Hospitals have become the backbone of surviving the COVID-19 pandemic as the transmission of the virus has spread like wildfire. Medical facilities face significant problems on how to accommodate a large number of infected patients. If accommodating the patients has been a challenge, providing an isolation room was a disaster no one has ever anticipated.

Many hospitals around the world are greatly affected by the COVID-19 virus pandemic. The rapid spread of the virus has forced the industry to rectify the standards of hospitals’ Air Handling Unit (AHU). In order to adapt, existing hospitals started their modifications, while new hospitals have adapted right away due to their advanced and new equipment. They are also investing in a thorough and Air Handling unit monitoring just to ensure safe ventilation for the hospital and its patients. There are also strategies and practices to incorporate into the hospital’s AHU unit to improve ventilation.

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5 HVAC Strategy Solutions

H.E.P.A. Filtration Recommendation

HEPA means “High-Efficiency Particulate Air“. In conjunction, HEPA filters could sift very small particles at a very high rate compared to conventional filters. It blocks small particles while allowing air to pass through.

Filters use a dense mat of fibers arranged in a specific configuration tested to trap 99.97% of particulates 0.3 microns or larger. Microns are one-millionth of a meter. It is how particles are measured. To give you a better idea of a micron’s size, we cannot visually see anything less than 10 microns.

The virus does not move by itself. These are generally bound to other types of particles, such as droplets. These respiratory particles are usually 5 microns in size and well above the minimum size filter. So, we can say that they are capable of blocking infectious particles.

H.E.P.A. Filtration Recommendation for Air Handling Unit System
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One caveat is that this feature comes with a cost. The high particle capture rate also presents higher resistance to airflow compared to other filters. It means that the blower on your HVAC equipment has to work harder. So, it uses more power.

Air Handling Unit Recommendations

Air handling units (AHU), are in medium to large commercial and industrial buildings. Air handlers condition and distribute air within a building. They take fresh ambient air from outside, clean it, heat it, or cool it. They may humidify it and then force it through some ductwork around to the designed areas within a building. It is vital to recognize the importance of bringing outside air into hospitals in a pandemic situation when planning a new hospital. It needs engineering your AHUs to handle dual conditions for heating and cooling coils. It must use minimum outside air intake for normal conditions. It must be 100 percent outside air for pandemic and emergency conditions. Standby heating and cooling capacity are configured to be utilized for increased outside air for these conditions.

It would encourage more hospitals to want to include standby cooling equipment in the design. It promotes the use of chilled water-cooling systems in more facilities. Air-cooled, direct expansion systems are standard in smaller facilities. Yet, it generally does not have extra capacity available. It needs to increase the outside air without compromising comfort.

Most building codes already require standby heating equipment. The intent would be to use available standby capacity for emergency conditions.

The current hospital code requires a minimum of 25 feet separation between exhaust and intake sources of outside air. However, this does not apply to economizer return fans. This area requires extra investigation. The best practices would dictate a similar separation from intake source if return fans use emergency exhaust.

Consider the use of high-intensity U.V. lights or other similar air treatment systems at the cooling coils. In addition to keeping coils clean, they can also be effective in killing a high percentage of virus particles passing through the AHU.

Negative Pressure Environment Recommendations

Negative pressure rooms have lower air pressure compared to the pressure outside the room. That is why they are called negative pressure rooms. Since air naturally flows from areas with higher to lower pressure, this means that when the door opens, particles cannot flow inside. This type of hospital room is where patients with infectious illnesses stay. These are also the isolation rooms.

A negative pressure room is essential, especially during a pandemic. But, most hospital ventilation systems are designed to handle a handful of these rooms. This puts extreme stress on hospitals that are not ready to accommodate a massive number of patients.

Some negative pressure rooms have a positively pressured anteroom. It is an airlock room that provides a safe area for health care professionals. It is used to change into personal protective clothing or P.P.E. Yet, this poses a risk of carrying infectious diseases inside the patient’s room.

Negative pressure rooms do not have to be individual rooms. Construction of new negative pressure rooms is more expensive. They need special attention to details, such as sealing all possible areas where air could flow unwantedly. It includes doors, windows, ceilings, and other parts of the room where air could easily penetrate.

