ASHRAE Releases Update to Ventilation Standard 62.1-2019 for Improving Indoor Air Quality

The publication of Addendum aa to ASHRAE Standard 62.1-2019 is expected to accelerate widespread adoption by HVAC systems design engineers of ASHRAE’s IAQ Procedure (IAQP) for improving indoor air quality and energy efficiency in non-residential buildings.

According to ASHRAE, Standard 62.1 has undergone key changes over the years, reflecting the ever-expanding body of knowledge, experience, and research related to ventilation and air quality.

While the purpose of the standard remains unchanged– to specify minimum ventilation rates and other measures intended to provide indoor air quality (IAQ) that is acceptable to human occupants and that minimizes adverse health effects– the means of achieving this goal has evolved paving the way for building emissions reductions and cost savings.


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Westwood MA-based enVerid Systems, the leading provider of sustainable indoor air quality solutions, commends ASHRAE for publishing Addendum aa to Standard 62.1-2019 as it removes the largest barrier to using ASHRAE’s IAQ Procedure (IAQP) to improve building energy efficiency and indoor air quality: the complexity of applying the IAQP. With the dual priorities of ensuring healthy indoor air and the need for energy-efficient buildings to reduce carbon emissions, Addendum aa is expected to accelerate the adoption of a key provision of the existing building ventilation standard that can accomplish both goals.

A major barrier to the adoption of the IAQP was the requirement for HVAC engineers to identify Design Compounds, formerly called contaminants of concern, and appropriate limits for each contaminant. Addendum aa addresses this by prescribing fourteen Design Compounds plus PM2.5 that must be controlled when using the IAQP. Addendum aa also prescribes Design Limits for each compound and PM2.5.

“The IAQP is more energy-efficient and cost-effective than the VRP because it allows for the use of air cleaning when calculating ventilation rates,” said Christian Weeks, CEO of enVerid Systems. “Under the IAQP, filtered indoor air can offset a portion of the outside air requirement to achieve a more cost-effective, energy-efficient design.

The VRP relies exclusively on large volumes of hot, humid, and cold outside air to dilute indoor-generated contaminants, which requires larger, more expensive HVAC systems and is very energy-intensive. Additionally, because the VRP is based on generic contaminant sources and emission rates, it is a less direct way to ensure good indoor air quality, especially for buildings located near permanent or seasonal sources of pollution. With the VRP and the IAQP now on equal footing in terms of implementation, we anticipate a rapid acceleration in the use of the IAQP by HVAC engineers and building owners eager to ensure healthy building environments while also achieving energy efficiency objectives.”

As we enter our “new normal” with a heightened focus on both IAQ and decarbonizing buildings, the IAQP offers the most direct way to ensure good IAQ most energy efficiency. With the main barrier to IAQP adoption now addressed by Addendum aa, all engineers and building owners should embrace the IAQP as best practice for achieving sustainable IAQ.

Additional information issued in Addendum aa can be found here.

Contact your ATI sales rep to learn more about enVerid Systems’ products for improving indoor air quality and reducing HVAC costs in all commercial building types covered by ASHRAE Standard 62.1.