Webinar: Engineering a Healthy Building

Providing Environments for Wellness

Questions from the Webinar:

WELL v2 Feature A12: Air Filtration is related to MERV ratings of filtration and filter maintenance.  Bipolar ionization is not an acceptable method to comply with this feature. 

WELL v2 Feature A13: Enhanced Supply Air, includes requirements for air treatment.  It requires projects to use supply air that is not recirculated (100% outside air), OR that is treated with carbon filters, media filters, and/or UVGI.  Previous versions of the WELL rating system (WELL v1) allowed for use of photocatalytic oxidation; but bipolar ionization is not currently an acceptable method to comply with this feature in WELL v2.

Some of these rating systems are more fitted for certain building types, for example:

  • RESET is really intended for new or existing office buildings and tenant spaces, and it not well adapted to apply to anything else yet.
  • Fitwel can be applied to new or existing office buildings, tenant spaces, retail, multifamily and senior housing, but doesn’t currently have any specific guidance for classrooms or other building types.
  • WELL is applicable for almost any type of new construction project, and while there is a pathway to achieve certification for existing buildings, it can be a very heavy and costly lift.
  • LEED, WELL Health-Safety Rating (WELL HSR) and Fitwel Viral Response Module (Fitwel VRM) could be applied to almost any building type, new or existing. However, older buildings may find it difficult to achieve Fitwel VRM due to the increased ventilation prerequisite requirements.

Absolutely.  All of these rating systems and standards can be applied to a tenant space. They each have different versions of their reference guides that can be used for application to commercial interiors projects.

While the industry is still researching and developing various building design strategies to help mitigate the spread of infectious aerosols such as COVID-19, and we will continue to learn more and refine those strategies for many years to come, maintaining effective air distribution has been known to be directly correlated with healthy buildings for decades.  As such, to the extent that simulation tools can help with evaluating the strengths and weaknesses of different design options with respect to air distribution effectiveness and airflow patterns within a space with a given set of conditions, they can be helpful with space planning relative to COVID-19 response.  However, air distribution is just one of many factors that need to be considered when it comes to post-pandemic design, so one piece of the puzzle that needs to be factored into a holistic design.

We may see some addenda for WELL Health Safety Rating and Fitwel Viral Response Module as new science emerges; however, a lot of the requirements in the rating systems are things we should be doing anyway, and they can help us better prepare for other emergencies and health and safety issues that will inevitably arise in the future.

Below are statements from Fitwel and WELL on this subject:

  • FITWEL: The VR module released to the market represents the most comprehensive, up-to-date knowledge on contagious disease, vetted by subject matter experts, and tested by a leading cross-section of real estate advisors. Fitwel’s operator, the Center for Active Design (CfAD), provides annual third-party certification of policies and protocols, and will annually update requirements in line with evolving science.

WELL:  As with the WELL Building Standard, the rating is designed to grow in specificity and specialty over time, adapting to accommodate diverse space types and geographies and to respond to new evidence and ever-evolving issues within its focus on facilities operations and management and health and safety.

Both the Fitwel Viral Response Module (Fitwel VRM) and WELL Health-Safety Rating (WELL HSR) are intended to support spaces during both emergencies and normal operating periods.  Both rating systems are intended to complement and reference, but not replace, health-based governmental guidance and requirements.

Yes.  There are requirements within several of these rating systems that are related to exterior space development.  For example, LEED has a credit category called Sustainable Sites, with several credits that focus specifically on the site.  Both Fitwel and WELL have requirements associated with outdoor spaces including lighting, amenities, walking paths, vegetated areas, and gardens, etc. 

The rating systems that were developed in response to the pandemic do not focus on exterior space.

The Muldavin Company Study from 2017 is a great comprehensive resource for WELL cost information.

We have completed several indoor air quality assessments for many clients. What we are finding is that recommendations differ depending on the age of the building and how it has been maintained.  In one building we may recommend retro-commissioning to meet current code ventilation requirements, while in another we may recommend utilizing UVGI within their existing systems.  Additionally, different space types and uses have different needs.  For example, one space may have an opportunity to utilize upper room UVGI, while another may benefit more from in-room air purification.

As it relates to HVAC, strategies identified in the WELL Health-Safety Rating (WELL HSR) system and Fitwel Viral Response Module (Fitwel VRM) are largely in-line with ASHRAE Core Recommendations. 

However, ASHRAE’s Core Recommendations were updated most recently in January 2021 to align with the latest scientific information available.  WELL HSR and Fitwel VRM rating systems have not yet been updated, and there a few items worth mentioning:

  • ASHRAE’s current Core Recommendation related to ventilation is to “provide and maintain at least required minimum outdoor airflow rates for ventilation as specified by applicable codes and standards.” Fitwel VRM goes beyond this requirement with a prerequisite that requires increasing ventilation air to the building beyond code minimums. 
  • ASHRAE recommends System Commissioning to verify that HVAC systems are functioning as designed. Commissioning is not required for WELL HSR and Fitwel VRM, but findings in a Ventilation Assessment (required for both WELL HSR and Fitwel VRM) could result in a recommendation to complete retro-commissioning.

RESET has two rating systems:  Core & Shell and Commercial Interiors.  The Core & Shell rating system requires monitoring of PM2.5, TVOC, and CO2, and the Commercial Interiors requires all of those plus CO.

As far as where the sensors are placed and how many sensors are needed, RESET has very specific requirements for quantities and locations that are based upon space types and building occupancy.  A RESET AP can help you navigate these requirements.

There are sensors out there that monitor multiple contaminants/gases with a single sensor.  We recommend talking with an Intelligent Buildings engineer to identify what makes the most sense for your specific application and provide information about the technology that is available.

The are no prerequisite requirements for minimum humidity levels within any of the rating systems.  However, there are optional credit requirements within WELL v2, Fitwel, and Fitwel Viral Response Module that require humidity levels to be maintained between 30% and 60%.