“We have reached a time where planning for a safe return to normal activities has become a priority. Safe operation of HVAC and building water management systems are critical components of building readiness and reopening.”ASHRAE President Darryl K. Boyce, P.Eng.
As governments around the world look to ease COVID-19 lockdowns and other restrictions, leading industry bodies in multiple countries are calling for a thoughtful and planned approach to the re-opening of buildings. Organisations such as ASHRAE (American Society of Heating, Refrigerating and Air-Conditioning Engineers), AIRAH (Australian Institute of Refrigeration, Air Conditioning and Heating) and others have urged special caution when re-opening buildings, as improperly or poorly maintained HVAC systems can contribute to spread of outbreaks like Legionella.
ASHRAE Epidemic Task Force chair, ASHRAE Environmental Health Committee voting member and 2013-14 ASHRAE Presidential Member Bill Bahnfleth stated, “Key elements of a strategy to limit the spread of the COVID-19 virus are to perform needed heating, ventilating and air conditioning (HVAC) system maintenance, including filter changes, and to run HVAC equipment prior to re-occupancy.” EP&T’s team of technical experts and analysts share this view, and have been providing advice and guidance to customers around the world accordingly.
As building operators prepare to re-open their buildings, welcome tenants and move closer to normal operations, sharing guidelines on some of the measures required to mitigate potential health risks should support more effective outcomes. These guidelines have been categorised into general recommendations, HVAC&R, electrical systems and other essential services.
- Building owners, managers and occupiers’ representatives need to collaborate and agree a planned approach to re-opening the building. At a minimum, the plan should incorporate measures to ensure occupant safety, social distancing and clearly defined communication protocols and channels.
By way of example, one of our customers has introduced the following initiatives:
- Posting signage and messaging with Centres for Disease Control and Prevention (CDC) and Communicable Diseases Network Australia (CDNA) guidelines in common areas, break rooms, bathrooms, and conference rooms
- Demarcating travel patterns within the tenants’ space
- Limiting conference room capacity
- Bringing in more outside air and changing filters for MERV 13
- Greater emphasis on cleaning high-touch surfaces, including doorknobs, on/off switches, thermostats and elevator buttons
- Providing disinfectant wipes and hand sanitiser stations in the lobbies/reception areas
- Retrofitting existing water taps in toilets with automated fixtures
- Disinfecting interior of shared equipment including staff refrigerators
- Tenants and occupiers should ensure that proper distancing is being followed within their premises:
- Make relevant changes to seating arrangements and posting signage in muster areas, kitchen, meeting rooms, etc.
- Install shields between desks that face each other
- Require employees and guests to check their temperature upon arrival
- Provide appropriate training and educating the staff on new office rules
- Remain up to date with the latest government guidelines, in addition to those issued by building management
- Arrangements must be made for safe, contactless and timely delivery of critical items including filters, office supplies, etc.
- All local, state and federal executive orders, statutes and advices regarding use of PPEs, regulations, guidelines, restrictions and limitations on use, occupancy and separation must continue to be followed until they have been officially relaxed or lifted.
- Review all procedures to consider the addition of “touchless” interactions where applicable. For instance, auto-flush valves are considered “touchless”. Use of revolving doors over opening swing doors in lobby/reception areas.
- Detect elevated skin temperature quickly, accurately and non-intrusively at point-of-entry into key facilities.
- Despite a focus on minimising operating costs, HVAC equipment and BMCS planned preventative maintenance should not be ignored. Building owners and service professionals should follow specific requirements as mentioned in their local by-laws to ensure compliance with regulatory standards.
- Extra caution, including use of PPE’s, should be taken while dealing with ventilation equipment, filters, condensate and duct cleaning.
- Air in the building should be flushed a minimum of 4 hours prior to reoccupation. The outside air and exhaust air dampers should be opened to their maximum while operating ‘flush out’ mode. System design parameters, OA temperatures and RH and HVAC capability should be accounted for while planning the timing and duration of these flush outs. Closely review the Indoor Air Quality (IAQ) while flush out is in operation to ensure the indoor temperature and humidity levels are within permissible limits.
- Check the condition and operation of devices such as enthalpy wheels, HEX’s, filters, etc. for leakages and cross-contamination.
- During the initial weeks of returning to normal building operations, closely monitor the operation of airside systems, cooling and heating systems and BAS to ensure they are operating as intended. Closely monitor equipment running in manual mode or turned off from the board or asset level. For sites using EP&T Global, your Technical Services Manager will assist with ensuring operations are optimised and unanticipated utility costs avoided.
- Review the agreed comfort conditions in the OTA’s and tenant leases and ensure acceptable setpoints and airflows are maintained in different zones within the building.
- Ensure that the system is calibrated to weather conditions, which have changed in the last 2 months as we enter winter in the southern hemisphere and summer in northern hemisphere.
- Check to make sure that the dampers (that may have been manually opened or shut to maximise OA intake during the pandemic) are rebalanced and operating in ‘auto’ mode to achieve design airflows in an energy-efficient manner.
- Check building pressure and air pressure in other critical interior spaces to ensure required levels are being achieved.
- In cooling systems, check:
- Refrigerant charge is adequate.
- Water levels, quality and chemical dosing is as intended (keeping in mind risks related to waterborne pathogens such as legionella pneumophila).
- Dehumidification levels and coil leaving air temperatures are within limits.
- Pump operation.
- Codes and manufacturer’s specifications/instructions are being followed.
- In heating systems, check:
- Fuel source is available and enabled.
- Flues and make-up air paths are open.
- Coil actuators are controlling to temperature. Heating elements are turned on at the disconnect.
- Codes and manufacturer’s specifications/instructions are being adhered to.
- For BMCS’s, check:
- Sensors are within acceptable calibration limits.
- Alarms are being generated and received in a timely fashion.
- [Optional] Establish an ‘epidemic mode’ of operation that will enable HVAC control strategies as recommended by different standards in a single action by the operator.
- Employ HVAC practices that focus on dilution and filtration.
- EP&T would recommend providing outside air for a few hours before and a few hours after occupancy each day.
- More advanced measures, such as HEPA filters and UVGI, can be considered for higher-risk areas, but require careful evaluation for each application and should be assessed separately to more generic measures.
Some of the above recommendations, including extending HVAC hours, upgrading to MERV 13 from MERV 8 filters, and letting in an additional outside air, may increase energy usage. The overall impact of these changes may contribute an approximate 4-8% increase in building energy consumption for a typical office building, depending on climate region.
Electrical Systems and other essential services
- Distributed DHW systems: keep these systems circulating. Maintain water temperature above 60°C to avoid microbial incursion. Do not let water temperature drop below 50°C. If circulation has been stopped, try circulating once every 2 weeks for a couple of hours at temperature. If the HW recirculating system goes down for an extended period, undertake a high temperature flush and pull the strainers prior to operations restart.
- Plug in all appliances that were unplugged during the lockdown periods. Check fire alarms and other equipment with battery backup power supplies.
- Have your essential systems including fire protection sprinkler systems, fire alarm systems, emergency lighting systems and other life-safety systems inspected in accordance with local and federal byelaws.
- Check the cabling, optical fibres and associated battery backups to ensure continuity of services including internet, IT, IOT, servers, BAS, LCS, communication systems and security systems.
- Diesel (backup) generators should be tested as required by codes, local jurisdictions and manufacturer’s recommendations.
For any further information, contact your Technical Services Manager at EP&T Global.