Ths. Nguyen Manh Hung

Head of M&E department, Sunjin Vietnam Joint Venture Company

Unlike previous outbreaks, in the current wave of COVID -19 outbreaks in Hanoi and a number of provinces/cities, the situation of infection is common, mainly in many cities. office buildings and high-rise apartment buildings. Due to the susceptibility of the new strain of COVID 19 virus spread through direct contact and airborne transmission, one of the main ways to increase the number of people infected with cross infection in office buildings, high-rise apartments are the ventilation and air conditioning systems. It is necessary to have recommendations from experts so that users can limit and prevent disease transmission in offices and high-rise apartments.

HUGE RISK OF CONFIDENCE FROM THE VENTILATION SYSTEMS IN OFFICE BUILDINGS AND HIGH-rise apartment buildings NOW.

Due to the characteristics of these buildings with very large space, with a large concentration of people, the working/living space is often closed, so there is always a great risk of the spread of COVID-19 disease. especially with the latest strains that have the ability to spread strongly in the air and spread the disease after 2 hours through the building’s air conditioning and ventilation system. According to a general preliminary assessment, the current office buildings and high-rise apartment buildings are being designed to organize ventilation despite ensuring safety, comfort and fire protection, but most of them have not been calculated to have the ability to prevent air pollution. prevent the spread of infection, as well as effectively isolate diseases with the ability to spread through the air such as Covid 19 that may occur in the future.

Hanoi Centerpoint Apartment (27 Le Van Luong, Hanoi), where the source of the COVID-19 disease originated, but due to its optimal design, it did not spread the disease inside apartments and commercial and service spaces.

According to the design experts of Sunjin Vietnam Joint Venture Company, which is in charge of many large-scale office buildings and high-rise apartment buildings, basically, both types of buildings are office buildings and apartment buildings. Currently, all high-rise buildings apply ventilation models, which are mainly applied vertically and horizontally with many different advantages and disadvantages.

For office buildings, in a working area with many people (maybe a whole floor), the ventilation system is designed in floors, with the intake and exhaust system usually draining to the roof. The air conditioning system is mainly designed to use central air conditioning systems with the characteristics of circulating return air directly from the room. Some other systems, more modern, but due to the requirement of energy saving, must recover part of the exhaust gas through the heat recovery system (PAU) to save energy, so there is still some old air in the system. rooms are rotated. In both cases, because the air recovery systems only have dust filtration functions, there are no membrane systems, bactericidal – virus filters, so the pathogens are viruses, bacteria, especially viruses. are viruses that have the ability to spread strongly in the air by recirculating air, increasing the risk of spreading to the entire floor.

The diagram of the centralized air supply system on the vertical axis with the air outlet on the roof for the office space of the high-rise office building (source: collectibles)

With apartments, although the design includes apartments with relative privacy, there are still many risks of disease transmission through the air-conditioning system – ventilation originating in public and private spaces in the apartment. apartment. With shared spaces such as: main lobby space, floor lobby, floor corridors, elevators, the design mainly still uses the central air conditioning system with the way of organizing air return and making use of exhaust gas to save energy. energy saving, similar to office buildings, along with the arrangement of many public service spaces in podiums such as shopping malls, restaurants, cafes, etc., so there is a risk of infection and disease transmission. great disease.

In addition, each apartment is arranged to use both horizontal ventilation (with an air-conditioning system that releases air directly to the private loggia balcony of each apartment) and vertical (with a ventilation system). system of air inlets for toilets and kitchens, circulating the intake air along the vertical axis to the roof running along and sharing it for floors). However, because the exhaust system follows the same way through a main shaft with a one-way valve installed, there is still great excellence in disease transmission, when pathogens are rotated, mixed, and moved in the shaft. pipe each floor as well as from the lower floor to the upper floor.

