Combating COVID-19: Engineering Design for Healthcare Facilities

By Prashant Jadhav

Prashant Jadhav, Business Head, Consistent Engineering Consultants sheds light on engineering design guidelines healthcare facilities can follow to fight the COVID-19 pandemic.

We are living in difficult times, as the world faces the first true pandemic of the 21st century. The very connectivity and ease of transport that allowed us to become a global family, has led to a dangerous virus spreading worldwide. The Novel Coronavirus 2019, or COVID-19, has already claimed more than 100,000 human lives, and affected hundreds of thousands more. What makes the COVID-19 such a deadly phenomenon?

It is the way that the COVID-19, 0.125 microns in size, has spread across the world in a short time. Reports state that transmission happens via respiratory droplets when an infected person coughs or sneezes. These droplets can land in the mouth, nose, or eyes of the people nearby or be inhaled into their lungs. However, airborne transmission from long distances is unlikely. 

The virus also endures on surfaces and gets transmitted if a person touching the surface then touches his eyes, ears, nose or mouth. As per a new study from the National Institutes of Health, CDC, UCLA and Princeton University, it can be detected on copper for up to 4 hours, on cardboard for up to 24 hours, and on plastic and stainless steel for 2-3 days. As it is difficult to avoid touching surfaces in daily routine, this is another chief way of the virus getting transmitted. 

Consistent Engineering has worked with healthcare authorities and institutions in India and the Gulf to ensure best possible arrangements for healthcare facilities. Let us look at some engineering design guidelines healthcare facilities can follow to fight the COVID-19 pandemic.

Engineering Guidelines for COVID-19 Healthcare Facilities

1. HVAC Design Parameters

ASHRAE 170- ventilation for healthcare facilities- was developed as guidelines for healthcare design in partnership with Facility Guidelines Institute (FGI), American Society of Healthcare Engineering (ASHE), along with the HVAC design manual for hospitals and clinics. Due to the pandemic, ASHRAE has published additional strategic guidelines for designing COVID-19 healthcare facilities as detailed below.

•           Differential Room Pressurization

The pressure maintained in various areas plays a major role in preventing infection transmission within the facility. The primary methods adopted for differential room pressurization are:

(a) Improving fresh air intake flow rate;

(b) Differential supply air and return air flow rate;

(c) Throttling of supply and return air terminals;

(d) Proper positioning of supply and return air terminals;

or a combination of the above approaches as required in different areas.

•           Dilution Ventilation

The principle of dilution is used to remove impurities from flowing media like air or water. This involves increasing intake of fresh, cleaner medium and simultaneously partly removing impure recirculated medium, helping to gradually purify it.

Normal air distribution systems, especially in general areas, are of recirculation type and there is a strong possibility of increase in infection quantum due to the presence of patients and visitors. Dilution ventilation recommends using higher fresh air flow rates to restrict such contamination.

•           Filtration

The High Efficiency Particulate Air (HEPA) filters and Ultra Low Particulate Air (ULPA) filters are designed to trap the majority of particulate contaminants from air streams. They can be used in healthcare facilities to contain airborne infectious pathogens, and filter out COVID-19 particulate matter. Their placement in supply or return air path or both, is based on needs of the patient & hospital staff, and criticality of healthcare function.

•           Laminar/Unidirectional Air Flow Regimes

For reception or diagnostics areas, the air distribution system can be designed for unidirectional flow, where clean conditioned air is supplied from the top (ceiling) and return air is collected at the bottom level. This ensures that relatively cleaner air is showered on the occupants, whether standing or seating, and assists in minimizing cross-flow contamination among visitors.

•           Source Capture Ventilation 

Local dedicated exhaust systems, also known as source capture ventilation can be used to capture and exhaust harmful contaminants and particles (generated by laboratory procedures), away from the medical staff in laboratory and diagnostic areas. Here, these systems would remove contaminated air from lab equipment, to be replaced with equal amounts of fresh air. 

•           UVGI Protection

UVGI stands for Ultraviolet Germicidal Irradiation, a disinfection method using short-wavelength ultraviolet light to destroy microorganisms such as bacteria and viruses. This can be paired with a filtration system like ULPA to sanitize air in healthcare facilities and protect medical personnel.

2. Design Philosophy for COVID-19 Hospital Block

Using above principles, the major areas of a COVID-19 hospital block can be designed. A typical COVID-19 block should have a separate area cordoned off from other regular blocks. This ensures the safety of the people who have come to the hospital for reasons other than testing for COVID-19.

Reception and Diagnostic/Testing Areas

The reception and diagnostic areas need a dedicated air handling unit with 15-20% fresh air to ensure proper dilution ventilation with pre and fine filters. Fresh air intake should be from a clean zone, and exhaust should be 5% more than fresh air intake to ensure slight negative pressurization, compared to corridors. Exhaust will have ULPA filters to arrest contamination.

