over heating and cooling. As a result, the temperature of the buildings may be colder or warmer than usual In some situations.

There are also buildings in which recirculation is present at the room level. While it will be switched off wherever possible, it has otherwise been assessed and does not pose a risk when combined with good ventilation* and correct air extraction (* good ventilation is the sufficient supply of clean outside air in accordance with the applicable rules and regulations). Aerosols, particles that may contain the virus, are adequately removed under good ventilation and therefore do not pose any additional risk.

If new insights are gained into the possible spread of the virus through ventilation systems, it may prompt a change in the ventilation method. For example, this situation applies to CO2-controlled rooms (where the ventilation depends on the number of people present but only responds when people have been present in the room for some time). These rooms are already being provided with a sufficient supply of fresh air.

If there are rooms that do not comply with the RIVM guidelines, the party responsible for the use of the building has been informed and the use of the room has been adapted to the possibilities. Possible adaptations include the following: the room is out of use or can only be used by one person. This information is always displayed outside the room.

  • Are the ventilation systems being maintained well?

    Facility Services has concluded a maintenance contract for all of the ventilation systems to ensure their safe and reliable use. Continual attention is paid to the timely replacement of filters and the modification of systems in line with the RIVM guidelines. During the period when employees were not permitted to work in the building, work on the climate control systems was accelerated if required. As a result, you can be sure that the systems are maintained well.

  • Does the ventilation in my building comply with the RIVM guidelines?

    Ventilation is the constant renewal of the air (24 hours a day). The outside air always replaces part or all of the inside air that is polluted by moisture, gases and possible pathogens. Ventilation can be achieved via natural (e.g. grilles or gaps) or mechanical ventilation (ventilation systems – definition: guidelines by the LCHV (National Centre for Hygiene and Safety); statutory requirements: Building Decree, Section 3.6).

    The UvA buildings must have natural or mechanical ventilation in accordance with the statutory requirements. Partial recirculation may also occur. Recirculation within a system that supplies air to the entire building – allowing the movement of air from one room to another – has been switched off in all buildings as a preventive measure, even though RIVM states the following in its advice on the matter: RIVM is nevertheless reluctant to advise against ventilation systems with central recirculation in which air is moved from one room to another, as there are no case studies in which these systems played a role in the spread of an infectious disease. In respect of central recirculation, the extracted air travels a relatively long distance before it is recirculated.

    Some rooms have partial recirculation for the purposes of climate control (cold air, for example). This method is safe to use for most applications combined with a ventilation system, given a supply of fresh air from the outside. Recirculation has been switched off or restricted where it is not safe. As a result, it might get warmer or colder than usual at a location. All the locations have been examined, whether they are offices or teaching locations. It is indicated at the entrance to each room how many people can be present in a room if the supply of fresh outside air is limited. The room will be properly ventilated if you stick to this maximum.

    If no instructions are provided for the room, the room can be used safely. However, you must obviously observe a distance of 1.5 metres and the usual hygiene measures. A brief overview for each campus is provided below.

    Please note: Ventilation is not the same as cooling and heating a room, even if it is supplied through the same air. In some cases, the temperature may not be optimal due to the additional ventilation measures and could occasionally cause inconvenience. It has been decided that good ventilation takes precedence over temperature optimisation during the coronavirus measures.

    Roeterseiland Campus

    Most of the buildings on campus are connected to the Central Energy Facility (CEF). Cooling, heating and the supply of fresh air take place through this system and various air-conditioning units. These units comply with the RIVM guidelines. REC G and L comply with the guidelines as well. During the renovation, these buildings were fitted with a modern ventilation system. REC E has a sufficient fresh air supply that complies with the RIVM guidelines. However, the air is not extracted for each individual room. This fact applies in particular to the smaller rooms. The advice is therefore to open the window regularly (for 10-15 minutes every 1-2 hours in accordance with the RIVM guidelines). Doing so is only necessary if there are several people in the same room or after a meeting, for example.

    REC JK has an older ventilation system. Work is currently being carried out on the installation to make the required modifications. It is already clear that 90% of the rooms can be put into operation. During the course of this week, we expect that the other rooms can be taken into use as well. In rooms for which the standard (Building Decree) is not achieved, the number of people permitted will be changed or the room will be made available for a maximum of one person.

    There are rooms in which both mechanical ventilation (via an air-treatment system with supply and extraction points in the rooms) and natural ventilation (ventilation by means of a grille or windows that can be opened) are present. Mechanical ventilation is highly useful for the prevention of aerosol formation. There is no need to open windows and doors for additional ventilation. However, additional ventilation does reduce the risk of infection. If you wish to provide additional ventilation, do so mainly when you are going to take a break; for example, during 10 to 15 minutes every 2 hours. This procedure will prevent excessive ventilation from adversely affecting the mechanical ventilation.

    University Quarter

    Many buildings in the city centre only have natural ventilation. See the FAQ on natural ventilation. Fans have been placed in the window to improve the natural ventilation in a number of cases. These fans do not require any additional maintenance or attention.

    Rooms in which mechanical ventilation is present comply with the guidelines. The installation is well maintained, while the filters were recently inspected and replaced if required.

    Amsterdam Science Park

    As all of the buildings at the Science Park are new or have been renovated, they meet all the requirements. This situation is in accordance with the RIVM guidelines. Only the Pavilion and Science Park 107 have a limited installation. The Pavilion has an extraction system and no forced supply of fresh air. Air supply takes place by means of natural ventilation. The recommendation for this location is to open windows regularly. Due to the forced extraction, the rooms can also be used safely by several people. However, a distance of 1.5 metres must obviously be observed. Science Park 107 has partial mechanical ventilation and partial natural ventilation. Any necessary actions and restrictions to the number of people in the room are stated at the entrance to the rooms.

    If I have questions about a specific room in a building, whom may I contact?

    Employees may get in touch with the Occupational Health and Safety Coordinator for advice on ventilation and climate control as well as for any technical questions. If they have any questions, students may contact

  • I have natural ventilation, what should I do or not do?

    There is no problem whatsoever if you are alone in a room. If you are working with several people in the same room without mechanical ventilation, additional outside air must be brought in regularly by opening windows and doors. RIVM specifies the following: regularly open opposing windows and doors for 10-15 minutes every 1-2 hours. This measure applies to both hot and cold periods. When entering a room with natural ventilation, the number of people that are permitted in the room and the need for regular ventilation are indicated by signs.

  • Can I use a table fan?

    Yes, it will not be a problem if you are alone in a room. If there are several people in a room, you will have to check that the airflow does not pass from one person to another. RIVM has therefore issued a negative recommendation. In this case, the use of several fans could offer a solution. Get in touch with the Occupational Health and Safety Coordinator for further recommendations as well as to register the fan. The reason is that it must be checked annually to ensure that it can be used safely. We do not recommend the use of an additional fan in a climate-controlled room.