SOLUTIONS TO ORGANIZATIONAL SYSTEM – Ventilation, PREVENTING DISEASE PRESENTATION IN APARTMENTS AND OFFICES
In the coming time, with the epidemic situation still evolving very complicated, and the occurrence of many new diseases spreading in the air is inevitable, the design and organization of the air conditioning system – through wind for office buildings and high-rise apartment buildings, in addition to meeting standards of safety, fire prevention and use facilities, etc., it is necessary to have a comprehensive renovation to ensure the ability to prevent immediate disease transmission. and long term.
In the opinion of Kts Le Van Hao – Deputy General Director of Sunjin Vietnam Joint Venture Company: In an office building, the general direction needed to design and organize the air conditioning and ventilation systems must be capable of isolating and disinfecting each part of the space to limit the spread of disease. For newly built office buildings and common spaces in newly built apartment buildings, it is necessary to design and install modern air conditioning and ventilation systems such as central air conditioning systems. High-level, there are disinfection filtration systems to ensure clean air circulation, and at the same time allow to turn on / off, isolating infected spaces immediately when there is an alarm of disease risk. ا ا With existing systems in existing office buildings, it is possible to additionally install a central control system. This is an automatic control system, which can be additionally integrated into existing systems, at a very reasonable price, and is relatively effective in limiting the spread of disease. At the same time, the architectural design of the spaces used inside the office building, the common space in the apartment building must be able to divide flexibly so that it can be opened and closed, limiting people entering and leaving the buildings. emergency situation.

Diagram of air conditioning and ventilation system according to local model for office space, shopping mall, public with high isolation ability when there is a risk of disease, limiting cross-infection.

Centerpoint Cau Giay apartment complex (110 Cau Giay, Hanoi) with full service public utilities, modern architecture, air conditioning system design with high independence, priority apartments Maximum use of the mouth to discharge to the outside environment, limiting cross-infection of diseases

The floor plan for organizing ventilation and air outlet is in the shape of Cau Giay Centerpoint apartment complex (110 Cau Giay, Hanoi, in which the new air supply is completely from the outside, the apartments give priority to maximum ventilation according to the outlet doors). independently to limit the spread of disease

For high-rise apartment buildings, the design of air conditioning and ventilation systems should limit vertical circulation, reduce the risk of cross-contamination between floors when an epidemic occurs, business Experience from a number of high-rise apartment projects that Sunjin Vietnam Joint Venture Company is the chief designer of such as Hanoi Centerpoint Apartment (27 Le Van Luong, Hanoi) and Cau Giay Centerpoint Apartment (110 Cau Giay, Ha Noi) Interior), although there is a risk of disease transmission arising inside the building, due to the optimal design of air conditioning and ventilation, the risk of disease transmission and cross-infection has been significantly reduced. illness for the occupants of the building. In order to effectively prevent the spread of disease between apartments, it is necessary to prioritize the design of the air-conditioning and ventilation system with the horizontal direction of air outlet. Exhaust outlets, air conditioner heaters can be arranged to release air in separate loggia balconies of each apartment, effectively limiting mixing and cross-contamination between apartments.

Diagram of the system of fresh air supply and independent ventilation for each apartment, limiting cross-infection of diseases (source: collection)

CONCLUSION

The fight against COVID-19 is still long and arduous. Along with the implementation of 5K as recommended by the Ministry of Health, ensuring a clean and airy living and working environment will help reduce the risk of infection and create a safe living environment for people. The building management, people working in office buildings, residents living in high-rise apartments can self-assess the air conditioning and ventilation system in the building being used (both according to vertical and horizontal), identifying risks of cross-contamination to limit the spread of disease through the ventilation system is very important. During the outbreak of the epidemic, the building management, residents, users … should limit turning on and opening the toilet exhaust fan if exiting along the vertical axis. At the same time, office buildings and high-rise apartments also need to strengthen the development of plans for deployment, self-adaptation, and proactive isolation of disease sources when risks arise. In particular, completing the air conditioning and ventilation systems for office buildings and high-rise apartments effectively limits the cross-infection of the complicated COVID-19 epidemic at this time as well as other types of diseases. New infectious diseases that will occur in the future will be something that needs attention and urgent implementation at this time./.