Importance of Ventilation Maintenance | COVID-19
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The Importance of Ventilation Maintenance
Your staff, customers and site visitors are far more aware of the condition of the environment in which they work or attend. Ensuring the quality of the air in workplaces and public spaces has always been a statutory requirement. Now more than ever, the need to ensure your ventilation systems are effectively and regularly maintained is essential.
Ventilation Maintenance Guidelines
REHVA (Federation of European Heating, Ventilation and Air Conditioning Associations) have recently updated their guidelines on how to operate Heating, Ventilation and Air Conditioning systems to prevent the spread of COVID-19 in workplaces. Part of this document covers recommendations for ventilation solutions and how to protect against airborne transmission which could be applied to existing buildings. The European Centre for Disease Prevention and Control (ECDC) has prepared guidance for public health authorities in the UK on the ventilation of indoor spaces, in the context of COVID-19. Some of the conclusions by ECDC are summarised here:
HVAC systems may have a complementary role in decreasing transmission in indoor spaces by increasing the rate of air change, decreasing the re-circulation of air, and increasing the use of outdoor air.
Building administrators should maintain heating, ventilation, and air-conditioning systems according to the manufacturer's current instructions, particularly concerning the cleaning and changing of filters.
Energy-saving settings, such as demand-controlled ventilation controlled by a timer or CO2 detectors, should be avoided.
High air volume and low air flow is desirable. Consideration should be given to extending the operating times of HVAC systems before and after the regular period.
Direct air flow should be diverted away from groups of individuals to avoid pathogen dispersion from infected subjects and transmission.
Organisers and administrators responsible for gatherings and critical infrastructure settings should explore options with the assistance of their technical/maintenance teams to avoid the use of air re-circulation as much as possible.
The minimum number of air exchanges per hour, following the applicable building regulations, should be ensured at all times. Increasing the number of air exchanges per hour will reduce the risk of transmission in closed spaces. This may be achieved by natural or mechanical ventilation, depending on the setting.
Fresh Air
It is a known fact the the transmission of COVID-19 can commonly occur in enclosed indoor spaces. Air should not be re-circulated, instead a steady flow of fresh air should be circulated through mechanical ventilation systems. In buildings where there are no mechanical systems, it is highly recommended to actively use openable windows, as much as possible. Even where there are mechanical ventilation systems, it is still recommended to open windows to boost ventilation further.
Exhaust ventilation systems for toilets should always be kept on 24/7, and make sure that under-pressure is created, to avoid faecal-oral transmission i.e. avoid opening windows, allow the air to be removed via the exhaust systems and create a vacuum in the toilets to avoid any virus plumes to spread out of the toilets e.g. when doors are opened to other areas. As a guide, the supply air volume should be 80% that of extract volume.
If the toilets do not have mechanical extraction systems or passive stacks, then open windows in other areas as well as the toilets (if they must be opened) to dilute any infectious plumes of air coming from the toilet areas.
The general guidance is to supply as much outside air as reasonably possible. Avoid concentrating people in small areas but maintain or enlarge the social distancing between persons (2-3 m minimum) to encourage the ventilation cleaning effect. To this end they have recommended that central re-circulation is avoided.
Airflow Management
While research and studies are still on going regarding how the coronavirus spreads via air, evidence suggests that measures to change indoor airflow patterns could play a role in reducing transmission. Three principles apply:
Encourage a vertical laminar, rather than turbulent airflow.
Ensure a slow, steady air speed.
Direct potentially contaminated air out of rooms and away from people.
Next, design stages and consideration for enhancing or replacing HVAC systems:
Replace fixed speed fan mop tor’s with variable-speed ones to enhance the control of airflow and allow for a minimum setting that produces lower speed airflow.
Introduce sophisticated airflow-control systems, such as those that are sensitive to pressure, to allow for smoother adjustments of air flow.
Install high-performance air-purification systems.
Further Information
Full details and recommendations from REHVA can be found in their updated REHVA COVID-19 Guidance Document here.
BESA (Building Engineering Services Association) have also produced a summary of the guidelines with additional content from CIBSE, you can read the BESA document here.
Do you require help or advice during this time?
If you require an assessment or maintenance of your ventilation systems, to ensure that meet statutory requirements, please get in touch.
We provide a range of building and statutory compliance maintenance services, ensuring our clients can provide safe and compliant buildings for their staff and customers.
