Buildings as a preventive barrier against COVID-19
Situations like COVID-19 are not isolated episodes
In the last 17 years, there have been at least 6 outbreaks (including the current one) capable of affecting the global population (SARS, MERS, Avian Flu, ZIKA and EBOLA).
Measures to prevent the spread through aerosols
Valuable work can be done by improving the indoor environmental conditions of office buildings to prevent the impact of situations like COVID-19.
Transmission of SARS-CoV-2 by air is sufficiently likely that airborne exposure to the virus must be controlled. Changes in the way buildings operate, including air conditioning and ventilation systems are required.
The airborne spread of pathogens occurs through droplets and aerosols produced when talking, coughing, breathing, etc.
Gravity causes large droplets to fall and settle on surfaces; however, the smaller droplets remain in the environment and can infect other hosts. Infectious aerosols can spread through the building via air distribution systems.
ASHRAE recommends HEPA (High-efficiency particulate air) localised air purification units as evidence level A
INTEGRATED HEPA SYSTEM FOR THE ELIMINATION OF PARTICLES, MICROORGANISMS AND GASES
4 etapas de filtración
Aire Limpio has SIHEPA® systems, purifying units comprising four stages of filtration:
- F7 pre-filter with antimicrobial treatment
- TiO2-impregnated ceramic activated carbon photocatalytic monolith
- UVGI Germicidal Ultraviolet Light Irradiation
- HEPA H13 filter with antimicrobial treatment
In addition to the four stages of filtration, you may opt for:
- A control system through mobile app
- Airborne particle probe
- Combined air quality probe (VOCs + Particles + CO2
They improve indoor air quality by filtering and eliminating pollutants in the places where they act, reliably preventing the entry of polluted air into adjacent areas.
These units are particularly useful in buildings in use or in projects, specifically for areas such as:
- High-occupation-density areas
- Meeting rooms
- Dining rooms/vending
- Communal areas (lift landings, etc.)
They operate as stand-alone systems, that are installed in false ceilings in High-occupancy-density areas.
SIHEPA® systems have a flow range from 1200 m3/h to 2,200 m3/h that can be used in several ways:
- As a highly efficient air purifier, installed in a false ceiling for High-occupancy-density areas. In this mode we recommend 5/6 air movements per hour.
- As a ventilation system, optimising air conditioning costs by reducing the supply of primary air and the thermal load per ventilation.
- As a control system, thanks to the airborne particle and air quality probes (VOCs + Particles + CO2).
As an air purifier, the reduction of pollutants is immediate due to the combination of integrated filters.
In addition, it is especially effective with biological pollutants as the effect is closer to people and airborne particles (to which COVID-19-type viruses often become attached).
It is installed in a false ceiling or wall and in any position.
Drawing of installation of stand-alone purification system with Photocatalysis and HEPA filter
|Model||PRE-FILTRATION||PURIFICATION||GERMICIDAL IRRADIATION||FINAL FILTRATION||FLOW (M3/H)||PRESSURE AVAILABLE (PA)||Consumo (w)||DIMENSIONS
|AL12||ePM2.5>90% (F9)||Ceramic Monolith
TiO2-impregnated activated carbon
|UVGI 254 nm||HEPA 99,5%||1.200||140||281||367 x 667 x 1.069|
|AL22||ePM2.5>90% (F9)||Ceramic Monolith
TiO2-impregnated activated carbon
|UVGI 254 nm||HEPA 99,5%||21.200||125||551||367 x 967 x 1.069|
Examples of installations
OBJECTIVES AND DESCRIPTION
The Árima building, located in Madrid at C/ María de Molina, 39 is a 4,000-metre complex spanning 4 floors and 24 parking spaces. Project goals are to improve air quality and reduce the building’s energy consumption.
The installation of SIHEPA® Integrated Systems for the Elimination of particles, microorganisms and gases is in line with an improvement in indoor air quality and the building currently has the LEED® Gold certification.
|Sistemas integrados SIHEPA®|
|Nº of Units||12|
|Reduction in microbial load||>99%|
Aire Limpio has worked on the project with the installation of 12 SIHEPA® systems in the false ceiling. In addition to the benefits of improving indoor air quality, SIHEPA® systems generate energy and maintenance savings.
WHAT VIRUSES AND BACTERIA DOES IT ELIMINATE?
PHOTOCATALYTIC SYSTEM FOR THE ELIMINATION OF MICROORGANISMS AND GASES
|Avian Flu (Influenza A)||99,9%||99,9%||99,9%||99,9%||99,9%||98%||98%||98%||98%|
|Vibrio comma (cholera)||99,9%||99,9%||99,9%||99,9%||99,9%||98%||98%||98%||98%|
|SPEED OF TRAVEL||99,9%||99,9%||99,9%||99,9%||99,9%||98%||98%||98%||98%|
|SPEED OF TRAVEL (m/s)||0,50||1,00||1,50||2,00||2,50||3,00||3,50||4,00||4,50|
Average air speed in Air Handling Units
OBJECTIVES AND DESCRIPTION
Children are much more likely than adults to be adversely affected by indoor air pollution in buildings, and younger children are less able to understand and clearly communicate their symptoms.
A poor or non-existent air purification system transmits asthma, rhinitis, allergies and spreads viruses… etc. Moreover, many school children miss class due to illnesses. Clean and healthy air is an essential requirement for the academic success of our children, given that air quality affects their cognitive development.