Corridors

The corridors should be kept positive with respect to both reception and diagnostic rooms with dedicated air handling units having pre filters/fine filters and UVGI protection. This ensures that contaminated air from reception or patient rooms does not enter the corridors.

Patient Rooms and associated Ante Rooms

There are two types of Patient Isolation Rooms:

Protective Environment (PE): Kept under relative positive pressure and mainly used for  immunosuppressed patients. For PE rooms, the aim is to protect the patient from surroundings.

Airborne Infection Isolation (AII): Kept under relatively negative pressure and used for patients likely to transmit infection to others- TB, chickenpox and now COVID-19. For AII rooms, the aim here is to protect the surroundings from the patient.

The airflow rates for a negative pressure room ensure the exhaust rate is 15% higher than supply airflow rate. Each patient room needs a dedicated toilet having exhaust with filters. A dedicated 100% treated FAHU with prefilter, fine filter and UVGI protection supplies conditioned air to anteroom and patient room. Anteroom is at positive pressure compared to the isolation room as well as the corridor. 

A particular recommendation to be noted is that there should be no indoor AC units in this area which can create moisture or provide a surface for contamination.

ASHRAE recommends provision of dedicated exhaust from patient rooms. However, impurities must be removed before the air is exhausted to the atmosphere by installing ULPA filters.

Considering limitations on design operating parameters like minimum air flow rate, minimum static pressure required to offset pressure drop of ULPA filter & other system components, a relatively larger centrifugal blower can be used, clubbing a number of negative pressure rooms. 

Areas allotted to Medical Staff

The areas allocated to medical staff need to be kept at maximum positive pressure as compared to all other areas. This will ensure that air will not flow into the medical area from the isolation areas, ante rooms or corridors, and protect the medical staff from potential infection.

Uninterrupted Operation of Systems

Continuity of operations round the clock is essential, as defined by the Healthcare Technical Memorandum (HTM) 06-01. The COVID-19 Block must have a standby exhaust and supply fan to ensure 100% redundancy and standby emergency power supplying round the clock exhaust and power to the facility.

Public Toilets 

Exhaust air from the public toilets situated in the cordoned-off hospital block can also be treated with filters to avoid the contamination as explained above.

Laundry Area

It is recommended to have a separate laundry section for COVID-19 patients, where  moving of used sheets/clothes does not affect other areas. Usually, laundry services are in the basement and inpatients’ rooms on top. As a potential source of contamination, it needs high precaution.

Laundry should be designed under negative pressure, with exhaust air flow rate higher than supply flow rate. The exhausted air can be filtered as described above. Workers must be given hygienic clothing, and wastewater from the laundry area must be disinfected before the drain.

The overall philosophy of adaptation of the ASHRAE principles is to minimize the exposure of the patient to external conditions and secure their surroundings and medical personnel.

3. Space Usage and Allied Design Parameters

a.      Converting existing treatment spaces

We can explore converting common bays into individual patient bays to ensure air circulation for a particular bay. The HVAC system airflow can be designed for effective utilization of space.

b.      Building pop-up facilities

Using free space outside the hospital building block but within hospital premises, an initial screening facility of incoming patients can be set up to decide who needs hospital admission. This will require electrical/plumbing facilities from MEP angle.

c.      Managing surfaces and touch-free control

Seamless material can be used for the flooring so that it does not have or develop cracks. With this, disinfectants can be used effectively.

At the same time, minimizing high contact elements like curtains and blinds, or creating mechanisms to avoid touch is a crucial aspect. With this in mind, we can develop touch-free controls for door handles, glowing of lamps, etc. through sensor-based smart MEP design.

d.      Displaying hand wash, sanitizers, foot-operated washbasins

At various crucial locations, we can provide foot operated wash basins to manage flow of water and avoid direct hand contact with the tap. Hand sanitizers can be kept in visible locations while hand wash basins and sanitizers can be placed at the entrance to public toilets.

The MEP system design thus, has to go hand-in-hand with architectural design, complying with the above measures. However, there are some essential precautionary measures that all healthcare facilities need to take to ensure the safety and effectiveness of its personnel.

Key Challenges for Indian Healthcare

Just as in other countries, the Indian healthcare system is struggling against this unprecedented adversity. There are a number of challenges faced by the healthcare structure in the country. Let us take a look at some of them, and how they can be addressed.

Shortage of Personal Protective Equipment

Healthcare personnel such as doctors, nurses and caretakers are essential warriors in this healthcare crisis. Hence, it is of utmost importance to protect them and ensure their well-being. Simple things like emphasizing hand hygiene, limiting the number of staff, and installing barriers to limit contacts with patients can be implemented. However, providing standard Personal Protective Equipment to all healthcare personnel is of paramount importance to ensure security from potential infection. This outbreak has created a global shortage of PPEs.

