The engineering community has been in one of the most in-depth design discussions in recent time with the presence of this new Coronavirus (SARS-CoV-2), and the impact potential to human health. Since the beginning of this year, and ongoing still, professional organizations, manufacturers and design consulting firms like ourselves have been absorbing as much information as possible to help provide due-diligent guidance for the building owners, architects, and contractors we work with through the design and construction process.

Above all, seek first to understand, as a building owner and as a design professional. It is important to first develop an understanding of performance expectations along with the existing facility capability, from the original design intent to the current state of operation and condition. Assemble a team of stakeholders and professionals that can begin the integrated process of reviewing documentation and providing recommendations or engineered solutions to occupant and operational needs of the facility.

Following these assessments and discussions we can break out our path forward generally into three core areas.

[I] First, we have become familiar with design considerations of engineered controls.

  • Building Ventilation and Controls:   Increasing outdoor airflow into the building for dilution of the outdoor air.
  • Considerations: Relief air path and capacity, control sequencing for pre and post occupancy purges, and existing equipment capacity to properly condition increased outside air to maintain indoor comfort. Building operation sequences and control component review to assist developing baseline data and scope of control for the facility. Indoor condition data may help provide confidence in building occupants regarding their indoor environment and exposure risks.
  • Filtration:   Minimum MERV 13 filtration capacity provided within air-moving equipment.
  • Considerations: Typical baseline filtration is selected at MERV 8. Fan/motor capacities may require adjustment for additional pressure drop across finer media. Replacement frequency and increased material costs and should be assessed within building maintenance budgets. Portable local filter equipment may be available to specialty spaces within the building or as a secondary higher filtration control to be utilized on an as-needed basis.
  • Temperature and Humidity Control:   Indoor temperature and relative humidity maintained within comfort standards, and 40-60% relative humidity (RH).
  • Considerations: ASHRAE Standard 55 outlines thermal comfort considerations to be maintained. Air distribution and balance should be reviewed to maintain adequate mixing or stratification (displacement and underfloor distribution. Humidity addition to the space may require additional sensors and monitoring, first-cost and maintenance of humidity (localized or central distribution) generating equipment, along with reheat of supply air due to evaporative cooling effects.
  • Air Distribution and Disinfection:   Thorough movement of air to dissipate or remove contaminants and particulates from the breathing zone of occupants.
  • Considerations: Air distribution effectiveness and quantity of air provided should be reviewed within the capacity of existing systems. Modification to systems or capacity can then be applied. Supply air can additionally be cleaned through the use of UV spectrum lamps, Bipolar Ionization (NBPI), photocatalytic oxidation, or direct dispersion of cleaners into the air stream. Air cleaning and distribution, especially the use of cleaners and ozone byproduct devices, should be adjusted through coordination with a design professional.

[II] Second, are occupant operational considerations. These vary from physically managed building entry and exit points to more subtle behavioral implications desired by occupants or owners. Additional cleaning of high contact surfaces, limited occupancy within the facility or certain spaces, health screening, or additional personal protective equipment (PPE) are some of the processes being addressed and currently revised. Many of these recommendations can be found directly through the CDC and local health authorities. More extensive modifications to building infrastructure should again be reviewed in conjunction with the applicable design professional to maintain overall health and safety compliance through current local codes and standards.

[III] Third, enhance your personal immune strength to the greatest extent possible. We all live and work indoors much of the time but benefit greatly from sunlight, fresh air, physical activity, and nourishment fitting to help keep us in peak health. Supplementary organizations such as the U.S. Green Building Council (USGBC), WELL Building Standard, Arc, and the Collaborative for High Performance Schools (CHPS) provide additional guidance and certification options to address and improve occupant health, comfort, and sustainable building practices.

For additional information, organizations such as ASHRAE have published extensive guidance and consolidated descriptions of considerations for improved indoor air quality. And don’t forget to contact your friendly neighborhood engineer and design professionals! We’re here to help navigate design options and impacts so your building can continue to meet your needs, and those of your occupants, for a healthier future. Building codes remain active, energy utilization and operational budgets retain a position of priority, but within that there remains the ability to develop the built environment into a more resilient means to human comfort and safety.