Return Air and Exhaust Air Recommendations

It is also worth noting that airflow supply and removal are essential to include in new hospital designs. Hospitals should avoid designs with discharged returns. All relief air should be ducted outside to reduce the risk of infectious particles entering the room. While fully ducted systems are desirable, they are not required. However, maintaining a clean environment and controlled pressure relationships needs a fully ducted system.

Supply and exhaust systems should prevent contamination of any area within the facility in fan failure. An exhaust fan should be located in the system to ensure that the entire duct is under negative pressure. They should observe careful connection. Any air leakage through duct joints will disrupt the pressure. It will possibly increase infectious particles into the system.

They should also provide a monitoring system. It will signal any malfunction in the supply and exhaust air system. Consider adding an audible alarm system in case of any system failure.

Ventilator Support Recommendations

A difficulty included in the COVID-19 retrofit projects was acquiring the right level of medical-grade air and oxygen. It is to support the ventilators necessary to treat the patients considered to be at critical stages.

Accuracy is crucial when estimating future ventilator loads during the design phase of a new hospital. Ventilators need access not just to medical-grade air but also to oxygen. It makes it problematic to turn traditional medical or surgical beds into Intensive Care Units or Critical Care Unit beds. It is best to consider using bigger pipes when designing a future hospital. Larger pipes have room for more medical air or oxygen. It would cut significant costs when compared to retrofitting medical or surgical floors. Doing so would also allow medical or surgical floors to be upgraded to Intensive Care Unit or Critical Care Unit beds with no trouble.

The minimum size for medical air and oxygen on patient floors should be ¾-inch, and runouts to individual rooms should be ½-inch. If a bigger ventilator load is to be expected, larger sizes may be more suitable.

Hospitals should consider the diversity of patients. The need for medical oxygen and air will vary from case to case. Not every patient requires the same amount of medical oxygen and air. It is of great importance that the hospital goes into details about the type or desired ventilator settings. Commonly, they do not consider diversity when planning to install a certain number of ventilators. Instead, they prefer modest value used in previous times.

AKCP Air Handling Unit Monitoring

Air Handling Unit Monitoring

The efficiency of air handling units (AHU) greatly impacts a building’s energy use. They are responsible for the control of temperature, humidity, filtration, and building pressurization.

Monitoring temperature of the return air, outside air, mixed air, and the supply and discharge lines. A basic Air Handling Unit monitoring system will analyze the thermal performance. Additional sensors for measuring static pressure, airflow, fan, and compressor kW give a more detailed analysis of the system.

Differential Air Pressure Sensor installed on the Air Handling Unit Filter. When pressure drop across the filter is high filters are dirty and require maintenance. Sensors are wireless with 10-year battery life.

Air Handling Unit Monitoring with Wireless Tunnel™ sensors

Wireless Pipe Pressure Sensors monitor the water or gas pressure and temperature on the input and discharge lines from the AHU.

With the air handling unit monitoring system, you can also remotely monitor every factor in the system. It can diagnose faults and will send you an immediate SMS and Email. This allows you to implement necessary actions. Some issues that can be identified are :

– Compressor Short Cycling
– Compressor Overheating
– Over or Under Pressure
– Dirty Air Filters

Conclusion

After a year, economies worldwide are starting to reopen. Hospitals too, which have suspended many elective procedures and noncritical surgeries for months, can now start accommodating more patients in closer proximity. But despite the blooming hope and preparation for the incoming “after”, healthcare officials still fear the possibility of a second wave of COVID-19.

Governments, AHU manufacturers, building engineers, and regulators are in the process of redesigning airflows. Urgent as it may seem, but a necessity for the preparation of the most awaited post-covid-19 world.

References Links:

https://www.facilitiesnet.com/healthcarefacilities/article/5-Hospital-HVAC-Design-Strategies-for-the-Post-COVID-19-World–19123

https://www.bdcnetwork.com/healthcare-design-post-covid-world

https://specializedeng.com/5-hvac-design-considerations-solutions-for-designing-future-flexibility/

https://www.fm-college.com/49234-2/

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