Air Curtains
June 27, 2021
The HVAC design is indispensable for fatal virus COVID- 19. The most of the existing hospital’s management has focused on modifying existing HVAC system to create negative pressure in its medical and surgical patient rooms.The new hospitals or the new wards of existing hospitals need to design for ultimate escape of the COVID-19. Following five Recommendations are essential to consider for HVAC solution.
1.Air Handling Unit (AHU):
This is the most suitable HVAC type of equipment that carry its clean function Air Handling Unit (AHU) handle dual conditions for heating and cooling coils: minimum outside air intake for normal conditions and one hundred pc outside air for pandemic and emergency conditions.
The AHU are of two types:
1.AHU with chilled water-cooling systems which has more facilities.
2.AHU with Air cooled, direct expansion systems which is commonly used in smaller facilities.
The most of the building codes require standby heating equipment. The intent would be to use available standby capacity for emergency conditions. A minimum of 25 feet separation between exhaust and intake of outside air requires as per Current Hospital Codess.
The high intensity UV lights or likewise air treatment systems at the cooling coils of AHU should be consider . they can even be effective in killing a high percentage of virus particles passing through the AHU.
2.Quality of Air for Ventilator:
The appropriate medical grade air and oxygen to support the ventilators need to treat the most critically ill patients is the most challenging aspects of the COVID-19.
It is necessary to assess future ventilator loads carefully during designing the building and infrastructure of a new hospital. Ventilators are especially requiring access to medical grade air as well as oxygen. which is why it is difficult to convert The traditional medical or surgical beds should be avoided to convert to ICU or CCU beds.
The medical air and oxygen on patient floors is provided through pipe lines. The minimum size of pipe should be ¾-inch whereas the runouts to each room should be ½-inch. The sizes of pipes will be according to anticipated load of ventilator volume . It may be larger size for higher ventilator load. The patient diversity is another important factor. The need of oxygen and medical air may vary from patient to patient. The desired ventilator settings is necessary to discuss with the hospital.
3.HEPA Filters:
HEPA stand for high-efficiency particulate air. We need to minimize the chance of future viruses spreading through hospital HVAC systems. HEPA filtration systems are extremely effective at capturing and removing airborne particles, microorganisms, and other contaminants from a facility’s indoor air. The air is distributed through HEPA filters.
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4.The pressurization system:
This is also a mechanical ventilation system. Positive and negative air pressure and created to allow the contamination air from room to the isolation/buffer room. The positive and negatives air pressures are maintained in such a way that air naturally flows area with higher pressure to areas with lower pressures.
The Construction of a negative pressure room requires special attention be given that include sealing all wall penetrations, use of monolithic, gypboard ceilings. Door seals and sweeps are also used. No doubt its much more expensive to construct.
5.Return and Exhaust Air:
As long as the intake of outside air is important, the return and exhaust air is also more important which should be the best practices in design of new hospitals. It should be avoided in re circulation of exhaust in any other mechanical room. The all return air must be ducted to the outside in order to reduce the risk of infections.
The standard /Code requires that return air grills be located in the headwall or over the patient bed in isolation rooms. The doorway location is more appropriate for non – infected patients that are vulnerable to being infected or immunosuppressed. Because these are conflicting directions, the location of the return grilles within the medical or surgical patient rooms should be thoroughly reviewed with the hospital during design.
Two return air grilles in a patient room should be designed , one by the bed and one by the door, The size of each grill should be for 100 % airflow. It would allow the facility to isolate one of the grills depending on operation i.e. normal or pandemic mode.
In lieu of using return fans for emergency exhaust, an choice to consider is installing dedicated pandemic exhaust risers with exhaust fans sized to exhaust the whole floor or other designated area.
6.UV Lights and untouch infrastructure:
UV lights are also required in the rooms for killing the virus . All the doors and water taps should be untouch and fully
automation.
