Hospitals and healthcare facilities have been significantly impacted during the COVID-19 pandemic. Due to an anticipated influx of patients with the infectious disease, healthcare facilities have been looking at all available space within existing facilities to safely admit and treat these patients. This need has brought on a requirement for these facilities to convert existing patient rooms and in some cases entire patient wings to negative pressure suites to safely house these patients while protecting staff. Different means and methods have been employed to convert these areas but now that they are operational, the maintenance staff need to be knowledgeable on how to maintain these areas safely.
In many suite conversions, the air handling equipment serving negative pressure patient areas has been set to exhaust 100% of the return air in the system and bring in 100% outdoor air to the suite. This configuration stops recirculation of air by the air system and provides for removal of potentially contaminated air directly to the outdoors. The maintenance staff should be monitoring these air handlers periodically to ensure that mixed air dampers remain 100% closed and the relief air dampers are 100% open and ensuring contaminated air is not re-circulated to the system. With these air handling units providing 100% outdoor air maintenance staff should also be monitoring the leaving supply air temperature and relative humidity, particularly on very cold or hot days. On high demand days, control overrides and setpoints may need to be altered to ensure code required internal setpoint ranges are being met.
With increased (100%) outdoor airflow, air filters within air handlers will likely need to be changed more often. Keeping up with filter changes will help maintain keep the supply air static pressure performance and energy efficiency of the unit; dirty filter lower both. Proper filter maintenance will also ensure heating and cooling coils within the air handler remain clean; this too which will optimize heat transfer and thus energy efficiency. Keeping air handlers running at design performance is necessary to provide the required supply air flow rate and meet code required air change rates.
Space pressure monitoring of newly created negative pressure suites should also be carefully monitored/checked to confirm these areas remain under negative pressure. There are many ways this can be accomplished. The most common way is a pressure monitoring device installed at the doorway between the negative pressure space and the adjacent neutral / positive space. These devices vary from simple mechanical types such as ball and tube indicators and more elaborate types such as electronic devices with digital displays that can be integrated to the BMS control system which will provide alarms and system response via the control system. If these visual or electronic indicators provide feedback that the space pressure is becoming neutral or positive, the maintenance staff should increase the return or exhaust fan airflow serving the area or adjust the supply airflow downward to get the area back to a negative pressure. Manual adjustment of duct-mounted or air terminal mounted volume dampers can also be done.
With the unpredictable nature of the COVID-19 virus, maintaining negative pressure areas are crucial to hospital staff and patient safety as well as decrease the chances of spreading the disease. The maintenance staff in these facilities need to be just as vigilant as the clinical staff.
Written by:
Stephen Picariello
Project Manager & Associate
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