Buildings with a building automation system (BAS), or some level of existing outdoor airflow monitoring, have the best shot at this credit, which can help you to monitor and maintain adequate ventilation levels throughout the building. If your building does not have a BAS, compliance will be more challenging.

Most buildings don’t already have the proper monitoring devices, and device installation along with the configuration of the existing ventilation system may make this credit time-consuming, challenging, and costly. Parts and labor costs are directly related to the quantity of densely occupied spaces, and the number of sensors that must be purchased and installed.

Install permanent monitoring systems

This credit requires installation of permanent, continuous monitoring systems that alert building operators when outdoor airflow in the building drops more than 15% below the minimum set point. Generally, every building that uses mechanical ventilation must install and maintain permanent outdoor airflow measurement devices in the outdoor air intakes to comply with this credit. These sensors must provide continuous monitoring and trigger an alarm for the building operator if the minimum outdoor airflow rate falls more than 15% below the design minimum rate.

If your building contains any densely occupied spaces, you must also install CO₂ sensors, but only in those spaces, to provide added indicators of reduced indoor air quality due to inadequate ventilation.

Follow each case in tandem

Many project teams need to follow the guidelines for Case 2 in addition to Case 1, if densely occupied spaces total more than 5% of total occupied square footage.

Common examples of densely occupied spaces include, but are not limited to:

• conference rooms,
• classrooms,
• presentation halls,
• cafeterias,
• and exercise facilities.

Case 2 requires CO₂ sensors to be installed in these spaces. CO₂ sensors are important here because they support the adjustment of the mechanical system to changes in daily use.

For example, a meeting room with five occupants may be adequately ventilated, but if the same room holds 25 occupants for another meeting, the ventilation may not be sufficient. A buildup of CO₂ in a densely occupied space will trigger an alarm, alerting building managers or operators that the ventilation set points must be adjusted to maintain good occupant comfort.

Natural ventilation is possible

It is possible to earn this credit with a natural ventilation system, but there have not been many cases of it, simply due to the relatively low number of naturally ventilated buildings attempting LEED-EBOM certification.

Natural ventilation is covered by Case 3, and any building has to follow this case if more than 5% of occupied spaces are naturally ventilated.

Consider these questions when approaching this credit

• Does your building have a history of problems with adequate outdoor air delivery, such as complaints of stale air, a “stuffy” feeling, or odors? If so, it would probably benefit from the use of these monitoring devices and practices.
• Does your building have variable ventilation loads due to changes in use from hour to hour or day to day? These buildings might see energy efficiency benefits from monitoring devices due to an increased ability to modulate loads.
• Does your building contain densely occupied spaces? These are areas that have a design occupant density of 25 people or more per 1,000 ft². If so, does the total square footage of all densely occupied space exceed 5% of the total occupied square footage? If it does, you must follow the Case 2 guidelines in densely occupied spaces, in addition to the Case 1 guidelines, in order to earn this credit.
• Do you already use a BAS to manage HVAC in your building?  If so, are you using sensors to monitor airflow rate and CO₂ concentration in occupied spaces?