Ventilation, air flows and filtration help reduce the concentration of SARS-CoV-2 in the air and therefore, the risk of airborne transmission. As an air purifier, the reduction of biological and chemical pollutants is immediate due to the combination of integrated filters and UVGI light irradiation
The Aire Limpio SIHEPA® systems act as a powerful air purification tool through 4 stages of filtration.
They eliminate airborne particles such as microorganisms (viruses, bacteria, fungi, yeasts) and gases in the areas where they act, reliably preventing the entry of polluted air into adjacent areas.
This technology has achieved several important credits in the BREEAM® and Verde® certifications.
Other practical cases
Building: Don Ramón de la Cruz, 84. Madrid.
Building: Torre Chamartín. Madrid.
Ernst & Young
Building: Torre Titania. Madrid.
Savills Aguirre Newman
Building: Pº Castellana, 81. Madrid.
What does the scientific community say?
The link between poor air quality and the spread of COVID-19
Hemos observado que un incremento de 1 μg / m³ en PM2.5 está asociado con un aumento del 8% en la tasa de muerte por COVID-19”
A small rise in long exposure to PM2.5 leads to an increase in the death rate from COVID-19.
Source: Xiao Wu et al, Exposure to air pollution and COVID-19 mortality, Harvard University 2020
The relationship between occupancy level and increase in CO2
Position Document on Infectious Aerosols
“High-efficiency particle filtration in centralised HVAC systems reduces the airborne load of infectious particles (Azimi and Stephens 2103). This strategy reduces the transfer of infectious agents from one area to another, when they share the same centralised HVAC system through recirculated air delivery. When appropriately selected and implemented, single-space, high-efficiency filtration units (whether ceiling-mounted or portable) can be highly effective in reducing or decreasing infectious aerosol concentrations in this space.”
“UVGI light inactivates microorganisms by damaging the structure of nucleic acids and proteins at the molecular level. The most important of these is deoxyribonucleic acid (which is responsible for molecular reproduction). An organism that cannot reproduce is no longer capable of causing disease. (Evidence Level A)”.
A. Highly recommended; good evidence.
B.Recommended, at least consistent evidence.
C.No recommendation for or against; benefits and harms too closely balanced to warrant a recommendation.
D.Recommend against; consistent evidence is ineffective or the harm outweighs the benefit.
E.Insufficient evidence to make a recommendation for or against on a routine basis
The inactivation effect of photocatalytic titanium apatie on SARS Virus
Han Wei, Zhang Banhe, Cao Wuchun, Yang Dongling, Taira I, Okamoto Y, Arai JI, Yan Xiyun
“Photocatalytic titanium apatite filter (PTAF) is a new material that has been reported to have an ability to absorb and inactivate bacteria.
The inactivation effect of PTAF on serious acute respiratory syndrome coronary virus (SARS-CoV) was tested. The results showed that PTAF filter inactivated/ decomposed SARS CoV up to 99.99% after 6 h interaction under the condition of
non-UV irradiation. However, under the condition of UV irradiation, PTAF and HAF both were able to inactivate/decompose SARS CoV completely. The study has provided the first evidences that PTAF could inactivate SARSCoV virus, suggesting that the PTAF material will be applied for the prevention of SARS-CoV as well as other viruses”
Protocol for the reoccupation of buildings during the COVID-19 pandemic
Paulino Pastor, Director General de Ambisalud
“Install local air filtration and purification units, either fixed or portable units for temporary back-up. These units should preferably include HEPA grade filters, and it is recommended that they incorporate UV lamps or even photocatalysis.
Select back-up purification units capable of treating sufficient air flow to achieve a significant number of movements per hour of the indoor air”.
MINISTRY OF HEALTH, GOVERNMENT OF SPAIN
“It has been shown that the risk of airborne infection with the SARS-CoV-2 virus inside buildings is higher when there is poor ventilation. By studying facilities, we can adapt the way they operate so that they act as an additional preventive measure against infection, and thus become part of the solution.
We would emphasise the recommendation to increase the filtration of recycled air, and if possible, using technologies with the lowest possible pressure loss. The use of UVGI ultraviolet light, widely known for inactivating all types of microorganisms, including viruses, is also recommended. Its use is recommended in batteries, or AHU ducts as an additional or complementary measure for surface maintenance.
In the case of premises where it is difficult to achieve satisfactory ventilation, the use of portable units equipped with high-efficiency HEPA filters is recommended in the areas to be treated. They must maintain a significant rate of hourly movements”
HVAC O&M recommendations guide for buildings to prevent the spread of COVID-19
This air filtration process is considered the standard for air purification. Highly efficient, it traps particles and does not release them into the air, it is safe for all respiratory problems. Difficult to integrate into existing equipment, there are stand-alone systems equipped with this type of filtration.
Germicidal ultraviolet light (UV-C)
This technology produces an invisible light that attacks pollutants by destroying their DNA instead of passing them through a physical filter. This proven technology is only suitable for killing viruses, bacteria and germs. It does not eliminate airborne particles.
This technology, similar to that described above, does not filter the air, but only sanitises it through combining UV-C and a TiO2 catalyst that generates highly disinfectant reagents. It has very high effectiveness against pathogens. It does not eliminate airborne particles. It is relatively easy to integrate into existing units such as ducts or AHUs, although it is also found in stand-alone systems.