We analyze the reasons why airflow in buildings is no longer a one-way street.
by Honeywell
Airflow is essential in a building's environment. It can impact building structural integrity, energy efficiency and environmental health. The latter has become an increasingly relevant issue as companies seek to return to their buildings and the industry adjusts to the new normal. Users will want healthier environments in the buildings in which they work, study, entertain and travel.
A modern healthy building improves the confidence and productivity of the people who use it and at the same time considers energy efficiency. The backbone of indoor air quality – made up of ventilation, humidity, temperature, filtration and pressurization – is the starting point for a healthy building. Every building has these vertebrae, however, they may not be optimized for the health of the building.
Out with the old air
It's one thing to walk into your home and feel "congested" or "rancid" and open the window or turn on a fan. That's not a possibility in a high-rise office or a hospital. Buildings with poor ventilation not only with uncomfortable, they can also be unhealthy. Buildings without good airflow control and monitoring can contribute to the spread of viruses, bacteria, pollen, contaminants, pathogens, and other contaminants.
More than just moving air in space, air quality in any building depends on the amount of new air coming in and the ability to expel old or "dirty" air. The process of applying controlled and intentional ventilation to buildings was established and is guided by ASHRAE 62.1 and other regional and international standards. Often for these standards the rate of change is essential: how many times per hour the volume of air in a space is replaced by new air by mechanical ventilation.
Exchange rate
Measuring the rate of air change happens when the air conditioning system is commissioned and rarely done again. This can lead to difficulties in verifying that the changes are being applied at the desired rate. Airflow measurement stations installed in air conditioning equipment and systems within a building measure and track airflow rates continuously through the building management system (BMS). This allows building owners to easily change the rate of change if the parameters of the guidelines change, without interruption of service or the expense involved in hiring a specialist to make the measurements and calculations. An adequate rate of change of air can dissipate odors, chemicals and carbon dioxide CO2, while balancing energy use and reducing disease transmission.
Know the latest guidelines
Monitoring and adjusting the airflow within a building can make occupants more comfortable and also plays a critical role in reducing the ability of aerosol-borne viruses or bacteria to spread. A study conducted by Yale University found that maintaining humidity levels within 40% to 60% relative humidity can significantly reduce the ability of a virus to reproduce and spread.
Updated ASHRAE guidance for inhibiting the spread of viruses includes:
• Increase outdoor air ventilation (highly polluted areas)
• Disable demand-controlled ventilation (DCV)
• Open the outside air gates as close to 100%, thus eliminating recirculation
• Consider portable air filters with HEPA filters
• Consider UVGI (ultraviolet germicidal irradiation), protecting occupants from radiation, particularly in high-risk spaces such as waiting rooms, prisons, and shelters.
• Consider altering equipment operating hours to ventilate buildings with fresh air two hours before and two hours after occupancy.
Airflow should not only be a consideration when a building is commissioned. It should be actively addressed based on season, occupancy, updated building guidelines and standards, and even factors such as minimizing the potential spread of a virus.
In many developed countries, people spend more than 90% of their days indoors, so the indoor air quality in the buildings in which we work, live and play needs to be optimized for health. Users will demand it. We can help building owners with it.