This severe lack of PPE is making the doctors and nurses vulnerable. As per WHO directives, any doctor or nurse should be allowed to care for the patients only for 4/6 hours. But the doctor to patient and nurse to patient ratio in India being way off the recommended standards, healthcare workers are working 10-11 hr shifts every day.

Solutions: The ideal situation would be to have a proper and plentiful supply of PPEs. But since that factor is at present not in control, the more important thing is to reduce the number of hours in a shift. Medical personnel need to be working in a maximum of 6 hour shifts and not handling more than a specified number of patients. This will not only limit their direct exposure but also give them time to recuperate in body and mind. 

Entry and Spread of Infection in Facilities

Most healthcare facilities are ill-equipped to deal with an infection of this magnitude, and need to be redesigned to create a separate COVID-19 block, along with implementing all the solutions outlined in the previous section. 

As per reports from Mumbai, over a hundred healthcare workers including nurses, doctors, and physiotherapists have tested positive for the virus. Major hospitals such as Jaslok, Wockhardt and Bhatia have been sealed off from the public, and others are working with a skeleton crew. Even other states such as Delhi and Kerala have registered a few such cases. The exposure of the healthcare workers is a heartbreaking development, as it endangers their lives and decreases the country’s capacity to respond to this crisis. Why is this happening?

In most cases, it appears that the patient had come in for some other ailment and had been asymptomatic at the time, only later developing the symptoms of COVID-19. By that time, the personnel interacting with him had been exposed and infected. This happens in one of 3 ways:

-           Direct infection from the infected or deceased patients

-           Infection from virus that stays on the surfaces

-           Infection from the medical kits, ventilators and machinery used

Solutions: The first measure is to limit points of entry into the hospital. This ensures proper screening of the people coming in for testing by setting up a screening facility for thermal scanning and checking for respiratory symptoms. 

Even so, the thermal check may not always yield results if the patient is asymptomatic during that time period. So, it is recommended that any person entering the hospital should first be classified as high-risk, medium risk or low-risk based on their ailment. Ex. Persons with dental, ENT or eye-related issue would be high-risk, since medical personnel would have to come in close contact with those parts of the body; while a person with a fractured leg would be low-risk.

• High risk patients should undergo a compulsory COVID-19 test, and only on being judged negative (time required is ideally within 48 hours) be allowed to proceed. If positive, they should be moved to the COVID-19 block.

• Low-risk ones, as well as those high-risk ones who tested negative, can be provided with gloves and basic masks and then allowed to go in.

There have also been cases where a patient was brought in a critical condition, and passed away before the test results came back positive. However, the staff members who had handled the body got infected. To avoid this, the body can be wrapped in thin protective plastic or equivalent safe material wherever contact is required, thus ensuring the safety of the staff.

 Now, as far as infected surfaces go, the clear answer is in disinfection. However, this needs to be carried out by the maintenance staff in between two shifts, as well as in some cases during shifts, with dedication and detail. In this case, only human diligence can help reduce the threat.

Bio waste generated in hospital from medical treatment, procedures, nursing along with clogged contaminated ULPA and HEPA filters, needs to be properly disposed of. The hospitals usually send such bio-waste to the local corporation-operated incinerators. In this case, particular care must be taken that any such material makes its way to the incinerators and any infectious material is completely eliminated.

Vulnerability of Individual GPs, ENT Specialists and Dentists

Individual General Practitioners, ENT Specialists, Ophthalmologists, and Dentists operating out of clinics are also extremely vulnerable at this time, as the patients coming to them might turn out to be infected. Recognizing this danger, there need to be some safety measures in place. 

Solutions: The ideal solution would be the government making easy-to-operate COVID-19 test kits, which can also be quite expensive, available to practicing doctors free of cost or at low rates, to avoid add-on burden falling on the patient.

Additionally, the government may need to provide safety kits to protect the face/body of doctors similarly free or at very low cost.

Endnote

At this time, treatment for COVID-19 patients is about preventive measures, as a cure is still in the developmental stages. Medical and healthcare personnel are the warriors at the frontlines of these measures, and ensuring their health and safety should be a primary concern. While the chances of infection cannot completely be eliminated, the above measures can prove instrumental in keeping it at bay, and giving humanity a fighting chance. 

However, our real strength lies in working together, following all the safety measures instituted by the government in order to flatten the curve and contain the spread. At the same time, we need to plan for the future stages regarding how to recover from this crisis physically, socially, and economically. I believe that working together we can overcome any calamity and emerge stronger than ever. Let us stay safe, take every precaution and do our duty towards humanity in this hour of crisis.