Switch AC systems to ‘full fresh air’ mode, says AREA Covid-19 guidance

Air conditioning and ventilation systems should be run during the Covid-19 pandemic on full fresh air - rather than in circulation mode - as a matter of best practice , new guidance from European cooling association AREA has concluded.

The organisation has said that evidence is presently inconclusive about the capacity to spread the coronavirus through the operation of air conditioning systems, with public authorities and scientists yet to deliver a formal stance. However, AREA has joined a number of HVACR bodies in setting out their own best practice guidance that urges continuous fresh air flow to help industry better eliminate potential risks concerning air quality.

The association said, “Whilst there is much that is not yet known about this novel coronavirus, early research published in the Lancet indicated that the primary transmission route is person to person.”

“The transmission of Covid-19 is thought to occur mainly through respiratory droplets generated by coughing and sneezing, and through contact with contaminated surfaces. The predominant modes of transmission are assumed to be droplet and contact.”

A key recommendation of the new guidance is to ensure air conditioning units and ventilation systems that cannot be shut down at present should be run on full fresh air mode to ensure better dilution of contaminated air that might post a potential risk.

The guidance stated, “The potential benefit to public health at this time outweighs the reduction in energy efficiency caused by not recirculating air. In all cases a full risk assessment should be carried out.

“Any airborne contaminants can be minimised by proper and effective filtration, regular maintenance and, where appropriate cleaning of ventilation systems, as set out in national application regulations and other professional use and maintenance guides existing in the sector.”

The guidance also touches upon the importance of carrying out a specific review of the needs of a certain area or building when performing maintenance work, including the impact that shutting a fan down may have on an engineer while performing their work. The guidance's recommendations should largely be seen as standard practice even outside of restrictions introduced due to Covid-19, according to AREA.

AREA said in the guidance, “No air should be flowing through the system without the correct filter in place and the operative should not be exposing themselves to any foul air flowing through or towards the system.”

Filter maintenance

Specialists are warned in the guidance about disposable filters and how they should handle these products as much as possible by their cardboard frame.  Engineers are asked to ensure the ‘filter media’ is untouched.

Filters removed from a system should be handled with care to prevent particulate matter getting loose. It should then be immediately put in a securely tied bag, according to the guidance.

The document added, “At this time, and if possible, the filter(s) should be left for at least 72 hours before being disposed of in a secure storage area.”

Similar advice is also detailed for washable plastic filters that AREA said should be handled from the frame edges, with filter media going untouched as much as possible.

The document stated, “The filter(s) should be scrubbed in warm, soapy water for a minimum of 20 seconds in line with recommendations for the washing of hands as a preventative measure.”

AREA has urged specialists to dry any washable filters before reintroducing them into equipment.

PPE

Procedures for making use of Personal Protective Equipment (PPE) is included in the guide, with the issue remaining a significant challenge in the UK where concerns remain about the limited stocks of suitable protective equipment available for healthcare professionals treating the pandemic.

AREA said in the guidance that the correct PPE should be worn at all times for maintenance work. This equipment should include:

• Gloves
• A face mask of a class appropriate for the work being undertaken – FFP2 mask or an FFP3 mask is preferable
• A disposable coverall suit

The guidance added, “Face fit testing must be completed before the wearing of any tight fitting RPE. It is important to note that if the RPE type changes due to lack of supplies then further face fit testing must be completed.”

AREA also reiterated the importance of basic hygiene good practice to prevent coronavirus transmission such as hand washing with soap and hot water for a minimum of 20 seconds, alongside maintaining social distancing of two metres between people on-site.