ASHRAE Standard 62.1 defines two design paths for determining minimum mechanical ventilation rates, as described below. These procedures are also adopted by the International Mechanical Code (IMC) as well as most building codes.

The ventilation rate procedure (VRP) is commonly adopted, likely because of its simplicity.

• Users set a minimum ventilation rate for their building type as listed in a table, and indoor air quality is assumed to be acceptable, regardless of building features.
• The VRP relies solely on bringing in high volumes of outside air to continuously replace indoor air and remove the contaminants generated by people, building materials, and furniture. The VRP often leads to an over ventilated space since the ventilation rates are designed to be highly conservative.

The Indoor Air Quality Procedure (IAQP) is performance-based, flexible, and more energy efficient. It is a calculated approach to ventilation that doesn’t depend entirely on outside air. AtmosAir DBD BPI technology takes advantage of the ASHRAE 62.1 IAQP guidelines to provide indoor air quality while saving energy.

• Ventilation rates are calculated based on contaminant source emission rates and desired indoor concentrations instead of prescribed by building use.
• Designers can take credit for source-control and removal measures like gas-phase air cleaning and can smartly titrate ventilation rate as needed.
• Using air cleaning technology such as AtmosAir DBD BPI technology is an acceptable method to decrease outside airflow beyond what is described in the VRP.
• AtmosAir provides mass balance analysis against the Design Compounds listed in Table 6-5, ‘Design Compounds, PM2.5, and Their Design Limits.’ The concentration limits, referred to as ‘design limits’ are specified in Table 6-5. Design ventilation shall be such that the calculated concentration of each DC, mixture of DCs, and PM2.5 does not exceed its limit.

Properly installing air purification systems (air cleaners) that clean the air continuously and efficiently from contaminants of concern is key to follow and apply the IAQP. ASHRAE 62.1 IAQP has the advantages of flexibly tailoring ventilation needs of a space based on its specific contaminants. Such user flexibility results in saving energy by adopting healthy but lower ventilation rates than those prescribed in the VRP.

The AtmosAir system is formally in compliance with ASHRAE 62.1-2022 Standard requirement and fits within the IAQP. This is clearly stated in the official interpretation recently published by ASHRAE. The typical outside air percentage reduction is 50%, but ventilation reduction can potentially be more, or less, dependent on a number of building design inputs.